JPS63136360A - Magnetic tape controller - Google Patents

Abstract

PURPOSE:To contrive to improve the tape utilizing efficiency without lowering system throughput by recording plural data blocks as one physical data block on a magnetic tape. CONSTITUTION:A data block sent from a data processing system 4 is stored in a data buffer 1 through an I/O processing section 3. A block counter 32 receives a count in advance and every time a data block is stored in the data buffer 1, the count is decremented. Moreover, the I/O processing section 3 stores the content of the buffer address register 31 before the data block is stored in the data buffer 1 and compares it with the content after the storage to obtain the block length of a logical data block 11, and the result is described in a block length description region 12. When the block count is finished, the plural stored logic data block 11 and the block length information 12 are recorded on a magnetic tape medium as one physical data block.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to the control of a magnetic tape device, and more particularly to a control method for recording data on a magnetic tape in a magnetic tape control device.

(Prior Art) Conventionally, a conventional magnetic tape control device employs a known method in which data blocks sent from a data processing system are recorded on a magnetic tape with the block length unchanged.

On the other hand, in order to improve the utilization rate of tape, a method is also known in which a data processing system collects a plurality of blocks and records them as one block.

(Problems to be Solved by the Invention) The conventional magnetic tape control device described above usually directly processes data blocks sent from a data processing system.
When recording on a magnetic tape, if the data block length is short, the interblock gap (Interblock Gap) that occupies the tape is
BG) The disadvantage is that the O ratio is large and the storage capacity of the tape is small.

In addition, in order to solve the above problem, a method is known in which a data processing system collects multiple blocks and records them as a single block to improve tape usage efficiency.
In this case, a large storage area must be taken up inside the data processing system, which has the disadvantage of reducing system throughput when multiple processing is being performed.

An object of the present invention is to eliminate the above-mentioned drawbacks and improve system throughput by equipping a magnetic tape control device with a blocking function and recording multiple data blocks as one physical data block on the magnetic tape. The magnetic tape system (III
The goal is to provide equipment.

(Means for Solving the Problems) The magnetic tape control device according to the present invention is a data buffered,
Buffer address register, block counter, and I
It is configured to include a /O processing section and a data control section.

The data buffer is for storing data sent from the data processing system.

The buffer address register is for controlling the data address inside the data buffer.

The block counter is for counting the number of data blocks inside the data buffer.

When writing data to the tape, the I/O processing unit calculates the block length from the difference between the contents of the buffer address register before and after storing the data in the data buffer.
Add block length information to the data block stored inside the data buffer and reduce the block count.
It is used to store multiple data blocks inside the data buffer until the block count is exhausted.

Data %tlJ (111 part executes writing to the magnetic tape when the block count is exhausted, and when reading data, deblocks the data via the I/O processing part based on the 9 block length information that is added at the time of writing.) It is a friend that transfers data blocks to the processing system.

(The current side) Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of a magnetic tape system according to the present invention. In FIG. 1, 4 is a data processing system, 1 is a data buffer of the magnetic chip 1 controller, and 3 is a ninth I/O processing unit that controls data exchange between the data processing system 4 and the data buffer 1. ,3
1 is a friend buffer address register that stores the address pointer of data buffer 1 when transferring data between data processing system 4 and data buffer 1;
32 is a block counter for counting the number of logical blocks stored in data buffer 1, 5 is a magnetic tape device, and 2 is a ninth data control for controlling data transfer between data buffer 1 and magnetic tape fet5. Department.

FIG. 2 is an explanatory diagram showing how the contents of the data buffer 1 in the magnetic tape mat shown in FIG. 1 are divided into blocks. FIG. 3 is an explanatory diagram comparing the recording operation of a data block from the data buffer l to the magnetic tape medium with the recording on the medium when /O is not turned on.

In the second section and FIG. 3, 11 is a logical data block, 12 is block length information, 51 is a magnetic tape medium, and 5 is a logical data block.
2 is a physical data block, 53 is a data block, 54
is the interblock gap (IBG).

Next, the present invention will be explained in detail with reference to FIGS. 1 to 3.

A friend data block 53 sent from the data processing system 4 passes through the I/O processing section 3 and is stored in the data buffer 1. A count value is given to the block counter 32 of the I/O processing section 3 in advance, and the count value is decremented each time a data block 53 is stored in the data buffer l. In addition, the I/O processing unit 3 stores the contents of the buffer address register 31 before the data block is stored in the data buffer 1, and stores the contents of the buffer address register 31 after t after the data block is stored in the data buffer l. Compare with the content. For this, data buffer 1
The block length of the logical data block 11 stored inside the data buffer l is determined, and the block length is written into the block length description area 12 defined inside the data buffer l.

Similarly, data blocks 53 are stored in data buffer l until the count of block counter 32 is exhausted. When the block count is exhausted, the nine logical cheater blocks 11 and block length information 12 stored in the data buffer 1 are recorded on the magnetic tape medium 51 as one physical data block 52.

When reading the data block 53 from the magnetic tape on the magnetic tape device fjt5, the data control unit 2 reads the physical data block 52 to the data buffer 1, and the block length recorded in the physical data block 52 is read out by the data control unit 2. Information 1
2, the data is decomposed into a plurality of logical data blocks 11 and transferred to the data processing system 4.

(Effects of the Invention) As explained above, the present invention provides a magnetic tape system 7n device with a blocking function and records a plurality of data blocks as one physical data block on the magnetic tape. Utilization efficiency can be increased by reducing the ratio of magnetic tape gaps.

Furthermore, since the data processing system uses only the storage area for one data block, there is no need to use a large storage area to block the data processing system; Since the capacity can be reduced, this has the effect of preventing a drop in throughput in a system that performs multiple processing.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of a magnetic tape control device according to the present invention. FIG. 2 is an explanatory diagram showing the contents of the data buffer in the magnetic tape control device according to the present invention. FIG. 3 is an explanatory diagram comparing the recording operation of data blocks from the data buffer to the magnetic tape medium with recording on the medium in the case where blocks are not formed. 1... Data buffer 2... Data control section 3.
... I/O processing unit 4 ... data processing system 5 ... magnetic tape device 11 ... logical data block 12 ... block length information 31 ... buffer address register 32 ... block counter 51 ... Magnetic tape medium 52 ... Physical data block 53 ... Data block 54 ... Gap between blocks Patent applicant NEC Corporation Representative Patent attorney Hisashi Inoro 21 Figure 2

Claims (1)

[Claims] a data buffer for storing data sent from a data processing system; a buffer address register for controlling a data address inside the data buffer; and a buffer address register for counting the number of data blocks inside the data buffer. When writing data to a tape, the block length is calculated from the difference between the contents of the buffer address register before and after the data is stored in the data buffer, and the block length is calculated from the difference between the contents of the buffer address register before and after the data is stored in the data buffer. an I/O processing unit for adding information on the block length to a data block to reduce a block count of the block counter and storing the plurality of data blocks in the data buffer until the block count is exhausted; When the block count is exhausted, writing to the magnetic tape is executed, and when reading, deblocking is performed via the I/O processing unit based on the block length information added at the time of writing, and the data is sent to the data processing system. 1. A magnetic tape control device comprising: a data control section for transferring blocks.