JP2001250340A - Magnetic recording and reproducing device and method for detecting bad spot - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic recording and reproducing device and bad spot detecting method which are capable of detecting bad spots more surely than heretofore when applied to a tape streamer for backing up the data of, for example, a server, etc. SOLUTION: The data is recorded in such a manner that the bad spots may be specified by any tracks or track sets in the recording units succeeding to at least the bad spots and the bad spots are detected by the data recorded in the manner described above.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording / reproducing apparatus and a bad spot detecting method, and can be applied to, for example, a tape streamer for backing up data in a server or the like. According to the present invention, at least in a recording unit following a bad spot, data is recorded so that the bad spot can be specified by any track or track set, and a bad spot is detected by the data thus recorded. This makes it possible to detect a bad spot more reliably than in the past.

[0002]

2. Description of the Related Art Conventionally, in order to record and reproduce desired data with high reliability, a tape streamer is designed so that data recorded by read-after-write cannot be used as a bat spot for recording / reproduction. It has been done.

That is, the tape streamer determines whether or not data recorded by read-after-write can be correctly reproduced at the time of recording, and executes a retry process if the data cannot be reproduced correctly. Furthermore, in the tape streamer, a part that cannot be correctly reproduced may be caused by, for example, a scratch on a magnetic tape. When the processing is completed, the data is recorded in a predetermined area of the magnetic tape. According to the position information of the bad spot recorded on the magnetic tape, the tape streamer does not use this bad spot portion for recording and reproduction.

[0004] Further, after data recording is completed, the power may be turned off before the position information of the bad spot is recorded on the magnetic tape. Therefore, if necessary, the bad spot is renewed by so-called recovery processing. This is detected and recorded on a magnetic tape.

FIG. 33 is a chart for explaining the detection of bad spots in the recovery process. The tape streamer configures one track set by a predetermined number of diagonal tracks, which is a predetermined processing unit, and assigns a logical ID (that is, a logical track set ID) whose value sequentially increases to each track set. The tape streamer allocates a predetermined number of track sets to one bank by bank management of the memory, and sets a predetermined flag (C flag) in a head track set of this bank to enable identification. Further, when a bit error that is difficult to correct is detected by the read-after-write, a plurality of track sets constituting the bank where the bit error is detected are all set to the bad spot BS, and the data of this bank is recorded again. Then, the retry process is executed. At this time, the tape streamer executes a retry process by setting one logical ID similarly to the track set of the bad spot BS so that the tape streamer skips over the bad spot BS and reproduces the logical IDs so as to be continuous.

Accordingly, in the example shown in FIG.
One bank is constituted by one track set, and the bank by the track set of logical ID 00 to 07 can be recorded and reproduced correctly, but the bank by the subsequent track set of logical ID 08 to 15 is difficult to reproduce correctly, so that a bad spot is formed. This is set in the BS. Further, the bank by the track set of the logical IDs 08 to 15 is set to the bad spot BS again because it is difficult to correctly reproduce even in the retry by setting the bad spot BS, and the bank was correctly recorded in the third recording. It has been shown.

In the detection of a bad spot in the recovery process, the tape streamer sequentially reproduces a magnetic tape to detect a bit error that is difficult to correct,
The bad spot BS is detected based on the continuity of the track set in which the flag is set. That is, in the example shown in FIG. 33, the track set of the logical IDs 00 to 07 is reproduced, and when a bit error that is difficult to correct is not detected, the possibility of the bad spot BS is low. The track set is provisionally set in the data area (in FIG. 33 (1), this provisional setting is indicated by reference numeral 1).

The tape streamer uses these logical IDs 00
Of the track sets No. to 07, the logical ID 00 of the track set in which the C flag is set is stored, and the subsequent track set is reproduced. In this case, in the track set in which the following C flag is set, the logical ID is the value 08, and the logical ID of the previously stored track set is set.
Therefore, the track set temporarily provisionally determined is determined to be a data area (denoted by a symbol D) other than the bad spot BS. In addition, as for the track sets from the logical ID 08 to the logical ID 15 that follows, if a bit error that is difficult to correct is not detected, it is provisionally set in the data area (FIG. 33).
(2)).

[0009] The tape streamer further comprises these logic I
Of the track sets from D08 to the following logical ID 15, the logical ID 08 of the track set in which the C flag is set is stored, and the subsequent track set is reproduced. In the reproduction of the subsequent track set (see FIG. 33)
(3)) If the logical ID of the track set in which the C flag is set is 08 and matches the logical ID of the previously stored track set, the bad spot is set for the track set temporarily provisionally determined first. The setting is changed to BS (reference B). For the track sets from the logical ID 08 to the following logical ID 15,
If a bit error that is difficult to correct is not detected, a temporary setting is made in the data area.

The tape streamer further stores the logical ID 08 of the track set in which the C flag is set among the track sets from the logical ID 08 to the subsequent logical ID 15, and reproduces the subsequent track set. In the reproduction of the subsequent track set (see FIG. 33)
(4)) Since the logical ID of the track set in which the C flag is set is 08 and matches the logical ID of the previously stored track set, the setting is changed to the bad spot BS in this case as well. I do. In the case of a track set from the logical ID 08 to the subsequent logical ID 15, if a bit error that is difficult to correct is not detected, the track set is provisionally set in the data area.

Since the logical ID of the track set in which the following C flag is set has the value 16, the tape streamer detects the track set of the logical ID 16 and detects the track set from the immediately preceding logical ID 08 to the following logical ID 15 Is a data area. When the tape streamer repeats these processes and obtains the position information of the bad spot, it re-records this position information at a predetermined position on the magnetic tape, thereby completing the recovery process for the bad spot.

[0012]

However, this method of detecting a bad spot is based on the premise that the logical ID of the track set with the C flag set can always be reproduced and that the data area can always be correctly reproduced. It is. On the other hand, when the track density is increased, the logical ID of the track set in which the C flag is set may not always be reproduced, or the data area may not be reproduced correctly.

As a result, the conventional method for detecting a bad spot has a practically insufficient problem when the recording density is improved.

That is, as shown in FIG. 34, when the track set set in the bad spot BS cannot be correctly reproduced (indicated by reference numeral 0 in FIG. 34 (1)), C is set immediately after the end of the bad spot BS. Even if the logical ID 08 of the track set to which the flag is set is detected (FIG. 34 (2)), in this case, the track set set to the bad spot happens to be correctly reproduced, and conversely, the track in the data area is It is possible that the set was not played correctly,
It becomes impossible to determine which of the banks has a track set based on the bad spot BS.

Also, as shown in FIG. 35 in comparison with FIG. 34, even if the bad spot BS can be partially reproduced, the track set with the C flag set cannot be reproduced in the track set following the bad spot BS. In this case, similarly, the bad spot BS cannot be correctly determined.

As shown in FIG. 36, in the conventional detection method, when only a part of the track set in the data area cannot be correctly reproduced, the bad spot BS can be correctly detected.

The present invention has been made in view of the above points, and it is an object of the present invention to propose a magnetic recording / reproducing apparatus or a method of detecting a bad spot, which can more reliably detect a bad spot as compared with the related art. It is.

[0018]

According to the first aspect of the present invention, the present invention is applied to a magnetic recording / reproducing apparatus, and a read-after-write process is used to perform a recording unit based on a predetermined number of tracks or a number of track sets. The retry process is executed in units of, and the area that could not be correctly reproduced is set as a bad spot, and the data of the bad spot that can specify the bad spot by any track or track set is at least related to the retry. Record on a track or track set.

According to the seventh or eleventh aspect of the present invention, when data can be correctly reproduced from a track or a track set by applying to a magnetic recording / reproducing apparatus or a bad spot detecting method, the track or the track The set is provisionally set in the data area, and any track or track set is a bad spot data that can specify a bad spot, at least a bad spot based on the data of the bad spot recorded on the track or track set related to the retry. The track or track set of the previous recording unit is specified, and the temporarily set track or track set related to the previous recording unit is set in the data area by the provisional setting and / or specification.

According to the first aspect of the present invention, the data of the bad spot that can specify the bad spot is recorded on at least the track or the track set related to the retry by any of the tracks or the track sets. Alternatively, if the track set is correctly reproduced, the bad spot can be specified, and the bad spot can be detected more reliably than before.

According to the seventh or eleventh aspect, when data can be correctly reproduced from a track or a track set, the track or the track set is provisionally set in the data area, and the track or the track set is set. The track or track set of the bad spot is specified from the data of the bad spot obtained, and a temporarily set track or track set related to the previous recording unit is set in the data area by provisional setting and / or specification. Since the data can identify the bad spot by any track or track set, if any track or track set is correctly reproduced, the bad spot can be identified, and the bad spot can be identified by that much. To more reliably detect bad spots. .

[0022]

Embodiments of the present invention will be described below in detail with reference to the drawings.

(1) Configuration of First Embodiment (1-1) Overall Configuration FIG. 1 is a perspective view showing a backup system according to a first embodiment of the present invention. The backup system 1 is configured by arranging a tape streamer 3 and the like on a large console 2. That is, in this backup system 1, a tape streamer 3, a power supply unit 4, and a CPU unit 5 are arranged in this order from the lower side of the front, and the transport mechanism 6 of the tape cassette is arranged on the back side.

The power supply unit 4 supplies power to each part of the backup system 1 and the CPU unit 5
Controls the operation of the entire backup system 1. The tape streamer 3 records data from a host computer on a tape cassette loaded by the transport mechanism 6, reproduces the data recorded on the tape cassette, and outputs the data to the host computer.

The transport mechanism 6 is configured so that a plurality of tape cassettes can be stored in the shelf 6A. Under the control of the CPU unit 5, the tape cassette held in the shelf 6A is transported and loaded into the tape streamer 3. Conversely, the tape cassette discharged from the tape streamer 3 is transported to the original shelf 6A. For this reason, the transport mechanism 6 is provided with an elevator 6B which is movable in the vertical direction of the console 2, a tape cassette which is mounted on the elevator 6B, takes a tape cassette in and out of the shelf 6A, and a tape streamer which is in contact with the tape streamer 3. Hand block 6C for putting in and out
And are arranged. In the tape cassette applied to the tape streamer 3 according to this embodiment, a non-contact type IC tag is arranged on the back surface,
A reader / writer that accesses the IC tag is arranged on the shelf 6A and the elevator 6B.

FIG. 2 is a block diagram showing the CPU unit 5 together with peripheral components. In the CPU unit 5,
The host computer interface (host computer IF) 5A is, for example, a SCSI (Small Computer S).
The host computer 8 is connected to the host computer 8 by a system interface, and takes in commands and data to be recorded from the host computer 8 and outputs them to the internal bus BUS. Status data, reproduced data, and the like are output to the host computer 8.

The streamer interface (streamer IF) 5B is connected to the tape streamer 3 by, for example, SCSI, and outputs a predetermined control command output to the bus BUS and data for recording to the tape streamer 3, and vice versa. The status data output from the tape streamer 3 and the reproduced data are received from the tape streamer 3 and output to the internal bus BUS.

The control panel 5D is a console 2
And receives various operations by the operator, and notifies the CPU 5C of the operations by the operator via the internal bus BUS. The driver 5E drives the elevator 6B and the hand block 6C under the control of the CPU 5C.

The CPU 5C controls a whole operation of the backup system 1 in response to a command from the host computer 8 by securing a work area in the memory 5F and executing a predetermined processing procedure. That is, when an access command is input from the host computer 8, it instructs the tape streamer 3 to record and reproduce a tape cassette. At this time, if the access command from the host computer 8 is for a tape cassette different from the tape cassette loaded in the tape streamer 3, the transport mechanism 6 is controlled to load the corresponding tape cassette into the tape streamer 3. When a format of a so-called virgin tape is instructed by the operator, the tape cassette is loaded into the tape streamer 3 under the control of the transport mechanism 6, and the tape streamer 3 is instructed to perform an initialization process.

(1-2) Configuration of Tape Streamer FIG. 3 is a plan view showing the front and back of the tape streamer 3. The tape streamer 3 has an insertion port 3A formed in the front (FIG. 3A) so that a tape cassette can be inserted into and discharged from the insertion port 3A. The tape streamer 3 is provided with connectors for various connections on the back surface, so that the tape streamer 3 can be directly connected to the host computer 8 without the CPU unit 5, for example.

(1-2-1) Format of Tape Streamer FIG. 4 is a schematic diagram showing a format of a recording track by the tape streamer 3. Tape Streamer 3
In (2), longitudinal tracks are respectively formed above and below the magnetic tape 10, and oblique tracks are formed between the longitudinal tracks. Here, one of the upper and lower longitudinal tracks is assigned to the controller track 10A, and a control signal for tracking control is recorded. The other longitudinal track is ID track 1
0B, and information for managing the diagonal track is recorded in a management table.

On the other hand, an oblique track is formed by sequentially arranging a set of recording tracks with positive and negative azimuth angles. Each diagonal track is formed so as to be divided into two by a substantially central portion, and a preceding recording track of a set of recording tracks has a tracking control part for tracking control at this central divided portion. An area TP in which a pilot signal is recorded is formed.

Further, as for the diagonal track, one track set is formed by two sets and four recording tracks, and the track set is formed as a unit. A track set ID used for identifying each track set is set in each track set, and this track set ID is assigned to a part of information to be recorded on the ID track 10B. As the track set ID, a physical track set ID that simply increases in all track sets and a logical track set ID that simply increases except for dummy, EOD, and the like are set. The track set ID is S
The time code is converted into a time code by MPTE and recorded on the ID track 10B.

Each diagonal track is allocated to the A track, B track, C track, and D track corresponding to each channel of the recording / reproducing system from the leading side of the track set.

The track set includes a user track set used for recording user data, a tape mark track set assigned to a tape mark indicating a file delimiter, and an EOD (End Of D) indicating an end of data.
ata) A distinction is made between a track set, a dummy track set forming a dummy track, and the like.

FIG. 5 is a schematic diagram showing the relationship between the track set thus formed and the ECC block which is an error correction processing unit. The tape streamer 3 divides user data or the like to be used for recording in predetermined block units and adds an error correction code to form an ECC block. In the tape streamer 3, data of eight ECC blocks is allocated to one track set. At this time, each of the ECC blocks indicated by the numerals 0 to 7 is divided into four equal parts in the direction of outer parity and assigned to each track, whereby the tracks are interleaved and recorded. In the data allocated to each track, the arrangement is changed and the data is subjected to word interleave processing and recorded.

FIG. 6 is a schematic diagram showing the ECC block. One ECC block is assigned user data of 77 × 190 bytes, and a 27-byte outer parity is generated for a 77-byte data string, and this outer parity is added to the data string. After an additional 2 × 104 byte block ID is added,
Block I in the direction orthogonal to the outer parity
A 12-byte inner parity is generated for a 192-byte data string including D, and the inner parity is added to the data string.

As a result, the ECC block is formed by adding an error correction code in a product code format and further adding a 4 × 104 byte synchronization pattern SYNC. Here, the block ID is an identification ID of the ECC block, and the synchronization pattern SYNC is a specific pattern indicating the start of the ECC block.

Thus, in the tape streamer 3, 7
One ECC block is formed by allocating 7 × 190 bytes of user data and the like, and eight ECC blocks are further formed.
The assignment of blocks to one track set results in 1170 in one track set.
40 bytes of user data and the like can be assigned.

FIG. 7 is a schematic diagram showing the data structure of 117040 bytes allocated to this one user track set. One track set has a format ID of 4 bytes at the beginning. Here, the format ID is an ID for format identification, and in this embodiment, a value FFFF0000h indicating that user data is recorded in a track set of four tracks.
Is described.

Subcodes are assigned to the following 136 bytes, tables such as VSIT, VIT, and BST to be described later, user data track sets, identification data of tape mark track sets, and logical track set IDs.
Etc. are assigned data for track set management,
A logical track set ID and the like are recorded.

The number of bytes obtained by subtracting the data length of the block management table from the subsequent 116884 bytes is allocated to recording of user data and the like. When assigning user data to this area, if the area cannot be filled with user data, dummy data is assigned.

The block management table is set to a maximum of 4096 bytes. Here, the tape streamer 3 is configured to be able to record and reproduce data in units of blocks of a set of track sets, and the block management table records a table used for managing these blocks. Further, in the track set, the next 12 bytes are allocated to reservation, and the remaining 4 bytes are allocated to EOD (End Of Data) indicating the end of one track set.

The tape streamer 3 records user data using a track set as a basic unit in this way, and records various management data.

FIG. 8 is a schematic diagram showing the overall layout of the magnetic tape 10. The magnetic tape 10 is a physical magnetic tape 10 excluding a leader tape connected to a reel.
A recording start position LBOT (Logical Beginning Of Tape) is set on the side on which the magnetic tape 10 has traveled a predetermined distance from the beginning PBOT (Physical Beginning Of Tape), and a similar physical end PEOT (Physical End Of Tape).
f Tape), a recording end position LEOT (Logical End Of Tape) is set on the scanning start end side of the magnetic tape 10.
Various data are recorded on the magnetic tape 10 between the recording start position LBOT and the recording end position LEOT, so that the magnetic tape 10 is used in a region near the leader tape where the error rate is relatively easy to deteriorate. . The magnetic tape 10 forms one physical volume between the recording start position LBOT and the recording end position LEOT.

The magnetic tape 10 has a recording start position LBOT
A run-up area is formed for a predetermined distance, and the magnetic tape running system can be servo-locked in the run-up area. Therefore, the magnetic tape 10
Oblique tracks are sequentially formed from this run-up area.

On the magnetic tape 10, a VSIT (Volume Set Table) is recorded following the run-up area, and the first physical track set ID for recording the VSIT is set to 0ID. Here, in the VSIT, various data for managing the logical volume between the recording start position LBOT and the recording end position LEOT are recorded. That is, VS
IT is the volume name of this magnetic tape, the file name recorded on the magnetic tape, and the V assigned to each file.
The physical track set ID and the like of the IT are recorded, so that the tape streamer 3 can access the VSIT so that the magnetic tape 10 can be identified. Further, each file recorded on the magnetic tape 10 and the recording position of each file are recorded. And so on. Where VS
One IT is formed by one track set (1 ID), and the same content is repeatedly recorded ten times to ensure high reliability.

On the magnetic tape 10, a VSIT retry area for 90 IDs is formed following the VSIT recording area. As a result, if necessary, the VSIT is re-recorded in the retry area to perform a recovery process or the like. It has been made executable.

Further, the magnetic tape 10 is formed such that a position margin band is subsequently formed for a predetermined ID, so that even if the VSIT is updated, the recorded data in the subsequent area is not affected at all. The magnetic tape 10
The area between the position margin band and the recording end position LEOT is allocated to the area of the logical volume.

FIG. 9 is a schematic diagram showing logical volumes assigned to this logical volume area. In the magnetic tape 10, data is recorded in file units with a tape mark TM being a file delimiter code interposed therebetween (FIG. 9A), and each file is configured by blocks. (FIGS. 9 (B) and (C)).

In the tape streamer 3, the DIT (Directory Information Table) and E
A unit including an OD (End Of Data) constitutes one logical volume. Here, the DIT is a table for managing one logical volume to which the DIT is allocated, and one length is formed by 40 IDs. DIT
As shown in FIG. 9 (D), the same content by this 40 ID is repeatedly recorded seven times, so that high reliability can be ensured.

Each of the DITs is assigned the run-up area described above with reference to FIG. 8, so that the servo system can be locked. Subsequently, a position margin band is arranged on the rear side so that, similarly to the VSIT, even if updated, the recorded data in the subsequent area is not affected at all.

DIT, as shown in FIG.
VIT (Volume Information Table) by D, 1ID
(Bad Spot Table) by LID, LID by 1ID
T (Logical ID Table), FIT by 20 ID (File
Information Table), 1ID UIT (User Inf)
ormation Table) is set. The DIT is set so that the remaining 16 IDs are reserved.

In the VIT, the physical track set ID is recorded in the VSIT, whereby the VIT can be accessed with reference to the VSIT recording, and the entire DIT can be accessed. In the VIT, a logical track set ID is set so as to match the physical track set ID. VI
T is assigned the volume label of the logical volume to which the DIT is assigned, the first physical track set ID of the user track set, and the last physical track set ID.

The BST is assigned position information of an area (hereinafter referred to as a bat spot) set to be unusable by the tape streamer 3 due to a scratch or the like on the magnetic tape 10. That is, in the tape streamer 3, when a bit error that is difficult to correct is generated by the read-after-write and retry processing at the time of recording, the data after this area is recorded again on the magnetic tape. In the tape streamer 3, for data newly recorded on the magnetic tape in this manner, an area where this data should be originally recorded is defined as a bad spot. In the BST, the physical track set ID at the start end and the physical track set ID at the end of such a bad spot are recorded.

The LIDT (Logical ID Table) is used for high-speed retrieval for each block, and data of a file number, a physical track set ID, and a block number is recorded for every 200 logical track set IDs. As a result, the tape streamer 3 can roughly detect the position of the block to be accessed and search for the head at a high speed.

The FIT is formed by recording a physical track set ID of a tape mark and a block number of each block. The UT is information indicating whether or not the volume has been updated. Status data indicating whether or not the volume has been updated is set to FFFFFFFFh before updating and 000000 after updating.
00h.

(1-2-1) Schematic Configuration of Tape Streamer FIG. 10 is a block diagram showing a tape streamer 3 according to such a format. In the tape streamer 3, the SCSI interface (SCSIIF) 2
1 is connected to the CPU unit 5 by a SCSI interface, and is directly connected to the host computer when the CPU unit is not used. The SCSI interface 21 inputs user data to be recorded and outputs it to the memory controller 22, and outputs reproduced data output from the memory controller 22 to the host computer. Further, the SCSI interface 21 notifies a command from the CPU unit 5 and the host computer 8 to the main CPU unit 23 via the memory controller 22. Conversely, it receives status and the like output from the main CPU via the memory controller 22 and outputs this status and the like to the host computer 8 and the CPU unit 5.

The memory controller 22 temporarily stores the user data input via the SCSI interface 21 in the buffer memory 24, and further stores the data stored in the buffer memory 24 in accordance with the processing of the subsequent ECC encoder (ECCENC) 25. Output according to timing. The memory controller 22 inputs the data of the block management table, the above-mentioned DIT, and the like corresponding data from the main CPU unit 23, temporarily stores the data in the buffer memory 24, and outputs the data to the ECC encoder 25. Conversely, during playback, the memory controller 2
2 temporarily stores the user data output from the ECC decoder (ECCDEC) 26 in the buffer memory 24 at a timing synchronized with the processing of the ECC decoder 26, and further stores the stored user data in the SC
Output to SI interface 21. In addition, D
In the case of IT or the like, data output from the ECC decoder 26 is output to the main CPU unit 23. The error detection result input together with the user data is notified to the main CPU unit 23 by accessing the main CPU unit 23.

The buffer memory 24 processes user data sequentially input in a bank structure in units of capacity corresponding to the above-mentioned predetermined number of track sets.
This constitutes a bank memory. As a result, in the tape streamer 3, the recording / reproducing process is executed and the retry process is executed using one bank configured in the buffer memory 24 as a processing unit. As a result, in a track set, when user data is recorded with a data amount less than one bank, a dermy track set in which dermy data is recorded instead of the user data is formed.

The ECC encoder 25 forms the ECC block described above with reference to FIG. 6 by generating and adding an error correction code to data output from the memory controller 22 and by adding a synchronization pattern and the like. Further, the ECC encoder 25 outputs the data of the ECC block by a plurality of systems corresponding to the arrangement of the magnetic heads. Further, at this time, the ECC encoder 25 outputs these data in a predetermined order, thereby executing inter-track interleaving and word interleaving processing.

The equalizer 28 converts the data output from the ECC encoder 25 into a serial data string by a plurality of systems corresponding to the arrangement of the recording heads, and further modulates the data by a method suitable for recording on the magnetic tape 10. As a result, the equalizer 28 generates a drive signal for driving the recording head, and drives the recording head mounted on the rotating drum 29 with this drive signal.

The rotating drum 29 is provided with a recording head of a predetermined system and a reproducing head for scanning the scanning trajectory of the recording head, and rotates at a predetermined rotation speed under the control of the servo circuit 31. This enables Tape Streamer 3
Are formed so that diagonal tracks are sequentially formed on the magnetic tape 10 running at a predetermined speed to record user data and the like, and that the recording result can be monitored by a reproducing head.

The equalizer 30 receives a reproduction signal from a reproduction head mounted on the rotating drum 29 during recording and reproduction, and performs waveform equalization and demodulation processing on the reproduction signal to thereby record data recorded on the magnetic tape 10. To play.

The ECC decoder 26 uses the equalizer 3
The output data of 0 is fetched, and error correction processing is performed using an error correction code added during recording. ECC decoder 2
6 outputs the user data and the like obtained by the error correction processing to the memory controller 22 together with the error detection result as the error correction processing result. This allows the tape streamer 3 to output data recorded on the magnetic tape 10 to the host computer 8 via the buffer memory 24, and to obtain data such as VSIT by the main CPU 23 as necessary. I have.

The ECC decoder 26 notifies the error detection result obtained in this way to the main CPU section 23 via the buffer memory 24.
Under the control of the U unit 23, processing such as retry can be executed as needed. ECC decoder 2
6 simply executes an error detection process at the time of recording user data, records the resulting error detection result together with the user data and the like in the buffer memory 24,
This makes it possible to determine whether or not the data recorded in the read-after-write processing has been correctly reproduced. The ECC decoder 26 stores such an error detection result in the buffer memory 24 by setting a corresponding error flag.

In doing so, the main CPU section 23 secures a work area in the random access memory (RAM) 33 and executes a predetermined processing procedure in response to a command input via the SCSI interface 21. The tape streamer 3 is mainly composed of a unit, controls the operation of the entire tape streamer 3, and notifies the host computer 8 of the status as required. In this process, the buffer memory 24 is accessed as necessary to obtain information such as VSIT and DIT reproduced from the magnetic tape 10, and further, based on this information, the operation of the drive system and the like of the magnetic tape 10 is controlled. I do. After recording the user data, the entire operation is controlled so that the corresponding DIT and VSIT are rewritten.

System Controller (Syscon) 34
Controls the operation of the mechanical system of the tape streamer 3 by exchanging data with the main CPU unit 23 executed via a dual port RAM (DP-RAM) 35. That is, in the tape streamer 3, the sensor 37 is disposed at a cassette insertion port or the like, and detects, for example, whether or not the magnetic tape 10 can be loaded, and notifies the servo circuit 31 of the detection. The capstan motor (M) 36 runs the magnetic tape 10 under the control of the servo circuit 31. The fixed head 38 forms the longitudinal tracks 10A and 10B of the magnetic tape 10 and outputs a reproduction signal of the longitudinal tracks 10A and 10B to the servo circuit 31.

The servo circuit 31 drives a predetermined drive system based on the detection result of the tape cassette by the sensor 37 to execute processing such as loading and unloading of the tape cassette, and loading and unloading of the magnetic tape 10. And the like. The servo circuit 31 drives the rotary drum 29 to rotate, and controls the rotation speed of the capstan motor 36 based on the determination of the reproduction result of the CTL track 10A based on the rotation phase of the rotary drum 29, thereby performing tracking control. Execute the processing of During reproduction, the servo circuit 31 executes these tracking control processes with reference to a tracking control pilot signal assigned to an oblique track of the magnetic tape 10.

On the other hand, when the magnetic tape 10 is initialized, the servo circuit 31 drives the fixed head 38 while the magnetic tape 10 is running at a predetermined running speed, so that the magnetic tape 10 10A and 10
Form B. The servo circuit 31 includes a fixed head 38
The obtained reproduction signal is processed to reproduce the management data, and the management data is output to the system controller 34. The time code assigned to the management data is obtained from a time code recorder (TCR) 4.
Output to 0.

In this initialization process, the time code recorder 40 sequentially generates a time code and outputs it to the servo circuit 31. The servo circuit 31 uses the time code and various data output from the system controller 34. The management data is generated by the fixed head 3
8 is driven. On the other hand, at the time of recording and reproduction, the time code obtained from the servo circuit 31 is replaced with the track set ID.
And output.

The system controller 34 controls the operation of the servo circuit 31 and also outputs the track set ID output from the time code recorder 40 via the main CPU 23 to the ECC encoder 25 and the like.

Interface CPU (IFCPU) 4
1 exchanges data with the main CPU unit 23 via the DP-RAM 42, thereby the shelf 6A, the elevator 6
In B, information on the tape cassette can be obtained, and further, data communication with another computer system is possible.

That is, in the tape streamer 3, the reader / writer arranged on the shelf 6A or the like uses the antenna (AN
T) 44 to I located on the back of the tape cassette 45
A radio wave is transmitted to the C tag 46, and this radio wave
When a response is obtained from the IC tag 6, various information relating to the tape cassette 45 is transmitted to and received from the IC tag.

The display CPU 49 inputs and outputs data transmitted and received between the IC tags via the memory label interface 47 to and from the interface CPU 41. The display CPU 49 displays various data on a predetermined display screen according to data input via the interface CPU 41. This display is, for example, display of information on a tape cassette loaded in the tape streamer 3.

The SIO 50 is, for example, RS-232C,
It is a serial interface such as RS-422, and transmits and receives maintenance information to and from external devices. The Ethernet IO is an Ethernet (registered trademark) interface, and is connected to a predetermined network so that various information can be transmitted and received.

(1-2-1) Bad Spot Detection Processing FIG. 11 is a table showing in detail the configuration relating to the processing of bad spots in comparison with FIG. In this embodiment, each track set is recorded with an error correction code CRC (Cyclic Redundancy Check) added to the subcode data, so that even if a bit error that is difficult to correct is generated in the user data, the subcode data is recorded. The data can be correctly reproduced.

Further, as shown in FIG. 12, each track set includes, in addition to the above-described logical track set ID and the like,
Bad spot ID number (BSID number), ID number (ID
No.) data and bank ID are set in the subcode data.

Here, the number of bad spot IDs is data indicating the number of track sets related to the immediately preceding bad spot with reference to a predetermined position. In this embodiment, the number of bad spot IDs is determined based on the start position of the retry. A significant value is set only for the bank that has been retried, and the value is set to 0 for a bank that has not been retried. Thus, the number of bad spot IDs indicates the number of track sets related to the immediately preceding bad spot in each bank.

On the other hand, the ID number indicates the number of track sets included in one bank, and the bank ID indicates the order of the track sets in each bank. Thus, in this embodiment, if at least one subcode is correctly reproduced in each bank by the bank ID, the head track set of the bank to which this track set belongs can be detected. When the correctly reproduced track set belongs to the bank immediately after the bad spot, the track set of the bad spot can be detected from the head track set of the bank based on the number of bad spot IDs.

Thus, in the example shown in FIG. 12, the bank by the track sets of the logical IDs 00 to 07 can be correctly reproduced. In this case, the value 00 is set to the number of bad spot IDs and the value 8 is set to the ID number of each track set. In addition, the value 0 is added to the track set of the logical IDs 00 to 07.
The bank IDs of value to 7 are sequentially set. For the banks by the track sets of the following logical IDs 08 to 15, the bad spot ID of each track set is used.
The number and the ID number are set to the value 00 and the value 8, respectively.
Are sequentially set. At this time, if a bit error for which error correction is difficult occurs in the track set of the logical IDs 08 to 15, the logical IDs 08 to 1 are set.
Track set No. 5 is set as a bad spot, these track sets are recorded again by the retry process, and in this re-recorded track set,
The number of bad spot IDs is set to a value of 8, which is the number of track sets related to the immediately preceding bad spot. If a bit error that is difficult to correct is generated in the re-recorded track set, the re-recorded track set of the logical IDs 08 to 15 is set as a bad spot again and recorded again. Track set, the bad spot I
The number D is set to a value 16, which is the number of track sets related to the immediately preceding bad spot. Further, the logic I
When the recording is completed correctly by repeatedly recording the track sets D08 to D15, the number of bad spot IDs and ID numbers of the track sets of the subsequent logical set 16 to 23 are set to 00 and 8, respectively. Will be set.

The main CPU 23 detects a bad spot on the basis of the subcode set in this way. Further, a recovery process is executed as necessary based on the bad spot detection result, and in this process, a bad spot is detected based on the subcode thus set.

That is, when starting access to the magnetic tape 10 according to an instruction from the CPU unit 5, the host computer, or the like, the main CPU 23 controls the operation of the servo circuit 37 via the system controller 34 to load the magnetic tape 10. Then, the VSIT is reproduced and acquired in advance. Further, the magnetic tape 10 is run so that the file specified by the host computer 8 can be accessed according to the VSIT.

That is, when the first file is recorded on the magnetic tape 10, the DIT is recorded at a predetermined interval from the VSIT, and then the data output from the host computer 8 is sequentially recorded on the magnetic tape 10. In addition, when appending to a previously recorded file, the DIT of the corresponding file is reproduced with reference to the VSIT recording, the end of the last block is detected from this DIT, and input from the host computer 8 is sequentially performed from this end. Record the data to be recorded. Further, after recording, DIT or the like is recorded. When data reproduction is instructed from the host computer 8, the position of the corresponding file is set to VSIT.
Then, the DIT is accessed and the data recorded on the magnetic tape 10 is reproduced according to the recording of the DIT.

In such a series of processing, the main C
At the time of recording, the PU 23 controls the system controller 34 so that the bad spot is not recorded in accordance with the BST recorded in the DIT (FIG. 9).
Control the operation of. On the other hand, at the time of reproduction, the main CPU 23 sequentially reproduces the magnetic tape 10 and
According to T, the user data obtained from the bad spot is not sent to the host computer,
Thereby, the user data obtained from the data area excluding the bad spot is selectively output to the host computer. In this reproduction process, the main CPU 23
Detects a bad spot separately based on the number of bad spot IDs described above with reference to FIG. 12, and if a difference is detected between the detection result of the bad spot and the BST, in this case, At the time of recording, the host computer is notified that the recovery is necessary because it is considered that the operation has been completed before the update of the BST which is the recording of the bad spot is not completed for some reason. The main CPU 23 notifies the host computer that recovery is necessary when the FIT, LIOT, and the like constituting the DIT are different from the reproduction result other than the BST in which the bad spot is recorded.

FIG. 13 is a schematic diagram for explaining the DIT recovery process in comparison with FIG. That is, when a recovery processing command is input from the host device, the main CPU 23 detects the mode of the recovery processing added to the command. Here this mode is B
In the case of instructing restructuring of data constituting DIT such as ST, FIT, LIOT, etc., the main CPU 23 rewinds the magnetic tape 10 to the starting end PBOT of the physical magnetic tape 10 as necessary, and then performs fast-forward playback. By V
Find the SIT. Further, as indicated by arrow A,
Regenerate VSIT and use this VSIT to rebuild DI
For T, the position of the file that is the corresponding user data is detected.

When the position of the file to be processed is detected in this way, the main CPU 23 moves the magnetic tape 10 to the recording start position BOD of the corresponding file by the same fast-forward, and then, as indicated by the arrow B, Play this file. At the time of this reproduction, the main CPU 23 constructs the parameters of the DIT file relating to the processing mode, and when the EOD of this file is detected, finds the DIT corresponding to this file. Main CPU2
3 re-records the DIT according to various parameters acquired by the reproduction process, as indicated by the arrow C, thereby reconstructing the DIT. The main CPU 23 has a DIT
Is completed, the magnetic tape is rewound if necessary, and the process is terminated.

In the case of a recovery process due to a difference between a bad spot detected by recording and reproduction of BST, the main CPU 23 executes a predetermined bad spot detection process when reproducing a corresponding file, thereby executing a bad spot. Is detected. Further, the BST is reconstructed based on the detected logical ID, and the DIT is reconstructed.

FIG. 14 is a flowchart showing a bad spot (BS) detection process in the recovery process. The main CPU 23 executes this processing procedure for each track set. That is, the main CPU 23
When one track set is reproduced, the process proceeds from step SP1 to step SP2, and it is determined whether or not the reproduced track set has already been provisionally set in the data area.
If a negative result is obtained here, the main CPU 23 proceeds to step SP3 and determines whether or not this track set has been correctly reproduced without occurrence of a bit error that is difficult to correct.

If a positive result is obtained here, the main CP
U23 proceeds to step SP4 and temporarily sets the bank to which this track set belongs in the data area. Here, the temporary setting of the track set is executed based on the ID number and the bank ID of the reproduced track set.
That is, for example, when the bank ID of the reproduced track set has the value 1 and the ID number is 8, even if the previously reproduced track set could not be reproduced correctly, the immediately preceding reproduced track set and subsequent reproduction 6 Eight track sets including one track set are provisionally set in the data area.

After executing the processing of step SP4, the main CPU 23 proceeds to step SP5. Here, the main CPU 23 determines whether or not the number of bad spot IDs of the reproduced track set is 0. If the number of bad spot IDs is a value other than 0, the main CPU 23
Move to step SP6, where the bad spot ID
After setting the track sets for the reproduced banks as bad spots by the number, the process proceeds to step SP7. On the other hand, if a positive result is obtained in step SP5, the process directly proceeds to step SP7.

Here, the main CPU 23 determines whether the provisional setting for the data area and the setting for the data area or the bad spot have been executed. If a positive result is obtained here, the process proceeds to step SP8, where the provisional setting is performed. If there is a track set related to the previous bank held as it is, the track set of this bank is set in the data area, and the process proceeds to step SP9 to end this processing procedure.

Thus, if at least one track set can be correctly reproduced in each bank except for the bad spot, the main CPU 23 can correctly specify the position of the bad spot. If a positive result and a negative result are obtained in step SP2 and step SP3, respectively, in this case, the main CPU
23 directly proceeds from step SP2 to step SP8 and ends this processing procedure. If a negative result is obtained in step SP7, the main CPU 23 also proceeds to step SP9 and ends this processing procedure.

In other words, in the case of FIG. 12, when all the track sets can be correctly reproduced, as shown in FIG. 12A, of the track sets of the logical IDs 00 to 07 relating to the first bank, the logical ID 00 corresponds to the logical ID 00. By the processing of step SP4 in the bad spot detection processing procedure for reproducing and executing the first track set, the logical I
Track sets D00-07 are provisionally set in the data area (indicated by reference numeral 1).

Further, as shown in FIG. 12 (2), of the track sets of logical IDs 08 to 15 set to the subsequent bad spots, a bad spot detection processing procedure for reproducing and executing the first track set related to logical ID 08 Of the logical ID 08
~ 15 track sets are provisionally set in the data area,
In addition, by the processing of step SP7, the track sets of the logical IDs 00 to 07 temporarily set in the data area are formally set in the data area (indicated by the symbol D).

As shown in FIG. 12 (3), of the track sets of logical IDs 08 to 15 set for the subsequent bad spots, a bad spot detection processing procedure for reproducing and executing the first track set related to logical ID 08 Of the logical IDs 08 to
Fifteen track sets are provisionally set in the data area, and by the processing in step SP6, the track sets with the logical IDs 08 to 15 relating to the immediately preceding bad spot are set as bad spots (indicated by reference numeral B).

As shown in FIG. 12 (4), of the track sets of the subsequent logical IDs 08 to 15, the logical ID 08
The track set of the logical IDs 08 to 15 is provisionally set in the data area by the processing of step SP4 in the bad spot detection processing procedure for reproducing and executing the leading track set according to the above. Track sets with logical IDs 08 to 15 relating to spots are set as bad spots (reference B
). Of the subsequent track sets of IDs 16 to 23, the logical ID 16 to 2 are reproduced by the processing of step SP4 in the bad spot detection processing procedure for reproducing and executing the head track set related to the logical ID 16.
Track set No. 3 is provisionally set in the data area, and by the processing in step SP6, the immediately preceding logical IDs 08 to 1 are set.
5 track sets are formally set in the data area. As a result, when all the track sets can be correctly reproduced, it is understood that the bad spot can be correctly detected.

On the other hand, as shown in FIG.
If it is difficult to correctly reproduce only the bad spot in the case shown in FIG.
Of the track sets D00-07, the track set with the logical IDs 00-07 is provisionally set in the data area by the processing of step SP4 in the bad spot detection processing procedure for reproducing and executing the head track set associated with the logical ID 00. (FIG. 15A).

Logical IDs for the following two bad spots
In the track sets 08 to 15, each track set is reproduced, and a negative result is obtained in the processing procedure of step SP2 and step SP3, whereby the processing is completed without any temporary setting in the data area (FIG. 15).
(1), indicated by reference numeral 0).

On the other hand, in this case, the step SP in the bad spot detection processing procedure for reproducing and executing the head track set corresponding to the logical ID 08 among the track sets corresponding to the subsequent logical IDs 08 to 15 relating to the subsequent retry.
By the processing of step 4, the track set of the logical IDs 08 to 15 is provisionally set in the data area, and step SP6
, The bad spot track set by the two immediately preceding banks is set as the bad spot. Further, in this case, since a positive result is obtained in step SP7, the track set of the logical IDs 00 to 07 left as it is temporarily set is formally set in the data area by the processing in step SP8. Logical ID 16 that follows
The track sets No. to No. 23 are processed in the same manner as described with reference to FIG. As a result, even if it is difficult to correctly reproduce only the bad spot, the bad spot can be detected correctly.

On the other hand, as shown in FIG. 16, when the partial track set set in the bad spot and the partial track set set in the data area following the bad spot are erroneously reproduced, the logical value related to the first bank is set. Of the track sets with IDs 00 to 07, the logical ID 00 is read and the leading track set is reproduced and executed.
Track sets 00 to 07 are provisionally set in the data area (FIG. 16 (1)).

A logical ID related to the next bad spot
In the track sets 08 to 15, the logical ID 0 is obtained by the processing of step SP4 executed by the first correctly reproduced track set (the track set having the logical ID 08) among these track sets.
Track sets 8 to 15 are provisionally set in the data area (FIG. 16A).

The logical ID 0 relating to the subsequent bad spot
In the track sets 8 to 15, each track set is reproduced, and a negative result is obtained in the processing procedure of step SP2 and step SP3, whereby the processing is completed without any temporary setting in the data area (FIG. 16).
(1)).

Further, logical IDs 08 to 15 relating to retries
In the track set No., a step SP based on the first correctly reproduced track set among these track sets (the track set having the logical ID 10) is performed.
4, the logical IDs 08 to 1 related to this retry
5 are temporarily set in the data area (see FIG. 1).
6 (2)), and the process of step SP6 using the track set of the logical ID 10 sets the bad spot track set for the two banks as the bad spot. By the processing in the subsequent step SP8, the track set relating to the first bank that has been left tentatively set is set in the data area (FIG. 16).
(2)). The subsequent track sets with logical IDs 16 to 23 are processed in the same manner as described with reference to FIG. 12 (FIG. 16 (3)). As a result, even when a partial track set set in the bad spot and a partial track set set in the data area following the bad spot are erroneously reproduced, the bad spot can be correctly detected.

On the other hand, as shown in FIG. 17, when only some of the track sets set in the data area are erroneously reproduced, the logical IDs 00 to 07 related to the first bank are set.
Even if any of the tracks in this bank cannot be correctly reproduced by the processing of step SP4 in the bad spot detection processing procedure of reproducing and executing the head track set related to the logical ID 00 among the track sets of
Track sets with logical IDs 00 to 07 are provisionally set in the data area (FIG. 17 (1)).

Thereafter, the track set of the data area and the bad spot is sequentially determined in the same manner as described above with reference to FIG. 12, so that even if a part of the data area cannot be reproduced correctly, the bad spot is accurately detected. (FIGS. 17 (2) to (4)). As a result, even if only some of the track sets set in the data area are erroneously reproduced, the bad spot can be detected correctly.

On the other hand, as shown in FIG. 18, when the bad spot is reproduced correctly but most of the data area is reproduced incorrectly, the logical I
As for the track sets D00 to D07, any of these track sets can be reproduced correctly (in this case, the track set with logical ID 04).
By the processing of step SP4 of the bad spot detection processing procedure, the track set of this bank is provisionally set in the data area (FIGS. 18A and 18B).

In the track set of the two banks related to the bad spot, the data area is not temporarily set but left (FIG. 18 (3)). Further, regarding the track sets of logical IDs 08 to 15 relating to the retry,
By performing the processing in step SP4 of the bad spot detection processing procedure using the track set (in this case, the track set having the logical ID of 10) that can be correctly reproduced from any of these track sets, the track set having the logical ID of 08 to 15 becomes the data area The track set by the two banks related to the bad spot is determined to be the bad spot by the same processing of step SP6. Also, by the processing of step SP8 based on this determination, the track sets of the logical IDs 00 to 07 are determined in the data area (FIG. 18 (5)). As a result, it can be seen that a bad spot can be specified if data is correctly reproduced in at least one track set in each bank not set as a bad spot (FIG. 18 (6)).

That is, as shown in FIG. 19, if any of the track sets with the logical IDs 00 to 07 relating to the first bank cannot be reproduced correctly, these track sets cannot be provisionally set in the data area by reproduction ( (1) of FIG. 19, it is difficult to determine the data area even after the bad spot is determined (FIG. 1).
9 (2)), thereby remaining as a track set (denoted by reference symbol E) which is difficult to detect. Incidentally, by executing the read-after-write process at the time of recording, such a situation is extremely limited and can be ignored in practical use.

(2) Operation of the First Embodiment In the above configuration, in the backup system 1 (FIGS. 1 and 2), the tape cassette housed in the shelf 6A by the management of the CPU unit 5 is a tape streamer. 3
, Then loaded and sequentially fixed head 3
8, the ID track 10B and the CTL track 10A, which are the longitudinal tracks of the magnetic tape 10, are recorded on the magnetic tape 10 (FIGS. 4 and 10). As a result, the track set ID based on the time code is recorded on the magnetic tape 10 as one of the management data in units of one track set. After that, after the magnetic tape 10 has been rewound, the V
The SIT is recorded (FIG. 8), whereby the volume name of the tape cassette is recorded, and the initialization process is completed. The tape cassette initialized in this way is
Under the control of the CPU unit 5, it is conveyed and stored at a predetermined position on the shelf 6A.

On the other hand, when data backup is instructed by the host computer 8, the CPU unit 5
When the tape cassette corresponding to the tape streamer 3 is not loaded, the corresponding tape cassette is taken out from the shelf 6A and set in the tape streamer 3. For the tape cassette loaded in the tape streamer 3, the tape streamer 3
And is stored in the shelf 6A.

When the tape cassette is loaded in the tape streamer 3 in this manner, the tape streamer 3 loads the magnetic tape 10 to reproduce the VSIT, and accesses the file specified by the host computer 8 from the VSIT. The magnetic tape 10 is made to run as much as possible. That is, when the first file is recorded on the magnetic tape 10, the DIT is recorded at a predetermined interval from the VSIT, and the data output from the host computer 8 is sequentially recorded on the magnetic tape 10. In addition, when appending to a previously recorded file, the DIT of the corresponding file is reproduced with reference to the VSIT recording, the end of the last block is detected from this DIT, and input from the host computer 8 is sequentially performed from this end. Record the data to be recorded. When data reproduction is instructed from the host computer 8, the position of the corresponding file is set to VSI.
The DIT is detected by detecting the T and the DIT is accessed, and the data recorded on the magnetic tape 10 is reproduced according to the recording of the DIT (FIG. 9).

That is, at the time of recording, after adding an error correction code in a product code format to user data sequentially input by the ECC encoder 25 (FIG. 6), inter-track interleaving is performed by four tracks forming one track set. 5 (FIG. 5) and are sequentially recorded on the magnetic tape 10 by interleaving between words. Further, the data is recorded on the magnetic tape 10 in units of banks set in the buffer memory 24.

At this time, in the tape streamer 3 (FIG. 12), four recording tracks formed on the magnetic tape 10 are set as one track set, and the bank control of the buffer memory 24 corresponds to one bank. For example, user data is sequentially recorded in units of eight track sets. Also, a logical ID whose value sequentially increases in the track set allocated to the user data is set in each track set so that each track set can be specified, and the user data is recorded.

In the recording process, the tape streamer 3 performs a read-after-write process, and when it is difficult to correctly reproduce data due to occurrence of a bit error that is difficult to correct, the tape streamer 3 is a recording unit using the eight track sets. The retry process is repeated for each bank. This allows the tape streamer 3 to record desired data with high reliability.

In the tape streamer 3, the logical ID of the track set is recorded as a bad spot in a portion where data could not be correctly reproduced in this manner. Further, the number of bad spot IDs, ID numbers, and bank IDs are set in each track set so that the bad spot can be specified from any of the track sets related to the following banks. As a result, if at least one track set can be correctly reproduced in each bank other than the bank set as the bad spot, the tape streamer 3 can detect the bad spot and further specify the data area. Bad spots can be easily and reliably detected.

Further, the number of bad spot IDs, ID numbers, and bank IDs are assigned to the subcodes of the track set together with the logical IDs, and are recorded with an error correction code added thereto. Bad spots can be reliably detected.

That is, the bad spot set in this way has its logical ID left in the recording, and after the recording of the file is completed, the magnetic tape 10 is rewound and recorded in the DIT. At this time, the VSIT is updated as needed (FIGS. 8 and 9). This enables Tape Streamer 3
Can detect the VSIT and DIT and can access the file specified by the host.

When the host instructs to play back a file and refers to the VSIT and the corresponding DIT record to execute the playback of the file, the difference between the DIT record and the result of the actual playback is obtained. Occurs, it is considered that the recording has been completed without updating the DIT for this file for some reason, so the tape streamer 3 notifies the host device of the need for recovery processing, and the recovery instructs the recovery by this notification. VIS
T is reproduced to reproduce the corresponding file (FIG. 13).
That is, regarding the bad spot, when a difference is detected between the BST, which is the position information of the bad spot recorded in the DIT, and the position information of the bad spot, which is actually reproduced and detected, the recovery processing is performed by the host device. The need is notified.

When the recovery process using the bad spot is instructed, the tape streamer 3 reproduces the corresponding file and sequentially detects the bad spot. Based on the detection result, the DIT is re-recorded and the recovery process is executed. Is done.

In this bad spot detection process (FIG. 14), it is determined whether or not data has been correctly reproduced for each track set. If the data has been correctly reproduced, the track set of the bank to which the track set belongs is determined. All are provisionally set in the data area. Further, when a bad spot ID number is set, the retry start track set which is the first track set of the bank to which this track set belongs is detected from the bank ID and ID number of this track set, and the retry start track set is detected. A track set corresponding to the bad spot ID number from the set is set as a bad spot. When a bad spot is determined in this way, and when a subsequent bank is provisionally set in the data area, the bank provisionally set in the data area is set in the data area.

Thus, the retry start track set can be detected from the bank ID and ID number of the track set, and the track set for the bad spot ID number can be detected from the retry start track set. By recording these data in the track set of each bank, if the tape streamer 3 can reproduce only one track set in each bank, a bad spot can be detected, and if various errors occur accordingly. However, (see FIGS. 15 to 19), a bad spot can be detected more reliably than before.

(3) Effects of the First Embodiment According to the above configuration, at least in the bank following the bad spot, the subcode data is recorded so that the bad spot can be specified by any track set. Thereby, a bad spot can be detected more reliably than in the past.

Further, by recording such information by adding an error correction code, it is possible to prevent a situation in which a bad spot makes it difficult to detect a bad spot. Bad spots can be detected.

(4) Second Embodiment In the processing described with reference to FIG. 14, the ID number which is the number of track sets constituting one bank and the bank ID which is the position of the track set in each bank are used for the processing. When one track set could be correctly reproduced by using this, all the track sets of the bank to which this track set belongs were provisionally set in the data area. Therefore, if the ID number does not match the number of track sets constituting one bank, for example, because the track set constituting the bank may be partially rewritten due to a connection process, etc. It is difficult to correctly provisionally set the data area, which makes it impossible to correctly detect a bad spot.

For this reason, in this embodiment, FIG.
According to the bad spot detection procedure shown in FIG. 21, a bad spot is detected by the number of bad spot IDs and the bank ID excluding the ID number, as shown in FIG. The tape streamer according to this embodiment has the same configuration as that of the tape streamer according to the first embodiment, except that the setting of the subcode related to the detection of the bad spot and the processing for detecting the bad spot are different. By being
Here, only this different configuration will be described, and redundant description will be omitted. The number of bad spot IDs, Bank I
The setting of D is executed in the same manner as in the first embodiment.

After reproducing one track set, the main CPU proceeds from step SP11 to step SP12 where it determines whether or not the data has been correctly reproduced without generating a bit error which is difficult to correct. If a positive result is obtained here, the main CPU proceeds to step S
The process moves to P13, and for a track set that can be determined to be a track set of a bank to which this track set belongs based on the bank ID of this track set, this track set is provisionally set in the data area. That is, when the bank ID of this track set is a value 0, in this case, since this is the head track set of this bank, only this track set is provisionally set in the data area. If the bank ID of this track set is value 2, it is known that the first track set of this bank exists 3 IDs earlier, so the front three track sets including this track set are stored in the data area. Set temporarily.

After executing the processing in step SP13, the main CPU proceeds to step SP14, and determines whether or not the number of bad spot IDs of the reproduced track set is 0. Here, if the number of bad spot IDs is a numerical value other than 0, the main CPU proceeds to step SP15, in which the number of bad spot IDs and the number of track sets related to the reproduced bank are set as bad spots.
Move to step SP16. On the other hand, step SP1
If a positive result is obtained in step 4, the process directly proceeds to step SP16.

Here, the main CPU determines whether the provisional setting for the data area and the setting for the data area or the bad spot have been executed, and if a positive result is obtained here,
Moving to step SP17, if there is a track set related to the previous bank held as it is temporarily set, after setting the track set of this bank in the data area,
The process moves to step SP19 and ends.

As a result, the main CPU can correctly identify the position of the bad spot if at least one track set can be correctly reproduced in each bank except for the bad spot even when the connection processing is performed. I have. In this way, the main CPU executes this processing procedure for each track set, and if a negative result is obtained in step SP12 or step SP16, the main CPU directly proceeds to step SP18 and ends this processing procedure.

As a result, as shown in FIG. 21, when all the track sets including the bad spot can be correctly reproduced, the track set of the logical ID 00 to 07 relating to the first bank is executed for each track set. By the processing in step SP13, the data area is provisionally set (FIG. 21 (1)). The track set of the logical ID 08 to 15 set to the next bad spot is also temporarily set in the data area by the processing of step SP13 executed for each track set, and the first track set related to the logical ID 08 of the subsequent bank is set. By the processing of step SP15, the track sets of the logical IDs 00 to 07 which are temporarily set and left are set in the data area (FIGS. 21 (2) and (3)).

The track set of the logical IDs 08 to 15 set to the following bad spots is also temporarily set in the data area by the processing of step SP13 executed for each track set, and the head associated with the logical ID 08 of the subsequent bank is set. The logic I temporarily set and left by the processing of step SP15 by the track set
Track sets D08 to D15 are set as bad spots (FIGS. 21 (3) and (4)).

Subsequently, logical ID 08 relating to the retry
Also, the track sets No. to No. 15 are temporarily set in the data area once by the processing of step SP13 executed for each track set, and set in the data area by the processing of step SP15 by the next track set related to the logical ID 16. (FIG. 21 (4)). As a result, the track sets to be sequentially reproduced are determined, and when all the track sets can be correctly reproduced, it can be understood that the bad spot can be accurately determined.

As shown in FIG. 22, when the bad spot cannot be reproduced correctly, the logical ID 0 is similarly set.
After the track sets 0 to 07 are provisionally set in the data area ((1) in FIG. 22), a negative result is obtained in step SP12 in the process for the track set of the two banks relating to the subsequent bad spot. The two banks related to these bad spots are temporarily processed without any provisional setting.

Logical IDs 08-
Step S executed for each of the 15 track sets
After each of these track sets is provisionally set in the data area by the processing of P13, the track set of the immediately preceding two banks is bad by the processing of step SP15 executed for the first track set of these track sets. The spot is set, and the first bank is set as the data area by the processing of step SP17 (FIG. 22 (2)). As a result, the track sets to be sequentially reproduced are determined, and it can be seen that even when the bad spot track set cannot be correctly reproduced, the bad spot can be accurately determined.

As shown in FIG. 23, when a continuous track set between a bad spot and a subsequent bank cannot be correctly reproduced, track sets with logical IDs 00 to 07 are temporarily set in the data area (see FIG. 1)),
For the track set for the next bad spot,
Only the track sets that are correctly reproduced are temporarily set in the data area, and the track sets that are not correctly reproduced are temporarily processed without being temporarily set in the data area. Regarding the track set of the subsequent data area, the first track set that is difficult to reproduce correctly is temporarily processed without being temporarily set in the data area.

When the process proceeds as described above and the track set is correctly reproduced in the bank related to the retry (the track set having the logical ID of 10), the track set is executed by the process of step SP13 for this track set. And the immediately preceding track set are temporarily set in the data area, and the track sets of the two banks are set as bad spots by the processing of step SP15. By the processing of the following step SP17, the track sets of the logical IDs 00 to 07 which are temporarily set are set in the data area (FIG. 23 (2)).

When the processing is performed in this manner, the track sets subsequent to the logical ID 11 relating to the subsequent retry are processed in the same manner as in the case of FIG. 21, and it can be seen that the bad spot can be correctly detected also in this case.

On the other hand, as shown in FIG. 24, when a part of the track set other than the bad spot cannot be reproduced correctly, in this case, the track sets (logical IDs 00 to 07) relating to this bank are reproduced sequentially and executed. As a result of the determination in step SP12, for the track set in which the error has occurred, the temporary processing ends without being temporarily set in the data area (FIG. 24 (1)). Further, a track set due to this error is a subsequent track set belonging to the same bank (a logical ID 05 track set).
Is reproduced correctly, the data area is provisionally set by the process of step SP13 using the correctly reproduced track set (FIG. 24 (2)).

In this case, similarly to the case where no error occurs, after the track set at the position where the error occurs is processed, the processing is performed in the same manner as described above with reference to FIG. (5))), so that the bad spot can be correctly detected in this case as well.

On the other hand, as shown in FIG. 25, there are many cases where it is difficult to reproduce correctly in each bank, and when only one track set can be correctly reproduced in each bank other than the bad spot, in this case, the first bank As a result of the determination in step SP12 executed by sequentially reproducing and executing the track sets (logical IDs 00 to 07) according to the above, for the track set in which the error has occurred, the temporary processing ends without being temporarily set in the data area (FIG. 25). (1)), when the subsequent track set (the logical ID 04 track set) belonging to the same bank has been correctly reproduced, these track sets are processed in the data area by the processing of step SP13 using the correctly reproduced track set. Is temporarily set (FIG. 25 (2)). However, in this case, for the track set related to the error following the correctly reproduced track set, the temporary processing ends without being temporarily set in the data area.

Subsequently, the track set relating to the bad spot cannot be reproduced correctly.
The temporary processing ends without being temporarily set in the data area (FIG. 25 (3)). Regarding the track set of the succeeding bank, the track set that cannot be correctly reproduced is
The temporary processing ends without being temporarily set in the data area. However, in the bank involved in this retry,
If any of the track sets can be correctly reproduced (Logic I
D10), and the immediately preceding logical ID is obtained by the processing of step SP13 related to this track set.
Track sets 08 and 09 are provisionally set in the data area at the same time, and the bad spot is determined by the processing in step SP15. Further, the track set temporarily set in the data area of the first bank is set in the data area by the processing of step SP17 relating to this track set (FIG. 25 (4)).

In this case, in the first bank,
Although a track set (denoted by reference symbol E) that is not determined but remains undetectable remains in the data area, it can be seen that a bad spot can be correctly detected even in this case.

Thus, according to this embodiment, FIG.
As shown in FIG. 6, it can be seen that if at least the last track set can be correctly reproduced in each bank other than the bad spot, the data area and the bad spot can be determined for all the track sets.

According to the second embodiment, it is determined whether or not reproduction has been correctly performed for each track set. If the reproduction has been correctly performed, the immediately preceding track set belonging to the same bank is determined as the data area. By determining the bad spot and the data area in the same manner as in the embodiment, even when the connection processing is performed, the bad spot can be reliably detected.

(3) Third Embodiment In the above-described second embodiment, the bad spot can be specified even when the connection processing is performed. However, as described above with reference to FIGS. If the last track set cannot be reproduced correctly, an undetermined track set will remain in the data area for this bank.

For this reason, in this embodiment, as shown in FIG. 27, a bank number is assigned to a subcode in addition to the number of bank IDs and bad spot IDs. Here, the bank number is a continuous number in each bank, and in a track set related to retry, similarly to the bank ID or the like, the immediately preceding value is applied as it is, and is reset when recording is started. Thus, in this embodiment, continuity can be confirmed in the banks on the continuous magnetic tape 10.

Further, in this embodiment, in the processing of step SP17 described above with reference to FIG. 20, the processing using this bank number is further executed. If one track set can be correctly reproduced, all the track sets can be determined not only for the bad spot but also for the data area.

That is, by assigning the bank number to the sub-code in addition to the bank ID and the number of bad spot IDs as described above and executing the processing procedure of FIG.
26 and FIG. 26, as shown in FIG. 27 to FIG. 31, when all the track sets can be correctly reproduced, etc., the bad spot is set in the same manner as in the second embodiment. A track set in which user data is recorded can be specified, and a data area can be determined.

On the other hand, the case of FIG. 25 is changed again to FIG.
As shown in the figure, even if only the track set in the middle of the bank can be correctly reproduced, if the discretely correctly reproduced track set is related to the processing of a continuous bank, the bank ID of the correctly reproduced track set is used.
Thus, the number of track sets in each bank can be determined, so that, for example, in bank 0, a track set that could not be determined in the data area is set in the data area as belonging to the same bank as a track set that was correctly reproduced. Can be.

For this reason, in this embodiment, after executing the processing of step SP18 described above, the main CPU further determines that an undetermined track set exists, such as the track sets of logical IDs 05 to 07 shown in FIG. It is determined whether or not to do. Further, when such a track set exists, it is determined based on the continuity of the bank number whether or not the bank is repeated with the same track set number.
Here, when it is determined that the bank is repeated by the same track set number, the main CPU uses the bank ID of the track set temporarily set in the data area to newly set the track set belonging to this bank to the data area. Set.

As a result, the logic I of bank 0 shown in FIG.
Track sets D05-09 and logical IDs 11-15 of bank 1 can also be determined as data areas.

According to the third embodiment, the number of track sets constituting each bank is determined and processed based on the continuity of the banks, so that each of the sets is more reliably compared to the second embodiment. The track set can be determined.

(4) Other Embodiments In the above embodiment, one bank as a recording unit is constituted by eight track sets.
The case where one track set is constituted by tracks has been described. However, the present invention is not limited to this. In the case where a bank which is one recording unit is constituted by a plurality of track sets other than eight track sets, furthermore, other than four tracks, The present invention can be widely applied to a case where one track set is constituted by a plurality of tracks, and a case where the processing of the track set is omitted and a plurality of tracks are simply set as a recording unit and a retry is performed.

In the above-described embodiment, the case where the present invention is applied to the tape streamer in combination with the transport mechanism has been described. However, the present invention is not limited to this.
For example, the present invention can be widely applied to a tape streamer configured to be directly connected to a host computer.

Further, in the above-described embodiment, the case of recording computer data has been described. However, the present invention is not limited to this, and can be widely applied to, for example, processing of video signals and audio signals. .

[0157]

As described above, according to the present invention, at least in a recording unit following a bad spot, data can be specified so that the bad spot can be specified by any track or track set. By detecting a bad spot from recorded data, a bad spot can be detected more reliably than in the past.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a backup system according to an embodiment of the present invention.

FIG. 2 is a block diagram showing the backup system of FIG. 1;

FIG. 3 is a front view and a rear view showing a tape streamer of the backup system of FIG. 1;

FIG. 4 is a schematic diagram illustrating a recording format by the tape streamer of FIG. 3;

FIG. 5 is a schematic diagram for explaining inter-track interleaving in the tape streamer of FIG. 3;

FIG. 6 is a schematic diagram illustrating an ECC block in the tape streamer of FIG. 3;

FIG. 7 is a schematic diagram for explaining a track set in the tape streamer of FIG. 3;

8 is a schematic diagram for explaining a physical volume of the entire magnetic tape in the tape streamer of FIG. 3;

9 is a schematic diagram for explaining each volume in the tape streamer of FIG. 3;

FIG. 10 is a block diagram showing the tape streamer of FIG. 3;

FIG. 11 is a chart for explaining user data.

FIG. 12 is a chart showing data for specifying a bad spot.

FIG. 13 is a schematic diagram used for describing a recovery process.

FIG. 14 is a flowchart illustrating a bad spot detection processing procedure.

FIG. 15 is a chart used for explaining bad spot detection when a bad spot portion cannot be reproduced correctly.

FIG. 16 is a chart used for explaining bad spot detection when a track set following a part of a bad spot cannot be correctly reproduced.

FIG. 17 is a chart used for explaining the detection of a bad spot when only a data area cannot be correctly reproduced.

FIG. 18 is a chart used for explaining bad spot detection when errors occur frequently except for a bad spot portion.

FIG. 19 is a table used for explaining the detection of bad spots when an error occurs frequently including a bad spot portion.

FIG. 20 is a flowchart illustrating a bad spot detection processing procedure according to the second embodiment.

FIG. 21 is a chart used for explaining bad spot detection when all track sets have been correctly reproduced according to the processing procedure of FIG. 20;

FIG. 22 is a chart used for explaining the detection of a bad spot when a bad spot cannot be correctly reproduced according to the processing procedure of FIG. 20;

FIG. 23 is a table used for explaining the detection of bad spots when a part of a bad spot and a subsequent track set cannot be correctly reproduced according to the processing procedure of FIG. 20;

FIG. 24 is a chart used for explaining bad spot detection when only the data area cannot be correctly reproduced according to the processing procedure of FIG. 20;

FIG. 25 is a chart used to describe the detection of bad spots when errors occur frequently including the bad spots in the processing procedure of FIG. 20;

FIG. 26 is a chart used for explaining bad spot detection when only the last track set of each bank has been correctly reproduced except for the bad spot portion according to the processing procedure of FIG. 20;

FIG. 27 is a chart used for explaining bad spot detection when all track sets have been correctly reproduced by the process according to the third embodiment.

FIG. 28 is a chart used for explaining bad spot detection when a bad spot portion cannot be correctly reproduced by the process according to the third embodiment.

FIG. 29 is a chart used to describe the detection of a bad spot when a track set following a part of the bad spot cannot be correctly reproduced by the process according to the third embodiment.

FIG. 30 is a chart used for explaining bad spot detection when only the data area cannot be correctly reproduced by the process according to the third embodiment.

FIG. 31 is a chart used for describing detection of a bad spot when an error including a bad spot frequently occurs in the processing according to the third embodiment.

FIG. 32 is a chart used for describing bad spot detection when only a track set in the middle of each bank can be correctly reproduced by the processing according to the third embodiment.

FIG. 33 is a chart used for explaining detection of a bad spot by a conventional process.

FIG. 34 is a chart used for explaining detection of a bad spot when a bad spot portion cannot be correctly reproduced by a conventional process.

FIG. 35 is a chart used to describe detection of a bad spot when a track set following a part of the bad spot cannot be correctly reproduced by a conventional process.

FIG. 36 is a table used for explaining bad spot detection in a case where only a data area cannot be correctly reproduced by conventional processing.

[Description of Signs] 1 ... Backup system, 3 ... Tape streamer, 5 ... CPU unit, 6 ... Transport mechanism, 8 ... Host computer, 10 ... Magnetic tape, 23 ... Main CPU unit, 24 ... ... backup memory, 25 ... E
CC encoder, 26 ECC decoder

Claims (14)

[Claims] 1. A magnetic recording / reproducing apparatus for recording desired data by sequentially forming tracks diagonally on a magnetic tape, by a read-after-write process, in units of recording units of a predetermined number of tracks or a number of track sets. A retry process is executed, and an area that cannot be correctly reproduced is set as a bad spot. In any of the tracks or the track sets, data of the bad spot that can specify the bad spot is at least a track related to the retry. Alternatively, a magnetic recording / reproducing apparatus for recording on a track set. 2. The magnetic recording / reproducing apparatus according to claim 1, wherein data of said bad spot is recorded by adding an error correction code. 3. The magnetic recording / reproducing apparatus according to claim 1, wherein the position information of the bad spot is recorded and held in a predetermined area. 4. The data of the bad spot includes data of the number of bad spots specifying the number of tracks or the number of track sets of the bad spot immediately before the recording unit related to the retry, and the number of tracks or the number of track sets of the recording unit. The magnetic recording / reproducing apparatus according to claim 1, wherein the data is data for specifying a track position or a track set position in the recording unit. 5. The data of the bad spot includes data of the number of bad spots specifying the number of tracks or the number of track sets of the bad spot immediately before the recording unit related to the retry, and the position or track set of the track in the recording unit. 2. The magnetic recording / reproducing apparatus according to claim 1, wherein the data specifies a position of the magnetic recording / reproducing apparatus. 6. The data of the bad spot includes data of the number of bad spots specifying the number of tracks or the number of track sets of the bad spot immediately before the recording unit related to the retry, and the position or track set of the track in the recording unit. 2. The magnetic recording / reproducing apparatus according to claim 1, wherein the magnetic recording / reproducing apparatus is data for specifying a position of the recording unit and data indicating continuity of the recording unit. 7. A magnetic recording / reproducing apparatus for reproducing desired data from tracks sequentially formed diagonally on a magnetic tape, wherein the magnetic tape is recorded by a predetermined number of tracks or track sets by read-after-write processing. The retry process is performed in units, and the area that could not be correctly reproduced is set as a bad spot. In any of the tracks or track sets, the data of the bad spot that can specify the bad spot is The magnetic recording / reproducing device is recorded at least on the track or the track set related to the retry, and when the data can be correctly reproduced from the track or the track set, the track or the track set is provisionally set in the data area, Bads data from the bad spot data A magnetic recording / reproducing apparatus comprising: specifying a track or a track set of a pot; and setting, by the provisional setting and / or the specification, a temporarily set track or track set related to a previous recording unit in a data area. 8. The data of the bad spot, the data of the number of bad spots specifying the number of tracks or the number of track sets of the bad spot immediately before the recording unit related to the retry, and the number of tracks or the number of track sets of the recording unit. And data for specifying a position of a track or a track set in the recording unit. The magnetic recording / reproducing apparatus further includes: a process of temporarily setting the track or the track set in a data area. 8. The data area specifying the number of tracks or the number of track sets of the recording unit, the track or the track set of the recording unit to which the correctly reproduced track or track set belongs is temporarily set in the data area. 3. The magnetic recording and reproducing device according to 1. 9. The data of the bad spot includes data of the number of bad spots specifying the number of tracks or the number of track sets of the bad spot immediately before the recording unit related to the retry, and the position or track set of the track in the recording unit. The magnetic recording / reproducing apparatus, in the process of temporarily setting the track or the track set in the data area, further includes data specifying the track position or the track set position in the recording unit. 8. The method according to claim 7, wherein a track or a track set of a recording unit to which the track or the track set that has been correctly reproduced belongs, and the reproduced track or the track set is temporarily set in the data area. Magnetic recording and reproducing device. 10. The data of the bad spot includes data of the number of bad spots specifying the number of tracks or the number of track sets of the bad spot immediately before the recording unit related to the retry, and the position or track set of the track in the recording unit. And data indicating the continuity of the recording unit. In the process of temporarily setting the track or the track set in the data area, According to the data specifying the position of the track set or the position of the track set, the track or the track set of the recording unit to which the correctly reproduced track or the track set belongs, and the reproduced track or the track set is temporarily set in the data area. , The provisional setting of the previous recording unit In the process of setting a track or a track set in the data area, the data indicating the continuity of the recording unit is used to determine the number of tracks or the number of track sets related to the continuous recording unit. 8. A recording unit to which a track or a track set to be set in an area belongs is set in the data area.
3. The magnetic recording and reproducing device according to claim 1. 11. Desired data is recorded on tracks formed diagonally in sequence, and a retry process is executed by a read-after-write process in units of recording units based on a predetermined number of tracks or a number of track sets. Along with
In a method for detecting a bad spot from a magnetic tape in which an area that cannot be correctly reproduced is set as a bad spot, the magnetic tape may detect the bad spot by any of the tracks or track sets. Specifiable bad spot data is recorded on at least the track or track set related to the retry, and the bad spot detection method is as follows: if data can be correctly reproduced from the track or track set, Alternatively, a track set is provisionally set in the data area, a track or track set of the bad spot is specified from the data of the bad spot, and the track or track set of the provisional setting related to the previous recording unit is specified by the provisional setting and / or the specification. The data area A method for detecting bad spots, wherein 12. The bad spot data includes: data of a bad spot number that specifies the number of tracks or track sets of the bad spot immediately before the recording unit related to the retry; and the number of tracks or the number of track sets of the recording unit. And data for specifying the position of a track or a track set in the recording unit. The method for detecting a bad spot includes the steps of: temporarily setting the track or the track set in a data area; The data or a track set of the recording unit to which the track or the track set that has been correctly reproduced is temporarily set in the data area by data specifying the number of tracks or the number of track sets of the recording unit. How to detect bad spots described in 11 . 13. The data of the bad spot includes data of the number of bad spots that specifies the number of tracks or the number of track sets of the bad spot immediately before the recording unit related to the retry, and the position or track set of the track in the recording unit. The bad spot detection method further comprises: in the process of temporarily setting the track or the track set in the data area, further specifying the track position or the track set position in the recording unit. 12. The data area according to claim 11, wherein a track or a track set of a recording unit to which the track or the track set that has been correctly reproduced belongs, and the reproduced track or the track set is temporarily set in the data area. Bad spot detection method. 14. The data of the bad spot, the data of the number of bad spots for specifying the number of tracks or the number of track sets of the bad spot immediately before the recording unit related to the retry, the position of the track or the track set in the recording unit. And data indicating the continuity of the recording unit. The method for detecting the bad spot, in the process of temporarily setting the track or track set in a data area, According to the data specifying the position of the track or the position of the track set, the track or the track set of the recording unit to which the correctly reproduced track or the track set belongs, and the reproduced track or the track set is provisionally set in the data area. Pertaining to the previous recording unit In the process of setting a temporarily set track or track set in a data area, the number of tracks or the number of track sets related to the continuous recording units is determined based on data indicating the continuity of the recording units, and from the determination result, 2. A recording unit to which a track or a track set set in the data area belongs is set in the data area.
2. The method for detecting a bad spot according to 1.