JPH04141868A - Magnetic tape controller - Google Patents

Abstract

PURPOSE:To detect the fault of a check code generation circuit by inputting the output of a check code generation circuit and write data to an error check circuit at the time of writing data. CONSTITUTION:At the time of writing, write data 21 transferred from a host device 20 is modulated into a write format on to a magnetic tape in a write circuit 1 and the check code generation circuit 2 generates a check code, which is added to write data 21 and is transmitted to a magnetic tape device 30. Then, write data with check code 11 from the write circuit 1 is inputted to a read circuit 3 through a selector 6 by control from a main control part 7. Inputted write data with check code 11 is transmitted to the error check circuit 4 and the presence or absence of the error of the check code which the check code generation circuit 2 generates is checked. Thus, error data occurring owing to the fault of the circuit in a magnetic tape controller can be prevented from being written into the magnetic tape and the fault of the internal circuit can immediately be detected.

Description

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

[Conventional technology]

Conventional magnetic tape control devices add data generated by a check code generation circuit to data sent from a host device when recording, and send the data to the magnetic tape device, and when reading, add data generated by a check code generation circuit to the data sent from the host device, and when reading, add data generated by a check code generation circuit to the data sent from the host device. An error check circuit was used to check and detect errors.

[Problem to be solved by the invention]

The conventional magnetic tape control device described above does not have a function to detect an error when a failure occurs in the check code generation circuit, so the erroneous check code is directly sent to the magnetic tape device, recorded on the tape, and played back. There is a problem that sometimes this error is detected for the first time.

[Means to solve the problem]

The magnetic tape control device of the present invention includes a check code generation circuit that adds a check code to guarantee write data transferred from a host device, and a check code generation circuit that uses the check code to prevent data errors in a read operation from the magnetic tape device. In the magnetic tape control device having an error check circuit for detecting an error, the output of the check code generation circuit and the write data are input to an official error check circuit when writing data.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram of one embodiment of the present invention. The magnetic tape control device 10 includes a write circuit 1 that controls writing of write data 21 transferred from the host device 20 onto the magnetic tape, a check code generation circuit 2 that generates a check code from the write data 21, and a magnetic Tape device 3
A read circuit 3 controls the read data 31 received from 0 and transfers it to the host device 20, an error check circuit 4 detects errors from the read data 31, and data from the write circuit 1 and from the magnetic tape device 30. The device is composed of a selector 6 that selects and inputs the data to the read circuit 3, and a main control section 7 that controls the operation of the entire device.

Next, the operation of this embodiment will be explained. During writing, the write data 21 transferred from the host device 20 is modulated into a format for writing onto the magnetic tape by the write circuit 1, and a check code is generated by the check code generation circuit 2 and added to the write data 21. , is sent to the magnetic tape device 30 as write data 11 with a check code.

Next, under the control of the main control unit 7, the write data 11 with check code is sent from the write circuit 1 via the selector 6.
is input to the read circuit 3. The input check code attached write data 11 is sent to the error check circuit 4, where it is checked for errors, and then sent to the check code generation circuit 2.
Checks the check code generated by .

On the other hand, during reading, read data 31 sent from the magnetic tape device 3o is input to the read circuit 3 via the selector 6. Furthermore, after the data error check is performed by the error check circuit 4, the host device N2o
will be forwarded to.

〔Effect of the invention〕

As explained above, the present invention prevents erroneous data caused by a circuit failure inside a magnetic tape control device from being written to a magnetic tape by inputting the output of the write circuit to the read circuit. can,
Furthermore, there is an effect that failures in internal circuits can be detected quickly.

[Brief explanation of drawings]

FIG. 1 is a block diagram of one embodiment of the present invention. 1... Write circuit, 2... Check code generation circuit, 3... Read circuit, 4... Error check circuit,
6... Selector, 7... Main control unit, 1o... Magnetic tape control device, 11... Write data with check code, 20... Host device, 21... Write data,
3o... Magnetic tape device, 31... Read data.

Claims (1)

[Claims] It has a check code generation circuit that adds a check code to guarantee write data transferred from a host device, and an error check circuit that uses the check code to detect data errors in a read operation from a magnetic tape device. 1. A magnetic tape control device, wherein the output of the check code generation circuit and the write data are input to the error check circuit during data writing.