JPH0312866A - Controlling system for start of write/read action - Google Patents

Abstract

PURPOSE:To shorten an access time by detecting a sector prior to a sector being the object of a read/write action by one, previously discriminating one having the possibility of a comparison error by means of a timer value and giving the instruction of the start of the read/write action to a format control part. CONSTITUTION:When a sector detection means 12 detects that a head reaches a position prior to the sector being the object of the write/read action by one when it comes to a state where the write/read action can be started, the sector detection means 12 starts a timer. A control means 13 giving the instruction of the start of the write/read action moves to an interruption processing based on an interruption signal from the sector detection means 12 and gives the instruction of the start of the write/read action to a format control means 11 based on the output of a discrimination means 14. When the timer does not reach a prescribed value, the control means 13 gives the instruction of the start of the write/read action to the format control means 11 by taking it to be no possibility of the comparison error. Consequently, one rotation- waiting is avoided. Thus, the access time can be shortened.

Description

[Detailed Description of the Invention] [Summary] Regarding a control method for controlling the start of a write/read operation in a magnetic disk device, a start control method for a write/read operation that reduces rotational waiting time and improves processing performance. A format control means for controlling write/read operations on a medium, a sector detection means for detecting a designated sector, and a timer activated by the output of the sector detection means to perform write/read operations. comprising a determining means for determining the start of an operation, and a control means for controlling the format controlling means based on the output of the determining means, and when the timer value does not reach a predetermined value, the controlling means writes to the format controlling means. The configuration is configured to instruct the start of a read operation.

[Industrial Application Field] The present invention relates to a control method for controlling the start of successive write operations in a magnetic disk device.

In recent years, it has become increasingly desirable for magnetic disk drives connected to computer systems to increase their data processing speed. However, the heads of magnetic disk drives cannot read/write
When on-tracking on a track with a target sector for a write operation, there is a waiting time of half a revolution on average until the target sector is read/written.

Therefore, in order to improve data processing speed, it is necessary to reduce such waiting time.

[Prior Art] In a conventional fixed-length sector format magnetic disk device, the format control unit uses the first sector pulse detected after an operation start instruction is sent from the MPU to the format control unit as a trigger. , the structure is such that a search operation for the sync byte and ID section is started. Therefore, the MPU must send an instruction to the format control section when the head is positioned at the sector one sector before the target sector of the read/write operation.

This will be explained based on FIG.

In FIG. 5, ■ to ■ are seek operations by the magnetic disk device (operations in which the head is moved onto the cylinder and track where the target block of the read/write operation is located)
10 and 11. The points at which preparations for the format control unit (setting values to each register) are completed so that the format control unit can perform read/write operations are shown.

Note that 4 indicates a block located at the beginning of the target blocks of the read/write operation, 5 indicates a location where a sector pulse is generated, and 6 indicates a location where an index pulse is generated.

The MPU constantly monitors whether the head position has reached n-1 in the figure, and in the case of ■ and ■ that the head has reached n-1, it instructs the format control unit to start read/write operations. Give instructions.

By the way, the MPU operates based on a microprogram, and there is a time gap between when it confirms that n-1 has been reached and when it sends an instruction to the format control section. It is necessary to pay attention to

However, in the case of ■, there is no margin for the subsequent sector pulse (for example, 2 μsec), and the subsequent pulse may have already been generated by the time the format control unit starts operating. A byte search operation is performed upon generation of the next sector pulse. For this reason, the format control unit controls the sector (n+1
), and a 10-copy conveyor error occurs. Therefore, M
A margin was provided for the time required for the PU to issue instructions to the format control unit.

This will be explained based on the flowchart of FIG.

In FIG. 6, in step S1, it is determined whether the head is located on the sector (n-2) two positions before the target sector (n) of the read/write operation, and the head is located on the sector (n-2).
2) If it is above, step S2 selects the sector (n-1) one position before the target sector (n) of the read/write operation.
Determine if there is a head on top. When the head is on sector (n-1), a command to start a read or write operation is sent to the format control unit in step S3, and it is determined in step S4 whether the operation of the format control unit has ended.

[Problems to be solved by the invention] However, in such a control method, first,
It is necessary to detect the sector two sectors before the target sector of the read/write operation, and when the MPU is ready to start the read/write operation, the head has already detected the target sector of the read/write operation. If it is located one position ahead, there will always be a wait for one rotation.

That is, in FIG. 5, if the motor waits at position n-2, not only the case (2) but also the case (2) will be forced to stop during one rotation.

As a result, there was a problem in that the average rotational waiting time increased and the processing performance of the device decreased.

The present invention has been made in view of such conventional problems, and an object of the present invention is to provide a start control method for write/read operations that reduces rotational waiting time and improves processing performance. It is said that

[Means to solve the problem] FIG. 1 is a diagram explaining the principle of the present invention.

In FIG. 1, 11 is a format control means for controlling write/read operations on the medium, 12 is a sector detection means for detecting a designated sector, and 14 is a timer activated by the output of the sector detection means 12 to write data. Determination means 13 is a control means for instructing the format control means 11 to start a write/read operation when the timer value does not reach a predetermined value.

[Operation] In the present invention, when the state where the write/read operation can be started, the sector detection means detects that the head has reached the position one position before the target sector of the write/read operation. Upon detection, the sector detection means starts a timer. The control means for instructing the start of the write/read operation is
Shifting to interrupt processing based on an interrupt signal from the sector detection means, the format control means is instructed to start a write/read operation based on the output of the determination means.

That is, when the timer value does not reach a predetermined value, the control means determines that there is no possibility of causing a conveyor error, and instructs the format control means to start a write/read operation.

Therefore, it is possible to avoid waiting for one revolution as in the case of (■) in FIG. 5, and thus the access time can be shortened. As a result, the processing performance of the magnetic disk device can be improved.

[Example] Embodiments of the present invention will be described below based on the drawings.

FIGS. 2 to 4 are diagrams showing an embodiment of the present invention.

In FIG. 2, reference numeral 11 denotes a format control section as a format control means, and the format control section 11 controls write and read operations on the medium.

12 is a sector detection circuit as sector detection means;
The sector detection circuit 12 is a microprocessor (control means)
(hereinafter referred to as MPU) 13 detects the specified sector, here the sector one sector before the sector to be read/written, and sends an interrupt signal to the MPU 13 and a start signal to the timer part 14. (See Figure 3(B)).

The timer part 14 has a function as a determination means, and starts the timer in response to a start signal from the sector detection circuit 12.
Determine the start of a read/write operation.

The timer part 14 includes a register 5 that holds the timer value from the MPU 13 and a decrement count register 16 that decrements the output value of the register 5.
a register 17 holding a value of 0'', and both registers 6.
17, a register 19 that stores the comparison result of the comparison circuit 18, and a reset circuit 20 that resets the internal operation of the timer section 13.

The register 19 outputs a determination signal for determining whether to start the format control unit 11, and the MPU 13 outputs a read/write signal to the format control unit 11 based on this determination signal.
Instructs to start the write operation (see FIG. 3(C)).

That is, the MPU 13 activates the format control unit 11 while the discrimination signal is on, and when the decrement count register 16 becomes 0, a timeout occurs.
The operation of the timer part 14 is stopped. The time it takes for the timer value to reach the predetermined value is determined by the sector pulse generation interval (Figure 3 (A).
), and the fetch cycle time of the MPU 13 (see FIG. 3(D)). In addition, 21
is the system bus.

Next, the operation will be explained.

FIG. 4 is a flowchart showing the operation of the present invention. be.

In FIG. 4, first, in step S11, it is determined whether or not there is a head on the sector immediately before the target sector of the read/write operation. If there is no head, the process returns to step S11, and if there is a head, the process proceeds to step S12. (The transition from step S11 to 812 is performed based on the interrupt signal 22 from the sector detection means, so the MPU can perform other internal processing during this time.) When it is in sector t, the sector detection circuit 12 sends an interrupt signal to the MPU 13.
and at the same time sends a start signal to the timer unit 14 (third
(see Figure (B)).

The timer part 14 is activated by the activation signal, the decrement count register 16 decrements the output of the register 15 that holds the timer value specified by the MPU 13, and the comparison circuit 18
The output of the register 17, which always holds the "0" value, is compared.

Next, in step S12, the MPU 13 determines whether the register 19 holding the comparison result of the comparator circuit 118 indicates a timeout. If the timeout has occurred, the process returns to step S11, and if the timeout has not occurred, the process proceeds to step S13.

In step S13, the MPU 13
1 to start a read/write operation, and in step S14 it is determined whether or not the operation of the format control section 11 has ended. If the process is completed, the process moves to the next operation; if the process is not completed, the process returns to step S14.

In this way, in this embodiment, when a timeout occurs, it is determined that there is a possibility of causing a conveyor error in the 10th copy, and the system waits for one rotation, and when it is not timed out, there is no possibility of causing a conveyor error in the ID section. Lead by determining that
Instructs to start write operation. Therefore, it is possible to reduce the access time on average by "one rotation time of the medium/the number of sectors in a track", and the processing performance of the magnetic disk device can be improved.

2 [Effects of the Invention] As explained above, according to the present invention, the sector immediately before the target sector of the read/write operation is detected,
Since the timer value is used to determine in advance what may cause a conveyor error in the ID section and to instruct the format control section to start a read/write operation, the access time can be shortened. As a result, the processing performance of the magnetic disk device can be improved.

[Brief explanation of drawings]

Fig. 1 is a diagram explaining the principle of the present invention, Fig. 2 is a program diagram showing an embodiment of the invention, Fig. 3 is an explanatory diagram of each signal, Fig. 4 is a flowchart showing the operation, Fig. 5 is an explanatory diagram of the conventional example, and FIG. 6 is a flowchart showing the conventional example. 11... Format control section (format control means), 2... Sector detection circuit (sector detection means), 3...
MPU (control means), 4...part of timer (discrimination means), 5-17.19...register, 8...comparison circuit, 0...reset circuit, 1...system bus 2. ...Interrupt signal line, 3...Start signal line. In the figure, 3 4

Claims (1)

[Claims] A format control means (11) for controlling write/read operations to the medium, a sector detection means (12) for detecting a designated sector, and a timer activated by the output of the sector detection means (12) for writing. The apparatus includes a determination means (14) for determining the start of a read operation, and a control means (13) for controlling the format control means (11) based on the output of the determination means (14), and the timer value reaches a predetermined value. If not, the control means (13) controls the format control means (11).
) is configured to instruct the start of the write/read operation.