JPH04220739A - Write hit control method for disk controller - Google Patents

Abstract

PURPOSE:To perform write-through operation and write-back operation by single-time device access when there is no write space for write data on a nonvolatile memory at the time of a write hit. CONSTITUTION:The disk controller updates data on a main memory 11 with write transferred from a host 2 and also stores the write data on the nonvolatile memory 12 for write-back operation when there are the write data present on the main memory 11. A cache control part 15 decides whether or not there is a storage area for the write data left on the nonvolatile memory 12 and when not, a cache control part 15 instructs the wire-back operation for other data on the same track on the nonvolatile memory 12 and write-through operation for the write data to a low-order transfer part 14, thus performing the write-back operation and write-through operation by single-time seek operation.

Description

[Detailed description of the invention]

[0001] (Table of Contents) Industrial applications Conventional technology (Fig. 4, Fig. 5) Problems that the invention aims to solve Means to solve problems (Figure 1) action Example (a) Description of one embodiment (Figures 2 and 3) (b) Description of other embodiments Effect of the invention

0002

[Industrial Application Field] The present invention updates the data in the main memory with the write data when write data transferred from a higher level exists in the main memory, and also stores the write data in the nonvolatile memory for write-back operation. The present invention relates to a write hit control method for a disk control device that stores.

Storage disk devices such as magnetic disk devices and optical disk devices are widely used as direct access storage devices (DASD) in computer systems. In such a system, a cache memory is provided in the storage disk control device, and a portion of the data in the storage disk device is moved to the cache memory in advance to shorten the data waiting time of the host.

[0004] In such a system, in the case of a write hit where the write data exists in the cache memory at the time of writing, a write back operation is performed in which the data in the cache memory is updated with the write data and the data is written to the device during free time. It is carried out.

[0005] For this write-back, the cache memory is provided with a non-volatile memory so that the data can be saved even if the power is turned off, and the write data is written together with the main memory of the cache memory.

[0006] At this time, if there is no storage area in the nonvolatile memory, write data cannot be written to the nonvolatile memory, so a countermeasure is required.

[0007]

2. Description of the Related Art FIG. 4 is a block diagram of a conventional technique, and FIG. 5 is a flowchart of a conventional write hit process.

As shown in FIG. 4, a magnetic disk control device 1 is located between a host (upper level) 2 and a magnetic disk device 3. As shown in FIG.

This magnetic disk control device 1 has a host 2
a channel adapter (upper side transfer unit) 13 for data transfer with the device 3, a device adapter (lower side transfer unit) 14 for data transfer with the device 3, and a main memory 11.
A cache memory 10 consisting of a non-volatile memory (NVS) 12 and a cache management unit 15 for managing the cache memory 10 are connected by a bus 16.

A part of the data of the device 3 is stored in the main memory 11, and write data for write back is stored in the nonvolatile memory 12.

Conventional write hit processing will be explained with reference to FIGS. 4 and 5.

■When SIO (start IO) comes from host 2 to channel adapter 13, channel adapter 1
3, this data (block 1
Request a judgment on whether or not A) is a light hit. The cache management unit 15 determines the storage status of the main memory 11, determines whether this data is a write hit, and if it is not a write hit, activates the device adapter 14 and performs normal writing to the device 3.

On the other hand, if it is a write hit, the cache management unit 15 determines whether there is space in the nonvolatile memory 12 to write this data. Non-volatile memory 12
If there is space to write this data, after updating the main memory 11 with this data, write the data to the non-volatile memory 12.
Write this data to .

[0014] Conversely, if there is no space to write this data in the nonvolatile memory 12, the cache management unit 15
is the non-volatile memory 12 for the device adapter 14.
A write-back instruction is issued to write the data (block 2A) to device 3.

[0015] As a result, the device adapter 14 grabs the device 3 through a seek operation, performs a write-back operation, and transfers the data (block 2A) to the device 3.
Finish writing to.

[0016]Next, the cache management unit 15 issues a write-through instruction to the device adapter 14 and channel adapter 13 to simultaneously write this data (block 1A) to the main memory 11 and the device 3.

[0017] As a result, the device adapter 14 can:
It seizes the device 3 by a seek operation, performs a write-through operation in collusion with the channel adapter 13, and finishes writing the data (block 1A) to the device 3 and main memory 11.

In this way, conventionally, in the case of a write hit when there is no space in the nonvolatile memory 12, a write-through operation is performed, and the write-through operation and the write-back operation are executed twice.

[0019]

[Problems to be Solved by the Invention] However, in the conventional technology, the device must be grabbed twice for one SIO, requiring twice the time, and the write hit efficiency is not improved. There was a problem that it was slower than write-through.

[0020] Accordingly, an object of the present invention is to provide a write hit control method for a disk control device that can execute a write-through operation and a write-back operation in one device access.

[0021]

[Means for Solving the Problems] FIG. 1 is a diagram showing the principle of the present invention.

Claim 1 of the present invention provides a cache comprising an upper transfer section 13 for transferring data to the upper layer 2, a lower transfer section 14 for transferring data to the storage disk device 3, a main memory 11 and a non-volatile memory 12. memory 10,
Cache management unit 1 that manages the cache memory 10
5, and when the write data transferred from the upper 2 exists in the main memory 11, the main memory 1
1 with the write data and stores the write data in the non-volatile memory 12 for write-back operation, the cache management unit 15 updates the write data in the non-volatile memory 12. Determine whether there is a storage area for data, and
2, the cache management unit 15 instructs the lower transfer unit 14 to write back other data on the same track of the nonvolatile memory 12 and write through the write data. , the write-back operation and the write-through operation are performed in one seek operation.

[0023] Claim 2 of the present invention provides the following in claim 1:
If there is no other data on the same track in the nonvolatile memory 12, the cache management section 15 instructs the lower transfer section 14 to perform a write-through operation of the write data.

[0024] Claim 3 of the present invention provides the following in claim 1:
The cache management unit 15 instructs the lower-side transfer unit 14 to perform the write-through operation after instructing the write-back operation if other data on the same track is a block earlier than the write data. However, if the other data on the same track is a block after the write data, the write-back operation is instructed after the write-through operation is instructed.

[0025]

[Operation] According to claim 1 of the present invention, when there is no storage area for write data in the non-volatile memory 12, a write-back operation of other data on the same track of the non-volatile memory 12 and a write-through operation of the write data are performed. Lower side transfer section 1
4, the write-back operation and write-through operation are performed on the same track, so both operations can be performed with one seek operation, improving write hit efficiency and contributing to time reduction.

In claim 2 of the present invention, the nonvolatile memory 1
If there is no other data on the same track in 2,
The write-through operation of write data is performed by the lower transfer unit 1.
4, the write-back operation for other tracks is not performed, so no extra time is taken for the write-back operation.

According to claim 3 of the present invention, if other data on the same track is a block earlier than the write data,
After instructing a write-back operation, a write-through operation is instructed, and if other data on the same track is a block after the write data, the write-back operation is instructed after instructing a write-through operation, so the device The write-back operation and the write-through operation can be performed continuously in accordance with the rotation of 3, making it possible to further shorten the time.

[0028]

Embodiment (a) Description of an Embodiment FIG. 2 is a block diagram for an embodiment of the present invention, and FIG. 3 is a write hit processing flow diagram of an embodiment of the present invention.

In the figures, the same parts as those shown in FIGS. 1, 4 and 5 are indicated by the same symbols.

■When SIO (start IO) comes from host 2 to channel adapter 13, channel adapter 1
3 requests the cache management unit 15 to determine whether this new data (block 1A) is a write hit.

[0031] The cache management unit 15 stores the main memory 1
1 and determines whether this new data is a write hit. If it is not a write hit, the device adapter 14 is activated and normal writing to the device 3 is performed. On the other hand, if it is a write hit, the cache management unit 15 determines whether there is space in the nonvolatile memory 12 to write this new data.

If there is space to write this new data in the nonvolatile memory 12, this data can be used to write the new data into the main memory 11.
After updating, this data is written to the nonvolatile memory 12.

■Conversely, if there is no space to write this new data in the nonvolatile memory 12, the cache management unit 1
Step 5 determines whether old data of the same track as the new data exists in the nonvolatile memory 12.

If there is no old data in the same track as the new data in the nonvolatile memory 12, the write-back operation will take time. A write-through instruction for simultaneous writing to the main memory 11 and device 3 (block 1A) is issued.

[0035] As a result, the device adapter 14
It seizes the device 3 through a seek operation, performs a write-through operation in collusion with the channel adapter 13, and writes data (block 1A) to the device 3 and main memory 11. On the other hand, if old data on the same track as the new data exists in the nonvolatile memory 12, the cache management unit 15 determines which comes first, the old data or the new data in the nonvolatile memory 12 on the same track.

■If the old data comes first, cache management section 1
5 is a non-volatile memory 1 for the device adapter 14.
A write-back instruction is issued to write the old data (block 2A) of block 2 to device 3, and then the device adapter 14 and channel adapter 13 write this new data (block 1A) to the main memory 11 and device 3 at the same time. Issue a write-through instruction.

[0037] As a result, the device adapter 14 grabs the device 3 through a seek operation, performs a write-back operation, and writes the old data (block 2A) to the device 3.

■Subsequently, device adapter 1
4 performs a write-through operation in collusion with the channel adapter 13, writes new data (block 1A) to the device 3 and the main memory 11, and ends.

On the other hand, if the new data comes first, the cache management unit 15 requests the device adapter 14 and the channel adapter 13 to perform a write-through to simultaneously write this new data (block 1A) to the main memory 11 and the device 3. Then, a write-back instruction is issued to the device adapter 14 to write the old data (block 2A) in the nonvolatile memory 12 to the device 3.

[0040] As a result, the device adapter 14 seizes the device 3 through a seek operation, performs a write-through operation in collusion with the channel adapter 13, and transfers new data (block 1A) to the device 3 and the main memory 1.
Write to 1.

■Subsequently, device adapter 1
4 performs a write-back operation and writes the old data (block 2
A) is written to the device 3, and the process ends.

In this way, when there is no write data storage area in the nonvolatile memory 12, the nonvolatile memory 1
2. Write back operation of other data on the same track,
The write-through operation of the write data is performed by the lower transfer unit 14.
The write-back operation and the write-through operation are restricted to the same track, and both operations can be executed with one seek operation, improving write hit efficiency and contributing to time reduction.

Furthermore, if there is no other data on the same track in the nonvolatile memory 12, the lower-side transfer section 14 is instructed to perform a write-through operation of the write data.
Since the write-back operation for other tracks is not performed, no extra time is taken for the write-back operation.

Furthermore, if other data on the same track is a block before the write data, write back operation is instructed, then write through operation is instructed, and other data on the same track is a block after the write data. In the case of a block, the write-back operation is instructed after the write-through operation is instructed, so as the device 3 rotates,
Write-back operations and write-through operations can be performed continuously, making it possible to further reduce time.

(b) Description of other embodiments In addition to the embodiments described above, the present invention can be modified as follows.

(2) Although the storage disk device has been described as a magnetic disk device, the present invention may also be applied to other storage disk devices such as an optical disk device.

(2) The destination of write-back operation and write-through operation may be fixed regardless of the destination of data on the same track.

The present invention has been explained above using examples, but
Various modifications are possible within the scope of the present invention, and these are not excluded from the scope of the present invention.

[0049]

[Effects of the Invention] As explained above, according to the present invention,
It has the following effects.

■ The write-back operation and the write-through operation are performed in the same manner by instructing the lower-side transfer unit 14 to perform a write-back operation for other data on the same track of the non-volatile memory 12 and a write-through operation for the write data. Since it is restricted to a track, both operations can be executed in one seek operation, improving the efficiency of write hits.

(2) Both operations can be executed in one seek operation, contributing to time reduction.

[Brief explanation of the drawing]

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

FIG. 2 is a block diagram for one embodiment of the present invention.

FIG. 3 is a flowchart of write hit processing according to one embodiment of the present invention.

FIG. 4 is a configuration diagram of a prior art.

FIG. 5 is a conventional write hit processing flow diagram.

[Explanation of symbols]

1 Magnetic disk control device 2 Host (upper) 3 Storage disk device 10 Cache memory 11 Main memory 12 Non-volatile memory 13
Channel adapter (upper transfer unit) 14 Device adapter (lower transfer unit) 15 Cache management unit

Claims (3)

[Claims] Claim 1: An upper-side transfer unit (13) that transfers data to an upper-layer (2), a lower-side transfer unit (14) that transfers data to and from a storage disk device (3), and a main memory (11).
) and a nonvolatile memory (12), and a cache management unit (15) that manages the cache memory (10), and the write data transferred from the upper level (2) is A disk that, when existing in the main memory (11), updates the data in the main memory (11) with the write data and stores the write data in the nonvolatile memory (12) for write-back operation. In the control device, the cache management section (
15) determines whether the non-volatile memory (12) has a storage area for the write data, and the non-volatile memory (12)
If there is no storage area in the cache management unit (15)
instructs the lower transfer unit (14) to write back other data on the same track of the nonvolatile memory (12) and write through the write data, and performs the write back operation and the write through operation. A write hit control method for a disk control device, characterized in that the write hit control method is performed in one seek operation. 2. If there is no other data on the same track in the nonvolatile memory (12), the cache management unit (15) performs a write-through operation of the write data to the lower transfer unit (14). 2. The write hit control method for a disk control device according to claim 1, further comprising instructing the write hit control method for a disk control device. 3. The cache management unit (15) informs the lower transfer unit (14) that if other data on the same track is a block earlier than the write data,
After instructing the write-back operation, instruct the write-through operation, and if other data in the same track is a block after the write data, then instruct the write-through operation, and then instruct the write-back operation. 2. A write hit control method for a disk control device according to claim 1, further comprising instructing a write hit control method for a disk control device.