JPS592278A - Magnetic tape controller - Google Patents

Abstract

PURPOSE:To obtain a magnetic tape controller which makes search of a specific data block on a magnetic tape possible which is designated by a central processor with no intervention of said central processor. CONSTITUTION:A bus control circuit 10 reads the contents of a specific data block designated by an address and a range out of a main storage and with an instruction ordering a search for the specific data block as well as the address and range of the main storage which stores the contents of the specific data block transmitted from a central processor via a bus 200. Then the read-out data is loaded to a local memory 60. When this loading is over, a magnetic tape control circuit 50 sets a flip-flop 40 and delivers an advance instruction to a magnetic tape device 100. The data read out of the device 100 are reproduced by a data reproducing circuit 30 and then delivered to a data comparison control circuit 20. The circuit 20 compares the data given from the circuit 30 with the data given from the memory 60.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Description of the technical field to which the invention pertains The present invention relates to a magnetic tape control device.

(2) Description of the Prior Art Conventionally, in a magnetic tape control device, there has been an operation of searching for a tape mark as an operation of searching for a specific block from among a large number of blocks on a magnetic tape.

However, in this operation, only two types of blocks, tape marks and data blocks, could be distinguished. ' Therefore, as a method for distinguishing between a large number of blocks, a method was devised in which a recognition pattern was written on the magnetic tape as part of the data of the data block. However, in this method, when searching for a specific data block, the magnetic tape device reads one data block, transfers the data to an area of the main storage device specified by the central processing unit, and analyzes the contents of the transferred data, and if it is not a specific data block, requests the magnetic tape device to read it again, and ends the series of control operations when it recognizes that it is a specific data block. It was necessary to carry out such actions. Therefore, this method has the drawback that it is necessary for the central processing unit to analyze the data block every time one data block is read, and that the central processing unit requires processing time for this purpose.

(3) Detailed Description of the Invention The present invention has been completed in order to eliminate the above-mentioned drawbacks of the conventional technology, and therefore, an object of the present invention is to enable magnetic tapes specified by the central processing unit to be processed without the intervention of the central processing unit. An object of the present invention is to provide a novel magnetic tape control device that allows searching for specific data blocks on the disk.

(4) Detailed Description of the Invention The above object of the present invention is to provide a data comparison control circuit that compares the content of data stored in a self-control device with the content of data read from a magnetic tape, and A magnetic tape control circuit that stops the running of the magnetic tape when a reading magnetic head of a magnetic tape device passes the matched data block when the comparison results of the circuits match. tape controller,
achieved by.

(5) Detailed Description of the Invention Next, a preferred embodiment of the present invention will be described in detail with reference to the drawings.

@1 Figure is a conceptual configuration diagram showing one embodiment of the present invention.

@1 In Figure 1, an embodiment of the magnetic tape control device according to the present invention includes a bus control circuit 10, a data comparison control circuit 20,
, a data reproducing circuit 30, a flip-flop 40, a magnetic tape control circuit 50, and a local memory 60. Father, magnetic tape controller is a magnetic tape device
100, and is also connected via a bus 200 to a central processing unit (not shown) and a main storage device (not shown).

The operation of the magnetic tape controller constructed in this way is as follows. The bus control circuit 10 is sent from the central processing unit via the bus 200 by the address and range value of the main memory where the contents of the specific data block are stored, and by a command to search for the specific data block. The contents of a specific data block specified by the address and range are read from the storage device, and the data is loaded into the local memory 60. When the loading is completed, the magnetic tape control circuit 50 turns on the flip-flop 40 and outputs a forward command to the magnetic tape device 100. The data read from the exhaust tape device a 100 is reproduced by the data reproduction circuit 30 and output to the data comparison control circuit 20. In the data comparison control circuit 20, the data from the data reproduction circuit 30 and the data from the local memory 60 are compared. In the data comparison control circuit 20, when a mismatch in the comparison data is detected, a reset bus is output to the flip-flop 40, and when all the pattern information of a specific data block is output from the local memory 60. , ends the comparison operation. When the magnetic tape control circuit 50 recognizes that the magnetic tape device 100 has detected the end of one data block, the magnetic tape control circuit 50 stores the data in the local memory 6.
0 and the state of the clip-flop 40. If some of the information stored in the local memory 60 remains unoutputted or if the flip-flop 40 is in a reset state, the magnetic tape control circuit 50 sets the flip-flop 40 and then outputs the next data block. Then, the same comparison operation as above is repeated.

Furthermore, when all the information stored in the local memory 60 is output and the clip-flop 40 is in the set state, the magnetic tape control circuit 50 outputs a stop command to the magnetic tape device 100 to stop the forward movement, Terminates execution of an instruction to search for a specific data block.

The present invention has been described above with respect to one preferred embodiment thereof, but
These are merely illustrative, and it goes without saying that the present invention is not limited to the embodiments described here.

(6) Description of effects of the invention As described above, according to the magnetic tape control device of the present invention, it is possible to search for a specific data block specified by the central processing unit without intervention from the central processing unit. .

[Brief explanation of drawings]

FIG. 1 is a conceptual diagram of an embodiment of the present invention. 10., bus control circuit, 20. , , data comparison control circuit 30 , , data reproduction circuit 40 . , , Clip-flop 50 , , Magnetic tape control circuit 60 . , Local memo 1c 100 , Magnetic tape device 200
,,, Busification Attorney Patent Attorney Yutabe Kumagai

Claims (1)

[Claims] A data comparison control circuit that compares the content of data stored in the self-control device with the content of data read out on the magnetic tape, and a data block that matches when the comparison results of the data comparison control circuit match. 1. A magnetic tape control device comprising: a magnetic tape control circuit that stops the running of the magnetic tape when a reading magnetic head of the magnetic tape device passes through the magnetic tape control circuit.