JPS5958672A - Offset seek control system - Google Patents

Abstract

PURPOSE:To attain the connection of a magnetic disc device having an offset seek (OSF) function to a magnetic disc device having no OFS function without changing a control microprogram, by the constitution that the OFS control is attained at the magnetic disc side. CONSTITUTION:When a read instruction is given to a terminal R, an FF7 is set. When the instruction is finished normally, the signal is given to a terminal NE to reset an FF22. If the readout instruction is finished abnormally, an FF11 is set via a signal given to terminals NAMF and NSBF and an output signal of the FF7. An AND circuit 12 goes to 1 with a target instruction given to a terminal ST, and the retrial number is counted by a counter 15 using a sequencer 16 via the FF14. The number decides the direction of the offset seek and the amount of offset. Then, the connection of the magnetic disc device having the offset seek(OFS) function to the magnetic disc having no OFS function is attained.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention provides an offset seek function (the entire position of the head accessing the target track is slightly shifted by 1-7
A function that makes it possible to read data recorded off-center from the center of the track) Compatibility with magnetic disk drives that are compatible with all types of magnetic disk drives, especially those that lack the offset seek function? The present invention relates to a k-th offset seek control method.

(bl) Prior Art and Problems In large-capacity magnetic disk drives, head positioning is generally done separately from data writing and reading. Head positioning to each track belonging to the same cylinder is performed seven times.

FIG. 1 is a schematic diagram of a magnetic disk device with a servo zone. ] positions each magnetic head indicated by 2 and 3 using a voice coil motor.

Reference numeral 2 designates a head for inputting/outputting data, and reference numeral 3 designates a servo head. 4 indicates the data zone of the magnetic disk disk, and 5 indicates the entire servo zone. The servo head 3 reads out the servo code in the servo engine 5, and the trunk head 2 on the same cylinder accesses it. However, due to various mechanical factors, the position of a track in a data zone on a magnetic disk disk may deviate from the position of the corresponding servo zone, and previously written data may be positioned by the servo zone. If the recording is not in the center of the track, the phenomenon may occur.

In such a case, if the position of head 2 that is accessing the track in question is ff1 (i = slightly), all the data can be output one after another. In this way, the position of head 2 ta *
qt--The offset seek function is used to shift the positioning device. Generally, as the track density increases, the width of each track becomes narrower, making it easier for the tracks to be misaligned relative to each other.

By the way, in order to have control compatibility with the American model, the diameter of the magnetic disk disk is the same, the transfer speed is the same, and the track density is the same. k'c
I have no choice but to make one intellect and one stone. However, as mentioned above, magnetic disk drives with increased track densities require offset technology, making them incompatible with older magnetic disk drives that do not have the conventional offset function. There are drawbacks.

+CI Purpose of the Invention In order to eliminate the above-mentioned drawbacks, offset seek control is performed on the magnetic disk device side? By making it possible to connect all magnetic disk devices with the offset seek function without changing the control microprogram, it is possible to connect all magnetic disk devices that do not have the offset seek function. Is there a f-offset seek control method? It is about providing.

fdl composition of invention non-invention! Does the 4th generation have an offset seek function? What are the conditions for fully activating the offset seek function in a magnetic tisf device? What is the method of detection and the conditions for complete offset seek operation? A detecting means is provided so that the magnetic disk drive performs an offset seek operation regardless of the control of the magnetic disk drive control Vem.

(El An embodiment of the invention) detects the state in which an offset seek is required on the magnetic disk drive side, issues all offset seek commands, monitors the read operation following the command, and performs an increased set seek if necessary. Change the direction or tk of the offset and issue all offset seek commands again. Or, depending on the case, release the offset state and set the center r (
It is a return item.

The conditions for fully activating the offset seek function in the non-method are as follows.

A data check occurred while the magnetic disk roasting device was continuously outputting all data, and an ECC (149 correction code)? After analysis, K was unable to obtain correct data, so the retry was made.A set target command was issued from the recording industry investigation magnetic disk control device.7. - Is it possible to operate the sequencer installed in the magnetic disk device or adapter? Start.

Further, the conditions for completely completing the offset seek operation in the non-method are as follows.

■ The specified number of retries has been reached, resulting in a retry out.

■ The head of the magnetic disk device has been switched, or ■ The magnetic disk device has performed a seek (head positioning operation) or a zero return operation (ltEzta and 0 head return operation to cylinder O).

■ The magnetic disk device is deselected (DEaEL doctor T selection is canceled).

■ IJ l-Fi was successful and the next read/write command was issued.

If any of the above five conditions is met, the sequencer ends its operation.

FIG. 2 is a block diagram of a circuit showing an embodiment of the invention. When a bladder removal command is input from the magnetic disk controller to the terminal box, the flip-flop 7 is set. When this read command ends normally, a normal end is issued to the magnetic disk control device from the adapter, and is input to the terminal NH via the OR circuit 6Tt and then to the flip-flop 7'k014. The free lug float 22i is reset via the circuit 23. However, the command to eject the bladder did not complete normally, resulting in a data checkerf, no address mark, failed (address mark could not be detected), or no synchronized byte failed (synchronized byte could not be detected). )
occurs, and when the data output ends abnormally, a no address mark efound is entered in the terminal DCK data check, a no synchronization byte φfound is entered in the fiM child N88P, and an OTt is entered. Times L124
After Ei k, the AND circuit 9 is set to "1" together with the output of the terminal Q of the flip-flop 7, and the flip-flop lli
set. When the flip-flop 11 is set to -gf, the flip-flop 7 is reset through the entire OR circuit 6. If the read command terminates abnormally due to data check, the magnetic disk controller will perform ECC(7)M analysis.
The instruction enters terminal ECC and ligates flip-flop 22. Data errors were corrected through ECC analysis.
If the function is active, a terminal IAK index alert signal is input from the magnetic disk controller, and the 8Nl) circuit 21yr"
01 (through the entire circuit 10, flip-flop 11
Reset. Resetting flip-flop 11
As a result, the terminal Q becomes 1''', and after the OR circuit V823k, the fringe front block is reset by 22. If the take error cannot be corrected by the ECC angle error analysis, a normal end is issued as described above, and the terminal NE is input to the OR circuit 6. and 2
3, the flip-flops 7 and 22 are completely reset. The magnetic disk controller has no address mark.
If data errors cannot be corrected by round-round, non-synchronized byte found, or ECC analysis, all magnetic disk devices are searched for the beginning of the record that is recording the target data in order to perform a complete re-read operation.
Set target commands to stimulate. π entering terminal ST
Due to the set target command, the AND circuit 12 becomes 61#, and the flip-flop 14 is set. The sequencer 16 is activated by setting the flip-flop 14, and at the same time, the flip-flop 11 is reset through the entire OR circuit 10.

Startup t't r: Sequencer 16 is flip-flop 17? Set, OR circuit 13? After that, all flip-flops 14 are reset. It shows that there is a flip-flop 17.

The sequencer 16 increments the counter 15 and counts the total number of retries. Also, depending on the number of times, offset seek 7
) Determine the direction and offset amount and set the command amount °T together with O.
After R times 1!320, the flip-flop 18 is reset. When the head reaches the beginning of the record, the magnetic disk drive interrupts the magnetic disk cutting distance 4. When the magnetic disk controller wakes up, the magnetic disk controller must perform a read operation.
An order? issue, and all flip-flops 18 are set via terminal RG'i. When the flip-flop 18 is set, the sequencer 16 outputs OII, the circuit 20? Afterwards, the flip-flop 18 is completely reset, and the flip-flop 14 is monitored until it is set again. If the re-read LIjL operation is completed normally, the flip-flop 14 will not be set, and after the re-read operation, the flip-flop 18 will be set again to process the next record, or The next track processing line 7 head switching command goes to terminal SHA, the seek start command goes to terminal SS, or the reset command goes to terminal S[
, or a deselect command is applied to the terminal SI-1 to complete the processing of the magnetic disk device.

When the flip-flop 14 is set and the flip-flop 18 is set again, the sequencer 16 outputs OR,
Flip-flops 18 and 17 via circuits 20 and 19i
? Reset. Also, terminal SHA, 8S.

When any of R, S, and SH becomes "1", ON- is turned on to circuit 1.
After o and 19 sessions, flip-flops 11 and 17 are reset.

If the reread operation fails, the Tanhi flip-flop 14 is set and the sequencer 16 enters the offset seek sequence again, repeating the above operation. If the counter 15 reaches the specified number of tryouts, the sequencer 16 outputs the flip-flop 14.
, 17.18 ((Resets and returns to the inactive state after resetting the counter 15. When the power is turned on, a reset signal is input to the terminal FOR as the initial reset m number, and the OR circuit 6
After 10, 13, 19, 20, 23'i, flip-flops 7.11, 14, 17, 18.21 are reset, respectively.

(fl As described in the detailed description of the invention, the present invention provides an offset seek function by changing the control microprogram in a magnetic disk control device that controls a magnetic disk that does not have an offset seek function. Increase memory capacity 7S
'Magnetic disk device? The effect is great because it can be connected and used as a support.

[Brief explanation of the drawing]

Is the servo zone in Figure 1? FIG. 2 is a block diagram of a circuit showing a simple embodiment of the invention. 1 is a voice coil motor, 2 is a write/read head,
3 is the servo head, 417t is the data zone, 5 is the servo zone, 7, 11.14, 17, 18.22 is the frame 11.
15 is a counter, and 16 is a sequencer. Akira 1 figure

Claims (1)

[Claims] In a magnetic disk device with an offset seek function,
Conditions to activate all offset seek functions? Means for measuring, conditions for ending offset seek operation, means for detecting all conditions, general means, and the fact that the magnetic disk device performs the offset seek operation without being controlled by the magnetic disk control device? Features an offset seek control method.