JPH02304784A - Servo track read/write system - Google Patents

Abstract

PURPOSE:To shorten the write time of servo information and to shorten the read cycle and hence to promote the stability of a seek control by cyclically permuting sectors of data with plural heads giving plural tracks a prescribed delay and writing the servo information to each sector. CONSTITUTION:The servo information of a DATA0 is written to the beginning of the data DATA0-DATA3, and the individual sectors of the DATA0 are cycli cally permuted by the heads 110-113 after giving a prescribed delay to the tracks TRK0-TRK3, and then the individual sectors are written in turn with the servo information. Next, in the case of the DATA1-DATA3, their individual write commencing sectors are set in the sectors of the tracks TRK1-TRK3 respectively, and they are cyclically permuted in a simmilar manner to the case of the DATA0, and then the individual sectors are written in turn with the servo information. By this method, the write time of the servo information is shorten, and moreover the servo sample time during the read is shortened so that the stability of the seek can be promoted.

Description

[Detailed Description of the Invention] [Summary] Regarding a servo track read/write method in which servo information is read/written in sector units to multiple tracks using a data surface servo method, the writing time of servo information is shortened, and the servo The purpose is to shorten the servo sample time when reading information and improve the stability of the seek, and uses multiple heads to read/write servo information in sector units to multiple trunks using the data surface servo method. In the servo track read/write method, when writing servo information, each sector of one data is written on multiple tracks using multiple heads.

Give the ivy a predetermined delay and rearrange it cyclically,
The servo information is written to each sector, and when reading servo information, the servo information written cyclically in a sector unit to a plurality of tracks is cyclically read by a plurality of heads.

[Industrial application field]

The present invention relates to a servo trunk read/write method that uses a plurality of heads to read/write servo information in sector units to a plurality of tracks using a data surface servo method.

[Conventional technology]

In magnetic disk drives, in order to perform seek control to correctly position the head on the track, seek control of the head is performed using closed-loop servo control while reading servo information that has been previously recorded on the magnetic disk surface. .

This closed-loop servo control includes servo surface servo and data surface servo. In servo surface servo, servo information is recorded on a dedicated servo surface.

On the other hand, with data surface servo, there is no dedicated servo surface;
This is a method in which servo information is written on the data surface, and there are two types: index servo, which writes servo information only at one location on the trunk, and sector servo, which writes servo information for each sector.

FIG. 7 shows a servo track write method in a conventional data surface servo. One cylinder consists of four trunks (TRK, ~TRK3) consisting of 32 sectors, and four heads 31. to 313, servo information is written for each sector. In each sector (X, Y), rXu indicates the logical number of the head, "Y" indicates the sector number, and indicates that the track TRKx is written by the head 31x. Also, servo information is written at the beginning of each sector.

rINDEXJ is an index mark indicating the physical origin of each track. Further, rSECTORJ is a sector mark generated at the start point (or end point) of each sector. TRK TRK and TRK2 I
Track TRK and TRK for NDEX mark
The phase of the INDEX mark 3 is shifted by 1/2 period as shown. By doing this, it is possible to increase the amount of servo information to be sampled.

FIG. 8 shows an example of servo information written to the data surface in sector format and data surface servo. 'GAP+~GAP,'' is a gap that distinguishes each sector or each field. rA
AGC information and a synchronization signal for correcting the level difference between the outer side and the inner side of the magnetic disk are written in the GC, 5YNCJ field. “Gray code + CYLJ
The gray code and cylinder number are written in the field. In the rODD/EVEN servo field,
ODD servo information and EVEN servo information are written. Data is written to the "data" field. rAGC, 5YNC, field ~ rODD/EVE
Servo information is constituted by each piece of information written in the "N Servo" field.

FIG. 9 shows the configuration of a magnetic disk device centered on the read/write portion of servo information. In the figure, 31. . . . 313 are heads, and an example of four heads is illustrated. Reference numeral 32 denotes a head switching circuit, which switches between the heads 31° to 313 in response to a head select signal from an interface circuit with a host device (not shown). When selecting heads 31o to 313, (00), (01), (10) and (1) are used as head select signals.
1) is generated.

A write circuit 23 writes servo information and data.

34 is a preamplifier that amplifies and shapes the read servo information and data. 35 is a data demodulation circuit;
Demodulates the read data. Reference numeral 36 is a sample and hold circuit, and the ODD/HOLD circuit of each read sector
Sample and hold EVEN servo information. 37
is a position control circuit, which controls the position of the head based on servo information read from each sector.

In this configuration, when writing servo information, a head switching signal (
00), the head 31° is connected to the write circuit 33, and each sector (0,0) to (0,I
Servo information is written to F).

This track TRKo and its sectors (0°0) ~ (
Seek control of the head 31° with respect to
This is performed by a servo loop consisting of a sample hold circuit 36 and a position control circuit 37.

Each sector (0,0) to (0,I
When the writing of servo information to F) is completed, the head 31□ is connected to the write circuit 33 by the head switching signal (10) from the interface circuit, and each sector (2,'
Servo information is written to O) to (2, IF).

When the writing of servo information to track TRK is completed, the head switching signal (0
1), the head 311 is connected to the write circuit 33, and each sector (1, O) to (1, IF
) is written to the servo information. When the writing of servo information to the track TRK is completed, the head switching signal (11) is sent from the interface circuit to the head 31.
3 is connected to the write circuit 33, and each sector (3°0) to (3°
, IF).

[Problem to be solved by the invention]

As mentioned above, the conventional servo track writing method for magnetic disk drives uses one head for one track to write servo information to each sector, and then switches the head for each track to write servo information. The lights were on.

For this reason, there was a problem in that it took time to write the servo track. For example, when writing servo information to four tracks per cylinder using four heads as shown in FIG. It takes time for the magnetic disk to rotate at least 3 times to write.
Next head 31. and 31. Writing servo information to tracks TRK and TRK3 also requires time for the magnetic disk to rotate at least three times, so a write time of 6 to 8 times per cylinder is required.

Also, for the INDEX marks of tracks TRK and TRK2, the INDEX marks of tracks TRK and TRK3 are
By shifting the EX mark by 1/2 period, the sampled servo information becomes larger than when the INDEX mark of each track is common, but the servo information is still insufficient to perform stable seek control. There was an inconvenience.

The present invention provides an improved servo track read/write method that reduces the write time of servo information, and further reduces the servo sample time when reading servo information, thereby improving seek stability. The purpose is to

[Means to solve the problem]

The means adopted by the present invention to solve the above-mentioned problems are as follows:
This will be explained with reference to FIG. FIG. 1 is a diagram showing the principle of the present invention, and FIG. 1 (A), (B), and (C) illustrate the read/write method for each servo track according to the present invention.

In FIG. 1 (A), (B), and (C), TRK0 to T
RK3 has four trunks that make up one cylinder.
4 heads 11. Through steps 113 to 113, servo information is written. Each sector (X.

In Y), "x" indicates the logical number of the head, "Y" indicates the sector number, and the track TRKx is written by the head llx. Servo information is written at the beginning of each sector.

rlNDEX is an index mark indicating the physical origin of each track. Further, rSECTORJ is a sector mark generated at the start point (or end point) of each sector.

Note that FIGS. 1(A), (B), and (C) show an example of the read/write method for each servo track according to the present invention. It is not limited to the number of sectors.

In order to perform each servo track write/write as shown in FIGS. 1(A), (B), and (C), the present invention is constructed as follows.

In other words, multiple heads are used to read/read servo information sector by sector onto multiple tracks using the data surface servo method.
In the read/write method for servo tracks to be written: (a) When writing servo information, each sector of one data is cyclically rearranged by multiple heads with a predetermined delay, and each sector is Writes servo information to a sector, and (b) When reading servo information, writes servo information cyclically written to multiple tracks in sector units.
It is configured to read cyclically using multiple heads.

[For production]

The operation of the present invention is explained by the read/write methods for each servo track shown in FIGS. 1(A), (B), and (C) (hereinafter referred to as method (A), method (B), and method (C)). An explanation will be given using an example. Since the read operation is obvious from the write operation, the write operation will be mainly explained below.

(1) Effect of method (A) The effect of method (A) will be explained with reference to FIG. 1(A). Now write the data as DATA,, DATAz,
It is assumed that there are four data: D AT At , ' D AT A3, and the servo information of DATA is written first.

The servo information of DATA is first written to sector (0,0) of TRK by the head 11°. Next, the head 111 writes to sector (0, 1) of TRK. As shown below, by the head 11□, T
Written to RKZ sector (0, 2), head 113
As a result, it is written to sector (0, 3) of TRK3.

When the head 113 finishes writing to the sector (0, 3) of the TRK, it returns to the TRK again and the head 11° writes to the sector (0, 4). In the same manner, the head 111 selects sector (0) of TRK.
, 5), and the head 11. As a result, it is written to sector (0, 6) of TRK, and head 11. According to
It is written to sector (0, 7) of TRK.

As described above, each sector of DATAO has four heads 11° to 11. As shown in the figure, the four tracks TRK to TRK3 are cyclically rearranged with a predetermined delay (one cycle), and servo information is sequentially written to each sector.

Next, in the case of DATA, ~DATA3, their write start sectors are tracks TRK, ) rack TRK2
．． ) rack TRK, sectors (1°o), (2,o),
(3,0) respectively. Hereinafter, in the same way as in the case of DATA, each DATA sector is divided into four tracks T by four heads 11° to 113 as shown in the figure.
RK, to TRK are cyclically rearranged with a predetermined delay (one cycle), and servo information is sequentially written to each sector.

The same process is performed when the number of tracks and heads is other than four.

By doing this, the track TRK.

Since the writing time of servo information for DATA and ~DATA:+ for ~TRK is only 4 to 5 cycles (N-N+1 cycle for Nt- rack), it is possible to shorten the writing time of servo information for each DATA. can.

(2) Effect of method (B) The effect of method (B) will be explained with reference to FIG. 1(B). As in method (A), the data is DATA,
, DATA, , DATA, , DAT A 3, and the servo information of D A T A o is written first.

The servo information in DATA is written in the same manner as in method (A). That is, initially the head 11. is written to sector (0,0) of T RK o.

Head 11 below. is written to sector (0, 1) of TRK, and written to sector (0, 1) of TRK2 by the head 112.
, 2) and is written by the head 113 to sector (0°3) of TRKff. When the head 113 finishes writing to sector (0, 3) of TRK3, it returns to TRK again, and the head 11° writes sector (0, 4).
) is written. Similarly, DAT
Each sector of the AO has four heads 110-11. According to
As shown in the figure, four tracks TRK to TRK3 are cyclically rearranged with a predetermined delay (one cycle), and servo information is sequentially written in each sector.

Next, in the case of method (B), the write start sectors of DATA, -DATA3 are track TRK, ~ track TRK.
3 first sector (1,0), (2,0), (3,0)
are set respectively. Hereinafter, in the same manner as in method (A), each DATA sector is divided into four heads 11° to 1
13, the four tracks TRK, ~T
A predetermined delay (one cycle) is applied to RK3 to cyclically rearrange the data, and servo information is sequentially written to each sector.

The same procedure is used when the number of trunks and heads is other than four.

By doing this, the track TRK.

The write time of servo information of DATA and ~DATA for ~TRK is 4 to 5 cycles (N), and N-N if the rack is
+1 period), it is possible to shorten the writing time of the servo information of each DATA.

(3) Effect of method (C) The effect of method (C) will be explained with reference to FIG. 1(C). D AT the data in the same way as method (A)
Ao, DATA+, DATAz-D
It is assumed that there are 4 data of AT A 3, and the servo information of DATA (+) is written first.

The servo information in DATA is written in the same manner as in method (A). That is, first, data is written to sector (0,0) of TRK by the head 11°. The head 11+ then writes to sector (0, 1) of TRK, and the head 112 writes sector (0, 1) of TRK z.
0,2), and is written by the head 113 to sector (0°3) of TRK3. When the head 113 finishes writing to sector (0, 3) of TRK3, it returns to TRK again and writes sector (0, 4) by head llo.
) is written.

However, in the case of method (C), the track TRK,
~Sector (0,0) of each DATA on TRK3 ~(3,
The predetermined delay given to 0) is set to 1/4 period or less.

Thereafter, in the same manner, each sector of DATAo is cyclically rearranged by four heads 11° to 113 with a predetermined delay applied to four tracks TRK to TRK3 as shown in the figure. , servo information is sequentially written to each sector.

When writing of servo information of DATAO consisting of 32 sectors (IF pieces) is completed, the next DATA.

The writing of servo information starts from the upper sector (2,0) of track TRK by the head 11°. below,
In the same manner as in the case of DATA, each sector of DATA is written on four tracks TRK, ~'I?, as shown in the figure, by four heads 11° to 113. A predetermined delay (1/4 cycle in the case of the figure) is given to RK3, and the data is cyclically rearranged, and servo information is sequentially written to each sector.

Similarly, sector (4,0) of trunk TRK
and (6,0) respectively as write start sectors, D
Servo information of ATAz and DATA3 is written.

The same process is performed when the number of tracks and heads is other than four. If the number of tracks and heads is other than N, the predetermined delay given to each DATA sector on the track is set to 1/N period or less.

By doing this, the track TRK.

Since the writing time of the servo information of DATAO~DATA3 for ~TRK is only 4 to 5 cycles (N-N+1 cycle in the case of a rack), the writing time of the servo information of each DATA can be shortened. I can do it. Furthermore, each D
Since the write cycle of servo information of ATA is shortened, the read cycle of servo information of each DATA is shortened, and servo information can be obtained continuously, so that the stability of seek control can be improved.

As explained above, in the present invention, each DATA sector is cyclically rearranged using a plurality of heads with a predetermined delay applied to a plurality of tracks, and servo information is written to each sector. It is possible to shorten the writing time of servo information in DATA. Also, each DATA
By shortening the write cycle of servo information, the read cycle (sample cycle) of servo information for each DATA is shortened, and servo information can be obtained continuously, thereby improving the stability of seek control. I can do it.

〔Example〕

In the embodiment of the present invention, taking the case of method (A) as an example, the first
This will be explained with reference to FIGS. FIG. 2 is an explanatory diagram of a magnetic disk device used to implement an embodiment of method (A);
Figure 3 is an explanatory diagram of the adder circuit of the same magnetic disk device;
The figure is an explanatory diagram of the transient detection circuit of the adder circuit.

(A) Structure of an embodiment of method (A) In FIG. 2, 11° to 113 are heads, and a case of four heads is illustrated. Reference numeral 12 denotes a head switching circuit, which switches the heads 11° to 113 in response to a head select signal from an interface circuit with a host device (not shown). When selecting heads 11° to 113,
As head select signals (00), (01), (10
) and (11) are generated.

A write circuit 13 writes servo information and data.

14 is a preamplifier, which amplifies and shapes the read servo information and data. 15 is a data demodulation circuit;
Demodulates the read data. 16 is a sample and hold circuit, and each read sector ODD/E
Sample and hold VEN's servo information. 17
is a position control circuit, which controls the position of the head based on servo information read from each sector.

18 is a ring counter which receives sector pulses from the interface circuit and cyclically outputs 0 to 3. In this case, the number of "O-3" is equal to the number of heads. The *INDEX mark is input from the interface circuit to the *CLR terminal (* indicates an inversion sign, the same applies hereinafter), and the ring counter is reset.

19 is also a counter, and CLK is input from the interface circuit.
A sector pulse is input to the terminal, and an *INDEX mark is input. Furthermore, from the adder circuit 20 described next,
Its output is supplied. *When the INDEX mark is input, the output of the adder circuit 20 is loaded in parallel to the counter 19 and added to the count value of the sector pulse.

As a result, as will be described in detail later, the address of the sector read/written by the operating head is output. The lower two bits of the output are used as head switching signals.

The adder circuit 20 receives the output of the ring counter 18, the head switching signal from the counter 19, and the *INDEX mark from the interface circuit, and outputs the initial value of the sector read/written by the head.

Next, the configuration of the adder circuit 20 will be explained with reference to FIGS. 3 and 4. FIG. 3 is an explanatory diagram of the configuration of the addition circuit 20, and FIG. 4 is an explanatory diagram of the configuration of the transient detection circuit of the addition circuit 20.

In FIG. 3, 201 is a multiplex, which receives the output (0 to 3) from the ring counter 18 and preset reference signals "0" to "3", and receives the input from the ring counter 20. Convert 0°1.2.3 to 0
0. Of, outputs 10.11.

Reference numeral 202 denotes a full adder, whose A terminal receives a -rad switching signal, and its B terminal receives the output of the multiplex 201. The C terminal is a carry input terminal and is in a grounded state in this embodiment.

203 is also a full adder, the output of the full adder 202 is supplied to the A terminal, and the head select signal from the interface circuit is supplied to the B terminal.

The C terminal is a carry input terminal and is in a grounded state in this embodiment. The addition result is output to the output terminal S0.

It is output from Sl and C (carry output) and supplied to the counter 19.

Reference numeral 210 denotes a transient detection circuit which detects head switching using the configuration shown in FIG. 4, generates a LOAD signal, and inputs it to the counter 19.

In FIG. 4, 211 is an EOR circuit, which receives the head select signal from the interface circuit and outputs the EOR circuit.
Generates an OR output.

212 is also an EOR circuit, which receives the head select signal inverted by the impeller 213 and generates its EOR output.

214 and 215 are monostable multi (hereinafter referred to as MS
Indicated by ), which receives the outputs of the EORs 211 and 212 and shapes them into pulse signals of a constant width. 214a and 21
4b and 215a and 215b are MS214 and 21
These are a capacitor and a resistor for the time constant that defines the pulse width of 5.

216 is an OR circuit, which is an OR circuit of MS214 and 215.
As an output, it generates the LOAD signal.

(B) Operation of the embodiment of method (A) The operation of the embodiment of method (A) will be described with reference to the operation timing chart of FIG. 1(A).

In FIG. 1(A), TRK to TRK3 are four tracks constituting one cylinder, and four heads 11
Reading/writing of servo information is performed by 113. r-INDEX is an index mark indicating the physical origin of each track, and rsEcTOR is a sector mark generated at the start (or end) of each sector. The contents of FIG. 1(A) are as already explained.

Since the read operation of method (A) is clear from the write operation, the write operation will be mainly explained below.

Now write the data as DATA,, DATA,, DATA2,
DATA, 4 data, first DATA. Assume that the servo information of is written.

When writing DATAO, a head select signal (00) is sent from an interface circuit (not shown).
is sent to full adder 203 and transient detection circuit 210. Also indicates the physical origin of the track TRK*
An INDEX mark is generated and sent to ring counter 18 and counter 19 to reset them.

Initially, the count values of ring counter 18 and full adders 202 and 203 are all 0. Therefore, since the output of the counter 19 is also O, the head switching signal for the lower two focuses becomes (00). Head switching circuit 12
receives this head switching signal (00) and switches the head l.
Select lo.

When the head 11° receives servo information from the write circuit 13 via the head switching circuit 12, it changes the track TRK.
Write to sector (0,0) of .

The seek control of the head 11° for this track TRK and each sector thereof is performed by the head 11o - head switching circuit 12 - preamplifier 14 - sample hold circuit 16 -
This is performed by a servo loop consisting of a position control circuit 17. The same applies to seek control for other tracks TRK to TRK3 and their respective sectors.

When writing of this sector (0,0) is completed, a sector pulse is detected and input to the ring counter 18 and counter 19 from the interface circuit.

When the ring counter 18 receives this sector pulse, it becomes 1.
The circuit 20 counts up the count value 1 and adds the count value 1.
multiplex 201.

When the multiplex 201 receives this count value 1, it converts it into an output (01) and sends it to the full adder 202. The full adder 202 adds this conversion output (01) and the head switching signal (00) from the counter 19 to obtain an added value (0
1) is sent to the full adder 203. The full adder 203 adds this added value (01) and the head select signal (OO) from the interface circuit, and sends the added value (01) to the counter 19.

This addition value (01) and the sector pulse are input to the counter 19, and the LO from the transient detection circuit 210 is input to the counter 19.
When the AD signal is sent, the added value (01) is loaded in parallel. However, since the LOAD signal is not input at this point, the addition value (Ol) is not loaded in parallel, and the sector pulse count value (01) is output. This count value (01) becomes a head switching signal (00) and is sent to the head switching circuit 12 and the full adder 202.

Similarly, the counter 19 outputs the count (
The number of shifts is counted up by one.

This makes the head llo 11+ 1lz
-113 and the sector number also changes to (00)-
By switching from (O1) to (10) to (11), servo information is written to each sector.

When the head 113 is reached, the count value of the ring counter 18 returns to 0 again, so the head 113 is reached.

Returning to , servo information is written to sector (04) of track TRK. Similarly, the servo information is transmitted to the head 11. sector (0,
5) and the track TRK is written by the head 11.
, and is written to sector (0, 7) of track TRK3 by the head 113.

As described above, each sector of DATAO is 4
As shown in FIG. 1(A), the heads 11° to 113 cyclically rearrange the four tracks TRK and -TRK3 with a predetermined delay (one cycle).
Servo information is sequentially written to each sector.

Next, in the case of D A T A r to D A T A :l, the logical number of each head that performs the write is 1.
, 2 and 3, and therefore the head select signals are set to (01), (10) and (11). As a result, as will be explained next, these write start sectors are sectors (1°0), (2,0), (3,
0) respectively.

For example, in the case of DATAZ, the head select signal is (
10). First ring counter 18, full adder 20
The count values of counter 2 and counter 19 are both O. The full adder 203 adds the count value (00) from the full adder 202 and the herad select signal (10), and sends the added value (10) to the counter 19. On the other hand, the transient detection circuit 210 receives the head select signal (10).
When received, a LOAD signal is generated by the configuration described above and sent to the counter 19.

Upon receiving this LOAD signal, the counter I9 loads the count value (10) from the full adder 203 in parallel to the count value (00) of the sector pulse, and then loads the count value (10) from the full adder 203 in parallel.
0) is output. Therefore, the head switching signal of the lower two bits of the output of the counter 19 becomes (10). The head switching circuit 12 receives this head switching signal (10) and selects the head 11□. As a result, D.A.
The write start sector of T A z is set to sector (2,0) of track TRK2.

Similarly, D A T A I and D A T A
Write start sectors No. 3 are set to sectors (1, 0) and (3, 0) of track TRK and trunk TRK, respectively. Below, in the same way as in the case of DATA,
Each DATA sector has four heads 11° to 11. As shown in the figure, a predetermined delay (one cycle) is given to the four trunks TRK to TRK3, and the trunks are cyclically rearranged, and servo information is sequentially written to each sector.

(C) Example of method (B) An example of method (B) will be described with reference to FIG. 1(B) and FIG. 5.

FIG. 5 shows the circuit configuration of the portion corresponding to the ring counter 18, counter 19, and adder circuit 20 of FIG. 2 in a magnetic disk device implementing method (B). Other configurations, namely heads 11° to 113, head switching circuit 12, write circuit 13, preamplifier 14,
The configurations of the data demodulation circuit 15, sample hold circuit 16, and position control circuit 17 are based on the method (A) explained in FIG.
It is the same as the magnetic disk device.

In FIG. 5, 204 is a selector counter, and C
It counts the sector pulses input to the LK terminal and outputs the count value. *INDEX to *CLK terminal
Reset when a signal is input.

205B is a multiplexer which outputs head select signals (Oo) to (11) and a preset reference number "0".
2-bit head select signal (
00), (01), (10) and (11),
4 bits <0000).

Output (0010) and (0011).

206 is a full adder, the A terminal of which is supplied with the sector pulse count value from the selector counter 204, and the S terminal of which is supplied with the output from the multiplex 205B. Child C4 is a carry input terminal and is in a grounded state in this embodiment. The S terminal is an output terminal and has 4 bits (
1 to IF) are output.

207 is a subtracter whose A terminal is supplied with the lower two bits of the 4-bit sector address output from the full adder 206, and whose S terminal is supplied with a head select signal.

The difference between the inputs of the A and S terminals is output from the S terminal as a head switching signal, and is supplied to a head switching circuit 2 (not shown).

Next, the operation of method (B) will be explained with reference to the operation timing chart of FIG. 1(B).

Observing the operation timing chart in Figure 1(B),
In the case of method (B), the sector address of the head 11° (
It can be seen that the sector address of the designated head can be obtained by adding the logical address value (0-3) of the designated head to 0,0)-(0,IF) as an offset.

The sector address and head switching signal for each designated head are obtained by the circuit shown in FIG. That is, the sector counter 204 counts the sector pulses of the head 11. Outputs the count value corresponding to the sector address. On the other hand, from multiplex 205B,
2-bit head select signal (1 to 3) is 4-bit 2
It is converted to a decimal signal and output.

Full adder 206 receives the converted output of the sector count value from sector counter 204 and the head select signal from multiplex 205B, and outputs the total added value as a sector address. Therefore, this sector address is the head 11. Each sector address is offset by the value of the head select signal.

The lower two bits of this sector address and the head select signal are input to a subtracter 207, and the value obtained by subtracting the latter from the former is output from the S terminal. The lower two bits of the sector address indicate the head switching signal, that is, the head address, as described in method (A), but in method (B), they are offset (added) by the value of the head select signal.

Therefore, by subtracting this head select signal value, a correct head switching signal is output from the S terminal of the subtracter 207.

For example, when writing DATA3 by the head 113, the head select signal is set to (11)=3 and the count value of the sector counter 204 is initially 0, so
The sector address output by full adder 206 is 3.

On the other hand, the head switching signal output from the subtracter 207 is O(
=3-3), and head 11° is selected. Therefore, the head 110 writes sector (3,0) as the write start sector, and each sector of DATA is written to four tracks TRK by the four heads 11° to 113 as shown in FIG. 1(B). ,~TRK.

A predetermined delay (-period) is applied to the data, the data is cyclically rearranged, and servo information is sequentially written to each sector.

Similarly, D A T A o, D A T A
The write start sector of I and DAT A z is track TRK.

are set in sectors (0,0), (0,1), and (0,2) of T.R.
A predetermined delay (-period) is given to K3, the data is cyclically rearranged, and servo information is sequentially written to each sector.

(D) Example of method (C) An example of method (C) will be described with reference to FIG. 1(C) and FIG. 6.

FIG. 6 shows the circuit configuration of the portion corresponding to the ring counter 18, counter 19, and adder circuit 20 of FIG. 2 in a magnetic disk device implementing method (C). Other configurations, namely head 11. ~113, head switching circuit 12, light circuit 13, preamplifier 14,
The configurations of the data demodulation circuit 15, sample hold circuit 16, and position control circuit 17 are based on the method (A
) is the same as the magnetic disk device.

Further, the configurations of the selector counter 204 and the full adder 206 are the same as the corresponding selector counter 204 and full adder 206 of the method (B) shown in FIG. Furthermore, the transient detection circuit 10 is the same as the transient detection circuit 0 described in FIGS. 3 and 4.

205C is a multiplex corresponding to 205B of method (B) in FIG. In the case of multiplex 205C, the reference signals are "0" and "8".

It is set to "16pa" and "'24". Therefore,
Head select signals 0, 1, 2 and 3 are respectively “0”.
”, “8”, “16” and “24°” and output. This converted output is supplied to the B terminal of the full adder 206 as an offset value corresponding to the specified heads 0 to 3. Ru.

A 2-bit sector counter 208 counts the sector pulses input to the CLK terminal and cyclically outputs the 2-bit count pulses O to 3. This output is used as a head switching signal. Also C
Output carry from Y terminal and selector counter 20
4 CLK terminal. *INDE to *CLK terminal
It is reset when the X signal is input.

In the case of formula (C), the head is 11° to 11. In other words, each time tracks TRK to TRK3 are switched, there is a delay of one round (one sector).
The carry generated at the CY terminal of 08 is 1 for each sector.
occurs. Therefore, this carry is method (A)
This corresponds to the sector pulse in method (B). Therefore, in general, for N heads (tracks), sector counter 208 is configured as an N-bit sector counter.

209 is an OR circuit, which generates an output when both the *INDEX signal and the LOAD signal generated by the transient detection circuit 210 are at high level, and outputs an output to the sector counter 204.
The sector counter 204 is reset.

Next, the operation of method (C) will be explained with reference to the operation timing chart of FIG. 1(C).

Observing the operation timing chart in Figure 1(C),
In the case of method (C), the sector address of head llo (
0,0) to (1,IF) are the logical address values "O" and "'I" of the specified head.

"0" corresponding to "2" and "3', respectively.

It can be seen that by providing offsets of "8", 16" and "24"' (in the case of four tracks), the sector address of the designated head can be obtained.

The sector address and head switching signal for such a designated head are obtained by the circuit shown in FIG. That is,
A 2-bit sector counter 208 counts sector pulses after being reset by the *INDEX signal, and cyclically outputs 2-bit count values O to 3. This output is supplied as a head switching signal to a head switching circuit 12 (not shown).

From the selector counter 208, four sector pulses, that is, heads 11° to 113 () rack TRK, -TR
A carry is generated from the CY terminal and supplied to the CLK terminal of the sector counter 204 every time the switching of K, ) completes one cycle. As explained above, one carry is generated for each sector.

On the other hand, the sector counter 204 is reset by the *INDEX signal input when there is a LOAD signal from the transient detection circuit 210, that is, when the head select signal is specified by the interface circuit. Therefore, the sector counter 204 is reset when a head select signal specifying one of the heads 11° to 113 is input, and thereafter the sector counter 208 is reset.
The number of carries, that is, the number of sectors inputted by the controller is counted and output.

On the other hand, the multiplex 205C receives the designated head switching signal ""o" from the head select signal,
Offset values “0” corresponding to “1”, “2°” and “3”
'' is output and supplied to the B terminal of the full adder 206.

Full adder 206 receives the sector counter value from sector counter 204 and the offset value from multiplex 205C, and outputs the total added value as a sector address. Therefore, this sector address is
．． Each sector address of the head select signal “0゛,”
1′”, “2”′ and 3″, respectively.
0''', '2', 16' and 24' offsets.

This causes the designated head to be Ilo, 11. ．． 112
and 113, each write start sector of DATA and -DATA3 is track TRK.

sectors (0,0), (1,0), (2,0) and (3
, 0), respectively. Below, four heads 11
o -11ff gives a predetermined delay (1/4 period) to the four tracks TRK, ~TRK, and cyclically rearranges them as shown in FIG. 1(C), and servo information is stored in each sector. are written in order.

Above is the case where the number of heads and tracks is 4 (2)
Although the embodiments of A), method (B), and method (C) have been described, the present invention is also applicable to cases where the number of heads and tracks is other than four.

〔Effect of the invention〕

As explained above, according to the present invention, the following effects can be obtained.

(]) Since the DATA sectors are cyclically rearranged using multiple heads with a predetermined delay applied to multiple tracks, and servo information is written to each sector, the write time of servo information for each DATA is can be shortened.

(2) By shortening the write cycle of servo information for each DATA, the read cycle of servo information for each DATA is shortened, and servo information can be obtained continuously, improving the stability of seek control. be able to.

[Brief explanation of drawings]

Figure 1 is the principle of the present invention, Figure 2 is an explanatory diagram of a magnetic disk device used to implement the embodiment of method (A) of the present invention, and Figure 3 is an explanatory diagram of an adder circuit of the magnetic disk device. , FIG. 4 is an explanatory diagram of the transient detection circuit of the addition circuit, FIG. 5 is an explanatory diagram of a magnetic disk device used to implement the method (B) of the present invention, and FIG. 6 is an explanatory diagram of the method (C) of the present invention. 7 is an explanatory diagram of the conventional servo track read/write method. FIG. 8 is an explanatory diagram of sector format and data surface servo information. FIG. 9 is an explanatory diagram of the conventional servo track read/write method. FIG. 2 is an explanatory diagram of a magnetic disk device used to implement a servo track read/write method. In FIG. 2, 11 to 113... Head, 12... Head switching circuit, 13... Write circuit, 14... Preamplifier,
15...Data demodulation circuit, 16...Sample hold circuit, 17...Position control circuit, 18...Ring counter, 19...Counter, 20...Addition circuit.

Claims (2)

[Claims] (1) In a servo track read/write method that uses multiple heads to read/write servo information in sector units to multiple tracks using a data surface servo method, (a) When writing servo information, each Sectors are cyclically rearranged using multiple heads with a predetermined delay applied to multiple tracks, and servo information is written to each sector. A servo track read/write method characterized by cyclically reading servo information written on a click using multiple heads. (2) In a servo track write method that uses multiple heads to read servo information sector by sector onto multiple tracks using a data surface servo method, each sector of one data is sent to multiple heads with a predetermined delay. given and rearranged cyclically,
A servo track write method characterized by writing servo information to each sector.