JPS62186324A - Buffer memory control system for disk controller - Google Patents

Abstract

PURPOSE:To improve the responsiveness by reading the data from this, transferring the data to a CPU when the data of a sector exist in a cylinder buffer memory and when they do not exist, fetching the data of a cylinder, in which the sector exists, from a driving device into the cylinder buffer memory. CONSTITUTION:When the data of the designated sector from a CPU do not exist on a cylinder buffer memory 12, a magnetic disk control device stores all sectors in the cylinder to a cylinder buffer memory 12, executes the data writing action to the cylinder buffer memory 12 and sets the address of the cylinder written in 12 through 27 to a buffer cylinder address register 5. At such a time, since 26 comes to be the active condition, 10 selects a head sector address register output line 20 side and transfers the data of the sector stored in the cylinder buffer memory 12 through 25 to the CPU.

Description

[Detailed description of the invention] [Industrial application field] The present invention is a magnetic disk control device for an electronic computer.

[Conventional technology]

- In the conventional method, the buffer memory is 1' or 2
Previously, it had a sector's worth of memory or one track's worth of memory, but recently, as semiconductor memory used as backup memory has rapidly become larger and cheaper, It has become easier to have buffer memory.

[Problem that the invention seeks to solve]

An object of the present invention is to provide a buffer memory control method that improves the responsiveness of reading data from a magnetic disk drive by reducing the frequency of access to the magnetic disk drive.

[Failure to solve the problem]

When a magnetic disk drive is used as a program residence in a computer system, the CPU reads data from the magnetic disk drive mostly through sequential access operations due to the local nature of program references, and is accessed in sector units. Add sector addresses of consecutive sectors to +
1, the read operation is often repeated. For that reason,
If the CPU were to scan the sector of the cylinder on the magnetic disk drive each time the CPU accesses a desired sector, the magnetic disk drive would have to wait for rotation each time. In addition, most of the access time of the magnetic disk drive is the seek time to position the head on the desired 7 rings, and the desired sector is placed on the head. Therefore, all sector data on the cylinder where the desired sector exists must be captured continuously (from the first sector of the first head on the same cylinder to the last sector of the last head on the same cylinder). devised.

〔Example〕

When reading a booter from a desired sector of a magnetic disk drive in response to a command from the central processing unit (CPU), the CPU
There is a magnetic disk control device located between the magnetic disk drive @Cj and the magnetic disk drive @Cj that decodes the data output command from the CPU, controls the magnetic disk drive, and reads and controls desired data.

(Figure 1).

On the other hand, the concept of a magnetic disk drive device is shown in FIG. That is, there are information storage units called tracks on concentric circles on the front and back sides of one or several magnetic disk disks. In the case of the magnetic disk shown in Figure 2, t of +0 glass (t-1)
There are 1 cylinder, and 1 cylinder is made of ΦO glass (m-1
) consists of m tracks. Furthermore, one track is composed of n sectors of +0 to (n-1). A sector is the minimum unit for writing or reading data from a magnetic disk drive.

FIG. 3 shows an example of a track format on a medium of a magnetic disk drive. One track is composed of n equally divided sectors, and each sector is divided into an address part representing the physical address of the sector and a data part storing actual data.

``Furthermore, the address section is composed of a cylinder address section representing a physical track address, a head address section, and a sector address section which is a physical sector address t-a.

This embodiment will be explained with reference to FIG.

1 is a cylinder address register that stores a desired cylinder address to be read on a magnetic disk drive device specified by the CPU, and the specified cylinder number from the CPU is multiplied by the cylinder address line 16 and set in the cylinder address register 1. Ru. A cylinder address register output line 19 outputs the contents stored in the cylinder address register 1. Reference numeral 2 denotes a head address register that stores information on a head address line 17 on which a head number designated for reading by the CPU (head number in the cylinder designated by the cylinder address register 1) is placed. 3 is a sector address register that stores information on the address line 18 with the sector number (cylinder address register 1 and head address register 2) specified to be read by the CPU.The outputs of the head address register 2 and sector address register 3 are It is carried on the head/sector address register output line 20. Reference numeral 9 denotes a serial/parallel conversion circuit that converts the serial data of the serial data line 38, on which the data read from the read head of the magnetic disk drive device is carried, into parallel data. The parallel data of 1 is output to the read data line 24. 6 is a cylinder register that records the cylinder address recorded in the address section of the sector of the magnetic disk drive in the serial-to-parallel conversion circuit 9. While scanning, the cylinder address is stored at the set timing of the cylinder register set signal line 28.

Similarly, 7 is a head register that stores the head address recorded in the address section of the sector in the serial/parallel conversion circuit 9, and stores the head address at the set timing of the head register set signal line 290 while scanning each sector. do. Similarly, 8 is a serial/parallel conversion circuit 9Vc, a sector register that stores the sector address recorded in the address field of the sector, and stores the sector address at the set timing of the sector register set signal line 30 while scanning each sector. do. 5 is 7su/dabatsu 7 amemory 1
This buffered cylinder address register indicates the address of the cylinder in which the same data as the information stored in the cylinder buffer memory 12 is stored, and is stored in the cylinder register 6 immediately after the cylinder data is stored in the cylinder buffer memory 12. The contents are stored by the signal on line 27 of buffered cylinder address register set 1g.

A comparison circuit 4 compares the contents of the cylinder address register 1 and the buffered cylinder address register 5, and activates the address coincidence detection signal line 26 when the contents of the two are equal. 10 is the head/
Select either the input information on the sector address register output line 20 or the input information on the head/sector register output line 21, and select the selected result on the circuit output line 22.
This is the selection to output to. Which input information to select is determined by the state of the address match detection signal line 26. In this embodiment, the head/sector address register output line side is selected when the address match detection signal line 26 is in the active state. Reference numeral 11 denotes an address generation circuit which specifies the upper bits of the address of the cylinder buffer memory 12. Here, the word length of the data part of each sector in FIG. 3 is 256i! Then, the address generated by the address generation circuit 11 is an address of the 9th bit or more (256 or more) from the lower digit in the binary address.

FIG. 5 shows the relationship between the address generation circuit and the cylinder buffer memory.

On the other hand, 13 is an address counter that specifies the lower 8 pits of the address of the /linda buffer memory 12. It is cleared before each sector on the track is scanned, and the data in the data section of the sector is read out and passed through the data line 24 to the cylinder buffer. Every time one word is stored in the memory 12, the count-up signal input line 350 counts up pulses.
+1 will be given. On the other hand, when data is continuously output from the cylinder buffer memory 12 and transferred to the CPU through the backup memory output data line 25, the address counter 13 is incremented by 1 for each word of data.

37 is an access operation to the cylinder buffer memory 12;
That is, it is a write/read timing input line for specifying whether data is to be written or read, and the access operation is specified by the write/continue operation specifying line 36. 14 and 15 are used when writing the data part of a sector in a track into the cylinder buffer memory 12. 31 is a sector counting circuit 1 before the write operation.
This is a clear signal line for clearing the clock signal 4 and the heradna counting circuit 15 to zero. The sector counting circuit 15 counts the number of sectors for one track (n in the case of the actual column), and the head count circuit 15 counts the number of heads constituting the l cylinder (m in the case of the example). do. That is, when the sector counting circuit 14 counts the sectors for one track, it sends one pulse to the final sector detection line 14, and this pulse increments the contents of the head φ counting circuit 15 by one.

34 is the last sector detection line in the cylinder, which becomes active after all the data of the cylinder has been written to the cylinder buffer memory 12, and the magnetic disk control device detects that all the data of the cylinder has been written to the cylinder buffer memory 12. It is convenient to do.

The operation of this implementation circuit will be explained below.

First, a case will be described in which data in a designated sector from the CPU does not exist on the cylinder buffer memory 12. Since the contents of the cylinder address register 1 and the buffered cylinder address register 5 do not match, the comparator circuit 4 detects that the address match detection signal line 26 does not become active, and the selection circuit 10 outputs the head/sector register output line 21. select. The magnetic disk controller selects a desired cylinder head track of the magnetic disk drive and scans the sectors of the track. The address of the sector detected first in this scanning operation is stored in the sector register 8, and the cylinder buffer memory 1 corresponding to the head address and sector address is stored in the sector register 8.
Determine the upper address of No.2. The lower address (8 bits) of cylinder buffer memory 12 is address counter 1.
3, and the data part of the sector is determined by l-
The data are stored in the cylinder buffer memory 12 separately.

The sector counting circuit 14 increments the data part of each sector in the cylinder buffer memory 12 by +1, and when all sectors in the track are stored in the cylinder buffer memory 12, K
m,! One pulse is sent to the sector detection line 33, and this pulse increments the head count circuit by +1. The magnetic disk control device repeatedly performs the same operation as above for the track whose head address is +1, stores all sectors in the cylinder in the cylinder buffer memory 12, and writes data to the cylinder buffer memory 12. , the address of the cylinder written in 12 is set in the back at cylinder address register 5 through 27. At this time, since 26 is in the active state, IO selects the head/sector address register output line 20 side and transfers the data of the sector stored in the cylinder buffer memory 12 to the CPU through 25.

On the other hand, when the data of the designated sector from the CPU exists in the cylinder buffer memory 12, the output 26 of the comparator circuit 4 becomes active, so the selection circuit 10 selects 26 as input information and addresses The data of the sector is transferred from the cylinder buffer memory 12 through the generation circuit 11 to the CPU through the output 25.

〔Effect of the invention〕

According to the present invention, when a magnetic disk device is used as a sequential file such as a program residence, most of the accesses to the magnetic disk device are only data transfer from the cylinder buffer memory to the CPU, and the computer It is possible to improve the responsiveness of the entire system.

[Brief explanation of drawings]

Figure 1 is a diagram showing the relationship between the CPU, magnetic disk controller, and magnetic disk drive, Figure 2 is a diagram showing the magnetic disk drive, Figure 3 is a diagram showing an example of the track format of the magnetic disk drive, and Figure 4 is a diagram showing the relationship between the CPU, magnetic disk controller, and magnetic disk drive. realizes the present invention 1
FIG. 5, a diagram showing an embodiment, is a diagram showing the relationship between the address generation circuit and the cylinder buffer memory in FIG. 4. 1... Cylinder address register, 2... Head address register, 3... Sector address register, 4
... Comparison circuit, 5... Buffered cylinder address register, 6... Cylinder register, 7... Head register, 8... Sector register, 9... Serial to parallel conversion circuit, 10... Selection circuit, 11... Address generation circuit, 12... Cylinder buffer memory, 13...
・Address counter, 14... Sector counting circuit, 15
... Heradna counting circuit, 16... Cylinder address line, 17... Head address line, 18...
Sector address line, 19... Cylinder address register output line, 20... Head/sector address register output line, 21... Head/sector register output line, 22... Selection circuit output line, 23...
... Buffer memory address line, 24... Read data line, 25... Backer memory output data line, 26... Address match detection signal line, 27.
...Buffer art cylinder address register set signal line, 28...Cylinder register set signal line, 29...Head register set signal line, 30
... Sector register set signal line, 31... Clear signal line, 32... Sector detection line, 33.
...Final sector production line, 34...Final sector detection line in cylinder, 35...Count-up signal manual line, 36...Write/continuous output operation designation input, 3
7...Write/successive output timing input line, 38.
...Serial data line.

Claims (1)

[Claims] 1. In a magnetic disk control device, a means for storing data for one cylinder (hereinafter referred to as a cylinder buffer memory) and a means for storing data for one cylinder (hereinafter referred to as a cylinder buffer memory), and a means for storing data for one cylinder, and a means for storing data for one cylinder, and a cylinder buffer memory corresponding to a head number and a sector number in one cylinder. The central processing unit (CPU) specifies the address of the sector (cylinder address, head address, sector address) to the magnetic disk control device in the data read operation of the sector. , if the data of the sector exists in the cylinder buffer memory, read the data from the cylinder buffer memory and transfer the data to the CPU; on the other hand, if the data of the sector does not exist in the cylinder buffer memory reads the data of the cylinder in which the sector exists (data of all sectors in the cylinder) from the magnetic disk drive device into the cylinder buffer memory, transfers the sector data to the CPU, and stores the data in the magnetic disk control device. A buffer memory control method for a disk control device characterized by shortening access time.