JPS63311427A - Executing system for seek head command - Google Patents

Abstract

PURPOSE:To perform a head positioning process with high efficiency by referring to a table to obtain a physical track address and the physical sector value in response to the logical track address pointed out by a seek head command. CONSTITUTION:In case only the physical track addresses and the physical sector value parts are stored in a logical/physical conversion table 11 in response to (m) pieces of logical track addresses, a logical/physical converting means 12 obtains the physical sector value and then a physical track address against the logical track address given from a seek head command. When the table 11 stores the physical track addresses and physical sector values corresponding to all logical track addresses, the logical track address given by the seek head command is used as it is for reference to the table 11. Thus the seek head command is carried out at a higher speed.

Description

[Detailed Description of the Invention] [Summary] A seek head command execution method in the m/n) rack emulation method of a variable-length DASD, in which a physical track address corresponding to each logical track address of an emulation target track and a physical A table storing sector values is provided, and the head positioning process is performed by referring to this table to obtain the physical track address and physical sector value corresponding to the logical track address specified by the seek head command. The physical track address and physical sector value corresponding to the track address can be quickly obtained, and the head positioning process can be performed efficiently.

[Industrial application field]

The present invention provides variable-length direct access storage (dir).
ect access storage device
: In the DASD subsystem, there is a seek command execution method that positions the head at the position on the track indicated by the seek head command, especially when the physical track capacity of the DASD is m/m of the emulation target track capacity. The present invention relates to a seek head command execution method when emulating m emulation target tracks with n physical tracks when n (m, n is a positive integer, m>n) times.

[Conventional technology]

When increasing the capacity of a DASD, with the recent advances in high-density recording technology, increasing the track capacity will increase the capacity of the DASD.
A method of expanding ASD capacity is often used. This method has the advantage that the capacity of the DASD can be easily expanded without increasing the size of the DASD.

However, when the track capacity of a DASD is increased, software compatibility with other DASDs having different track capacities becomes a problem.

Conventionally, in order to maintain software compatibility between a DASD with a large track capacity and another DASD with a smaller track capacity, track emulation has been performed in the following manner.

(a) A method in which one physical track of a DASD with a large track capacity is divided into N parts to create N logical tracks of another DASD.

(b) A method in which only the capacity of the track to be emulated is used on one physical track of a DASD with a large track capacity.

However, method (a) has the advantage of being able to perform track emulation by effectively utilizing the expanded capacity of the DASD, but this is only possible if the physical track capacity is N times the capacity of the track to be emulated. There was a restriction that it could not be done.

On the other hand, Yama's method has the advantage of not being subject to such restrictions, but on the other hand, it has the disadvantage that the surplus portion of the physical track is discarded, and the expanded capacity of the DASD is not effectively utilized.

Furthermore, in either method, the physical track capacity of the DASD is m/n of the emulation target track capacity.
(m, n are positive integers, m > n), it is not possible to perform emulation that effectively utilizes the DASD capacity, and the increase in DASD track capacity is
There was a problem that this did not lead to an increase in ASD capacity.

In order to solve these problems, a track emulation method (hereinafter referred to as , m/n) rack emulation method) has been proposed by the same applicant.

Next, the principle of this m/nl-rack emulation system will be explained with reference to FIG.

In Fig. 7, PT, PT, ... PT).

... are each physical track of the DASD.

Each physical track has an index mark (index-1
~1ndex-(m-1)), and each physical track is divided into m sub-tracks. In the figure, t,'r=-, (j=0~n-l)
indicates each sub-track of the logical track LTi (i=o to m l).

Each physical track PT, ~PT-32, etc. is m/n times the emulation target track capacity of the compatible DASD. Therefore, if the capacity of each physical track PT, .about.P T <n-1), etc. is C1, the emulation target track capacity is 02, and the capacity of each sub-track is C5, the following equation holds true.

C,=C,Xm C,=CEx- Than this, Ct = Cp X = C3Xn becomes.

In other words, the emulation target track capacity of the DASD that is compatible with n sub-tracks it c
Since we have t, we can emulate that track format. Generally, the physical track capacity for n can emulate m emulation target tracks of a compatible DASD.

In FIG. 7, LTi-■~LT, -,,-,, :(
i-0 to m-1) respectively indicate m emulated logical tracks.

This m/n) rack emulation method is similar to the conventional 1
n logical tracks (n-1, 2t.
), one logical track may span two physical tracks, such as an LT.

Therefore, in the conventional system, track switching using a seek head command was simply a matter of switching the physical head, but in the m/n emulation system, this conventional track switching method cannot be used. That is, in the m/n emulation system, when one logical track spans two physical tracks, the end of the logical track does not match the end of the physical track.

To solve this problem, the physical track address and physical sector value are calculated from the logical track address given by the seek head command, and if one logical track spans two physical tracks, the logical sector value is Calculate whether it is above m/n
A track positioning control system for correctly positioning the head in an emulation system has been proposed by the same applicant.

The present invention makes head positioning processing in the m/n track emulation method more efficient by providing a logical/physical conversion table that stores physical track addresses and physical sector values corresponding to each logical track address of the emulation target track. The purpose of this invention is to provide a method for executing a seek head command that can be executed automatically.

[Means for solving problems]

In the m/n emulation method, m logical tracks are emulated using n physical tracks, so when a logical track address is specified, the corresponding physical track address and physical sector value are uniquely determined.

Therefore, if you calculate the physical track address and physical sector value corresponding to each logical track in advance and create a table (logical/physical conversion table), you can correspond to each logical track by referring to this logical/physical conversion table. The physical track address and physical sector value can be quickly obtained.

Moreover, since the physical track addresses and physical sector values corresponding to the logical track addresses appear cyclically regarding m logical tracks, it is easy to create a logical/physical conversion table.

Hereinafter, the means taken by the present invention to achieve the above-mentioned object will be explained with reference to FIGS. 1 and 2. Figure 1 shows
FIG. 2 is a block diagram of the basic configuration of the present invention, and FIG. 2 shows a table of physical track addresses and physical sector values corresponding to logical track addresses.

In FIG. 1, IO is a control device that determines the physical track address and sector value corresponding to the logical track address given by the seek head command from the host device, and controls the positioning of the head.

In the control device 10, 11 is a logical/physical conversion table, as illustrated in FIG.
Physical track address PT corresponding to (i=0, 1, 2...)! (i=0, 1, 2°...) and physical sector value PSi (i=o11, 1...) are stored.

12 is a logical/physical conversion means which refers to the logical/physical conversion table 11 and converts the physical track address PT! corresponding to the logical track address LTi given by the seek head command. and find the physical sector value ps5.

[For production]

The operation of FIG. 1 will be explained with reference to FIG. 2.

Prior to the start of operation, each logical track address LT+(i.=0.1,
2. ...) corresponding physical track address PTゑ
(i-0, 1, 2,...) and physical sector value PSi
(i=0, 1, 2...) is stored.

In the m/n emulation system, the physical track address PTz and physical sector value PSt corresponding to each logical track address LT1 appear cyclically for every m logical tracks, as shown in FIG. That is, the physical track address PTm is PTj□! (j
=0, 1, 2,...), and the physical sector value ps5 is PS jn** = P S .

It is represented by (j-0, 1, 2,...). therefore,
Instead of storing physical track addresses and physical sector values corresponding to all logical track addresses, the logical/physical conversion table 11 stores physical track addresses and physical sector values corresponding to the first m logical track addresses LT+ (i=o to m-1). It is possible to use one in which only the physical track address and physical sector value portion are stored.

The logical/physical conversion means 12 refers to the logical/physical conversion table to obtain a physical track address PT+ and a physical sector value ps5 corresponding to each logical track address LTL given by the seek head command.

When the logical/physical conversion table 11 stores only the physical track address and physical sector value portion corresponding to m logical track addresses LTi (i=o to m-1), the logical/physical conversion means 12 , the logical track address L T j given by the seek head command
For a44, the physical sector value PS1 is determined by referring to the logical track address LTi portion of the logical/physical conversion table 11, and the physical track address P74m and direct are calculated.

If the logical/physical conversion table 11 stores physical track addresses and physical sector values corresponding to all logical track addresses, the logical/physical conversion table 11 is stored using the logical track address given by the seek head command as is. can be referred to. Therefore, although the capacity of the logical/physical conversion table is larger than when storing physical track addresses and physical sector values corresponding to the m logical addresses described above, seek head commands can be executed more quickly. .

If the command issued following the seek head command is a set sector (set sector) command, the logical/physical conversion means 12 further converts the physical track corresponding to the logical sector value indicated by the set sector command. Calculate address and physical sector values (
The specific calculation method will be described in detail in the Examples section).

As described above, by using the logical/physical conversion table, it is possible to obtain the physical address and physical sector value corresponding to each logical track address given by the seek head command more quickly than when calculating by calculation. , positioning of the head allows processing to be executed efficiently.

〔Example〕

Embodiments of the present invention will be described with reference to FIGS. 3 to 6. FIG. 3 is an explanatory diagram of the configuration of one embodiment of the present invention, and FIG. 4 shows the logical track address LT, physical track address PT!, in the same embodiment. , a related explanatory diagram of the logical sector value LS= and the physical sector value PS1, and FIG.
FIG. 6, which is an explanatory diagram of the physical conversion table, is a flowchart of the same embodiment.

(A) Configuration of Embodiment In FIG. 3, the control device 10, logical/physical conversion table 11, and logical/physical conversion control means 12 are as described in FIG. 1.

21a, 21b, etc. are magnetic disk devices used as DASD.

A magnetic disk control adapter (ADP) 22 performs various magnetic disk controls such as selection control of a predetermined magnetic disk device, access control to the selected magnetic disk device, read/write control, etc. according to each command from the control device 10. I do.

In the control device 10, a channel interface control unit 13 controls the interface between the channel of the host device and the control device 10.

A device interface control unit 14 controls the interface between the ADP 22 and the control device 10.

In the logical/physical conversion control means 12, 121 is a register section, which includes a logical track address register (LTADR) 121a in which the logical track address LTi specified by the seek head command is stored, and a logical sector address in which the logical sector value LSi is stored.・Register (LSADR
)12 l b.

a physical track address register (PTADR) 121C in which a physical track address PT corresponding to the logical track address is stored; a physical sector address register (PSADR) 121C in which a physical sector value PS corresponding to the logical track address is set; ) 121d, a new physical track address register (NPTADR) 121e in which a new physical track address corresponding to the logical sector value LS1 indicated by the set sector command is stored, and a new physical sector value corresponding to the logical sector value is stored. New Physical Sector Address Register (NPSADR)
121 f are provided respectively.

Note that the register section 121 includes each address register 12.
In addition to 1a to 121f, there are also registers for storing data, commands, etc. that are being processed by the control device 10, but since they are not necessary for the explanation of this embodiment, their illustrations are omitted.

122 is a control microprocessor (control MPU)
It has a control section 122a and a calculation section 122b inside, and has a logical track address LT= (i=0.1, 2...
・Processing to obtain the physical track address PT and physical sector value PS corresponding to (the same applies hereinafter), logical sector value LS
, a new physical track address NPT and a new physical sector value NFS corresponding to , are calculated. Note that the control MPUI 22 also controls the operation of a data transfer control unit and the entire control device 10 (not shown).

123 is a ROM in which various control programs and initialization programs used by the control MPU 122 are stored.

124 is a common bus, and the above-mentioned logical/physical conversion table 1 is
1. Register section 121. Control MPUI22, ROM1
23, each interface control unit 13 and 14 are connected in common.

FIG. 4 shows the logical track address LTi, physical track address PT, logical sector value LSi, and physical sector value PSt (1=Ot 1
t 2 s...).

The space between the left and right indexes (Index-0) is one physical track. m=3. nw2, one physical track is equally divided into three sub-tracks by indexes 1 and 2, and one logical track is formed by two sub-tracks.

Assuming that one logical track is formed by two consecutive sub-tracks and the number of sectors in each sub-track is 100, the correspondence shown in FIG. 4 is obtained. That is,
(a) Logical track address LTi (1”0,3,
6,9. C,...,r) are physical track addresses P
Corresponding to the T track address (i 0, 2, 4, 6° 8, ... eq), the value of the first physical sector is 0''. (bl logical track address LTt (1 = 1
*4* 75AsDe・”r+1) is the physical track address PTA (i=0,2,4゜6.8...
・pq), the first physical sector value is "200'". (C) Logical track address L
T! (i=2.5,8.B,E.

..., r+2) is the physical track address PTi (
i-1, 3, 5, 7, 9, . . . q+1), and the leading physical sector values are all "100".

Therefore, m! 3.fi! 3/2 which is 2
The logical/physical conversion table 11 in the truck engineering migration method is as shown in FIG. In this embodiment, in order to quickly perform address conversion processing, it is assumed that physical track addresses and physical sector values corresponding to all logical track addresses LT0 to LTr*1 are stored.

(B) Operation of the embodiment The operation of the embodiment is explained with reference to the processing flowchart in FIG.
A description will be given according to the processing steps.

■ Step Sl When a seek head command is issued to the control device 10 from the channel of the host device, the control MPU 122
will be forwarded to.

The control unit 122a of the control MPU 122 retrieves the logical track address LTi from this seek head command and stores it in the LTADRl 21a, and then refers to the logical/physical conversion table 11 to obtain the logical track address LTi.
Physical track address PT corresponding to T1! For example, if the logical track address is LT, the corresponding physical track address PT is determined by referring to the logical/physical conversion table 11.

-O1 physical sector value pso-200 is immediately determined.

The control unit 122a uses the thus obtained physical track address PT! and physical sector value PSi, PTADR
l 21 C and PSADR 121d, respectively.

■Step S2 The control unit 122a selects the physical track address PT which corresponds to the logical track address LT! and physical sector value PS
When the process for determining i is completed, the end of the seek head command is reported to the channel via the channel interface control unit 13, and the next command is received.

■ Step S3 When positioning the head that performs read/write on the track of the magnetic disk, the head is positioned at the start of the track, and the head is positioned at the start point of the track, and the head is positioned at the start point of the track, and the head is positioned at the starting point of the track, and the head is positioned at the starting point of the track, and the head is positioned at the starting point of the track, and the head is positioned at the starting point of the track. In some cases, a value is specified and the head is positioned in the sector of this sector value. In the latter case, a set sector (set 5ector) command indicating the logical sector value LS() is issued from the channel.

The control unit 122 determines whether the next command received from the channel is a set sector command.

■ Step S4 If the command is not a set sector command, logical track LT! Since the head is positioned at the starting point of
Logical track address LT obtained in step SI above
Directly corresponding physical track address PT! The head is positioned using the physical sector value Psi and the physical sector value Psi.

The control unit 122a sets the physical track address PTi obtained in step S1 to a predetermined magnetic disk device (referred to as 21a) via the ADP 22, and causes the head of the physical track address to be selected. Next, an internal set sector command is created in the control device IO, the physical sector value PSt taken out from the PSADR 121d is set therein, and the command is sent to the ADP 22.

■ Step S.

The ADP 22 sends the magnetic disk device 21a the physical sector value PS! specified by this set sector command. command to position the head accordingly.

When the magnetic disk device 21a finishes positioning the head,
The sector interrupt is notified to the control device 10 via the ADP 22.

The control unit 122a of the control device 10 notifies the channel of this sector interrupt and waits for the next command. This completes the seek head command processing when the command received following the seek head command in step S is not a set sector command.

Next, a description will be given of processing when the command received following the seek head command is a set sector command.

■ Step S6 If it is a set sector command in step S, as can be seen from Figure 4, the logical track address is ■
In the case of LT: i=o, 3, 6, '-, r, ■LTA: 1==1, 4, 7. −, r+1, @LT=: i=2 * 5 * 8, .
Depending on the case of r+2, the corresponding physical track address (new physical track address NPTi) and physical sector value (new physical sector value NPSi) differ.

The control unit 122a causes the calculation unit 122b to calculate whether the logical track address LT1 matches with any of the above-mentioned ■, ■, or @, and performs the following processes depending on the result.

■Step 5fft38: ■For the group If the logical track address LTL is for the group ■, as is clear from FIGS. 4 and 5, the new physical track address NPT and new physical sector value NPSi are
They match the physical track address PT and physical sector value PSt found in .

From this, the control unit 122a controls the physical track address PTi in the PTADR 121C and the PSADR 121d.
Physical sector address PS! are selected as the new physical track address NPTi and the new physical sector value NFS.

■ Step 89-S1. : ■ In the case of a group ■ In the case of a group, i.e., logical track address LT, i=
1.4 In the case of y 7 , A , ·”, r + 1, the corresponding physical track address and physical sector value are determined depending on whether the logical sector value LSi is in the first half subtrack or the second half subtrack. There will be a difference.

As is clear from FIG. 4, when the number of sectors of the sub-track is 100, the logical sector value LSi≦99
When , it exists on the first half sub-track, and LS > 99
When , it exists on the second half sub-track.

Logical sector value LS! exists on the first half subtrack, the corresponding new physical track address NPTi is
NPTi=PTi, and the corresponding new physical sector value NFS is given by NFS+=LS+200.

Furthermore, when the logical sector value LSi is on the second half sub-track, the corresponding new physical track address NPT1 is:
NPT,−PT51, and the corresponding new physical sector value NPS, is NPS,=LS! It is given by -100.

The control unit 122a uses the calculation unit 122b to calculate the logical sector value LS.
Determine the magnitude relationship between i and 99 (step S9)
.

If LSI≦99, the logical sector value LS exists on the first half sub-track, so the control unit 122a sets the physical track address PT! obtained in step Sl! (i
-0, 2, 4, 8,...) as the new physical track address NPT! (Step 310).

Furthermore, the calculation unit 122b calculates the corresponding new physical sector value NP.
Si is determined from NPSt=LS=+200 (step S++).

If LSD>99, the logical sector value LS exists on the latter sub-track, so the calculation unit 122b calculates the PT
Take out the physical track address PT Todoroki in ADRl 21 c, and set the new physical track address NPTi to NP
Tt=PT! +1 (step S+z).

Also, the corresponding new physical sector value NPS, NPSi
``'LSt -100 (step S1).

■ Step 514tS+s: For @group, logical track address LT! is a group of O, as is clear from FIGS. 4 and 5, the new physical track address NPT! matches the physical track address PT1 obtained in step S1. In addition, the new physical sector value N P
S! is given by NFS, =LS++100.

Therefore, the control unit 122a selects the physical track address PT in the PTADR 12IC as the new physical track address NPTi (step S).

Further, the calculation unit 122b calculates the corresponding new physical sector value NF.
Calculate S direct from NFS positive = LS value + 100 (step S + s) - New physical track address NP found in above ■ ~ ■
T! and the new physical sector value NPSi is NPTADRl
21e and NPSADRl 21f, respectively.

[Phase] Step S +6 e SS New physical track address NPTi and new physical sector value N in the above ■~■
When PSi is determined, the control unit 122a sends a new physical track address NPT to a predetermined magnetic disk device 21a via the ADP 22, and causes the head of the new physical track address to be selected.

Next, an internal set sector command is created in the control device 10, a new physical sector value NPSi is set therein, and the command is sent to the ADP 22 (step 516).

Thereafter, the process of step S explained in the above-mentioned section (2) is performed, and when the head positioning based on the predetermined new physical track address NPT1 and new physical sector value NFSm is completed,
A sector interrupt is notified and seek head command processing is completed.

Although one embodiment of the present invention has been described above, the present invention includes
In addition to this 3/2 track emulation method, an m/n track emulation method is generally used. Further, as already mentioned, the logical/physical conversion table may store only the physical track addresses and physical sector values corresponding to m logical track addresses.

〔Effect of the invention〕

As explained above, according to the present invention, by using the logical/physical conversion table, it is possible to quickly obtain the physical track address and physical sector value corresponding to each logical track address given by the seek head command. Therefore, the head positioning allows processing to be performed efficiently.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of the basic configuration of the present invention, and FIG. 2 shows logical track addresses (LTi), physical track addresses (PTi), and physical sector values (PS+
), FIG. 3 is an explanatory diagram of the configuration of an embodiment of the present invention, and FIG. ) and physical sector value (PS), FIG. 5 is an explanatory diagram of the logical/physical conversion table of the same embodiment, FIG. 6 is an operation flowchart of the same embodiment, and FIG. 7 is m/
FIG. 2 is a diagram explaining the principle of an n-track emulation method. 1 and 3, 10...Control device, 11...Logical/physical conversion table, 12...Logical/physical conversion means, 13...Channel interface control unit, 14...Device Ink face control unit, 21... Magnetic disk device, 22...
-Magnetic disk control adapter (ADP). Patent Applicant: Fujitsu Gyusemei Co., Ltd. / 1. LTi, PTi, and 1/: PSi's Heku-Sekkonki No. 2
Diagram sensual punishment refinement' Figure 3

Claims (2)

[Claims] (1) The physical track capacity of a variable-length direct access storage device is m/n (
m and n are positive integers, and when m>n), the control device (10) receives a seek head command from the host device.
This is a seek head command execution method when m emulation target tracks are emulated with n physical tracks by: (a) Each logical track address of the emulation target track (LT_i: i=0, 1, 2) ,...) corresponding to the physical track address (PT_i: i=0, 1, 2
,...) and physical sector values (PS_i: i=0, 1,
2,...) are stored in the logical/physical conversion table (1
1) and (b) refer to the logical/physical conversion table (11) to determine the physical track address (PT_i) and physical sector value corresponding to the logical track address (LT_i) specified by the seek head command from the host device. (PS_i)
A seek head command execution method characterized in that a control device (10) is provided with a logical/physical conversion means (12) for determining . (2) If the command following the seek head command is a set sector command, logical/physical conversion means (12)
Based on the physical track address (PT_i) and physical sector value (PS_i), a new physical track address (NPT_i) and a new physical sector value (NPS_i) corresponding to the logical sector value (LS_i) specified by the set sector command are determined. A seek head command execution method according to claim 1, characterized in that: .