JP2550139B2 - Magnetic recording device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a magnetic recording device using a magnetic tape,
In particular, the present invention relates to a large-capacity, highly reliable magnetic recording device suitable as a peripheral device for a computer.

[Prior Art] Due to the recent advances in magnetic recording technology, VTR and DAT (Digita
l Audio Tape), the recording and reproducing technology of the helical scan method using the rotary head has been put into practical use, and the recording density has improved, and in combination with digital signal processing technology, magnetic tapes for VTRs and DATs have been developed. The development of computer devices that use them has become active.

In these devices, voice and the like are converted into digital signals and recorded on tape. Therefore, the recorded data can be used by the computer instead of the voice.

Examples of such devices include Japanese Patent Publication No. 60-25826 and Japanese Patent Laid-Open No. 60-171678.

In addition to the tracks recorded by the rotary head, they also have a fixed head for searching because they have a search function for selectively recording and reproducing at any recording location of the magnetic tape required as a peripheral device of a computer. Is used to record control data above and below the track, and this portion is used as search control data.

In this method, since the control data is recorded in a place independent of the data, it can be easily searched.

However, the place where the control data is recorded is near the edge of the magnetic tape, and there is a problem that it is susceptible to dirt and damage.If this control data becomes unreadable, the search function required as a computer device cannot be realized. , Reduce the reliability of the entire system.

Further, in a magnetic tape device, access time is generally long. In the control using the fixed head, when the tape is run at high speed, the control information cannot be read,
High speed access is not possible.

Also, with a system that uses a method that changes the azimuth on adjacent tracks, such as a DAT recorder, especially in a device that slightly overlaps adjacent tracks with a wide head, it is possible to re-record on the previously recorded track. When recorded, the data is overwritten on the adjacent track, and the data cannot be read correctly from this track. Therefore, even if the control data as in the conventional example is used, re-recording cannot be performed for each track. is there.

In addition, the computer and the peripheral devices generally transmit and receive data in units determined by the system. Usually, the size is often 256 to 1024 bytes. However, a magnetic recording device using the azimuth recording method using a rotary head can realize a large capacity because of its high recording density, but the amount of data recorded in one track is large and rewriting for each track is difficult. There is 25
Recording / playback cannot be performed in units of 6 to 1024 bytes.

These have not been considered in the prior art.

[Problems to be Solved by the Invention] The above conventional technology cannot provide an environment satisfying the basic unit of transmission and reception generally required as a peripheral device of a computer.

Also, in order to increase the storage capacity of the magnetic tape, the track intervals are made as narrow as possible. Therefore, the area for recording control data provided above and below each track is also narrowed, and there is a problem that effective data cannot be recorded.

It is an object of the present invention to provide a magnetic recording apparatus using a helical scan type magnetic tape, and particularly a method and a configuration most suitable for using the magnetic recording apparatus using the azimuth recording method as a data recording apparatus of a computer. Especially.

[Means for Solving the Problems] A group which is a unit of recording / reproduction on a magnetic tape is
It consists of multiple tracks and consists of a data area that can be used for recording and reproducing data from an external device, and a test word for detecting and correcting data errors due to dirt or damage to the magnetic tape.

In this case, the unit of data transmission / reception with the external device is 25
It is generally set to an integral multiple of 6 bytes. Therefore, the data area in the group is set to an integer multiple of 256 bytes, and data errors that occur in the running direction of the magnetic tape are detected.
When an efficient inspection word is added for correction, an empty area is created due to the relationship between the number of tracks in the group, the data area, and the inspection word.

This area is used as a system area and is used as an area for storing information necessary for transmitting / receiving data to / from an external device, and a group, which is a unit of recording / reproducing on / from a magnetic tape, is required as a peripheral device of a computer. It can be incorporated into the operating system of various computers by controlling the physical units.

[Operation] The group recorded on the magnetic tape is once read into the buffer memory. At this time, the check word added at the time of recording is used to check an error in the read data and correct the error, and is not stored in the buffer memory.

A data area and a system area are stored in the buffer memory. The magnetic recording device analyzes the data in the system area in the buffer memory and responds to the instruction from the external device in the unit of data transmission / reception with the external device indicated by the data.

At the time of recording, the data sent from the external device is temporarily stored in the data area of the buffer memory, the system data defined by the magnetic recording device is stored in the system area, and the inspection word is added at the same time as the system area. To record.

Therefore, since error correction is performed not only on the data but also on the system area, no malfunction occurs.

In addition, the data to be stored in the lead-in area for managing the logical blocks assigned to the group is increased in reliability by multiple recording in multiple groups,
Since there are no data errors even during repeated recording and playback,
There is no malfunction.

[Examples] Examples of the present invention will be described below.

FIG. 1 shows the first embodiment, and FIG. 2 shows an overall block diagram of the magnetic recording apparatus of this embodiment.

FIG. 1 is a detailed block diagram of the system control circuit in FIG.

The system control circuit 26 includes a microcomputer 1, a system control unit 2, a system area management unit 3, a group ID analysis unit 4, a generation unit 5, a block ID list analysis unit 6, a generation unit 7, a lead-in area management unit 8, and a tape. ID analysis generator 9
Composed of.

The magnetic recording apparatus according to the present invention comprises a cylinder 10 shown in FIG.
Read head 11, write head 12, read / write circuit 1
3, verify circuit 14, servo circuit 15, cylinder motor 1
6, capstan motor 17, reel motor 18, DAT signal processing circuit 19, sub-code control circuit 20, drive control circuit 2
1, DAT code decoding circuit 22, memory control circuit 23, layered ECC (ERROR CORRECTION CODE) circuit 24, memory
25, system control circuit 26, SCSI (SMALL COMPUTER SYSTE
M INTERFACE) 27 and mechanical drive circuit 28.

The magnetic recording apparatus of the present invention is based on the recording format of a DAT recorder, uses a head that rotates together with the cylinder 10 mounted on the circumference of the cylinder 10 like a VTR, and uses a magnetic tape as shown in FIG. A track having a width of 13.6 μm as shown in the figure is formed obliquely to the running direction of the magnetic tape.
In the present invention, the azimuth recording method is used, and recording is performed so that adjacent tracks have different azimuth angles.

Further, the head is formed with a width of 20 μm, which is slightly wider than the track width, and the write head 12 at the time of recording records while overlapping tracks with different azimuths.

In order to use as a data recording device by connecting to a computer, a search function at an arbitrary place, a recording function at an arbitrary place, and a reproduction function at an arbitrary place are required. However, in the case of recording a track, when a track is rewritten in order to record the track by overlapping with different azimuths, the adjacent track is deleted, and the data of the deleted track cannot be correctly reproduced.

Therefore, FIG. 4 shows a group format which is a basic unit of recording / reproducing for collectively recording / reproducing on / from a magnetic tape.

A group is composed of 32 frames (meaning 64 tracks because 2 tracks are called 1 frame), and the first 3 frames and the last 1 frame are gaps between groups. Therefore, 28 frames from the 3rd frame to the 30th frame are set as the data recording area.

Figure 5 shows the DAT track format standardized at the DAT conference. The track is divided into 16 areas, and each area is defined as shown in the figure. The PCM area in the figure is an area for recording data. Information for high-speed search is recorded in the subcode area. ATF (Automatic
In the Track Finding area, a signal for servoing is recorded so that the rotary head can trace the track correctly.

Further, two heads of + azimuth and −azimuth alternately trace the track. Each head reads the ATF area of the track recorded in azimuth that matches its own azimuth, applies servo, and reads the PCM area and subcode area.

FIG. 6 shows the subcode format of this embodiment.
In the subcode area in the track, a 2-byte sub ID and
16 DAT blocks consisting of 32 symbols of data
Included. Two DAT blocks compose one pack data.

An address is assigned to each DAT block, and 32 symbols of even addresses and 32 symbols of odd addresses, that is, 64 symbols in total, form one pack data. The pack data is composed of eight packs from pack 1 to pack 8, and each pack is composed of eight 8-bit data.

Each pack is from PC1 to P, as shown in Fig. 6 (b).
It consists of C8, and the upper 4 bits of PC1 are "1" as an item
110 ", the upper 8 bits of the group number to which this track belongs to PC2, the lower 8 bits of the group number to PC3, and the gap flag set when bit 7 of PC4 indicates that this frame is a gap (GAPF), PC
The lower 5 bits of 4 are the frame number in the group, the format count is reserved in PC5, PC6 is reserved for future expansion, and the error detection vertical parity defined by the following equation is recorded in PC7.

Bit 7 of PC7 = Parity of PC1 Bit 1 of PC7 = Parity of PC2 Bit 2 of PC7 = Parity of PC3 Bit 3 of PC7 = Parity of PC4 Bit 4 of PC7 = Parity of PC5 Bit 5 of = PC6 Parity of PC7 Bit 6 = 0 PC7 bit 7 = 0 PC8 is a parity for detecting an error of PC1 to PC7 defined by the following equation.

PC8 = PC1 + PC2 + PC3 + PC4 + PC5 + PC6 + PC7 However, + is the exclusive OR (mod2).

The pack 8 is an error detection parity for the packs 1 to 7, and is C1 parity defined by the DAT standard.

There are eight packs, but in the case of high-speed search, the same data are all recorded to improve the detection probability of this subcode.

[Group Format] The group format of the present invention shown in FIG.
FIG. 7 shows a block layout for enabling access by a logical block from an external device connected to
The system area format is shown in FIG.

In this embodiment, a logical block format is shown as a device that can be directly accessed among SCSI devices.

Of the group consisting of 32 frames, the remaining 28 frames excluding the first 3 frames and the last 1 frame as a gap are used as a data recording area.

The data that can be recorded on one track is 2880 bytes according to the DAT track format. Therefore, 28 frames have 161280 bytes.

However, an integer multiple of 256 bytes is usually used as a logical block of a computer. So 28
Of the frame data, 131072 bytes (256 x 512 bytes) is the data area that can be used by the user.

Of the remaining 30208 bytes, 4736 bytes are used as the system area used by the device itself, and 25464 bytes are used as the parity for error correction using the Reed-Solomon code. The remaining 8 bytes are unused. This parity is
In order to correct the data error along the running direction of the magnetic tape, it is added to the data in both the data area and the system area, and it is continuous with the error correction by the double-encoded Reed-Solomon code used in the DAT track. Data can be corrected even if a track burst error occurs.

[Operation] The recording / reproducing method and the high-speed search method will be described below.

This embodiment is a magnetic recording device that realizes random access by randomly selecting and selecting a block from among the types of devices connected to a computer, and supports a command system of a SCSI random access device. .

In FIG. 2, the magnetic tape (not shown) is loaded on the cylinder 10 by a tape loading mechanism (not shown).
It is wrapped 90 degrees.

The microcomputer 1 in the system control circuit 26 is
Whether or not the magnetic tape is loaded in the apparatus is checked by a detection circuit (not shown), and waits until it is loaded.

When detecting that the magnetic tape is loaded, the microcomputer 1 drives the tape loading mechanism (not shown) by the mechanical drive circuit 28 to wind the magnetic tape around the cylinder 10. The magnetic tape is loaded or loaded, the micro-computer 1 instructs the drive control circuit 21 to "rewind mode", and the drive control circuit 21 sets the servo circuit 15 to the rewind mode. The servo circuit 15 drives the reel motor 18 to rewind the magnetic tape. The drive control circuit 21 detects the transparent tape portion (leader tape) of the magnetic tape and notifies the drive control circuit 21 that the tape has been rewound. Therefore, the drive control circuit 21 drives the servo circuit 15 to set the stop mode. The microcomputer 1 reads the lead-in area via the lead-in area management unit 8 in order to know how the magnetic tape loaded by the tape ID analysis / generation unit 9 is used.

The lead-in area is composed of 12 groups, and a tape ID as shown in FIG. 9 is recorded when the tape is first used. This ID uses the data area of one group, and the same value is recorded in all 12 groups in the lead-in area.

The tape ID [(E) in the figure] and the block number list [(F) in the figure] are recorded in the data area in each group of the lead-in area. In the first byte of the tape ID, a code (format code) indicating in what format this tape is used is recorded.

 The format of this embodiment is code "01".

At the 3rd byte, a code indicating the length of the tape in use is recorded. The values are as follows.

Tape length: 00 Unknown tape length 01 60m tape 02 40m tape 03 30m tape 03 20m tape A code indicating the access type of the tape is recorded in the second byte. The value should be:

Access type: 01 Direct access The total number of groups recorded on the tape is recorded at the 4th and 5th bytes. This data is used up to the middle of the tape, and is set to "0" when the number of groups in the entire tape is unknown.

When the tape is used up to the middle of the tape, EOI (End Of Information) is recorded at the 6th and 7th bytes, and the group number indicating that valid data is not recorded after this is recorded.

From the 9th byte to the 24th byte, the volume name indicating the contents of this tape is recorded at the user's request.

In the 25th to 36th bytes, record the date when this tape was formatted.

The recorded content consists of 4 bytes of the year, 2 bytes of the month, 2 bytes of the day, 2 bytes of the hour, and 2 bytes of the minute.

In the 37th to 48th bytes, record the date when the tape was last taken out from the device in a similar format.

The 49th to 51st bytes are the program name that formatted the tape, and the 52nd to 59th bytes are
The version of the program is recorded.

The microcomputer 1 reads the tape ID from the lead-in area by the lead-in area management unit 8 and analyzes it by the tape ID analysis / generation unit 9, but when data is not recorded on the new tape, a new one is sent via the SCSI 27. Tell the external device that it is a tape. When the magnetic recording device of the present invention is connected to the host computer as an external device, this information is created in the extended sense data by setting the check condition bit of the status of SCSI27, and the host computer can generate this extended sense data. Sent to the host computer when a command to read is issued.

The host computer, which is found to be a new tape, notifies the user of that fact and, when the tape is formatted at the user's request, sends a format command to the magnetic recording device via the SCSI 27. A parameter corresponding to the tape ID is also transmitted with this command.

The microcomputer 1 of the magnetic recording apparatus of the present embodiment, which receives this format command, detects that the magnetic tape is BO
After confirming that it is in the T (Begin Of Tape) position, record the group format described above on the tape.

After receiving the format command, the microcomputer 1 instructs the drive control circuit 21 to the “recording mode”. The drive control circuit 21 sets the servo circuit 15 to the reproduction mode, and the cylinder motor 16 drives the cylinder 10 to 2000 rp.
Rotate at a constant speed at m. At the same time, the tape is driven at a constant speed by the capstan motor 17 and the reel motor 18, and the cylinder 10
Becomes constant speed, and the microcomputer 1 executes group recording at the timing shown in FIG.

The data input to the DAT code decoding circuit 22 is input to the DAT signal processing circuit 19 as recording data [(D) in the figure]. The microcomputer 1 sends the subcode data to the subcode control circuit 20 in advance. DAT signal processing circuit 1
9 is a read / write circuit from time T2 after 8-10 conversion of the subcode data [(C) in the figure] of the frame number 0 input at time T1 and the recording data already input.
Record to +13 azimuth and −3 azimuth from time T3 [(A) in the figure]. The read head 11 immediately reads the signal recorded by the write head 12 [(B) in the figure] and performs verification.

The microcomputer 1 stores the format data in the memory 25. First, the data in the lead-in area is stored, but the parameters received by the tape ID analysis / generation unit 9 as parameters are stored in the memory 25 according to the format. The total number of groups, tape length, and EOI group number, which are unknown at this point, are all 0. The date when the tape was finally taken out from the device is also set to 0 at this point. Also, the block ID list generation unit 7 clears the block ID list to 0 and initializes it. Since the system area is not used in the lead-in area, this area is set to 0.

The microcomputer 1 sends the subcode data in the lead-in area to the subcode control circuit 20. The lead-in area management unit 8 starts the group number from -12, increments by 1 and records the same data with 12 groups up to -1 as the lead-in area. After recording 12 groups as the lead-in area, the groups are recorded in order from the group number 0 as a data group usable by the user.

The microcomputer 1 sets 0 in the data area at the time of formatting, and the system area management unit 3 sets the group
The group ID is set in the system area by the ID generation unit 5. At this time, the head block number and the number of blocks of each group are obtained from the block length specified by the format parameter and recorded. If the block length is 512 bytes, the number of blocks in the group is 256. Also block I
The D-list generating unit 7 creates a list in the system area using each block as normal data.

For the group ID addresses 0 to 2, the numbers from the beginning of the tape of the first block belonging to the group are set. A code indicating the size of the block in the group is set in the address 3. The addresses 4 and 5 are set to the number of blocks in the group. Now, with a format command from the host computer, set the logical block length to 512.
If it is instructed to use bytes, the number 0 is assigned to the first group of the data group following the lead-in area, and the addresses 0 to 2 of the system area are assigned with the number 0.
Set “0”. A code "01" indicating 512 bytes is set to the address 3, and "256" is set to the addresses 4 and 5 as the number of blocks in the group.

At the time of formatting, all the data areas are set to 0, and parity is added to the data area and the system area using the layered ECC circuit 24 and stored in the memory 25.
The memory control circuit 23 transmits this data to the DAT code decoding circuit 22, adds the error correction parity defined in the DAT track, and outputs it to the DAT signal processing circuit 19 as serial data. Upon receiving this data, the DAT signal processing circuit 19 performs 8-10 conversion of the data in accordance with the data format in the track, inputs the data to the verify circuit 14, and at the same time, writes it to the tape with the write head 12 via the read / write circuit 13. Record the signal.

Since the frame numbers 0 to 2 and 31 recorded in the subcode are gap frames, GAPF shown in FIG. 6 is set.

At this time, the read head 11 reads the data recorded by the write head 12 and inputs it to the verify circuit 14 via the DAT signal processing circuit 19. The verify circuit 14 compares the recorded signal with the read signal to check whether they match. The number of unmatched signals for each track is transmitted to the microcomputer 1. Microcomputer 1
Calculates the number of unmatched signals for one group and determines whether the error correction is possible. A threshold that can be set by the user is used for this determination, and if the signals do not match within N% of the error correction capability, it is determined that the signal was correctly recorded and the processing is continued.

 The value of N is set to 50 by default.

If a signal mismatch above this threshold is detected, this group is not recorded correctly and is not used anymore, instead the same group is recorded next. Therefore, when the same group number is continuously read, the group read first is skipped as an invalid group.

In the next glue, the number is incremented by 1 and since there are 256 blocks in group 0 at addresses 0 to 2 in the system area, the number "256" of the first block in group 1 is set. When the head block number of each group is confirmed, this block number is registered in the corresponding location of the block ID list. Same as group 0 for address 3 "01"
The number of blocks in the group is "256" at addresses 4 and 5.
Set, and record on the tape in the same way.

Hereafter, the same processing is sequentially performed at the end of tape EOT (E
nd Of Tape) and lead-in area management section 8
Stores the last group number for recording in the lead-in area.

FIG. 11 shows the tape format in this embodiment.

When the formatting up to EOT is completed, the microcomputer 1 instructs the drive control circuit 21 to "stop mode", and the drive control circuit 21 sets the servo circuit 15 to the stop mode to stop the tape. After that, the microcomputer 1 instructs the drive control circuit 21 to "rewind mode" and sets the servo circuit 15 to the rewind mode. As a result, the pinch roller (not shown) is released from the capstan, and the reel motor rewinds the tape.

When the microcomputer 1 is notified by the system control unit 2 and the drive control circuit 21 that the BOT has been detected, the microcomputer 1 once instructs the drive control circuit 21 to enter the “stop mode” and causes the servo circuit 15 to stop the reel motor 18. afterwards,
In order to update the tape ID and block list of the lead-in area, the drive control circuit 21 via the system control unit 2
Instruct the “after-recording mode”. This mode is used when updating the data area, system area and parity in each group. In this mode, the subcode area is not updated and only the PCM area in the track is rewritten. The signal read by the read head 11 is read out by the DAT signal processing circuit 19 via the read / write circuit 13, and the subcode is taken out and sent to the subcode control circuit 20. Here, the subcode is inspected. This data is sent to the microcomputer 1
Is received and analyzed to detect the frame number of the group to start recording, and activates the DAT code decoding circuit 22. The correction parity is added by the layered ECC circuit 24 in the same manner as when recording the data, and the data for the lead-in area sent to the DAT code decoding circuit 22 by the memory control circuit 23, while applying servo to the read head 11, When the target track is being traced by the write head 12 in "read mode", the subcode area and ATF area are read and then switched to "write mode".
Read and write data sent to the AT signal processing circuit 19
Record through 13.

By repeating this, the tape ID and the block ID list are recorded in the lead-in area.

With respect to the format, the processing is completed as described above, and thereafter, recording and reproduction can be performed with a logical block address.

Now, consider the case where the host computer issues a command to read the logical block with block number n + 1 in FIG. The host computer sends to the microcomputer 1 a command to read the block of logical block number n + 1 via SCSI. Prior to sending the command, the host computer checks if the SCSI27 bus is being used by another device, and if not, obtains the usage right. Next, the ID given to the magnetic recording apparatus of the present invention is sent to the bus. When the microcomputer 1 inspects the bus and detects that the same data as the ID given to itself is output to the bus, the microcomputer 1 receives a command from the host computer.

Upon receiving the command, the microcomputer 1 instructs the drive control circuit 21 to perform the "playback mode", and the servo circuit
Cylinder motor 16, capstan motor 17, through 15
Each of the reel motors 18 is driven. The signal read by the read head 11 is selected by the DAT signal processing circuit 19, and the subcode data is transmitted to the subcode control circuit 20. After performing an error check here, this data is transmitted to the microcomputer 1, Read the group number on the tape. The corresponding start block number in the block ID list is extracted and compared with the target block number. If the target block number n + 1 is large, "search" is performed in the direction in which the group number increases, and if it is small, the "search" is performed in the direction in which the group number decreases.

The target block number n + 1 is larger than the first block number n of the group N in the block ID list.
Since it is smaller than the first block number m of 1, the group N is "searched".

While the "search" is being executed, the host computer waits for data, so the SCSI 27 is dedicated. Therefore, during this time, the device connected to the other SCSI 27 cannot use the bus, which lowers the bus usage efficiency. To avoid this, the microcomputer 1 sends a save pointer message and a disconnect message instructing the host computer to disconnect the SCSI27 bus before executing the "search". When the host computer receives this message, it stores the memory address where the data to be read next is stored in the specified memory, and once the SCSI address is reached.
27 Stop using the bus. On the other hand, the microcomputer 1 once relinquishes the right to use the SCSI27 bus after sending this message. Therefore, in this state, the bus is unused and other devices can use the bus.

In this way, "search" with the bus disconnected once
To execute.

"Search" runs the tape at 200 times the recording / reproducing speed, and controls the rotation speed of the cylinder 10 so that the relative speed of the tape and the head becomes the same as the normal recording / reproducing speed.
Read the contents of the subcode to detect the desired group.

When the search direction is determined, the microcomputer 1 informs the servo circuit 15 via the drive control circuit 21 whether the search is a forward search or a reverse search. Servo circuit
15 drives a reel motor 18 to run the tape 200 times in the designated direction. The servo circuit 15 controls the sum of the reel pulses taken from the reel on the supply side and the reel on the winding side of the tape to be a constant value. At the same time, if the rotation of cylinder 10 is forward searched, 3000 rp
m, control to 1000 rpm for reverse search. At this time, the head will cross a plurality of tracks. With the azimuth of the head, the signal of the track of the same azimuth gives a large output, and the signal of the track of a different azimuth gives a small output, so the number of crossed tracks can be known by counting the number of large output signals. You can Therefore, the reel motor 18 is controlled so that this number becomes constant.

In this state, the signal output from the head is a part of the track, and whether or not two DAT blocks in the subcode provided in the track can be read consecutively without error is determined by the DAT signal processing circuit 19 and the subcode. The control circuit 20 detects. When correctly detected, this subcode is sent to the microcomputer 1 and the group number included in the subcode is compared with the target group number N.
If they match, the microcomputer 1 instructs the servo circuit 15 to enter the "stop mode" via the drive control circuit 21,
Once the reel motor 18 is stopped, the cylinder 10 is
After returning to 00 rpm, the reel motor 18 is used to move the tape to a position where the first track of the group number N can be reproduced while inspecting the group number in the subcode. After that, the drive control circuit 21 and the servo circuit 15 are set to the "reproduction mode", the read signal is processed by the DAT signal processing circuit 19, the subcode is sent to the subcode control circuit 20, and the data is the DAT code decoding circuit. Send to 22. The subcode control circuit 20 analyzes the subcode and sets the frame number 3
To activate the DAT code decoding circuit 22. DAT code decoding circuit
22 starts operation by a signal from the subcode control circuit 20, decodes the received signal in the reproduction mode, and stores the data for each track in the memory via the memory control circuit 23. When the data of up to 30 frames is stored in the memory, the microcomputer 1 uses the layered ECC circuit 24 in the memory control circuit 23 to perform error correction.

At this time, the subcode control circuit 20 inspects the subcode of the next group to see if it is N + 1 next to the previously read group N or remains N. If the group number is N, the group read first is a defective group as a defective group at the time of formatting, so the data is invalidated and the data of the next succeeding group is similarly read. If the group number is N + 1, the processing is continued as it is.

The result of error correction is stored again in the memory 25, and the system area management unit 3 retrieves the first block number n in the group via the group ID analysis unit 4 and calculates the addresses up to the target block number n. . The microcomputer 1 performs reselection with the host computer in order to acquire the right to use the SCSI27 bus which was temporarily abandoned at this point. As a result, when the SCSI27 bus is connected, the contents of the target block n are taken out from the data area and the data is sent to the host computer via the SCSI27. At this time, if the data has been read correctly, a good condition is set in the status and sent to the host computer, and the read command is ended with a command complete message. If an error has occurred, a check condition flag is set in the status and sent, a code indicating the cause of the error is stored in the sense status, and this data is sent in response to a request from the host computer.

A method of recording data in the logical block number n will be described.

The host computer secures the right to use the bus and selects the magnetic recording device as in the case of reading in order to send a data write command to the magnetic recording device of the present invention via the SCSI 27. When the magnetic recording device of the present invention is selected, a write command is sent.

Upon receiving the write command, the microcomputer 1 of the present embodiment searches the group to which the logical block to be recorded belongs, so that the SCSI 27 is used in the same manner as in the case of reading.
A disconnect message is sent to the host computer via the to disconnect the bus. Next, the drive control circuit 21,
The "reproduction mode" is instructed to the servo circuit 15, and the group N to which the block number n belongs is read by the same method as described above.

After reading the data of group N into the memory 25, the microcomputer 1 executes reselection to read the data to be recorded from the host computer,
Send a reconnect message. Receiving this, the host computer reconnects the SCSI27 bus and sends the data to the SC.
Send to SI27. The microcomputer 1 receives this data and stores it from the address of the memory 25 corresponding to the block number n of the data of the group N read.
After receiving the specified data, during data transfer
It checks whether or not a parity error has occurred on the SCSI27 bus, returns a good status if the transfer is correctly performed, sends a command complete message, and ends the write command. If a parity error has occurred, set a check condition in the status and set the error content in the sense data. Of course, when a sense status command is received from the host computer, this data is sent out to notify the contents of the error.

At this time, the data is not actually recorded on the tape yet. This is because it takes a lot of time to read the data of the same group from the tape again when a command to access the same group is issued, so to minimize this overhead,
Only when access to a different group is instructed, the data in the memory 25 is recorded in the read group,
After that, control is performed to access the designated group. The data is recorded in the same manner as the recording described in the description of the format. However,
The data is different.

As described above, according to this embodiment, since it is possible to access in the logical block set by the user, there is an effect that connection with various computers can be facilitated. Further, since a high-speed search by group number can be realized, a large-capacity file can be searched at high speed.

Embodiment 2 FIG. 12 shows a second embodiment of the present invention.

The overall block diagram of the magnetic recording apparatus of the present invention is the same as FIG. FIG. 12 shows the system control circuit 26 in FIG.
3 is a detailed block diagram of FIG.

The system control circuit 26 includes a microcomputer 1, a system control unit 2, a system area management unit 3, a group ID analysis unit 4, a generation unit 5, a block ID list analysis unit 6, a generation unit 7, a lead-in area management unit 8, and a tape. It is composed of an ID analysis generation unit 9, a subcode management unit 30, and a block number analysis generation unit 31.

This embodiment uses the same group format shown in FIG. 4 as that of the first embodiment, and supports the command of the device which randomly accesses the logical block among the data recording devices of the computer.

FIG. 13 shows the subcode format of this embodiment.
Four of the 16 DAT blocks assigned as subcodes are used as one unit, and the first two blocks have the same data as in the first embodiment. The blocks in which the lower 2 bits of the address of the next DAT block are “10” and “11” are the data having the item “1101” in PC11 as shown in FIG. Stores the number of the first block in the group from the beginning of the tape. Therefore, the block numbers of the same number are stored in the subcodes of the frames belonging to a certain group.

FIG. 14 shows an explanatory diagram of the tape format of this embodiment.

The same group ID and block ID list as in the first embodiment are stored in the system area in the group. Furthermore, the first
The format of the tape ID in the lead-in area shown in the above embodiment is also the same. However, the format code is "02", and there is no block number list of the lead-in area provided in the first embodiment.

The operation of each circuit and each part in response to commands such as read, write and format from the host computer is almost the same as that of the first embodiment.

However, in the present invention, the logical block number designated by the host computer is used as the "search" information.

For example, the logical block number designated by the host computer for access is n + 1.

It is the same as the first embodiment until the microcomputer 1 receives the command and disconnects the SCSI 27 bus to search the designated block. When performing the search, the microcomputer 1 performs the 200 times search using the drive control circuit 21 and the servo circuit 15 as in the first embodiment. In this embodiment, the block number analysis / generation unit 31 analyzes the subcode sent to the subcode control circuit 20 via the DAT signal processing circuit 19 during the search. When the target block number is n + 1, the block number "q" is recorded in the subcode of group N-1. In addition, the block number “n” is assigned to the group N and the group N + 1.
The block number of "m" is recorded in. In the "search", since the head crosses a plurality of tracks, the subcode data is discretely read. Therefore, the microcomputer 1 compares the block number in the read sub-code with the target block number, and when the read block number is larger than the target block number in the case of forward search, the target block number in the case of reverse search. Drive control circuit 2 when smaller
1. Instruct "stop mode" to the servo circuit 15.

After this, the subcode is inspected in detail for each track as the "playback mode" via the drive control circuit 21 and the servo circuit 15, and the group immediately preceding the group that first exceeded the target block number, in this example, Lead group N.

By the command sent from the host computer,
A read or write operation is performed, but this method is the same as in the first embodiment.

As described above, according to the present embodiment, it is possible to perform a search with a logical block number designated by the host computer, and it is possible to perform a correct search even if a part of the tape cannot be read correctly.

Embodiment 3 FIG. 15 shows a third embodiment of the present invention.

The overall block diagram of the magnetic recording apparatus of the present invention is the same as FIG.

In the present embodiment, among the devices connected to the SCSI 27, commands as a device for performing sequential access are supported as in a general magnetic tape device.

In this embodiment, a microcomputer 1, a system controller 2, a system area manager 3, a group ID analyzer 4, a generator 5, a block ID list analyzer 6, a generator 7, a lead-in area manager 8, a tape ID analyzer. It is composed of a generation unit 9 and a file mark analysis generation unit 40.

The track format and group format are the same as those in the first and second embodiments.

FIG. 16 shows the format of the system area of this embodiment. Addresses 0 to 5 of the group ID store the same values as in the first and second embodiments. Therefore, the data area in the group is divided and managed in the same blocks as in the first and second embodiments.

In this embodiment, the numbers of the file marks belonging to this group are stored in the addresses 6 to 8. A file mark is data indicating a file and a file delimiter of data on a tape, and a device for performing a sequential access is basically controlled by this mark. Addresses 9 and 10 store the number of file marks in the group.

Also, create a block ID list from the system area address 200 (hexadecimal) and place it in the location corresponding to each block.
The block ID shown in (C) is stored.

This block ID indicates the type of each divided block, and stores the control code of the upper 4 bits of the 0th byte of the block ID as shown in the figure.

The control code “0000” indicates that the block is a normal user data block. "0001" and "0010" can be set and used by the user via the host computer as special data and control data, respectively. Next, "0011" is used as a file mark to indicate that the block corresponding to this position is not a data block but a block indicating a file delimiter. The data in the block are all "0".

The subcode format of this embodiment is the same as that of the first embodiment.

The format of the lead-in area of this embodiment is shown in FIG. The tape ID and block number list are the same as in the first embodiment.

In the tape ID, "03" is recorded in the format code of address 0, and the access type of address 1 is recorded in code "02" indicating sequential access.

The file mark list consists of addresses 4100 (hexadecimal) to 80FF (16 hexadecimal) of the data area of the group in the lead-in area.
It is created by the file mark analysis generation unit 40.
This list stores the number of blocks allocated as file marks in the blocks in each group.

In the present embodiment, since the sequential access is supported, it is possible to use the magnetic tape in order from the beginning without formatting the magnetic tape in advance.

When a new tape is loaded by the mechanical loading circuit 29 by a tape loading mechanism (not shown), the microcomputer 1 causes the tape ID analysis / generation unit 9, the block ID list analysis unit 6, and the generation unit 7 via the lead-in area management unit 8. The group data of the lead-in area is generated by. After that, the drive control circuit 21 and the servo circuit 15 are set to the "recording mode" to record the lead-in area. Addition of code by layered ECC circuit 24, creation of track data by DAT code decoding circuit 22, D
The recording / reproducing of the group via the AT signal processing circuit 19 has been described in the first and second embodiments. At this time, if the host computer does not instruct to record the data, the contents of the block number list and the file mark list are all recorded as 0. When the recording in the lead-in area is completed, the drive control circuit 21 and the subcode control circuit 20 are once instructed to enter the "stop mode", and the command from the host computer is awaited.

When the user requests writing of data, the host computer issues a write command to the magnetic recording device. Similar to the first and second embodiments, the magnetic recording apparatus of this embodiment is selected according to the SCSI protocol, and the write command and data are sent out via the SCSI 27.

Upon receiving the write command from the host computer, the microcomputer 1 temporarily stores the data in the memory 25. When this data reaches or exceeds 128 Kbytes of data for one group, the system area management unit 3 sets necessary data in the system area.

The host computer sends and receives data in logical block units. After recording one file,
The host computer issues a write file mark command. This indicates a file-to-file delimiter. Normally, recording of a file ends with this write file mark command. Upon receiving this command, the microcomputer 1 records the file mark code “0011” in the control code of the corresponding block by the block ID list generation unit 7. Also, the lead-in area management unit 8 stores the number of the first file mark in the group at the position of the corresponding group in the file mark list. After this, if recording of the next file is instructed, this continuation is executed.

When the data that does not satisfy the group is still stored in the memory 25, the host computer issues a command to record the data in the memory on the tape and ends the process. This prevents the error in which the data remaining in the memory 25 is not recorded on the tape because the processing ends while the data remains in the memory.

Therefore, the microcomputer 1 that receives this command blocks as in the recording of the file mark described above.
A file mark code is recorded in the location of the corresponding block by the ID list generation unit 7, and is recorded on the tape even if this group is not filled with data of 128 Kbytes.

When a data write command is issued next to this command, the microcomputer 1 searches the last group recorded by the previous command in the same manner as in the first embodiment, and searches this block. The block ID list analysis unit 6 retrieves the block in which the last file mark code is recorded in the memory 25, and the data is stored after the block. After that, the same recording is performed and the data is sequentially recorded on the tape.

 FIG. 18 shows a tape format diagram of this embodiment.

On the other hand, when reading the data recorded on the tape by a read command from the host computer, a method of reading the data from the file mark from the beginning of the tape to the next file mark is used. First, the host computer issues a command to rewind the tape. Upon receiving this command, the microcomputer 1 controls the reel motor 18 through the drive control circuit 21 to rewind the tape, and when the transparent portion of the leader tape is detected, the operation is stopped. After that, the host computer issues a command to skip n file marks, for example. Upon receipt of this command, the microcomputer 1 searches the file mark list by the lead-in area management unit 8 and takes out what number group the n-th file mark belongs to. For example, if the group N has the nth file mark, the group N is searched. The search method is the same as in the first embodiment. When the group N is read, the block ID list analysis unit 6 searches the block ID list in the system area to find the nth file mark. The microcomputer 1 informs the host computer that it has detected the target file mark, and the host computer instructs to read the data from this file mark.

The microcomputer 1 sends data from the corresponding address in the memory 25 to the host computer via the SCSI 27. If the next file mark exists in the same group, the data up to this file mark is sent. If there is no next file mark in the group,
The next group is read until the file mark is found and the data is sent.

The microcomputer 1, which is instructed to take out the tape from the apparatus by a tape take-out switch (not shown) or a tape take-out command from the host computer, stores valid data after the last group recorded up to now. Indicates no
Record EOI (End Of Information). The EOI records the value of the format count in the subcode data as a value obtained by reducing the format count of the group in which the data is recorded by one. 0 is stored in the other data area and the system area. At the same time, the lead-in area management unit 8 stores the group number in the EOI group number in the tape ID, and stores the final block number in the corresponding address in the tape ID. After this, the tape is rewound and the data in the lead-in area is updated.

As described above, according to the present embodiment, at the same time that the sequential access that has been performed by the conventional magnetic tape device can be realized, the file mark can be searched at high speed, and a large-capacity and high-access magnetic recording device can be realized. is there.

Embodiment 4 FIG. 19 shows a fourth embodiment of the present invention.

The overall block diagram of the present invention is shown in FIG. 2, and FIG. 19 is a detailed block diagram of the system control circuit 26.

The system control circuit 26 includes a microcomputer 1, a system control unit 2, a system area management unit 3, a group ID analysis unit 4, a generation unit 5, a block ID list analysis unit 6, a generation unit 7, a lead-in area management unit 8, and a tape. ID analysis generation unit 9, subcode management unit 30, block number analysis generation unit 31,
The file mark analysis / generation unit 40 is used.

The track format and group format are the same as in the first to third embodiments.

The group ID as the block format is the same as that in the third embodiment.

The present embodiment is a magnetic recording apparatus that realizes sequential access as in the third embodiment, but it is possible to set a variable-length byte unit block for data transmission / reception with a host computer. 3 is different from the third embodiment. . This is the recording method used in the conventional 1/2 inch MT. This embodiment is a method for maintaining compatibility with this method.

An ID indicating the type of block is recorded in the block ID list of each group. A control code is set in the upper 4 bits of the first byte as in the third embodiment. The number of subsequent bytes is set in the lower 4 bits. From the second byte, the corresponding block length in the group is shown. Therefore, the block length is set in byte units, such that 1 byte is 255 bytes or less and 2 bytes is 65535 bytes or less. This block ID is set for each block, and the file mark is set in the control code as in the third embodiment. In this embodiment, the file mark does not assign a block, but merely indicates the position of the file mark.

 FIG. 20 shows the subcode format of this embodiment.

Of the subcode data, the DAT block in which the first bit of the DAT block address is "0" is the same as the subcode in the second embodiment.

In the subcode in which the first bit of the DAT block address is "1", the upper 4-bit item of PC11 is "1101", and PC15 to PC17 indicate the first file mark number in the group, and PC12 to PC14 indicate Set the number of the subset to which the first block in the group belongs. The subset is information for handling a plurality of files as one set, and is numbered sequentially from the beginning of the tape.

Further, when the file mark is stored in the upper 4-bit control code of the first byte of the group ID, the subset number is stored in the second and subsequent bytes, and the number of bytes is stored in the lower 4 bits of the first byte.

Between the host computer and the magnetic recording apparatus of this embodiment, the number of bytes in one block is set in advance.
This is done using the SCSI "modeset" command. It is set when checking what kind of device is connected to SCSI before actually recording and reproducing.

When a tape is loaded in the magnetic recording apparatus of this embodiment, the lead-in area is read and checked to see if the tape is unused or in what format.

If the tape is already used, the format code of the tape ID is "0" indicating the format of this embodiment.
4 "is checked. If they do not match, an error is returned to the host computer. If they match, the first group can be read and the block length can be known.

When the tape loaded in the device is an unused tape and the lead-in area cannot be read, the host computer is informed that the tape is an unused tape, and the block length is set to a predetermined value in the device. In this embodiment, this value is
512 bytes.

In response to a mode set command from the host computer, the tape ID analysis / generation unit 9 causes the format code (“04” in this embodiment) and access type (“0” in this embodiment).
2 ") is set, undetermined data is set to" 0 ", the lead-in area is recorded through the lead-in area management unit 8 as in the third embodiment, and the stop mode is temporarily set.

When a write command for recording data is issued by the host computer, the bus use right of the SCSI 27 is acquired according to the defined protocol as in the third embodiment, and the SCSI 27 is connected to the magnetic recording apparatus of this embodiment. After that, the data is stored in the memory 25, and when it becomes 128 Kbytes or exceeds 128 Kbytes, it is recorded on the tape according to the group format. At this time, the system area management unit 3 creates a group ID and a block ID list as in the third embodiment and records them together with the data area. At the same time, the subcode management unit 30 stores the data in the format shown in FIG.
It is created by the file mark analysis generation unit 40 and recorded via the subcode control circuit 20.

In some cases, the block may extend over the group due to the relationship between the block length and the 128K byte data area of the group. For example, assuming that the number of bytes that can be recorded in the current group is 300, at this time, data that can be recorded within 128 Kbytes is recorded in the current group. In the block ID in the block list for this block, a code “0001” indicating special data is stored as control data, the number of bytes is “0010”, the number of valid bytes is “02” in the second byte,
Store "00" in the 3rd byte. This indicates that the corresponding block length is 512 bytes, but the number of data in this group is insufficient, and the block is connected to the next group. Therefore, in the block ID of the first block list of the next group, the control code is "0001", the number of bytes is "0001", the number of valid bytes is "00", and the third byte is "D4 (16 Dec: 21 in decimal
2) ”and indicate that it is a continuation of the previous group.

 The tape format of this embodiment is shown in FIG.

In addition, a subset is configured to handle multiple files as one set. When the host computer instructs the ten files to be recorded into one subset, the microcomputer 1 causes the subcode management unit 30 to store a number in the subset number of the subcode data. , When recording a group, record at the same time.

When reading data, a search is performed in file mark units as in the third embodiment, and the data from the file mark to the next file mark is sent to the host computer.

Also, when performing access with a subset number,
Search by subset number. In this case, the operation is realized in the same manner as the file mark search shown in the third embodiment by using the subset number instead of the file mark number in the subcode as the search target.

As described above, according to this embodiment, the conventional 1/2 inch MT
At the same time as realizing the same operation as the above, a high speed search of a file mark or a high speed search by a subset number becomes possible, which has the effect of improving the data access speed.

Fifth Embodiment FIG. 22 shows a block diagram of a fifth embodiment of the present invention.
The overall block diagram of the present invention is the same as FIG. 2, and FIG. 22 is a detailed block diagram of the system control circuit 26.

The system control circuit 26 includes a microcomputer 1, a system control unit 2, a system area management unit 3, a group ID analysis generation unit 40, a block ID list analysis generation unit 41, a subcode management unit 30, a block number analysis generation unit A42, and a file. Mark analysis generation unit A43, subset number analysis generation unit A44, lead-in area management unit 8, block number analysis generation unit B4
5, a file mark analysis generation unit B46, a subset number analysis generation unit B47, and a tape ID analysis generation unit 9.

The track format and group format are the same as those in the first to fourth embodiments.

FIG. 23 shows a system area format diagram of the fifth embodiment. The group ID stores the number of the first block, the number of the first file mark, and the number of the first subset belonging to this group. The address 0 stores a flag that permits the use of each of these numbers. Which of these numbers is used by the microcomputer 1 according to an instruction from the host computer is selected by setting a flag corresponding to a block number, F for a file mark number and S for a subset number in the figure. To do.

At the time of recording this group, the microcomputer 1 sets the group ID in the system area by a flag and, at the same time, selects the selected number by the subcode management unit 30 by the block number analysis generation unit A42, the file mark analysis generation unit A43, Via the subset analysis generator A44,
Set to subcode data and record.

 The format of this subcode is shown in FIG.

For example, if the block number is selected, the pack of the item "1110" shown in the second embodiment and the pack of the item "1101" shown in FIG. 24 are recorded as the subcode data. The group ID is recorded in each pack, and the starting block number and the number of blocks in the group are recorded.

Similarly, if another number is selected, the pack of the item "1110" and the pack corresponding to the selected number are recorded in the subcode. It is possible to select more than one of these numbers, and the items in the pack distinguish these numbers.

FIG. 25 shows the lead-in area format of this embodiment. At the beginning of the group ID recorded in this area,
Record the format code. This code indicates what kind of information is recorded as information for searching. Show the correspondence diagram between the format code and the data to be recorded.
See Figure 26.

In the reference area shown in FIG. 25, a descriptor indicating how the magnetic recording device of the present invention uses the data area in the lead-in area is stored. When the area code is "01", the block number analysis generator B45 stores the same list as the block number list shown in the first embodiment at the address in the data area stored in the next 3 bytes. Indicates that.

Therefore, when the format code is "01", the block number analysis generation unit B45 of the lead-in area management unit 8 determines the target block number and the group number to which this block belongs, as in the first embodiment. Take out from the list and search by group number.

Similarly, with the format code “02”, the information recorded in the reference area of the lead-in area is not used,
The block number analysis generation unit A42 of the subcode management unit 30 searches for the target block number. This method is the same as in the second embodiment.

Similarly, in the case where the file mark search and the subset number search are performed in the same way, each subcode area is searched for, and each list in the lead-in area is used via A of each analysis generation unit. The analysis generator B is used to search for the target number.

Of the area codes in the reference area, “10 (16
)) Indicates that the defect group list is stored. This means that after recording the data on the tape,
The verify circuit 14 in FIG. 2 checks whether or not the data is correctly recorded, and if the data cannot be read correctly even if error correction is performed, the group number and , A list storing the numbers of alternative groups. Therefore,
The microcomputer 1 reads the group number to which the data designated by the host computer belongs from the pack of subcode data, compares it with the defect group number in this list, and if it is the number registered in this list, substitutes it. Group number is extracted, and this group is searched again to record / reproduce target data. In this embodiment, the microcomputer 1 counts the number of the defect groups, and when the number exceeds 10% of the total number of groups, it is set as the usage limit of this tape and the host computer is notified. This limit value can be set by the user with the mode data of the mode command by the host computer.
Can be changed.

Further, in this embodiment, the area codes “80”, “81” (16
) Was assigned to a list that recorded the number of accesses for each group. This list records the number of times of reading and the number of times of writing for each group, and the microcomputer 1 grasps how much the same place on the tape is used.
Normally, when a magnetic tape is repeatedly used at the same place, the magnetic surface of the tape is damaged by the head and the traveling system mechanism, and the error increases. Therefore, there is a limit to the repeated use of the tape. However, since it is difficult for the user to control the number of times the tape has been used, when requested by the host computer, the microcomputer 1 sends this list to the host computer to inform the user of the tape usage status.

Since these lists are updated by the use of the tape, the updated list is re-recorded at a predetermined place in the lead-in area when the tape is taken out from the magnetic recording apparatus of this embodiment.

At the end of the reference area, a descriptor indicating the end with the area code "00" is stored. The microcomputer 1 recognizes this descriptor to know the end of the reference area. Therefore, if the first area descriptor of the reference area is this code, it indicates that the reference area is not used.

When the unused tape is used for the first time, the format code in the group ID of the lead-in area is
Set by the mode data in the SI27 mode set command. The host computer selects a format code so that it can be used most optimally depending on the application of the magnetic recording apparatus of this embodiment.

As described above, according to the present embodiment, the search method and the tape format can be switched depending on the format code, and the host computer can select the most suitable usage method for the application. There is. Further, there is an effect that the defect list of the reference area of the lead-in area can be used to grasp the degree of damage of the tape and the use limit of the tape from the read or write count list.

EFFECTS OF THE INVENTION According to the present invention, in a helical scan type magnetic recording device, a plurality of tracks are set as a group, and a search function to an arbitrary place necessary for a storage device of a computer is used by using this group as a basic unit of recording and reproduction. The user data area and the error correction code area in the group are different from the inconvenience that occurs because the user data area in the group is larger than the normal recording / playback unit of the computer due to the rewriting function and the efficiency of error correction. In the area, the user data area can be divided into sizes convenient for the computer to handle and control, so you can easily connect to the currently operating computer and operating system,
In addition to being available, there is an effect that it can be used in place of the magnetic recording device that has been used conventionally.

Further, since the group number recorded in the subcode, the block number, the file mark, the subset number, etc. can be searched at high speed, a high speed access which is not possible in the past as a data recording tape device of a computer is possible. The device can be realized.

[Brief description of drawings]

FIG. 1 is a block diagram of the first embodiment, FIG. 2 is a block diagram of the entire system of the present invention, FIG. 3 is an explanatory diagram of a recording method, FIG. 4 is a group format diagram of the present invention, and FIG. 5 is a DAT.
FIG. 6 is a track format diagram of FIG. 6, FIG. 6 is a subcode format diagram of the first embodiment, FIG. 7 is a system area explanatory diagram, FIG. 8 is a system area format diagram of the first embodiment, and FIG. 10 is a timing diagram, FIG. 11 is a tape format diagram of the first embodiment, FIG. 12 is a block diagram of the second embodiment, and FIG. 13 is a second diagram. FIG. 14 is a subcode format diagram of the second embodiment, FIG. 14 is a tape format diagram of the second embodiment,
FIG. 15 is a block diagram of the third embodiment, FIG. 16 is a system area format diagram of the third embodiment, FIG. 17 is a lead-in area format diagram of the third embodiment, and FIG.
FIG. 19 is a tape format diagram of the embodiment, FIG. 19 is a block diagram of the fourth embodiment, FIG. 20 is a subcode format diagram of the fourth embodiment, and FIG. 21 is a tape format diagram of the fourth embodiment. FIG. 22 is a block diagram of the fifth embodiment, FIG. 23 is a system area format diagram of the fifth embodiment, FIG. 24 is a subcode format diagram of the fifth embodiment, and FIG. 25 is a fifth embodiment. FIG. 26 is a format code explanatory diagram of the lead-in area format of the embodiment. Explanation of symbols 1 ... Microcomputer, 2 ... System control unit,
3 ... System area management section, 4 ... Group ID analysis section,
5 ... Group ID generation unit, 6 ... Block ID list analysis unit, 7 ... Block ID generation unit, 8 ... Lead-in area management unit, 9 ... Tape ID analysis generation unit, 10 ... Cylinder,
11 …… read head, 12 …… write head, 13 …… read / write circuit, 14 …… verify circuit, 15 …… servo circuit, 16 …… cylinder motor, 17 …… capstan motor, 18 …… reel motor, 19 …… DAT signal processing circuit, 20
...... Sub code control circuit, 21 ...... Drive control circuit, 22
...... DAT code decoding circuit, 23 ...... Memory control circuit, 24 ...... Layered ECC circuit, 25 ...... Memory, 26 ......
System control circuit, 27 …… SCSI, 28 …… Mechanical drive circuit,
30 …… Subcode management unit, 31 …… Block number analysis / generation unit, 40 …… File mark analysis generation unit, 41 …… Block
ID list analysis generator, 42 ... Block number analysis generator A, 43 ... File mark analysis generator A, 44 ... Subset number analysis generator A, 45 ... Block number analysis generator B, 46 ... File Mark analysis generation unit B, 47 ... Subset number analysis generation unit B.

Claims (12)

(57) [Claims] 1. A magnetic tape having a rotary head on the circumference thereof, which is wound around a cylinder rotating at a slight angle with respect to the running surface of the magnetic tape, is formed with a diagonally small track, and the track is formed in the track. A magnetic recording device for recording / reproducing information indicating the position of a track, information for allowing a rotary head to correctly travel on the track, and digital information, and a basic unit (group) for recording / reproducing a plurality of tracks.
In a magnetic recording device configured to be handled as a data recording device, a data area in which an external device connected to the outside of the magnetic recording device accesses information in the group unit, and a basic unit for transmitting and receiving information to and from the external device (block ), A buffer memory having a system area for storing the size of the block), the data area is divided into the blocks, the blocks are stored in the system area, and transmission / reception with the external device is performed in block units. In the case of receiving from the external device, the received information is temporarily stored in the buffer memory, and the information stored in the buffer memory is the basis of the recording / reproducing of the magnetic recording device. When the unit is met or exceeded, recording on the magnetic tape is started, and in the case of transmission to the external device, from the magnetic recording device. It reads information of each loop once in the buffer memory, a magnetic recording apparatus and transmits the information to the external device in divided block units by said system area management unit. 2. The magnetic recording device according to claim 1,
A block ID list analysis unit and a block ID list generation unit are provided, the block ID list generation unit stores the block length in the system area, and the block ID list analysis unit analyzes the block length stored in the system area. A magnetic recording device, which controls transmission and reception of information with the external device. 3. The magnetic recording apparatus according to claim 2, wherein the number of the group is recorded in an area for recording information indicating the position of the track in the track of the magnetic tape. Furthermore, it has a group ID analysis and generation unit, and creates a list showing the block numbers indicating the numbers from the head of the magnetic tape of the head block of each groove,
The group number including the block number designated when transmitting / receiving information to / from the external device is taken out, the information of the group having the group number is read out, and then the read out information is stored in the system area. A magnetic recording device characterized in that by using the block number at the beginning and the designated block number, which position in the data area is the target block is calculated, and information of the calculated block is transmitted or received. . 4. The magnetic recording apparatus according to claim 2, wherein the number of the group is recorded in an area for recording information indicating the position of the track in the track of the magnetic tape. A block number indicating the number from the head of the magnetic tape of the block is recorded in an area indicating the position in the track belonging to the group, the designated block number is compared with the recorded block number, and designated. A magnetic recording device characterized by detecting a group to which a generated block belongs. 5. The magnetic recording device according to claim 3,
When recording digital information, a check word for detecting and correcting an error occurring in the magnetic tape is added to the information in both the data area and the system area, and the error detection and correction are completed within the group. A magnetic recording device having a configuration. 6. The magnetic recording apparatus according to claim 5,
The magnetic recording device has a lead-in area management unit that manages the lead-in area by providing, as a lead-in area, a plurality of groups that are not used for exchanging information with the external device at the beginning of the magnetic tape. A block ID list is created in which the first block of each group is registered in the data area within the group that belongs to the lead-in area, and recording / playback of each block is executed according to the block ID list, and at the same time, the external device stores the magnetic tape When it is instructed to add information to the unused area, the information is added for each group, and the start block number of the added group and the number of blocks in the group are recorded in the block ID list. A magnetic recording device characterized by performing recording and reproduction using an ID list. 7. The magnetic recording device according to claim 6,
The magnetic recording device has a memory for reading the block ID list from the lead-in area when the magnetic tape is loaded, and the blocks read in the memory until the magnetic tape is taken out of the magnetic recording device. High-speed access and reproduction of each block is executed based on the ID list, and when information is instructed to be added from the external device, the block is added in units of groups on the magnetic tape, and the start block number of the group and the group Number of blocks of the magnetic tape is added to the block ID list in the memory, and when the magnetic tape eject switch is instructed by the external device or the magnetic tape eject switch, the block ID list in the memory is read by the magnetic tape. After rerecording in the in-area, remove the magnetic tape from the device. The magnetic recording apparatus according to symptoms. 8. The magnetic recording device according to claim 1, wherein
The number of the block from the head of the magnetic tape and the size of the block are stored in an area for recording the positional information of each track, and the number and the size are managed as information of block detection and recording / reproduction. A magnetic recording device having a configuration including a system area management unit that operates. 9. The magnetic recording apparatus according to claim 6,
The group is divided into a data area and a system area, the data area is subdivided into blocks suitable for exchanging information with the external device, and information indicating the size of the block in the system area and the first block are magnetic tapes. The information indicating the number of the block from the beginning, the number of blocks in the group, and the code indicating the type of each block are stored, and different codes are stored in the information to be recorded on the magnetic tape and the block indicating the information delimiter. When the allocation is instructed to record the information delimiter by the external device, a block having a code indicating the information delimiter is recorded at the end of the recorded information, and the external device is instructed to search for the information delimiter. Then, the information is read from the magnetic tape in group units, the code assigned to the system area block is checked, and the information Ri magnetic recording apparatus characterized by being configured to perform a search to detect a code indicating. 10. The magnetic recording apparatus according to claim 9, further comprising storing the number of codes indicating the breaks of the information recorded in the group in the system area, and at the same time exchanging information with the external apparatus. Create a list of groups formed on the magnetic tape in the group formed in the unused lead-in area, and provide the information indicating the first information delimiter code of each group from the beginning of the magnetic tape. When the user has registered and is instructed by the external device to search for an information delimiter, the list of groups is referred to, the number of the group to which the code indicating the desired information delimiter belongs is extracted, and the group number is searched at high speed. ,
A magnetic recording apparatus, characterized in that the group information is read and a designated place is searched from the number of codes indicating the division of the information registered in the system area. 11. The magnetic recording device according to claim 10, wherein a code for indicating that there is a delimiter of information between the blocks is stored. . 12. The magnetic recording device according to claim 3, 4, 7, 8 or 11, wherein a block number, a code number indicating a delimiter between data and a plurality of data are provided in the system area. At least one of the grouped subset numbers is stored, and in the position detection area (subcode) in the track, the group number, the first block number in the group, the first data delimiter code number in the group, and the group At least one of the first subset numbers of the above is stored, and is controlled to perform a high-speed search using the designated number by the format code recorded in the lead-in area.