JPH064449A - Disk controller - Google Patents

Abstract

PURPOSE:To reduce a burden of a host device, and also, to enhance the read-out processing efficiency. CONSTITUTION:In the disk controller 2 for controlling a disk device 3 in which a logical track sectioned by an end-of-file is formed on a physical track, and reading out a designated record based on a command chain issued from a host device 1, this disk controller is constituted by providing a control means 4 for reading out all records extending from the next record of a search object record on the physical track to a terminal on the physical track, in the case where a flag sets a read track command to be valid against the physical track when the command chain provided with the flag is received, and reading out all records extending from the next record of the search object record on the physical track to the end-of-file read out in the beginning, in the case the flag sets the read track command to be valid against the logical track.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disk controller for controlling a disk device in which one or more logical tracks are formed on a physical track, and more particularly when a host device instructs to read one logical track. The present invention relates to a disk control device that reduces the load on a host device and improves read processing efficiency.

In a magnetic disk device used as an external storage device of a computer system, a record in which a data length recorded in a count section indicates zero, that is, an end of record under the control of an operating system (OS).
A file (EOF) is used to create one or more logical tracks on a physical track, and read track
A command chain including a command may instruct reading of this logical track.

When a read track command is issued, the magnetic disk control device cannot distinguish between a physical track and a logical track. Therefore, the physical track starts from the record next to the record to be searched on the physical track. Although all the records up to the upper end are read, it is desirable to avoid reading records on unnecessary logical tracks.

[0004]

2. Description of the Related Art When a central processing unit of a computer system issues a command chain including a read track command to a magnetic disk control device, conventionally, the next record of a search target record on a physical track of the magnetic disk device is issued. From the record to the end on the physical track are read out and transferred to the central processing unit.

Therefore, even when a plurality of logical tracks are created on a physical track by using EOF under the control of the OS, all the records after the record next to the search target record on the physical track have been read.

[0006]

As described above, in the prior art,
When the central processing unit creates one or more logical tracks on the physical track of the magnetic disk unit and reads all the records from one of the logical tracks, the record next to the record to be searched on the physical track is temporarily deleted. Therefore, it is necessary to read all the records up to the end of the physical track and then extract the records on the logical track required by the central processing unit.

Therefore, the load on the central processing unit is increased, and records on unnecessary physical tracks are read in addition to the records on the required logical tracks, so that wasteful time is required and the read processing efficiency decreases. There is a problem.

In view of the above problems, the present invention specifies whether the read track command is valid for a physical track or a logical track from the central processing unit side. The purpose is to allow the magnetic disk controller to read only the records on the logical tracks required by the central processing unit.

[0009]

FIG. 1 is a block diagram for explaining the principle of the present invention. The disk control device 2 controls a disk device 3 in which one or more logical tracks separated by an end of file are formed on a physical track, and a command including a read track command issued by the host device 1 Reads the specified record based on the chain.

When the command chain having a flag for instructing whether the read track command is valid for the physical track or the logical track is received, this flag is received. Read the record on the physical track, or
A control means 4 for determining whether to read a record on one logical track is provided.

When this flag makes the read track command valid for the physical track, the total length from the record next to the search target record on the physical track to the end on this physical track. If all the records are read, and this flag enables the read track command for the logical track, the end of the first read from the record next to the searched record on the physical track. Read all records up to the file.

[0012]

With the above arrangement, the disk controller 2 controls the control means 4 in order to specify the physical track record read or the logical track record read by the flag provided in the command chain by the host computer 1.
Under the control of, only the record of the designated logical track can be read.

Therefore, since only the record of the logical track required by the host device 1 is read, unnecessary records are not read, the read processing efficiency is improved, and the record required by the host device 1 is improved. Since the process of extracting is unnecessary, the load on the host device 1 can be reduced.

[0014]

2 is a block diagram of a circuit showing an embodiment of the present invention, and FIGS. 3 to 6 are diagrams for explaining the operation of FIG.

The processor 8 of the disk controller 2 reads a program stored in the control memory 9 to operate, and a command chain sent by the higher-level device 1 via the interface circuit 5, for example, DX (Define Eetent) (later). Command to specify the subsequent operation), LR (Locate Recor
When d) (command for instructing write or read operation and command for searching record to be processed) and RT (Read Track) (command for instructing to read track) are received, the disk device 3 is controlled via the interface circuit 7. , LR
Position the head in the cylinder specified by.

Then, the flag provided in the LR is checked,
Check whether this command indicates that the command is valid for the physical track or the logical track.

If it is valid for the physical track, the record number of the count portion of the record read from the track followed by the specified head positioned in the specified cylinder is checked, and the specified record number is determined. When the search target record is read and the LR instructs the reading, the interface circuit 7 and the data from the record read next to this search target record to the final record of the track followed by this head are recorded. Transfer to the host device 1 via the transfer control circuit 6 and the interface circuit 5.

FIG. 3 shows an example of a physical track.
On the physical track 10 shown in (A), the home address HA is recorded following the index, and then a plurality of records are recorded from record R (0) to record Rn + 2.

Therefore, if the record R (1) shown in FIG. 3A is the record to be searched, the processor 8 is shown in FIG.
As shown in (4), all the records from the record R (2) to the record Rn + 2 are transferred as described above.

FIG. 4 shows a case in which one logical track is provided on the physical track 10. As shown in FIG. 4A, the record R (1) is the search target record and the record Rn is EOF. Then, the processor 8 checks the flag provided in the LR, and if this command indicates that the command is valid for the logical track, the record R (2) to the record R (2) is read as shown in FIG. 4 (B). All records up to Rn are transferred to the host device 1.

That is, the processor 8 recognizes the end of the logical track because the data length recorded in the count portion of the record Rn indicates zero, and instructs the data transfer control circuit 6 to record the record Rn. The transfer of the record read thereafter is stopped from the next record.

In FIG. 5, the home address HA is recorded following the index on the physical track 10, and a plurality of records are recorded from the record R (0) to the record Rn. The physical track 10 is a logical track. The case where a plurality of are provided is shown.

Then, as shown in FIG. 5A, the record R
If (1) is the search target record, and record Rk, record Rm, and record Rn are EOF, the processor 8 indicates that the flag is valid for the physical track, as shown in FIG. As shown, record R (2)
To all records Rn to Rn are transferred to the higher-level device 1.

FIG. 6 shows a case where a plurality of logical tracks are provided on the physical track recorded from the record R (0) to the record Rn. As shown in FIG. 6 (A), the record R (1) is Assuming that the record Rk, the record Rm, and the record Rn are EOF in the record to be searched, if the flag indicates that the flag is valid for the logical track, the processor 8 records as shown in FIG. 6 (B). R
All records between (2) and record Rk are transferred to the host device 1.

That is, since the processor 8 reads the search target record R (1), the first read EOF, that is, the data length recorded in the count portion of the record Rk indicates zero. EO this record Rk
When it is determined to be F, the end of the logical track is recognized, and the data transfer control circuit 6 is instructed to stop the transfer of the record read from the record next to the record Rk.

As shown in FIG. 6C, if Rk is the search target record and record Rk, record Rm, and record Rn are EOF, the processor 8 confirms that the flag is valid for the logical track. In the case shown, as shown in FIG. 6 (D), since the data length of the count part of the record Rm is zero, the EOF read first is determined, and the record Rk + 1 to the record Rm are determined.
All records up to are transferred to the higher-level device 1.

As shown in FIG. 6 (E), if Rm is the record to be searched and record Rk, record Rm and record Rn are EOF, the processor 8 confirms that the flag is valid for the logical track. In the case shown, all the records between the record Rk + 1 and the record Rn are transferred to the host device 1, as shown in FIG.

FIG. 7 is a flow chart for explaining the operation of FIG. The processor 8 monitors the reception of the command chain in step (1), and when receiving the command chain, positions the head in the cylinder designated in step (2).

Then, in step (3), the completion of positioning of the head is waited, and when the positioning of the head in the designated cylinder is completed, it is checked in step (4) whether or not the data read instruction is issued. In (5), check whether the flag indicates that the physical track is valid.

When the flag indicates that the physical track is valid, all records from the record read next to the record to be searched in step (6) to the last record of this track are read out, and the upper device Transfer to 1. Then, the process returns to step (1).

If the flag does not indicate that the physical track is valid but the logical track is valid in step (5), the record read next to the record to be searched in step (7) indicates that this track is valid. EO read first
All records up to F are transferred to the higher-level device 1. Then, the process returns to step (1).

When instructed to write the data in step (4), the processor 8 proceeds from the record next to the record to be searched to the designated record in step (8).
The data sent by the higher-level device 1 is written. Then, the process returns to step (1).

[0033]

As described above, according to the present invention, when a logical track is created on a physical track, only the record of the logical track required by the host device is read, so that an unnecessary record is not read. The read processing efficiency is improved, and the process of extracting the records required by the upper-level device is not necessary, so that the load on the higher-level device can be reduced.

[Brief description of drawings]

FIG. 1 is a block diagram illustrating the principle of the present invention.

FIG. 2 is a block diagram of a circuit showing an embodiment of the present invention.

FIG. 3 is a diagram (part 1) for explaining the operation of FIG. 2;

FIG. 4 is a diagram for explaining the operation of FIG. 2 (No. 2)

FIG. 5 is a diagram (part 3) for explaining the operation of FIG. 2;

FIG. 6 is a diagram (part 4) for explaining the operation of FIG. 2;

FIG. 7 is a flowchart illustrating the operation of FIG.

[Explanation of symbols]

 1 host device 2 disk control device 3 disk device 4 control means 5, 7 interface circuit 6 data transfer control circuit 8 processor 9 control storage 10 physical track

Claims (1)

[Claims] 1. A read track command issued by a higher-level device (1) for controlling a disk device (3) having one or a plurality of logical tracks separated by an end of file on a physical track. Whether the read track command is valid for the physical track or the logical track in the disk controller (2) that reads the specified record based on the command chain including When receiving the command chain provided with a flag for instructing, the control means (4) for determining whether to read the record on the physical track or the record on one logical track based on the instruction of the flag (4 ) Is provided and the flag enables the read track command to the physical track, the server on the physical track is H. All the records from the record next to the target record to the end on the physical track are read, and if the flag makes the read track command valid for the logical track, on the physical track. The disk controller characterized in that all the records from the record next to the record to be searched to the end of file read first are read.