JPS6361440A - Magnetic tape device - Google Patents

Abstract

PURPOSE:To prevent the service life of a magnetic tape from being shortened even re-positioning is performed, by writing data on the magnetic tape at a time after the quantity of write data accumulated in a data accumulating part exceeds a prescribed quantity. CONSTITUTION:An interface part 2 intervenes between a CPU1 and a magnetic tape device, and performs the input/output of the data between those devices. The data accumulating part 3 has a prescribed capacity, and accumulates input data through the interface part 2. A magnetic tape control part 5 controls a transfer part 3 to start data transfer from the transfer part 3 to a magnetic tape driving part 4 when the data quantity in the data transfer part 3 exceeds a reference quantity. In the titled device, since the minimum running distance by a time when the next re-positioning operation is generated when the magnetic tape is started up once, can be guaranteed, it is possible to prevent the sections of the magnetic tape being run only for the re-positioning from being overlapped. In this way, it is possible to suppress the number of times to rub the same surface of the magnetic tape at minimum.

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present invention relates to a magnetic tape device.

(Prior Art) When writing data in a magnetic tape device, the magnetic tape must be running at a constant speed. Therefore, when writing data to a magnetic tape, a repositioning operation is performed. This repositioning operation will be explained using FIG.

In FIG. 5, the vertical axis corresponds to the running speed of the magnetic tape, and the horizontal axis corresponds to the position of the magnetic head on the magnetic tape. Tape speed is I+I+.

11 Q IT, there are three states of "-", 11 +
The II side represents that the magnetic tape runs in the forward direction, and the "-'° side represents that the magnetic tape runs in the reverse direction.

A position of "0" indicates that the magnetic tape is stopped. This figure 5 shows that the magnetic head changes from A to B over time.
, C, D, E, F. When initially stopped at point A, when a write command is accepted, the magnetic tape begins to run slowly in the forward direction, and when it reaches point B, it starts writing data. The time from point B to point 0 is determined by the write data. If write commands are repeatedly sent from the central processing unit, a plurality of boot blocks will be written one after another, so the zero point will be postponed more and more, and the tape running distance will become longer. When there is no more write data, the tape speed is decelerated and stopped at point D. When the receiver receives this tangent write command, the tape is run in the opposite direction from D to E-+F so that writing can be resumed from point 0 again. If you start the next damaging motion from one point, you will follow the path of the broken line.

In a magnetic tape device that performs repositioning in this manner, both the time and distance required for the magnetic tape to go from a stopped state to a constant speed running state, and the time and distance for the magnetic tape to go from a constant speed running state to a stopped state are both large. When repositioning occurs, a command from the central processing unit must be waited for, and unnecessary friction occurs between the magnetic tape and the magnetic head, shortening the life of the magnetic tape and the magnetic head. For this reason, it is necessary to devise ways to reduce the number of times the magnetic tape is started and stopped as much as possible.

The simplest solution is to increase the processing speed of the central processing unit. If the speed of the central processing unit is fast, it can issue a command to write the next data block immediately after one data block has been written onto the magnetic tape, so the magnetic tape device does not have to stop tape running. You can now move on to the next old behavior. However, in this method, it is necessary to input write data continuously at high speed to the magnetic tape tear, and this method has a large limitation in use.

Therefore, in practice, a method has been adopted in which a data storage and transfer device is interposed between the central processing unit and the magnetic tape device in order to alleviate the limitations on the processing speed of the medium-heat processing device. Conventionally, the primary purpose of this method is to shorten the magnetic tape write processing time, so the tape starts running as soon as it receives a write command from the central processing unit, and then the data is transferred to the data storage and transfer device. When the tape reaches a constant speed running state, the data stored in the data storage and transfer device is transferred to the magnetic tape device. Generally, the speed at which data is sent from the central processing unit to the data storage and transfer device is extremely fast, so multiple data blocks are sent to the data storage and transfer device from the time the tape is started until the actual reading of data begins. It can be stored inside.

(Problems to be Solved by the Invention) However, how many data blocks can be stored depends on the processing speed or processing method of the central processing unit. Therefore, even with this method, in extreme cases, the magnetic tape may stop after recording just one data block. In this case, since the distance traveled by one tape run is small, the vA head passes over the same magnetic tape surface many times for repositioning, which significantly shortens the life of the magnetic tape. There was a point.

The present invention has been made in consideration of the above circumstances, and it is an object of the present invention to provide a magnetic tape device that does not shorten the life of the magnetic tape even if it is repositioned.

[Structure of the invention]

(Means for Solving the Problems) In order to achieve the above object, a magnetic tape device according to the present invention exchanges data between a magnetic tape drive unit that drives a magnetic tape and reads and writes data, and an external device. an interface unit for input/output; a data storage unit that stores write data input via this interface unit; The present invention is characterized in that it further includes a control section that controls the magnetic tape to be stored at one time by driving the magnetic tape so that more than the predetermined amount of accumulated write data is stored at one time.

(Function) Since the vA magnetic tape device according to the present invention is configured as described above, the amount of data to be written on the magnetic tape is always greater than a predetermined amount. The magnetic head does not pass over the same location multiple times.

(Actual Example) A magnetic tape device according to an embodiment of the present invention is shown in FIG. The central processing unit (CPU) 1 sends a write command as well as write data and a read command to this magnetic tape device.
It receives continuous data from a magnetic tape device.

An interface unit (INTF) 2 is interposed between the central processing unit 1 and the magnetic tape device, and is used to input and output data between these. Data storage and transfer unit (
BtJF) 3 has a predetermined capacity, stores write data input from the central processing unit 1 via the interface unit 2, and transfers it to the magnetic tape drive unit (MTU) 4. The magnetic tape drive unit 4 serves to drive the magnetic tape so that a magnetic head (not shown) can write and read data. The magnetic tape control unit (MTC) 5 is the interface unit 2
, data storage and transfer device 3, and magnetic tape drive unit 4, and controls the entire magnetic tape device.

Next, the operation of this embodiment will be explained with reference to FIGS. 2 to 4.

First, the processing operation for command reception will be explained using the flowchart shown in FIG. In the command reception process, it is first checked whether a command has been sent from the central processing unit 1 (step 11). If a command has been sent, a command busy status is sent to the central processing unit 1 to prohibit issuing the next command (step 12). After that, the receiver receives the command and stores it in the command registration byte (
Step 13). The process returns to step 11 in preparation for accepting subsequent commands.

Next, the write processing operation will be explained using the flowchart shown in FIG. First, determine whether the command is registered or not (step 21). If the cloak is registered,
Determine whether the registered command is a write command (step 22). If it is a write command, determine whether there is free space in the data storage and transfer unit 3. Step 23): There is free space. Central processing Gi place only in case 1
Then, transfer of the write data to the data storage transfer unit 3 via the interface unit 2 is started (step 24).

Next, it is determined whether the data transfer of the write data from the central processing unit 1 to the data storage transfer section 3 has been completed (step 25). When the data transfer is completed, it is determined whether data is being transferred from the data storage and transfer section 3 to the magnetic tape drive section 4 (step 26). If data is not being transferred, the amount of data stored in the data storage and transfer unit 3 is checked and it is determined whether the amount is larger than a predetermined standard (step 27). Here, the standardity is the amount of data such that the distance required when the data is recorded on the magnetic tape is equal to or greater than a predetermined range. If the amount of data in the data storage and transfer unit 3 exceeds the reference bar, data transfer from the data storage and transfer unit 3 to the magnetic tape drive unit 4 is started (step 28
).

Next, it is determined whether the data transfer from the data storage transfer section 3 to the magnetic tape drive section 4 has been completed (step 29).
). If it has been completed, it is further checked whether there is any data to be transferred next in the data storage transfer unit 3 (step 30).
). If there is data to be recorded, the data running of the magnetic tape drive section 4 is continued, and data transfer from the data storage and transfer section 3 to the magnetic tape drive section 4 is resumed (step 31).
.

If there is no data to be recorded, the magnetic tape drive section 4 is forced to run the data (step 32).

Next, the process returns to the first step 21 and repeats the above process.

In this way, according to this embodiment, once the magnetic tape is started, the minimum distance traveled until the next repositioning operation occurs is guaranteed, so the section of the magnetic tape that runs only for repositioning is You can prevent them from overlapping each other. This has the effect of reducing the number of times the magnetic head rubs the same surface on the magnetic tape.

The above effects will be explained using a specific example. As shown in FIG. 4, in this embodiment, a plurality of data blocks (three in FIG. 4) are recorded in a j-overlapping manner, so A, B, C, D, E are recorded on the magnetic head.

Take route F. However, when the data blocks are repositioned one by one to increase the distance by micrometers as in the conventional method, the path shown by the broken line is taken. Therefore, conventionally, for example, the magnetic head would have to reciprocate five times in the section between f and d for repositioning. In contrast, in this embodiment, the magnetic head passes only once, and the magnetic tape does not deteriorate.

Although the present invention has been described based on the above embodiments, it goes without saying that various modifications can be made within the scope of the present invention.

〔Effect of the invention〕

As described above, according to the present invention, even if repositioning is performed, the life of the magnetic tape is not shortened.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of magnetic tape loading according to an embodiment of the present invention, FIGS. 2 and 3 are flowcharts showing the operation of the magnetic tape device, and FIG. 4 is a diagram showing the operation of the magnetic tape device. , FIG. 5 is a diagram showing the operation of a conventional magnetic tape device. 1...Medium heat 1! I! Apparatus, 2... Interface unit, 3... Data V product transfer unit, 4... Magnetic tape drive unit, 5... Magnetic tape ti control unit. Applicant's agent Mr. Sato Figure 3

Claims (1)

[Scope of Claims] A magnetic tape drive unit that drives a magnetic tape to read and write data; an interface unit that inputs and outputs data between an external device; and a write input that is input via the interface unit. a data storage unit that stores data; and after the write data stored by the data storage unit exceeds a predetermined amount, the magnetic tape drive unit drives the magnetic tape to simultaneously collect write data that exceeds the predetermined amount; A magnetic tape device comprising a control section for controlling writing.