JP2892785B2 - Disk system and boot method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an external storage device for a computer, and more particularly, to a collective disk system using a large number of small disk devices and a method of starting the same.

[Conventional technology]

A system for obtaining a high transfer rate by arranging a plurality of disks and simultaneously recording and reproducing them is disclosed in JP-A-1-250128.
And electronic design 1987.11.12 p4
5 (Electronic Design Nov. 12, 1987 p45). This is, as shown in FIG.
1 to 215 are grouped into a plurality. It is desirable that these disk devices are rotationally synchronized by a rotation synchronizing mechanism 220 to an external reference clock or to one disk among a plurality of disks. The data sent from the host (not shown) via the interface 230 is divided by the sequencer 240 into arbitrary units such as bits or bytes, and even blocks.
Further, error correction data such as parity is generated. These data are obtained by the control circuit 250 of each disk device.
Almost simultaneously, it is recorded on the disk device. During playback, the data read from the disk device at the same time
Is transmitted to the host via the interface 230 restored to the original data. Control circuit 250 and sequencer 240
The intermediate buffer 260 is for absorbing a rotational deviation between the disks. These include an interface 230, a sequencer 240, a control circuit 250, a buffer 260, and a processor 270.
Is controlled by

By recording and reproducing data on N + 1 disks (one parity) in this way, the transfer speed can be apparently increased by N times the transfer speed of one disk. Further, by adding a redundant disk (parity disk in this example), correct data can be reproduced even if one data disk is broken.

In addition, Compcon '89 Spring 1989.2, p118 (COMPCON
As shown in FIG. 3, '89 spring Feb. 1989, p118) discloses a configuration in which a plurality of disk groups 281 to 284 (referred to as parity groups) shown in FIG. 2 are connected. . Disks belonging to the parity group perform high-speed transfer by simultaneously performing recording and reproduction, and perform data recovery within the group when a disk in the group is broken. This known example further discloses the following technique. That is, another group 291 to 295 (this is called a power group) is formed orthogonal to the parity group. The power supply to the disk and the power supply to the cooling fan are performed in units of this group. By doing so, even if one of the power groups fails, only the one disk in the parity group becomes unable to reproduce data, and the above-described data recovery method functions effectively.
Data recovery becomes possible.

[Problems to be solved by the invention]

However, the above-mentioned known example does not consider at all that the starting current when a large number of disk devices are started simultaneously becomes large. That is, as shown in FIG. 4, the power supply current immediately after the start-up of the small disk
More than twice the current is required. This current flows for at most several tens of seconds. Now, the number of disks to be supplied by one power source is D (this corresponds to the number of parity groups), the steady-state current value is I (A), and the steady-state current is k immediately after startup.
If it is required twice, it is a short time immediately after startup,
I × k × D (A) is required as the size of the power supply.

To solve this problem, Japanese Patent Application Laid-Open No. 57-3265 discloses a technique for shifting the timing at which power is supplied to a disk device. This method has the effect of reducing the power supply capacity, but when the number of disks to be turned on increases as in a collective disk system, it takes a long time to complete the startup of the entire system. I will.

An object of the present invention is to complete the startup of a disk system within a certain period of time with a relatively small power supply.

[Means for solving the problem]

In order to achieve the above object, according to the present invention, several sets of disks in a disk system are set, and the set is activated as a unit.

In general, the number of disks constituting each set is set so as to decrease in the order of the set to be started. This is because, for example, the remaining power of the power supply after the first set is activated is a value obtained by subtracting the current for maintaining the steady state of the first set of disks from the original power supply size. . The number of disks to be started first may be set so as not to exceed the capacity according to the capacity of the power supply to be used. Alternatively, the number may be determined as follows.

Now, assume that D disks are activated from one power supply. At this time, the steady current per disk in the steady state is required to be I (A), and k times that is required at startup. If the number of disks to be activated first is D / k, the current at the time of activation is the current when all the disks are operating in a steady state, that is, ID (A).

Next, a method of determining the number of disk sets to be started after the second disk will be described. Basically, the number of disks in the second and subsequent sets should not exceed the power supply capacity.
However, as an efficient setting method, when D / k disks are in a steady state (for example, after several tens of seconds), the next disk set is started. The number of disks in the next set x
Is basically a number obtained by dividing the margin of the power supply current when the D / k disks are in the steady state by kI. In the above case, it is given by the following equation.

The number of disks must be an integer, so D /
The k disks and the values in the above equation may be rounded down to the decimal point. In this way, if you decide on the number,
Although the number of disks may remain, the maximum value of the power supply current may be I × (D−1 + k) (A) even when the disks are started.

In some cases, disks in a parity group are rotationally synchronized with one disk as a master.
In such a case, the master disk needs to be started before other disks. Therefore, as long as a plurality of master disks can be started at the same time, the master disk may be included in the set of disks to be started first, and one master disk may precede all disks. There is also a method of starting.

[Action]

The maximum current of the power supply can be reduced by starting the disks in groups at different times so that the startup currents do not overlap, and the disk system can be started within a certain time by using several disks. Can be completed.

〔Example〕

FIG. 1 shows a first embodiment of the present invention. The power supply current immediately after startup per magnetic disk used in the present embodiment has the characteristics shown in FIG. 4, and requires a power supply current of 2 A during normal operation and 4 D during startup. The time during which the starting current 4A flows is 30 seconds. The connection method of the magnetic disks used in this embodiment has a configuration similar to that of the known example of FIG.
The number of disks belonging to 310 is 5, 1 power group 320
The number of disks belonging to the system is 8, and the number of disks in the entire system is 40. The number of power groups is 5, and if the present invention is not applied, 5 power supplies that can accept 4 (A) × 8 (pieces) = 32 (A) are required. Note that the interface 230 and the sequencer 240 are common parts of the system, and it is preferable that the interface 230 and the sequencer 240 be duplicated with a battery separate from the magnetic disk. The buffer and the control circuit are logic circuits, and although they are in the same power group, they will be power supplies of different voltages. If the power is stepped down from the disk drive power supply, it must be included in the power supply allowable current. The current of these logic circuits depends on the circuit scale, but is much smaller than the motor drive power supply, and is 0.3 A or less in this embodiment.

When the present invention is applied, the number of disks to be activated at a time may be four, two, one, and one disk per power group in that order. In this embodiment, as shown in FIG. 1, four, two, one, and one groups a330, b340, c350, and d360 from the top.
To form Further, the motor drive control circuit shown in FIG. 5 sets the time from the power-on of all the systems to the start of motor drive for each of the groups a330, b340, c350, and d360 to prevent overlapping of the start-up currents. In the case of the present embodiment, each group is delayed by 30 seconds. group
a330 is the spindle motor 3 almost simultaneously with the power ON signal 370
80 is switched on by the driver 390. Group b340
Takes 30 seconds to the timer 400 and turns on the spindle motor 380 30 seconds after the power ON signal 370. Similarly, the group c350 turns on the spindle motor 380 one minute later, and the group d360 turns on the spindle motor 380 one minute and 30 seconds later.

At this time, the transition of the starting current of the power supply of each power group is as shown in FIG. 6, which is 18 A at the maximum, which can be reduced to almost half of the value before application. The time required for all the disks to reach the specified number of revolutions was 30 seconds × 4 groups = 2 minutes. If the present invention is not applied, in order to limit the current of this power supply, the disks must be started one by one, and the time required for all the disks to reach the specified rotation speed is 30 seconds × 8 disks = It takes 4 minutes. This value was also reduced to half.

In the above embodiment, the number of disks to be started is 4
Although the description has been made of the case where the number of the power supplies is 2, 3, 1, and 1, the power supply may be performed in four, two, two, or three times if there is enough power. At this time, the power supply current needs to be 20 A, but after 1 minute and 30 seconds, all the disks can be set to the specified rotation speed. Thus, the number of disks to be started can be changed depending on the size of the power supply and the required time.

A second embodiment of the present invention will be described with reference to FIG. In the figure, the disk is represented by one circle. In the present embodiment, the disks in the parity group are rotationally synchronized with one disk as a master. At this time, the master disk may be any disk in the parity group, but it must reach the specified number of revolutions before the other disks. A method for applying the present invention in such a case will be described below. In this embodiment, the number of parity groups is four and the number of power groups is four, and the disks used are the same as in the first embodiment. The master disk must be activated first in the parity group. In FIG. 7, the disks that are the intersections of the respective parity groups and power groups are selected diagonally, and one disk at a time is selected.
Start the disks 411, 412, 413, 414. After that, the groups a420 and b430 shown in FIG. However, discs that have already been started are excluded. The transition of the power supply current of each power group at this time is shown in FIG. 8, and may be 10 A at the maximum. If the same activation is performed without applying the present invention, 16A is required, and it is clear that the effect of the present invention is obtained.

Next, another embodiment of the present invention will be described with reference to FIGS. 9 and 10. FIG. In the second embodiment, the parity group,
FIG. 9 shows the case where the number of parity groups is smaller than the number of power groups, while FIG. 9 shows the case where the number of parity groups is larger than the number of power groups. At this time, the master disk 440 for rotation synchronization is stored in each parity group.
When set, a power group in which no master is set appears in FIG. 9, and a power group in which a plurality of master disks are set appears in FIG. Also at this time, applying the present invention,
In the figure, a group a450, a group b460, and a group c470 are set, and the disks may be sequentially started by being shifted from the start by a time at which the number of rotations becomes constant. By doing this,
Obviously, the effects of the present invention can be obtained.

FIG. 11 shows another embodiment of the present invention. Also in this figure, the magnetic disks 551 to 560 are indicated by circles. The present embodiment aims at realizing a very high transfer rate, in which a parity group is constituted by a plurality of magnetic disks, and these are arranged side by side to perform recording and reproduction on all the disks at once. . That is, when data to be recorded is sent from a higher order (not shown), the interface 23
Via 0, the data is divided into arbitrary units which are sequencers I510. This data is temporarily stored in buffers I 511 to 513, and then further divided by sequencers II 521 to 523.
The divided data is stored in buffer II 531-540, control circuit 541.
Through 550 to the respective magnetic disks 551 to 560.
During reproduction, data is reproduced through the reverse process.

At this time, for power supply to each disk device, a separate power supply may be provided for each disk, but the number of power supplies becomes extremely large. Each parity group, which is each sequence
II This is a group of disks belonging to 521 to 523. Redundant disks are connected to each parity group,
Considering that, for example, from the power supply A571, the disk 55
If power is supplied one by one from each parity group such as 1,552,558 and the power supply B572 from the disks 552,556,559, a highly reliable system can be realized in which data can be recorded and reproduced even if the power supply fails.

Note that the interface 230, the sequencer I 510, the buffer I 511 to 513, the sequencer II 521 to 523, and the like are common parts, and it is desirable to use a separate power supply and duplicate them to ensure reliability. Also, buffer II 531-540, control circuit 54
Numerals 1 to 550 denote logic circuits. Although they are in the same power group, they may be different power supplies of different voltages or may be transformed from a disk drive power supply and supplied with power.

As described above, if power is supplied from each power supply to each magnetic disk belonging to each parity group to form a power group, the same method as in the first embodiment can be taken, and the effect of the present invention can be exhibited. ,it is obvious.

Incidentally, in the disk device, each power supply may include an emergency battery in case of an accident such as a power failure. If the present invention is applied to such a configuration, the load on the battery when the disk system is started with the battery in an emergency is reduced, and the reliability is further improved.

Although the embodiment of the present invention has been described using the magnetic disk device, it is apparent that the optical disk device, the floppy disk device and the like are also effective if the characteristics of the spindle motor are as shown in FIG. is there.

Further, the above-described embodiment has described the method for efficiently turning on the power in the sequence when the power of the disk group is turned on. However, a situation in which a load is applied to a power supply in a disk drive is, in addition to the above-described power-on, an operation in which an actuator equipped with a plurality of magnetic heads positions the head at a target track position on the disk, This occurs at the time of seeking and also when operating the recording / reproducing amplifier for performing the recording / reproducing operation. Also in these operations, it is considered that if the disk group is moved at a time, the power supply will be overloaded. Even in such a situation, it is apparent that by applying the present invention, the disk devices can be grouped and the operation timing can be gradually adjusted so as not to overload the power supply.

〔The invention's effect〕

According to the present invention, since starting is performed for each of a part of the disk groups, it is not necessary to prepare an unnecessarily large power supply for driving the disks. In addition, the time required for all the disks to reach the specified number of revolutions can be shortened as compared with the method of individually starting.

In addition, when the entire system needs to be driven by a battery, by applying the present invention, the startup time can be shortened and the maximum load current can be suppressed, so that the battery capacity can be reduced. There is also an effect.

[Brief description of the drawings]

FIG. 1 is a block diagram of a disk system for explaining a first embodiment of the present invention, FIGS. 2 and 3 are block diagrams for explaining a conventional technique, and FIG. 4 is a diagram of a disk spindle motor. FIG. 5 is a graph illustrating current characteristics immediately after startup, FIG. 5 is a block diagram illustrating a motor drive control circuit, and FIG.
FIG. 5 is a graph illustrating a change in power supply current according to the first embodiment;
FIG. 7 is a block diagram for explaining a second embodiment of the present invention, and FIG.
FIG. 9 is a graph showing a change in power supply current in the second embodiment of the present invention. FIGS. 9 and 10 are configuration diagrams for explaining the third and fourth embodiments of the present invention. FIG. 6 is a configuration diagram of another embodiment of the present invention. 211-215 …… Disk device, 220 …… Rotation synchronization mechanism, 230
…… Interface, 240 …… Sequencer, 250 …… Control circuit, 260 …… Buffer, 270 …… Processor, 310…
... Parity group, 320 ... Power group, 330-36
0,420,430,450-470 …… Disk boot group, 370…
… Power ON signal, 380 …… Disk spindle motor, 3
90: Driver, 400: Timer, 411-414,440: Master disk.

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hirosuke Seo 1-280 Higashi Koikebo, Kokubunji-shi, Tokyo Inside the Central Research Laboratory, Hitachi, Ltd. (56) References JP-A-57-3265 (JP, A) JP-A-61 -20125 (JP, A) JP-A-59-16163 (JP, A) JP-A-2-94060 (JP, A) JP-A-2-128359 (JP, A) JP-A-51-7071 (JP, Y1) (58) Fields investigated (Int. Cl. ⁶ , DB name) G11B 19/00 G11B 19/02 G11B 19/20

Claims (16)

(57) [Claims] In a disk system for performing recording and reproduction on a plurality of disks, when power is supplied to the plurality of disks, the plurality of disks for performing recording and reproduction includes a plurality of disks each having at least one set including a plurality of disks. Set of
A power-on method for a disk system, wherein the power-on time for rotating each set of disks is shifted. 2. When assembling a disk for performing recording and reproduction, the ratio between the starting current and the steady-state current of one disk is k.
2. The method according to claim 1, wherein when the number of said plurality of disks to be recorded and reproduced is D, the first power supply is applied to D / k disks. . 3. The plurality of disks are divided into a plurality of disk groups each including a plurality of disks each having a master disk for rotational synchronization, and one set of the plurality of sets includes the plurality of disk groups. 2. The method according to claim 1, wherein each of the master disks is included. 4. The method according to claim 3, wherein each of said master disks is supplied with power from a separate power supply. 5. The disk group is divided into a plurality of disk groups each including a plurality of disks each having a master disk for rotational synchronization, and the plurality of disk groups are formed as one set of the plurality of disks. 2. The power-on of a disk system according to claim 1, wherein when the master disks cannot be selected one by one and power is supplied from another power source, a plurality of master disks are supplied from the same power source. Method. 6. The power supply of the set having the master disk is a first power supply.
When the ratio between the starting power of one disk and the steady-state current is k, and the number of the plurality of disks for recording / reproducing is D, the second number of disks is D / k. 5. The method according to claim 3, wherein the power of the disk system is turned on. 7. In a disk system having D disks for recording and reproducing data and a power supply for driving the D disks, a plurality of disks less than D are simultaneously activated as a set. A disk system, characterized in that: 8. The disk system according to claim 7, further comprising means for activating at least a part of another disk after activating a plurality of disks whose number is less than D, and after starting current flows. 9. The disk system according to claim 7, wherein said starting current is within the capacity of said power supply. 10. The disk system according to claim 7, wherein the current at startup does not exceed D × I, where I is a steady current for driving the disk. 11. The number less than D means that a steady current for driving one disk is I, and a starting current is kI (a ratio between a starting current of one disk and a steady current is k). 9. The disk system according to claim 8, wherein a quotient obtained by dividing D by k is an integer obtained by rounding down the decimal part. 12. At least a part of said another disk device is a number of units determined by the following equation: X = (1 / k) × (1-1 / k) × D 12. The disk system according to claim 11, wherein: 13. The D disks are divided into a plurality of parity groups and have a number of power supplies less than D for driving the disks, at least one of the power supplies being at least one of the disks. The disk system according to claim 7, wherein the disk system is configured to start disks belonging to different parity groups. 14. A disk drive having a plurality of disks, wherein said plurality of disks are grouped into a plurality of disk groups having at least one disk group having a plurality of disks, and each disk has a motor. Also, the disk device has a control circuit for setting a time between power-on of the disk device and start of the motor included in each of the disk groups, corresponding to each of the disk groups. Disk device to be used. 15. The disk device has a plurality of parity groups, each parity group has a master disk that synchronizes rotation with disks in the parity group, and all the master disks are the plurality of disk groups. The disk belongs to one disk group in the group.
14. The disk device according to 14. 16. The disk device has a plurality of parity groups, each parity group has a master disk that synchronizes rotation with the disks in the parity group, and the control circuit includes all the master disks. 15. The disk device according to claim 14, wherein the start of the motor is earlier than the start of the motors of a plurality of disks other than the master disk.