JPS6316490A - Magnetic tape device - Google Patents

Abstract

PURPOSE:To immediately know the drop-out of a record by always holding the number of a block under processing in a register and comparing a block number recorded on a magnetic tape with the contents of the register via a host device at the time of reading. CONSTITUTION:A reading instruction of a magnetic tape 3 is issued from a system 0 and read data are transferred to the system 0 via a data line 20. A head byte (record number RO) of the data received via the line 20 is compared with a record number in the system 0. When coincidence is obtained from said comparison, it is known that data are read normally. While the drop- out of a record is shown if no coincidence is obtained from the comparison. In the same way, a head byte (record number R1) received via a data line 21 is compared with a record number in a system 1 when a reading instruction is delivered from the system 1.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic tape device, and more particularly to a countermeasure against block deletion of data recorded on a magnetic tape.

[Conventional technology]

Conventionally, this type of magnetic tape device has transferred data recorded on a magnetic tape according to the recording density in response to a read command sent from a host device.

At the same time, reading errors were only checked and reported every time one block was read.

[Problem that the invention seeks to solve]

The above-mentioned conventional magnetic tape device has the disadvantage that since it can only check for data read errors each time one block is read, if one block is missing due to some reason on the medium, it takes a lot of time to investigate the cause. .

[Means for solving problems]

A magnetic tape device of the present invention includes a register for storing a record number sent from a host device, a means for reading the record number from the register according to an instruction from the host device, and a means for writing the record number to the register according to an instruction from the host device. and a control section having means.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a third embodiment of the present invention. In Figure 1,
In this embodiment, a magnetic tape device 100 includes a magnetic tape 3, a control section 1, and a register 2, and is connected to a magnetic data control device (not shown). The control unit 1 has a register 2
, and also controls the entire magnetic tape device 100. The register 2 is a register that is controlled by the control unit 1 via the control signal 12 and stores the record number currently being processed. The control unit 1 connects a control signal line 10 to the magnetic tape controller #O, a control signal line 11 to the magnetic tape controller #1, a control signal line 12 to the register 2, and a control signal line 12 to the magnetic tape 3 handling unit. It has a control signal line 13,
Furthermore, the data line 20 with the magnetic tape control device #O and the data line 21 with the magnetic tape control device #1 are connected to the register 2.
It has an access data line 22 to the magnetic tape 3 and a data line 23 to the magnetic tape 3, respectively.

The magnetic tape 3 used in this embodiment has a mark indicating the starting end of the magnetic tape (hereinafter referred to as "rBOT").
A 1-byte block number is recorded at the beginning of each recorded block from the beginning (called r tape ).

Next, when reading the magnetic tape 3, a host device (not shown) sends a signal to the magnetic tape device 1 via a control signal line 10.
When a command to read the magnetic tape 3 is issued to 00, the control unit 1 decodes the read command and drives the reel to read the magnetic tape 3 via the control signal line 13. After a certain period of time has elapsed, the contents of the magnetic data 3 are sent to the control unit 1 via the data line 23, and one block of data is further transferred from the control unit 1 to the host device via the data line 20.

Similarly, when a read command is issued via the control signal line 11, one block of data on the magnetic tape 3 is transferred to the host device via the data line 21.

The control signal line 11 and the data line 21 and the control signal line 10 and the data line 20 are each used bare, and are connected to the 1 system and the O system, respectively.

When data on the magnetic tape 3 is read from the 0 system and the 1 system, read commands are alternately received. Before receiving a read command from the O system, the contents of register 2 are sent from the O system to the O system via the data line 20. The 0 system uses the data sent via this data line 20.
1” added value (record number to start processing from now on)
(hereinafter abbreviated as record number). ), and the value added by "1" is stored in the register 2 of the magnetic tape device via the control signal line 10 and the data line 20.

Next, a command to read the magnetic tape 3 is issued from the O system. The read data is then transferred to the O system via data line 20. In the 0 system,
The first 1 byte of data sent via the data line 20 (
The record number RO) is compared with the record number above, and if they match, it means that the reading was successful.
When there is a mismatch, it indicates that a record is missing.

Similarly, when a read command is issued from the 1st system,
The first 1 byte of data sent via the data line 21 (
A comparison between the record number R1) and the above record number is performed in the 1-system system.

The value of register 2 is that magnetic tape 3 is rBOT.

When located at , it is cleared to "0" via the control signal line 12.

〔Effect of the invention〕

As explained above, the present invention always holds the block number for the block currently being processed in the register, and compares the block number recorded on the magnetic tape with the contents of the register at the time of reading in the host device, thereby preventing missing records. It has an effect that can be immediately noticed.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1...Control part, 2...Register, 3...Magnetic tape, 1o, 11, 12.13...Control signal line, 20°21.22.23...Data line, 100...・Magnetic tape device.

Claims (1)

[Claims] It includes a register that stores a record number sent from a host device, a control unit that has means for reading the record number from the register according to an instruction from the host device, and means for writing the record number to the register according to an instruction from the host device. A magnetic tape device characterized by: