JPS58169271A - Data buffer control method - 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] Both Technical Fields of the Invention The present invention relates to a data buffer control method, particularly a magnetic disk control device that performs read/write in units of one sector, and provides at least two data buffers. 1, so that the data 0 is written and overwritten on a fixed pattern such as all rOJ, and 1
The present invention relates to a data buffer control system which makes it possible to easily perform a process of summarizing data K in a size of one sector by filling all "0"s following data that does not fit in a sector unit.

(2) Technical Background and Problems Traditionally, in so-called sector format magnetic disk control devices, a data number buffer for one sector is created and one all "0" is created, as will be described later with reference to FIG. A fixed pattern write circuit is provided to write a fixed pattern such as 1-11! at the end of data transfer of one sector or more. When it becomes necessary to transfer data that is less than one sector, the data that is less than one sector is filled with all "0"s and transferred as one sector.

In this case, since the new data is overwritten while the original old data remains on the data buffer, it is necessary to correctly manage from which position all "0"s are added. Yes, a data contention counter is provided to check where valid data is present.

(C) Purpose and Structure of the Invention In view of the above points, the present invention simplifies the process of adding all "0"s and enables processing without being aware of the size of the valid data. The purpose is to Therefore, the data buffer control method of the present invention is a disk system mt&flt that controls a disk device in which read/write is performed sector by sector.
In this case, at least two data buffers are created that are sufficient to store one read/write unit for the disk drive flK, and while data is being written to one of the data buffers, the other data buffers are A fixed pattern write circuit is provided for writing a fixed pattern to one of the fixed patterns, and when writing the data, the fixed pattern is controlled to overwrite the state in which the fixed pattern is stored, and The present invention is characterized in that when reading data, the contents stored in the data buffer are read out for one read/write unit and transferred. This will be explained below with reference to the drawings.

(D) Embodiment of the Invention FIG. 1 shows the main configuration of an embodiment of a magnetic disk control device related to the present invention, FIG. 2 shows a conventional configuration of the buffer circuit shown in FIG. 1, and FIG. The figure also shows the configuration of an embodiment of the present invention relating to the above buffer circuit.

In Figure 1, 1 is the host system, 2 is the magnetic disk controller, 3 is the disk drive, 4 is the control circuit, 5 is the host system driver/receiver, and 6 is the host interface control circuit. represents a buffer circuit, an 8#i series/parallel control circuit, and a 9/fi format control circuit.

For example, consider a case where the host system l transfers data toward the disk writing drive 3 side.

In this case, the magnetic disk controller 2d host system l
The buffer circuit 7 receives one sector worth of data from the buffer circuit 7.
data buffer, and transfer one sector worth of data from the data buffer to the disk drive 3.
It is made to transfer towards the side. When data is transferred from the disk drive 3 side to the host system 1 side, it may be considered that the above operation is performed in reverse.

In the above transfer, for example, when transferring more than a lid to 1-, there are cases where the last data is less than one sector. The appendix is added and transferred as data of l sector size.

Figure 2 shows the conventional configuration of the buffer circuit shown in Figure tJX1.0 Code 1o#'i in Figure 2Buffer memory for one sector (constituting the data buffer)
, 1ltj buffer address counter accesses 4th buffer Φ memory 104C.

12 is a data counter to which an address is given, and manages the position of valid data written on the buffer memory 10. 13 is a control circuit for the buffer circuit, and 14 is an OJ write circuit. ing.

For example, during data transfer from the host system, one sector worth of data is written onto the buffer memory 10, and during this time the data counter 12 counts the number of valid data on the Fi memory 10. YoK
One sector worth of data written on the memory 10 is read and transferred to the disk drive 3 via the data path. At this time, if data less than one sector of valid data is written onto the buffer memory 10 as described above, KFi, the disk drive 3@
When transferring the valid data to the buffer φ memory 10
The above data counter 12 indicates that it has been read from
, and after that all "0" is checked.
” The write circuit 14 writes all “0” following the above valid data.
'' pattern is added to the data, and the data is collected into one sector and transferred to the disk drive 3@ in good format. That is, valid data is checked by the data counter 12. The reason for performing such a check is that when less than one sector worth of data is written on the buffer memory 10, 1/Cd old data remains on the buffer memory 10, and there is no overflow on top of it. - This may be due to the fact that in order to perform writing, it is necessary to correctly manage the existence range l of the valid data.

FIG. 3 shows the configuration of an embodiment of the present invention corresponding to FIG. buffer·
Two memories are prepared, and when data is written to either one of the buffer memories 10-1 and 10-2, all "0" is written to the other buffer memory.
” is all “0” write circuit 14-1 and Fi14-2
Controlled to be written via. That is, for example, when data for l sectors is written to the buffer memory 10-1, all "0" write times M14-2
As a result, all "
0'' is written, and all old data remaining in the buffer memory 10-2 is cleared to all ``0''.

One sector worth of data written to the buffer memory 10-1 is read and transferred to, for example, the disk drive 3 via the data bus, but once that transfer is finished, it is transferred to the next one. 14-
All "0"s are written by IK. That is, all old data remaining on the buffer memory 10-1 is cleared to "0".

At this time, if the data written on the buffer memory 10-2 is less than one sector, then the valid data will be stored in the first sector on the buffer memory 10-2. is written, and all "0"s are written for the valid data and subsequent data.

For this reason, when the contents of the buffer memory 1O-2 are read as one sector worth of data to be transferred from the buffer memory 1O-2 to the disk drive 3 side, for example, when the contents of the buffer memory 1O-2 are read as one sector worth of data, the first half of the data KFi for the current wIl sector is read. Valid data exists in the second half, and all rOJ is packed in the second half. That is, the data is transferred in exactly the same form as expected in the configuration shown in FIG. Furthermore, in this case, there is no need to be aware of how much valid data exists in one sector #i.

(Trout) As has been made clear above, according to the present invention, as can be seen by comparing Fig. 2 and Fig. 3, how much valid data exists in the read/write unit data? This eliminates the need for management, making control much easier.

[Brief explanation of drawings]

FIG. 1 shows the configuration of an embodiment of a main part of a magnetic disk ## apparatus related to the present invention, FIG. 2 shows a conventional configuration of the buffer circuit shown in FIG. 1, and FIG. 1 shows the configuration of an embodiment of the present invention. In the figure, 1#i host system: lt magnetic disk control unit, 3 a disk drive, 7 a buffer circuit, 10 buffer memory, 114 d buffer address counter, 13 a buffer circuit control circuit section, ll
t represents an all “0” write circuit. Patent applicant Fujitsu Limited

Claims (1)

[Claims] In a disk control device that controls a disk device in which read/write is performed in sector units, at least two data buffers are provided that are sufficient to store one read/write unit for the disk device, and each A fixed pattern write circuit is provided which writes a fixed pattern to one of the data buffers while writing data to the other one, and when writing the data, the fixed pattern is Controls overwriting of the museum data on the stored state, and when reading data, reads and transfers the contents stored in the data buffer for the above-mentioned one read/write unit. A data buffer control method characterized by nine functions.