JPS62222467A - Track access control method for disk devices - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Table of Contents] Overview Industrial Field of Application Conventional Technology Problems to be Solved by the Invention Means for Solving the Problems (Fig. 1) Working Example (a) Magnetic Disk Mechanism Section (Fig. 2, Fig. 3) (b) Explanation of the configuration of the control means (Fig. 4) (Explanation of C1 initial processing (Fig. 5, Fig. 6, Fig. 7)) (d) Description of the access processing Explanation (Fig. 8, Fig. 9, Fig. 10, Fig. 11, Fig. 12) (el) Explanation of other embodiments Effects of the invention [Summary] A head is moved to a track on a disk to access a track having servo information. In a track access control method in which access is performed by correcting the offset amount measured by the timer, a timer is provided, the offset amount is invalidated by the timer's time alarm, and the offset amount is updated by measuring the offset when a seek command is received. By prohibiting read output to the upper level when a seek command does not arrive for a predetermined period of time, the offset update is performed without affecting the upper level.

(Industrial Application Field) The present invention provides a disk device such as a magnetic disk device, in which a data track and a servo track are provided on a disk.
The present invention relates to a track access control method that uses an offset amount obtained from a servo track as a correction amount for track access, and particularly relates to a track access control method for a disk device that can update the offset amount without affecting the upper layer.

In recent years, in rotary disk drives 1 and q such as magnetic disk drives, the track spacing on the disk has become smaller due to the demand for higher density and larger capacity.

In such disk devices, the position of the trunk may shift due to the accuracy of the head installation and expansion and contraction of the disk due to temperature rise.In high-density devices, this cannot be ignored, and such position shifts are detected and corrected. The need has arisen.

[Conventional technology]

For this reason, it has been proposed to provide a servo trunk by writing servo positioning information on a portion of the track of a magnetic disk.

In this conventional technology, a head is positioned on a servo track, the contents of the servo track are read by the head, the positional deviation of the head with respect to the servo track is detected from successive outputs, and this is used as an offset amount to be applied to subsequent data tracks. It was used as a correction amount during access.

On the other hand, such positional deviation changes as the temperature rises, and therefore the offset amount also needs to be updated. Conventionally, as a method for updating this offset, the servo track is periodically accessed, the amount of offset is measured, and the amount of offset is updated.

[Problem that the invention seeks to solve]

However, since such offset updating is executed asynchronously with the higher level, if the higher level is in the middle of an offset update operation when it issues a seek command, it cannot accept it, and therefore the higher level cannot accept the offset update operation of the disk device. There is a problem in that it creates a burden to issue commands while monitoring.

SUMMARY OF THE INVENTION An object of the present invention is to provide a track access control method for a disk device that can perform offset updating without interfering with issuing higher-level commands.

[Means for solving problems]

FIG. 1 is a diagram explaining the principle of the present invention.

In the figure, 1 is a rotating disk, which has many trunks, and servo information is written in some of the tracks. 2 is a head, which reads/writes the contents of the tracks of disk L. 3 is a moving means for accessing and moving the head 2 in a direction intersecting the trunk of the disk 1; 4 is a control means for moving the head 2 to access a designated track in response to a seek command; In addition to controlling the means 3, the head 2 accesses a track having servo information by offset measurement processing to measure the offset amount, and the offset amount is used as a correction amount at the time of the aforementioned track access.

TM is a timer, which invalidates the offset by timeout and prompts the offset update.

Further, the control means 4 invalidates the offset i after a timeout, performs offset measurement processing when receiving a seek command, and prohibits read output if a seek command is not received for a predetermined period of time.

[Effect]

In the present invention, when the timer TM times out,
), the offset it is invalidated, and the control means 4 measures and updates the offset when receiving a seek command after timeout, and executes the seek command.

That is, the amount of offset is required when a seek command from a higher level is given, and the amount of offset is not required when no seek command is given. Therefore, it is only necessary to update the offset measurement when receiving a seek command, and thereby the upper level can issue a command without being aware of the offset measurement update operation.

This means that the offset measurement is updated in synchronization with the host.

Furthermore, if a seek command does not arrive for a predetermined period of time after the timeout (until the next timer timeout), that is, if the head remains located at the same address, the offset amount will change from the previous time after the next timeout, and the trunk The head is misaligned. Therefore, even if the receiver executes a read/write command that does not involve a seek command, it will not be able to correctly read/write to the trunk, so the output of the read output from the head to the upper level is prohibited, and the upper read/write command is executed. In contrast, error detection is performed at the higher level, a try operation is performed from the higher level, and the offset is updated.

That is, in such a case, a seek command is issued as a try from the higher level, and thereby it is possible to perform an offset/node update similar to that shown in FIG. 1(B).

〔Example〕

(Description of al magnetic disk mechanism section FIG. 2 is an explanatory diagram of the magnetic disk mechanism.

In the figure, 1a, 1b, and IC11d are magnetic disks,
In this example, a servo track SVT shown in FIG. 2(B) is provided on the lower surface of the magnetic disk lc.
are provided mixedly in the data trunk, and the top surfaces of the other magnetic disks 1a, 1b, 1d, and 1c are provided with only data tracks, and 11 is a spindle motor, which is centered on the rotating shaft 10. magnetic disk la
, 1b, lc, and ld, and 12 is a servo position detection mechanism, which is directly connected to the spindle motor 1 and generates a HOLL signal corresponding to the writing position of the positioning information of the servo track SVT. thing,
2a, 2b, 2c, 2d, 2e, 2f, 2g, and 2h are magnetic nodes that read/write the magnetic disks 1a to 1d, and 3a is a voice coil motor (hereinafter referred to as VC
The magnetic heads 2a to 2h are supported via leaf springs and are moved in the radial direction of the magnetic disks 1a to 1d.

Therefore, the magnetic disks 1a to 1d are connected to the spindle motor 1.
1, and the VCM 3a rotates the magnetic node 2a.
2h moves in the radial direction of the magnetic disks 1a to 1d to access a desired track.

As shown in FIG. 2(C), the trunk arrangement of the magnetic disk 1c is such that, for example, when tracks θ~400 are physically set, the lOO track is one zone, and three servo tracks are placed in the center of the zone. An SVT is provided.

That is, physical track addresses “49”, “50”, “5”
1", '149", "150", "1511," 249
”, “250”, 6251”, “349”, “350”
, '351'' are servo tracks SVT, and the others are data tracks.On the other hand, logical trunk addresses are sequentially assigned from the left to the data tracks excluding the servo track SVT.For example, the physical track address "
400'' is a logical trunk address of 388. In each zone, the offset amount obtained from the servo track of that zone is used as the correction M.

FIG. 3 is an explanatory diagram of the servo trunk.

As shown in FIG. 3(A), the servo trunk SVT includes:
Three pieces of positioning information are written in one revolution at predetermined intervals starting from the index, and the servo position detection mechanism 12
outputs a Hall signal corresponding to the position including positioning information 1 in accordance with the rotation of the spindle motor 1.

As mentioned above, the servo track SVT is composed of three trunks, and the positioning information written in the three trunks is written in the half of the track at the top and center of the figure in area A, as shown by the diagonal lines of each trunk. In area B, signals are written in half of the tracks at the center and bottom of the figure.

Therefore, when the magnetic head 2 is positioned at the center of the three servo racks, if it is located at the center trunk of the servo trunk shown in (■) in FIG. The throat output will be as shown in Figure 3 (B),
The peak hold outputs of the A region and the B region are at the same level, and the offset, which is the output difference between A'aHa2 and the B region, is zero. On the other hand, if the head is located above the center trunk of the servo track shown in ■ in Figure 3 (A), the head output via the amplifier will be as shown in Figure 3 (C), and the peak hold output will be A. The output of area B becomes larger than that of area B, and the output difference between area A and area B takes a positive value, resulting in a positive amount of offset, as shown in ■ in Figure 3 (A). If the position is below the center track of the servo trunk, the head output via the amplifier will be as shown in Figure 3 (D), and the peak hold output in the area B will be smaller than that in the area B. The output difference between area A and area B takes a negative value, and a negative offset amount is obtained.

This offset amount is proportional to the distance away from the center of the center track. Therefore, the offset foot can be obtained by positioning the head with the center trunk of the servo trunk as the target, reading the positioning information in synchronization with the hall signal, and taking the difference. It will be done.

(b) Description of the configuration of the control means FIG. 4 is a block diagram of a control means according to an embodiment of the present invention.

In the figure, the same components as those shown in FIG. is a comparator, and the servo position detection mechanism 12
One that pulses the output of and outputs it as a Hall signal.
Reference numeral 5 denotes a main control unit that executes initial processing and access processing to be described later; 6 a drive unit that controls the positioning of the VCM 3a based on the amount of movement and offset from the main control unit 5; and 7 a reading unit. The read output of the magnetic head 2r is given to the main control section 5 or a higher level.

That is, the control means 4 includes a main control section 5, a driving section 6, and a reading section 7.
It consists of

50 is a step pulse count, which counts the number of step pulses according to the logical relative address as a seek command from the upper disk controller, and 51 is a manual register, which is an ID that latches the direction of movement from the upper level.
A latch 51a, a vO clutch 1b that launches a VO multiplied signal indicating zero speed of a VCM 3a of a VO detection circuit, which will be described later, and a HOLL latch 51C that latches a Hall signal from a comparator 13 (FIG. 3(A)); 52 is a microprocessor (hereinafter referred to as MPU), which performs initial processing and access processing to be described later by executing a program; 53 is an address decoding circuit;
Decode the address from U52 and write each register, DA
C, a device that generates ADC enable signals, counters, and timer load signals; 54 is a read-only memory (
55 is the aforementioned timer TM, which stores processing programs such as the initial processing program and access processing program necessary for the processing of the MPU 52, and parameters such as the physical track address of the servo trunk. , a timer value is loaded, and when the timer value becomes zero due to clock counting, an interrupt signal is issued to request the MPU 52 to perform an interrupt process (offset correction update process), and 56 is a random access memory (hereinafter referred to as RAM). ), a target physical track address storage register (hereinafter referred to as TCRP) 56a, and a target logical trunk address storage register (hereinafter referred to as TCRL) 5.
6b, current physical trunk address storage register (hereinafter P
CRP) 56C1 Current logical track address storage register (hereinafter referred to as PCRL) 56d, each zone (1
- n) offset correction amount storage register 56e that stores the offset correction amounts IC1 to Cn, and a correction confirmation table 56f that stores a flag for checking whether the offset correction amounts C1 to Cn of the correction amount storage register 56e are valid. It is something that you have.

57 is a difference counter, which is loaded with the number of moving tracks that is the difference between the target physical trunk address and the current physical track address from the MPU 52, and is subtracted by the track cross pulse caused by the movement of the VCM 3a; 58a is a digital-to-analog converter (hereinafter referred to as (referred to as DAC), which sets the offset correction amount from the MPU 52, converts it into an analog amount, and outputs it;
Reference numeral 8b is an analog-to-digital converter (hereinafter referred to as ADC), which converts the peak-held signal of the servo trunk read signal from the reading section 7, which will be described later, into a digital value and provides it to the MPU 52; 59 is an output register; A direction latch 59a whose movement direction is set by , a seek latch 59b whose movement direction is set by MPU52, and a seek latch 59b whose movement direction is set by MPU52.
2, the RD latch 5 is set to prohibit output of glued data from the magnetic head 2f in the reading unit 7.
9c and TRO, which is set by the MPU 52 to indicate to the upper level that the head is at track address "0".
The latch 59d and the SC latch 5 set by the MPU 52 to indicate to the upper layer that the seek operation has been completed.
9e, A-BUS is an address bus, and the address from the MPU 52 is transferred to the address decoding circuit 5.
3 and ROM 54, D-BUS is a data bus, which connects MPU 52, stem pulse, counter 50, input register 51, ROM 54, timer 55,
RAM56, difference counter 57, DAC58a
, ADC 58b, and output register 59.

60 is a target speed generation circuit, which generates a target speed Vc of an amount proportional to the contents of the differential counter 57 and a polarity according to the direction of movement of the direction luff 59a of the output register 59; A speed error detection circuit detects and outputs the error △V between the target speed Vc from the target speed generation circuit 60 and the actual speed Vr created by the speed creation circuit described later from the encoder 3b of the VCM 3a. 62 is a speed creation circuit. A circuit 62 is a circuit that differentiates the position signal from the encoder 3b to generate the actual speed Vr of the VCM 3a, and a circuit 63 is a track cross pulse generation circuit, which appears every time a track is crossed from the position signal from the encoder 3b. 64 is a VO detection circuit which generates a trunk cross pulse to subtract (count down) the above-mentioned difference counter 57, and detects from the actual speed Vr of the speed generation circuit 62 that the actual speed of the VCM 3a has become zero. 65 is an adder circuit that detects and generates a 0 signal and supplies it to the O launch 51b of the input register 51.
A multiplexer 66 (hereinafter referred to as MPX) generates a positioning output by adding the position signals from the output resistors 59 to ΔV of the speed error detection circuit 61 and the adder circuit 65 depending on the contents of the seek latch 59b of the output register 59. The positioning output of the sea clutch 59b is selectively outputted.
67 is a VCM drive circuit which is composed of drive transistors and drives the VCM 3a with the output of the MPX 66.

70 is a peak hold circuit, which holds the peak of the read output of the magnetic head 2r and outputs it to the ADC 58b, and is used for offset detection as explained in FIG. 3; 71 is a data pulse generation circuit; 72 is a pseudo data creation circuit that generates pseudo data, and 73 is a multiplexer (hereinafter referred to as MPX).
), and the output register 59 RD U・7CH 59
The data pulse of the data pulse generation circuit 71 and the pseudo data of the pseudo data generation circuit 72 are selectively outputted depending on the contents of c, and the pseudo data is output at the cent of the RD latch 59c, and the data pulse is output at the reset of the RD clutch 9C. It is output to the upper level.

Therefore, the main control section 5 receives a step pulse and a direction as a seek command from a higher level, and outputs a track 0 signal and a seek complete signal to the higher level. In addition, the main control section 5
gives a movement amount and an offset correction amount to the drive section 6, receives the ■0 signal from the drive section 6, and receives a peak hold signal from the reading section 7.

The drive unit 6 includes a position control loop consisting of the encoder 3b, a track cross pulse generation circuit 63, and a differential counter 57, and a speed control loop consisting of the encoder 3b, a speed generation circuit 62, and a speed error detection circuit 61. , perform positioning control of the VCM3a to the target trunk,
After the speed of the VCM 3a reaches zero, the output of the adder circuit 65 performs positioning correction control including offset correction.

The reading section provides a peak hold signal for offset measurement to the main control section 5, and outputs data pulse 2 or pseudo data as read data to the upper level.

When the power is turned on, the main control unit 5 executes the following initial processing (described in C1) and obtains the offset correction amount for each zone of the magnetic disk in advance.

After this, command reception from the higher level is permitted, the access process described in (d) is executed, the data trunk of the magnetic disk is accessed, read/write is performed, and at the same time, the offset correction amount is periodically corrected. , it is possible to perform offset correction corresponding to offset fluctuations due to temperature changes.

(C) Description of initial processing FIG. 5 is an initial processing flow diagram, FIG. 6 is an explanatory diagram of the seek control subroutine, and FIG. 7 is an explanatory diagram of the offset measurement subroutine.

(2) When the MPU 52 receives the power-on signal, the MPU 52 performs seek control to move the magnetic heads 2a to 2h to the trunk "O" position.

Although it is not clearly shown in the configuration of Figure 4, an outer guard bunker is provided outside the trunk zero in Figure 2.
V is applied from the drive unit 6 via the differential counter 57 so that the magnetic node 2f moves toward the outside of the magnetic disk.
The CM 3a is driven, and when the magnetic head detects the outer guard bunker, it stops, and the VCM 3a is similarly driven to position the magnetic head on the inner track "0".

After locating at the reference position of trunk "0" in this way, the MPU 52 moves to the PCRP which is currently the address register.
56cSent "O" to SPCRL56d.

■Next, the MPU 52 reads the servo track address of zone 1 of the ROM 54 (physical address "50" in FIG. 2), sets this as the target trunk address, and uses the TCRP
56a and set the servo correction flag in the built-in register.

(2) A seek control subroutine, which will be described later in FIG. 6, is executed to position the magnetic head 2f at the target trunk (servo track).

(2) Next, the MPU 52 executes an offset measurement subroutine to be described later in FIG. 7, measures the offset from the read output of the servo trunk, and calculates a correction amount.

0 Next, the MPU 52 sends the target physical address of the TCRP 56a to the I'CRP 56c as the current physical address.

(2) The MPU 52 determines whether all servo tracks have been read from the contents of the built-in sequence register, and if not, reads the servo trunk address of the next zone from the ROM 54, sets it in the TCRP 56a, and returns to step (2).

■In this way, the MPU 52 reads all servo tracks and sets the offset correction amounts for all zones (4 zones in FIG. 2 (C)) in the correction storage register 56e, and then resets the servo correction flag. , TCRP56a
points to physical address 0 and executes the seek control subroutine shown in FIG. This positions the magnetic head at trunk "0".

■The MPU 52 then uses the PC, which is the current address register.
RP56c and PCRL56d are set to "0", and a value is loaded into the timer 55, and the timer 55 is activated.

0 Next, the MPU 52 sets the TRO latch 59d and SC latch 59e of the output register 59 to 1, and sets the track 0.
Raise the signal and seek complete signal to the upper level and notify that command reception is possible.

FIG. 6 is an explanatory diagram of the seek control subroutine.

This is a routine for moving the magnetic head to a desired trunk, and in addition to seeking to the servo track in FIG.
This is commonly used for seeking to data tracks and seeking to servo tracks, which will be explained in the access processing of FIG. 8.

(Sl) The MPU 52 calculates the difference between the target physical address of the TCRP 56a in the RAM 56 and the current physical address of the PCRP 56C, and uses this as a moving vehicle to set the cell l-L in the difference counter 57 and the direction rasotchi 59a of the output register 59. Set the direction. Furthermore, five output registers 59b are connected.

As a result, the MPX 66 is selected to output the error ΔV of the speed error detection circuit 61 to the VCM drive circuit 67, and the target speed generation circuit 60 is set to the target speed according to the direction of the direction latch 59a according to the content of the difference counter 57. The speed error detection circuit 61 outputs the error Δ between the speed Vc and the actual speed Vr of the speed generation circuit 62, and MPX
The VCM 3a is driven by the VCM drive circuit 67 via the VCM drive circuit 66.

By driving the VCM 3a, a trunk cross pulse is output from the I/rank cross pulse generation circuit 63, and the difference counter 57 is subtracted. Therefore, position control and speed control are performed, and the magnetic head approaches the target physical trunk address by the VCM 3a.

(S2) On the other hand, the MPU 52 uses the difference counter 5
7, the content of the counter 57 is zero, and it is checked whether the hit target physical address has been reached. When the content of the counter 57 becomes zero, it is assumed that the target physical address has been reached, and the VO clutch of the input register 51 is then activated. Check the contents of 1b.

As mentioned above, when the VO detection circuit 64 detects that the actual speed Vr has become zero, it emits the ■0 signal, so the VO multiplier signal is latched by the VO clutch 1b, and when ■0 latch = 1, the speed of the VCM 3a becomes zero. It is determined that this is the case, and positioning control is started.

(S3) The MPU 52 first clears the sea latch 59b of the output register 59. As a result, the MPX 66 is switched to the adder circuit 65 side.

(S4) Next, the MPU 52 checks the servo correction flag, and if the servo correction flag is set, it is an offset measurement, so the MPU 52 sets the DAC 58a to O, and
Conversely, if the servo correction flag is not set, the MPU 52 uses TCRP to perform offset correction in normal access.
The offset correction amount of the zone to which the target physical trunk address 56a belongs is read from the correction amount storage register 56e and set in the DAC 58a.

As a result, the adder circuit 65 outputs the sum of the output of the DAC 58a and the position signal of the encoder 3b to the MPX6.
6 to the VCM drive circuit 67, and the VCM 3a is subjected to so-called fine control.

In this case, in normal access, offset correction is performed using an offset correction amount. Then, the MPU 52 waits for a certain settling time, and then exits this routine.

FIG. 7 is an explanatory diagram of the offset measurement subroutine.

This routine reads the servo signal of the servo track and
This is a routine for measuring the offset amount, and is used for the initial processing in FIG. 5 and the offset correction amount measurement processing in FIG. 10.

(S5) The MPU 52 selects H01 of the input register 51,
Reset the L latch 51C.

As explained with reference to FIG. 3, the 1■○LL signal is output by the rotation of the spindle motor 11 in synchronization with the position of the servo trunk positioning signal. For this reason, the MPU 52 checks whether the I(○ HOLL latch 51c is reset, the HOLL signal is generated, and the HOLL latch 51C is sent.

(36) If the HOLL latch 51C is set, the magnetic head 2r is reading the servo track positioning signal.
The A-area servo signal and the B-area servo signal obtained by peak-holding the output of the magnetic bed 2f by the peak-hold circuit 70 are sequentially read through the magnetic bed 8b.

(S7) Next, the MPU 52 executes the operations shown in FIGS.
As explained in (D), the offset correction amount C and the offset direction are calculated from the read A signal and B signal.

(S8) Furthermore, the MPU 52
The offset correction 1c related to the bending zone of the servo trunk is written, the corresponding flag in the correction confirmation table 56f is set, and the routine is skipped.

Description of fd+ access processing FIG. 8 is an access processing flow diagram, FIG. 9 is a logical address/physical address conversion processing flow diagram, and FIG. 10 is an offset correction measurement]1 constant processing flow diagram.

(i) The MPU 52 reads the contents of the step pulse counter 50 and checks whether the contents of the counter 50 are zero. As mentioned above, since a relative logical address is given as a seek command by the number of step pulses from the higher-level controller, the fact that the counter 5o is zero means that a seek command is being waited for.

(ii) On the other hand, if the counter 50 is not zero, the MPU 52 transfers the contents of the step pulse counter 50 to the target logical trunk address register TCRL 56b of the RAM 56, since the step pulse and direction have been given as a seek command from the higher order.

Then, the MPU 52 waits for a certain period of time, reads the contents of the step pulse counter 50 again, compares it with the above-mentioned read contents of the TCRL 56b, and if they are not the same, updates the TCRL 56 b with the read contents and repeats this step.

(iii) The MPU 52 confirms that the read contents are TCR
If it is determined that the content of L56b is the same as the previous read, it is determined that the step pulse has ended, the ID latch 51a of the input register 51 is read, and the specified direction is obtained.

Next, the MPU 52 calculates a target logical track address according to the specified direction from the logical relative address of the TCRL 56b and the current logical address of the PCRL 56d, and
Cent to RL56b.

Next, this target logical trunk address is converted into a target physical address by the process shown in FIG. 9, and transferred to the TCRP 56a.

As shown in Fig. 2, if three servo tracks are set for each zone of 100 tracks, if the target logical trunk address is 49 or less, it is set as physical trunk address - logical track address, and the target logical If the trunk address is between 49 and 146, set the physical track address - logical track address + 3. If the target logical trunk address is between 146 and 249, set the physical trunk address - logical track address + 6, and if the target logical track address is 249. If it is between 340 and 340, it is converted to the target physical trunk address as physical trunk address - logical trunk address + 9. If the target logical track address is 340 or more, it is converted to the target physical trunk address as physical track address - logical track address + 12. This conversion allows the upper level to access the logical trunk address of the data trunk only without being aware of the existence of the servo track.

(iv) The MPU 52 determines the zone corresponding to the target physical track address of this TCRP 56a, and
The flag corresponding to the zone in the correction confirmation table 56f of M56 is confirmed.

The meaning of checking this flag is that, as explained in FIG. 10, after the timer 55 has elapsed, in order to update the offset correction amount, the flag in the correction confirmation table 56f is reset, and the offset correction amount is not updated. until
This is because the offset correction amount in the correction wheel storage register 56e is invalidated.

If the flag is set, the offset correction amount in the correction amount storage register 56e is valid, and the process proceeds to step (vi). If the flag is raised, the offset correction amount is invalidated and the offset below step (V) is set. After carrying out the correction amount measurement process (FIG. 10), the process proceeds to step (vi).

(V) First, the MPU 52 sets the servo correction flag and transfers the target physical track address from the TCRP 56a to the PC.
Move to RL56d.

Next, the MPU 52 reads the servo track address that falls within the zone of the target physical trunk address from the ROM 54, transfers it to the TCRP 56a, executes the seek control subroutine of FIG. 6, positions the magnetic head 2f on the servo track, and further The offset correction subroutine shown in FIG. 7 is executed to obtain the offset correction amount for the zone, store it in the correction amount storage register 56e, and set the flag for the zone in the correction confirmation table 56f.

Next, the MPU 52 resets the servo correction flag and T
The target servo track address of CRP56a is transferred to PCRP56c as the current physical track address, and the PCR
TCR the target physical track address saved to L56d.
Return to P56a, and finally reset the VO latch 51b.

(vi) Next, the MPU 52 executes the seek control subroutine of FIG. 6 based on the target physical trunk address of rcRpsga and the current physical track address of PCRP 56c, and positions the magnetic head on the data track of the target physical trunk address.

MPU 52 thereby moves the target physical trunk address of TCRP 56a to PCRP 56c as the current physical 1-rack address, and sets the target logical trunk address of TCRL 56b as the current logical trunk address.
Transfer to ζPcRL56d.

(vii) Next, the MPU 52 resets the stamp pulse counter 50 and the o latch 51b, and further
52 checks the contents of PCRL 56d to check whether the head is on track ``0'', and if the contents of PCRL 56d is O, it is assumed that the head is on track ``0'', sets the TRO latch 59d, and gives a trunk 0 signal to the upper layer. PCRL56d
If the content of is not 0, it is assumed that it is not in track "0",
Reset TRO latch 59d.

(viii) Next, the MPU 52 switches the RD latch 59c to the reset mode L-L, switches the MPX 73 of the reading section 7 to the data pulse generation circuit 71, sets the SCC latch 51, raises the seek complete signal to the upper level, and executes step (i). ).

Therefore, the upper level reads the read pulse from the magnetic head of the data pulse generation circuit 71 via the MPX 73 as read data, checks the track number of the I rack, and if it is a read command, obtains the following read data, and if it is a write, it is shown in the figure. Write data to the corresponding track from the write section that is not connected.

FIG. 11 is an explanatory diagram of the interrupt processing routine.

The magnetic disk is rotated after the power is turned on, and the temperature of the mechanism gradually rises until it reaches a certain temperature.

Therefore, due to this temperature rise, the trunk position shift amount of the magnetic disk changes, and it is necessary to update the offset correction amount.

Therefore, the timer 55 is started, and when the timer 55 finishes counting the load value and times out, an interrupt is made to the MPU 52 to execute this routine for updating the offset/7t correction amount.

■First, when the MPU 52 receives an interrupt, the RAM
56 in the correction confirmation table 56f.

(2) If all the flags in the correction confirmation table 56f are not "0", the MPU 52 sets all the flags in the correction confirmation table 56f to "0" and forcibly disables the offset correction port.

Then, the MPU 52 loads the value into the timer 55 again and starts the timer 55.

- On the other hand, if all the flags in the correction confirmation table 56f are "0", the MPU 52 has not received a single seek command during the period in which the timeout occurred, and therefore the offset update shown in FIG. 8 is performed in that period. It is determined that this is not done at all, and in this case, the RD clutch 9c is set and the MPX7
3 is outputted from the pseudo data generation circuit 72 as read data to the upper level, and the output from the data pulse generation circuit 71 is prohibited. Furthermore, the TRO latch 59d is reset and the 1-rack 0 signal to the upper level is dropped.

Then, the MPU 52 again loads the value into the timer 55 and starts the timer 55.

FIG. 12 is an explanatory diagram of the overall operation of these access processes.

As shown in FIG. 12(A), when the power is turned on, the offset correction amount of each zone is measured by the initial processing shown in FIG. 5, and each offset correction amount C1 to Cn is set in the correction amount storage register 56e, and The flag in the confirmation table 56f is turned on and the timer 55 is activated.

Therefore, during the period of the load value T1 of the timer 55, the offset correction for all zones is valid, and access based on the offset correction is executed in response to a seek command for each zone.

Next, when the timer 55 times out and the cycle T1 ends, the offset correction amounts of all zones are invalidated by the interrupt process shown in FIG.

On the other hand, the timer 55 is activated for the next period T2.

If a seek command is received in this state, step (v) of the access process shown in FIG. 8 measures the offset correction amount for the zone of the track address indicated by the seek command, and updates the offset correction amount for the corresponding zone in the correction amount storage register 56e. Then, the flag of the corresponding zone in the correction confirmation table 56f is turned on, and access based on the updated offset correction is executed.

At this time, the reason why offsets are not updated for all zones is to avoid prolonging the access time for this seek command, and the offsets necessary for accessing the specified trunk are updated. Therefore, in period T2, the offset of only the corresponding zone of the track specified by the seek command is updated. For example, when the seek command for the first zone is
, the offset update is performed only for the first zone,
Offset correction becomes effective.

On the other hand, as shown in FIG. 12(B), if no seek command has arrived in the previous cycle Tn-1, this cycle Tn-
In +, no offset update is performed at all.

Therefore, the head is on a trunk accessed before period Tn-s, and the offset is before period Tn-1? +I
The trunk is accessed by i amount.

If a seek command comes at this cycle Tn, the offset will be updated in the same way as in FIG. When , the access processing shown in FIG. 8 is not performed, and only read/write is performed.

Since the relationship between the head and the trunk at this time is accessed by the offset correction amount before the cycle Tn-1, there is a possibility that a deviation has occurred at the cycle Tn, and therefore correct read/write cannot be guaranteed. .

Therefore, if a seek command does not arrive at cycle 7'n-1 and all the flags in the correction confirmation table 56f are zero, the RD rough reach 59c is sent in step (■) in FIG. 11, and a data pulse is created by the MPX 73. The output of circuit 71 is prohibited.

As a result, even if the upper level simply reads the same address, since the read data is pseudo data from the pseudo data creation circuit 72, it cannot confirm the trunk number, determines it as an error, and performs a retry operation.

This retry operation is a seek command to track "0", and the seek to track "0" in step (2) in FIG.
”, it sends a seek command to the relevant trunk address. As a result, the offset is updated by the access process in FIG. 8 in the same way as in FIG. 12 (A), and the updated offset correction amount is access to the track address is performed, and the RD clutch 9C is reset, making it possible to output the output of the data pulse generation circuit 71 as read data.Also, the period of the timer is proportional to the temperature rise. ,'rl,'l'
It is best to gradually lengthen the length as z・-.

telExplanation of other embodiments In the embodiment described above, the seek command from the upper level is “ζ
Although relative logical addresses are given as pulses, absolute logical addresses may also be given.

Although the present invention has been described above using one embodiment, the present invention can be modified in various ways according to the gist of the present invention, and these are not excluded from the present invention.

〔Effect of the invention〕

As explained above, according to the present invention, the host can issue commands without being aware of the offset update operation of the disk device, and if the offset/update is not performed for a predetermined period, the read output is disabled. By prohibiting this, the error can be recognized by the higher level, and this has the effect of allowing the offset to be updated by a trial operation, allowing the offset update to be executed in synchronization with the higher level without changing the interface of the higher level.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of the principle of the present invention, Fig. 2 is an explanatory diagram of a magnetic disk mechanism according to an embodiment of the present invention, Fig. 3 is an explanatory diagram of the servo trunk of Fig. 2, and Fig. 4 is an explanatory diagram of an embodiment of the present invention. 5 is an initial processing flow diagram of an embodiment of the present invention; FIG. 6 is an explanatory diagram of a seek control subroutine of an embodiment of the present invention; FIG. 7 is an offset diagram of an embodiment of the present invention. An explanatory diagram of the measurement subroutine, FIG. 8 is an access processing flow diagram of an embodiment of the present invention, FIG. 9 is a logical address/physical address conversion processing flow diagram in FIG. 8, and FIG. 10 is an offset correction amount measurement diagram in FIG. 8. FIG. 11 is an explanatory diagram of the interrupt processing routine in FIG. 8, and FIG. 12 is an explanatory diagram of the overall operation. In the figure, 1--disk, 2-head, 3-moving means, 4--controlling means, TM-timer.

Claims (1)

[Scope of Claims] A moving means (3) for moving the head (2) in a direction intersecting the tracks of the rotating disk (1), and moving means (3) for moving the head (2) to a specified track in response to a seek command from a higher level. )
control means (4) for controlling the moving means (3) to access a track having servo information; In a track access control system of a disk device that controls the moving means (3) using the amount of correction, a timer (TM) is provided in the control means (4), and when the timer (TM) times out, the offset amount is invalidated. When receiving the seek command, the offset amount is measured and updated, and if the seek command does not arrive for a predetermined period of time after the timeout, read output from the head to the upper level is prohibited. A track access control method for a disk device characterized by: