JPH03164924A - Magnetic disk access system - Google Patents

Abstract

PURPOSE:To process each access at high speed even though plural application programs have simultaneous accesses to a magnetic disk by processing with preference a command that satisfies the continuous command processing conditions. CONSTITUTION:A magnetic disk control part 4 accepts a command block 2 and registers it into a command queuing part 5. Then the part 4 carries out an access to a magnetic disk related to the block 2 satisfying the continuous command processing conditions and if included in the part 5. If not, the part 4 waits for a time equal to the command waiting time. Then the part 4 performs an access related to the block 2 having the largest waiting time in the part 5 if the part 4 cannot accept the block 2 that satisfies the continuous command processing conditions despite a due waiting time. Thus is possible to process each access to the magnetic disk at high speed when plural application programs 1 have simultaneous accesses to the magnetic disk.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic disk access system, and more particularly to a magnetic disk access system using a multitasking operating system.

[Conventional technology]

Conventionally, this type of magnetic disk access method uses, for example,
This was realized with the configuration shown in Figure 2 (Figure 2 shows
FIG. 1 is a block diagram showing the configuration of an example of a conventional magnetic disk access method.

The operation of the conventional magnetic disk access method will be explained below with reference to FIG.

Application program 1.1 program for each application program in 11 to 1n (n is a positive integer) The same applies to the relationship between the command blocks 21 to 2n and the command block 2), which sends a magnetic disk (magnetic disk on the magnetic disk device 7) access request command to the command management unit 3 in the operating system (not shown). (Command block 2 containing the access request command (command block 2 for magnetic disk access)
).

The command management unit 3 passes the command block 2 to the magnetic disk control unit 31 (magnetic disk control unit in the conventional magnetic disk access method) in the operating system.

When the magnetic disk control unit 31 receives the command program 2 issued from the application program 1, it issues the necessary 110 (input/out put) command to the magnetic disk device 7, and It waits until there is a 1101 completion interrupt from the device 7.

When the magnetic disk device 7 completes the processing (magnetic disk access) related to the I/O command requested by the magnetic disk controller 31, the magnetic disk device 7 sends the i/o command to the magnetic disk controller 31.
/o Notify end interrupt.

The magnetic disk control unit 31 performs an i/o v! : When activated by the slave side, it issues a command completion notification to the command management unit 3.

As a result, the command management unit 3 causes the application program 1 that issued the command block 2 for magnetic disk access to terminate the command (the command block 2
notification of the completion of processing related to the above).

Through each of the above-described processes, the application program 1 accesses data in the magnetic disk on the magnetic disk device 7.

Note that, due to the physical characteristics of the magnetic disk device 7,
In order to read the data written on the magnetic disk, the following time is required.

■ Time required for the read head to move to the cylinder that stores the required data (seek time) ■ Time required for the sector that stores the required data to rotate to the bottom of the read head (rotation wait time) Here The seek time and rotational waiting time vary greatly depending on the relative relationship between the position of the data to be read on the magnetic disk and the position of the data read at that time. For this purpose, each time is usually expressed using the average j-time. Each time in the current magnetic disk device has approximately the following value for boat fishing.

■ Average seek time: 20 to 100 ms ■ Average rotational waiting time: approximately 8 ms [Problem to be solved by the invention] In the conventional magnetic disk access method described above, multiple application programs (for example, the second If a plurality of application programs 1) among the application programs 11 to ln in the figure access the magnetic disk at the same time, there is a drawback that the time required for the magnetic disk access increases for the following reasons.

The reason why the time required to access the magnetic disk increases will be explained with reference to FIG. 2 and FIGS. 3(a) and 3(b).

When command blocks 2 for magnetic disk access are issued from the plurality of application programs 1 to the magnetic disk control unit 31, each command block 2 is sent from the command management unit 3 to the magnetic disk control unit 31 in the order in which they are issued. passed to.

Normally, since the application program l issues only one command block 2 to the same process (the magnetic disk control unit 31 is also one process), the application program li (i is a positive integer from 1 to n) While performing magnetic disk access based on command block 21, other application programs 1
j (j is a positive integer of l-n other than i) issues a command block 2j for magnetic disk access, and when the magnetic disk access from the application program 11 is completed, the magnetic disk control unit 3I executes the application program J. The magnetic disk will be accessed from "1".

Each application program 1 usually accesses different files (files in the magnetic disk of the magnetic disk device 7), and these files are often cocatenated in different cylinders in the magnetic disk. '' In order to access the magnetic disk from two series of application programs 1j, seek time is often not required.

Therefore, in the process of sequentially processing a plurality of command blocks 2 passed from a plurality of application programs 1, it is highly likely that the magnetic disk control unit 31 will need to perform a seek for each command block 2.

Here, as mentioned above, since the average seek time is several times to ten times as large as the average rotational waiting time, command blocks 2 for accessing the magnetic disk from multiple application programs simultaneously When the application program 1 is issued, the magnetic disk access time of the specific application program 1 becomes extremely long.

For example, as shown in FIG. 3(a), multiple magnetic disk accesses from one application program 1:]gram 1 (the magnetic disk accesses are from the same application program 1, so data in the same cylinder is 3(b) (rAP in Lesson 31(b),
When comparing the multiple magnetic disk accesses from two application programs 1 as shown in (J and rAP2J indicate different application programs 1), it is found that the multiple magnetic disk accesses of each application program 1 are The time required is much longer in the case shown in FIG. 3(b).

In view of the above points, an object of the present invention is to provide a magnetic disk access method that can process each magnetic disk access at high speed when multiple application programs access the magnetic disk multiple times at the same time. It's about doing.

[Failure to solve the problem]

In the magnetic disk access method of the present invention, an application program receives a command block for magnetic disk access issued via a second management unit, registers it in a command block queue, and satisfies continuous command processing conditions. Command block: If one block exists in the command block queue, performs magnetic disk access regarding the command block, and if there is no command block that satisfies the continuous command processing condition in the command block queue, waits for the command waiting time. - Waits for a command block for magnetic disk access that satisfies the continuous command processing condition to be accepted, and if it cannot accept a command block that satisfies the continuous command processing condition even after waiting for the command waiting time, the command block queue is sent. A magnetic disk control unit that executes magnetic disk access for the command block with the maximum waiting time, and a command block queue that is set and referenced by this random disk control unit (coran 1ζ for magnetic disk access).
(including determination of continuous command processing conditions related to blocks)
The magnetic disk drive apparatus includes a 1man 1'/1-Ewing section for performing the following operations, and a timer monitoring section for managing command waiting time related to waits sent to the magnetic disk control section.

[Effect]

In the magnetic disk access method of the present invention, the magnetic disk control unit receives a command block for magnetic disk access, registers it in the command block queue, and if there is a command block that satisfies the continuous command processing condition in the command block queue, the corresponding command block is registered in the command block queue. If there is no command block queue in the command block queue that executes magnetic disk access related to the command block and satisfies the continuous command processing condition, the command block for magnetic disk access that satisfies the continuous command processing condition is If a command block that satisfies the continuous command processing condition cannot be accepted even after waiting for acceptance for the command waiting time, execute magnetic disk access for the command block with the longest waiting time in the command block queue, The command queue ink unit manages a command block queue set and referenced by the magnetic disk control unit, and the timer monitoring unit manages command waiting time related to wait in the magnetic disk control unit.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an embodiment of the magnetic disk access method of the present invention. The magnetic disk access method of this embodiment is based on the application program 11.
1n, command blocks 21 to 2n, a command management section 3, a magnetic disk control section 4, a command queue ink section 5, a timer monitoring section 6, and a magnetic disk device 7. (The same components as in the conventional magnetic disk access system shown in FIG. 2 are indicated by the same reference numerals).

Referring to FIG. 4, the processing of the magnetic disk control unit 4 is as follows:
Wait step 401 and activation factor determination step 40
2, command block registration step 403, command execution determination step 404, continuous command processing condition satisfying command block search step 405, command block extraction step 406, k (k is a natural number) addition step 407, and command block Issue step 4
08, command execution flag ON step 409, command end notification step 410, command execution flag OFF step 411, 1w calculation step 41
-2, time measurement request step 413, k and tw setting step 414, waiting command block presence/absence determination step 415, and leading command block extraction step 4
It consists of 16.

Referring to FIG. 5, the command queue ink section 25 includes a command registering means 51 and a command extracting means 5.
2, command search means 53, and command block queue 54 (waiting command blocks are managed by queue 1' pointer 55 and queue tail pointer 56). Section 4).

Referring to FIG. 6, the timer monitoring section 6 includes a one-time request means 61 used by the magnetic disk control section 4.

Next, the operation of the magnetic disk Acnus system of this embodiment configured as described above will be explained.

Application programs 11 to 1n, which are application programs running in the computer system to which this embodiment is applied, each have one command block 21 to 1n, in order to issue commands to the magnetic disk control unit 4.
There is ′ζ with 2n.

When the application program l (any application program among the application engine programs 11 to 11) issues a command block 2 to the magnetic disk control unit 4, the command management unit 3 in the operating system (not shown) issues the command block 2. It is passed to the magnetic disk control unit 4 within the operating system.

The magnetic disk control unit 4 normally waits, as shown in step 401 in FIG.

The processing of the magnetic disk control unit 4 when the command block 2 is received as described above during the wait in step 401 will be described.

In this case, the magnetic disk control unit 4 performs the following processing (see steps 403 to 409 in FIG. 4).

In step 402, in determining the activation factor (factor for activation from a wait state; factors include command block reception, i10 end interrupt, timeout, etc.), it is determined that the activation factor is the occurrence of reception of command block 2. The received command block 2 is passed to the command queue ink unit 5. The command registration means 51 in the command queue ink unit 5 registers the command block 2 in the command block queue 54. This registration is
Command block 2 (
In FIG. 5, this is done by adding the command block 2 after the command 7ri2m (m is a positive integer from 1 to n) (step 403).

Next, it is determined whether or not the magnetic disk device 7 is currently executing a command (processing a magnetic disk access) (step 404).

If it is determined that the magnetic disk device 7 is executing the command, the process returns to step 401 and waits.

If it is determined in step 404 that the command is not being executed, the current cylinder position (read head position) in the magnetic disk device 7 is compared with the cylinder position related to magnetic disk access, which is the content of the command block 2;
Based on the comparison, control is passed to the command search means 53 in the command queue ink unit 5 in order to determine whether or not there is a command block 2 that satisfies the continuous Vt command processing conditions in the command block queue 54. . The command search means 53 sequentially searches for command blocks 2 that satisfy the continuous command processing condition from the command block 2 (command block 21 in FIG. 5) instructed by the queue head ink 55, and determines whether a corresponding command block 2 exists. Then, the command number of the command block 2 is returned to the magnetic disk control unit 4, and if the corresponding command block 2 does not exist, an error notification is returned to the magnetic disk control unit 4 (step 405).

Here, the continuous command processing condition is a condition expressed by the following equation.

2Δts 1C2-C1l<tw tw=tmax-2 to Δts...Average seek time for one cylinder C1...
Current cylinder position C2...The reception is at cylinder position 6 related to the command block tw...Command waiting time tmax x...Maximum command waiting time k...Continuous command processing number Continuously by the search in step 405 If there is a second command block 2 that satisfies the command processing conditions, control is passed to the command extraction means 52 in order to extract the command block 2 from the command block queue 54 in the command queue ink section 5.

The command extracting means 52 extracts the command block 2 specified by the command number, which is the search result of the command searching means 53, from the command block queue 54 (step 406).

Furthermore, 1 is added to k (step 407), the command block 2 is issued to the magnetic disk device 7 (step 40B), a command execution flag (a flag that is set to ON when a command is being executed. Magnetic disk control) Step 409)
, the process returns to step 401 and waits.

If the command block 2 that satisfies the continuous command processing condition does not exist in the command block queue 54 in the search in step 405 (if an error notification is returned from the command search means 53), the process returns to step 401 and waits.

Subsequently, during the wait in step 401, i/
Magnetic disk control unit 4 when an O end interrupt occurs
The processing will be explained.

In this case, the magnetic disk control unit 4 performs the following processing (see steps 410 to 413 in FIG. 4).
.

In the determination of the activation factor in step 402, the activation factor is i.
/o Since it is determined that the end side is included, the command management section 3 is notified of the end of the processing related to command block 2 (step 410), and the command execution flag is set to OFF.
F (step 411).

Next, the command waiting time tw (tw=tmax2')
Step 412), the command waiting time t
A time measurement request for w is made to the timer monitoring unit 6. Timer monitoring section 6
When a specified time (command waiting time tw) has elapsed, the time measurement requesting means 61 wakes up the secondary time requesting process (magnetic disk control unit 4).
) (step 413).

After issuing the time measurement request in step 413, the process returns to step 401 and waits.

Finally, the processing of the magnetic disk control unit 4 when a timeout occurs during the wait in step 401 (when woken up by the time measurement requesting means 61) will be described.

In this case, the magnetic disk control unit 4 performs the following processing (see steps 414 to 416 in FIG. 4).
.

In the determination of the activation factor in step 402, it is determined that the activation factor is the occurrence of a timeout, so the number of consecutive command processings k is set to "1", and the command waiting time tw
is set to [tmax-2J (step 414).

Next, it is determined whether or not there is a waiting command block (an unissued command block 2 forming the command block queue 54) in the command queue ink unit 5 (step 415).

If there is a waiting command block in this judgment,
(Step 41
6), control is transferred to step 408;

If it is determined in step 415 that there is no waiting command block, the process returns to step 401 and waits.

By performing the above-described processing, the magnetic disk control unit 4 preferentially processes commands that satisfy the continuous command processing condition among the command blocks 21 to 2n issued from the application programs 11 to 1n.

FIG. 7 is a diagram showing the relationship between the number of consecutive command processings and the command waiting time tw.

As shown in this figure, the command waiting time tw decreases rapidly as the number of consecutive command processings k (the number of times the continuous command processing condition 0 is continuously satisfied) increases. Therefore, by appropriately setting the maximum command waiting time tmax, it is possible to adjust the number of consecutive executions of command blocks that satisfy the continuous command processing condition. Thereby, it is possible to avoid a situation where only the command block 2 from the same application program I is accepted and the other application program I (command block 2 of the application program I) is locked out.

【Effect of the invention〕

As explained above, the present invention provides the following advantages by accessing the magnetic disk based on determining whether a command block received from an application program satisfies the continuous command processing condition. and (2) occur, and even if a plurality of application programs access the magnetic disk multiple times at the same time, each magnetic disk access can be processed at high speed.

(2) By waiting for a certain period of time (command waiting time tw) to issue a command block that satisfies the continuous command processing conditions, the number of unnecessary seeks can be reduced.

■ By appropriately adjusting the maximum command waiting time tmax, it is possible to avoid a situation where only command blocks from the same application program are executed and command blocks from other application programs are locked out (see If an attempt is made to reduce the number of seeks shown in the table without limit, a lockout as described above will occur, so this problem is prevented.)

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention. FIG. 2 is a block diagram showing the configuration of an example of a conventional magnetic disk access method. FIGS. FIG. 4 is a flowchart illustrating the processing of the magnetic disk control unit in FIG. , Figure 5 is a block diagram showing the configuration of the command queue ink unit in Figure 1, Figure 6 is a block diagram showing the configuration of the timer monitoring unit in Parts 1 and 7, and Figure 7 is a block diagram showing the configuration of the timer monitoring unit in Figure 1. FIG. 7 is a diagram showing the relationship between the number of times and command waiting time. In the figure, 11~In・Abrication Soyon Program, 21~2n
・Command book 1 click, 3...Command management section, 4...Magnetic disk control section, 5...Command)・-1-Knee ink section 6...
・Timer monitoring unit, 7...Magnetic disk device, 51...Command money means, 52...Command extraction means, 3 53 ・ 4 55 ・ 56 ・ 1 Command search means, Command block queue・Cue Hesodobo Ink, ・Cue Tail Boink, ・Time measurement request means.

Claims (1)

[Claims] When an application program receives a command block for magnetic disk access issued via a command management unit and registers it in a command block queue, and a command block that satisfies continuous command processing conditions exists in the command block queue. If there is no command block in the command block queue that satisfies the continuous command processing condition, the command block for magnetic disk access that satisfies the continuous command processing condition is executed after waiting for the command waiting time. If a command block that satisfies the continuous command processing condition cannot be accepted even after waiting for the command waiting time, the magnetic disk executes magnetic disk access for the command block with the maximum waiting time in the command block queue. a control unit; a command queue ink unit that manages a command block queue set and referenced by the magnetic disk control unit; and a timer monitoring unit that manages a command waiting time related to a wait in the magnetic disk control unit. A magnetic disk access method characterized by: