JPH03260852A - External storage device - 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 examples (Figs. 2 and 3) Effects of the Invention [Summary] With regard to external storage devices, the present invention aims to increase the cache capacity of external storage devices and to maintain memory on the cache semi-permanently even in the event of an unexpected power cut. On the other hand, it is equipped with a disk control device that reads/writes data via a cache storage device, and a parallel transfer disk is provided as an auxiliary storage device of the disk control device, and the parallel transfer disk is connected to the magnetic disk device that is to be controlled. Configure it to be used as a non-volatile cache.

[Industrial application field]

The present invention relates to an external storage device, and more specifically,
It is used in disk control devices that perform various controls on magnetic disk devices, and is particularly designed to provide a large-capacity cache capable of high-speed data transfer, as well as to retain data on the cache even in the event of an unexpected power cut. Regarding storage devices.

[Conventional technology]

In general, high-speed disk writing technology for magnetic disk devices uses a semiconductor memory cache, which has a shorter access time than the disk, in the disk controller to take advantage of the high-speed data transfer between the cache and the channel. .

The reason for this is that if data is written directly to a disk that ultimately stores and retains data written by the host, it will not be possible to overcome the physical limitations of disk performance.

The cache described above is a technology that focuses on locality of access to external storage and can speed up access to the majority of all real devices with a smaller amount of storage that can be accessed at high speed.

In high-speed writing using a cache, when the control device returns a completion status upon completion of writing data on the cache, the host considers that the data has been written to the device. After this, before the data in the cache is written back to the device, the memory used for caching the written data should be made non-volatile, such as by upgrading the battery bank, in case the disk subsystem is powered off. use something

[Problem to be solved by the invention]

The above-mentioned conventional devices had the following drawbacks.

In other words, if you need a larger cache,
It is difficult to guarantee long-term back-amplification in a semiconductor memory with buffer backup.

SUMMARY OF THE INVENTION The present invention aims to eliminate such conventional drawbacks, increase the capacity of a cache, and enable storage on the cache to be retained semi-permanently even in the event of an unexpected power cut.

[Means to solve the problem]

FIG. 1 is a diagram showing the principle of the present invention, and in the figure, 1 is a disk control device, 2 is a cache control section, 3 is a parallel transfer disk control section, 4 is a parallel transfer disk, and 5 is a magnetic disk device.

In order to achieve the above object, the present invention includes a disk control device 1 that performs read/write of data to a magnetic disk device 5 via a cache storage device, and also serves as an auxiliary storage device of the disk control device. A parallel transfer disk 4 is provided, and the parallel transfer disk 4 includes:
This is used as a nonvolatile cache for the magnetic disk unit W5 that is to be controlled.

[Effect]

Since the present invention is configured as described above, it has the following effects.

The disk control device 1 performs various controls such as reading/writing data on the magnetic disk device 5 .

Upon read access to the magnetic disk device 5 from the host device, data is transferred to the host device and at the same time is staged to the parallel transfer disk 4 by the parallel transfer disk control section 3 in the cache control section 2. Thereafter, access to this track is made to the parallel transfer disk 4, and high-speed read/write can be realized.

The parallel transfer disk 4 described above can achieve a larger capacity at the same cost than a semiconductor memory, and is itself a magnetic disk and nonvolatile.

In general, a disk allows a seek to a nearby cylinder faster than a normal seek, and the locality of accessing data in the cache is greater than the locality of data on a real device.

Therefore, as in the present invention, the high-speed parallel transfer disk 4
By using , a cache effect can be expected due to high-speed data transfer and shorter seek time. Therefore, the parallel transfer disk 4 satisfies the conditions as a write cache.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

FIG. 2 is a block diagram of one embodiment of the present invention, and FIG. 3 is a partially detailed block diagram of the embodiment.

In the figure, the same reference numerals as in FIG. 1 indicate the same parts, 6 is a host computer, 7 is a channel, 8 is a buffer, and 9 is a data distribution and aggregation unit.

The host computer 6 and channel 7 are the host devices.
For example, as the parallel transfer disk 4, 8
A number of magnetic disk drives (#1 to #8) are used. This parallel transfer disk 4 is controlled by a parallel transfer disk control section 3 provided within the cache control section 2 of the disk control device l.

This parallel transfer disk control unit 3 is provided with a buffer 8 and a data distribution and aggregation unit 9. When data is transferred to and from the outside, data is transferred via the buffer 8, and the data distribution and aggregation unit 9 transfers the data. distribution or aggregation.

For example, if 1 byte is 8 bits, when writing 1 byte of data to the parallel transfer disk 4, the data distribution and aggregation unit 9 distributes the data into 1-bit data, and simultaneously writes the data to the corresponding disks #1 to ##. 8 and written.

That is, data of 1 focus is simultaneously written to each of the eight disks #1 to #8.

When reading data from parallel transfer disk 4,
After reading one bit of data from each of the disks #1 to #8, the data distribution and aggregation unit 9 aggregates the data into 1-byte units, and then transfers the data to the outside via the buffer 8.

As mentioned above, the disk control device 1 has the cache control section 2, and the cache control section 2 has the parallel transfer disk control section 3 therein, thereby allowing faster access than the normal magnetic disk device 5. The parallel transfer disk 4 is controlled.

When a read access is made to the magnetic disk device 5 from the host computer 6 via the channel 7, the read data is transferred to the host computer 6 and at the same time is staged to the parallel transfer disk 4 through the cache control unit 2. . From now on, access to this trunk will be made to this parallel transfer disk 4 side,
Read/write is performed at high speed.

When the cache function is stopped or the free space on the parallel transfer disk 4 runs out due to an instruction from the host computer 6, the most recently accessed track on the parallel transfer disk 4 is The data is written back to the magnetic disk device 5.

Additionally, if data to be written back is left on the parallel transfer disk due to an unexpected power cut, etc., the data will be retained on the parallel transfer disk 4 until the next power is turned on.
When the power is turned on, the cache control unit 2 checks the parallel transfer disk 4, detects that data remains, and writes it back to the magnetic disk device 5.

Although the embodiments have been described above, the present invention can also be implemented as follows.

(1) Any (plural) number of parallel transfer disks 4 may be used.

(The 21Mi disk device 5 may be configured with a plurality of units.

〔Effect of the invention〕

As explained above, the present invention has the following effects.

+1) Compared to a high-speed write device using a semiconductor memory using a conventional Panteri bank amplifier, a cache with a larger capacity and capable of high-speed data transfer can be realized.

Even in the event of an unexpected power cut, data stored in cache can be retained semi-permanently.

[Brief explanation of drawings]

FIG. 1 is a principle diagram of the present invention, FIG. 2 is a block diagram of one embodiment of the present invention, and FIG. 3 is a partially detailed block diagram of the above embodiment. 1--Disk control device 2--Cache control unit 3--Parallel transfer disk control unit 4--Parallel transfer disk 5--Magnetic disk device

Claims (1)

[Claims] A disk controller (5) that reads/writes data to/from a magnetic disk device (5) via a cache storage device.
1), a parallel transfer disk (4) is provided as an auxiliary storage device of the disk control device (1), and the parallel transfer disk (4) is a non-volatile storage device of the magnetic disk device (5) to be controlled. An external storage device characterized in that it is used as a storage cache.