JPH01146106A - Magnetic tape running controller - Google Patents

Abstract

PURPOSE:To improve the throughput by changing the acceleration for positioning in accordance with a used cartridge tape. CONSTITUTION:The occurrence of a momentary speed variance is detected from a data block read by a momentary speed variance detecting circuit 17, and a momentary speed variance counting circuit 20 counts a number M of times of occurrence of the momentary speed variance of the data block processed after positioning, and a repositioning counting circuit 12 counts a number P of times of repositioning operation. A momentary speed variance/error counting circuit 22 counts a number Q of times of simultaneous occurrence of momentary speed variance detection and error detection in the data block processed after positioning. A reverse running distance control circuit 11 changes the value of the reverse distance given to a capstan control circuit 13 based on the counted value. The reverse running distance is changed in accordance with the frequency in occurrence of momentary speed variance of a cartridge tape in this manner, thereby optimizing the repositioning time to give the best throughput to the processing of data on the tape.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention is applied to a magnetic tape device. The present invention relates to a magnetic tape running control device that performs positioning control. In particular, the present invention relates to a magnetic tape running control device in a cartridge magnetic tape device that operates in a streaming mode.

〔overview〕

The present invention is a travel control device for a cartridge magnetic tape device operating in a streaming mode, in which the throughput can be significantly improved by changing the acceleration during positioning depending on the cartridge tape used.

[Conventional technology]

Cartridge magnetic tape devices that operate in streaming mode read or write data blocks while continuously running without starting or stopping within normal block intervals (hereinafter referred to as IBG), and stop operation in the following three cases. will be held.

(1) An error was detected in the By-th data block that was read or written.

(2) After writing the BMth data block I
Although the tape traveled the BG distance, the write command for the next BN 41st data block was not received.

(3) B: After reading the first data block, the tape ran until the read head touched the BN+1st data block, but no read command was received.

In particular, the cartridge magnetic tape device has the above-mentioned (1) to (
After entering the stop operation in 3), for example, in the case of item (1), in order to read the Bxth data block again,
In the case of (2), the repositioning operation is performed to erase the B1th data block, and in the case of (2) and (3), to read and write the B+1st block. enter.

Conventionally, this type of positioning control has been performed at B (IBG detection or overrun detection point) and C as shown in Fig. 2.
(stopping point of capstan and tape) and decelerate between C
- D (the point where the tape starts running at a constant speed), accelerates in the opposite direction, decelerates again between E (IBG detection or overrun detection point) and F (capstan and tape stop point), and then decelerates again between F and G. (The point at which the tape starts running at a constant speed)
data block BN or BN+
However, instantaneous velocity fluctuations of the cartridge tape occur closer to point G between G and H, and the frequency of occurrence varies greatly depending on the cartridge tape itself.

[Problem that the invention seeks to solve]

Therefore, in the conventional car) + Judge magnetic tape device,
In consideration of driving a cartridge tape that has the highest frequency of instantaneous speed fluctuations, it is necessary to increase the reverse travel distance D-E during positioning.
When entering the repositioning operation, D-E and G-H
This has the drawback that the time required for execution of instructions from the host device increases, resulting in poor throughput.

The present invention eliminates the drawbacks of the conventional positioning control method, and aims to provide a magnetic tape running control device that shortens the time required for repositioning operations and has good throughput.

[Means for solving problems]

The present invention includes an error detection circuit to which a read signal of a cartridge magnetic tape operating in a streaming mode is input;
A magnetic tape running control device comprising repositioning means for stopping the running of the magnetic tape, causing it to run in reverse, and further stopping the running of the magnetic tape in accordance with the detection output of the error detection circuit, further comprising a circuit for detecting instantaneous fluctuations in the tape running speed. The repositioning means includes means for increasing or decreasing the distance traveled in reverse from a standard value in accordance with the detection output of the circuit.

The repositioning means includes means for increasing/decreasing the distance to be traveled in reverse according to the number of times of detection by the error detection circuit, and the repositioning means includes means for increasing/decreasing the distance to be traveled in reverse according to the number of times of detection by the error detection circuit. Preferably, the vehicle includes means for increasing or decreasing the distance traveled.

[Effect]

Detects instantaneous speed fluctuations, changes the reverse traveling distance during repositioning, and controls the reverse traveling distance in response to data block errors during instantaneous speed fluctuations to shorten the time required for repositioning and improve throughput. can be done.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.

In the embodiment of the present invention, in a cartridge magnetic tape device that operates in a streaming mode, a capstan motor 15 that drives the magnetic tape, a servo circuit 14 that is connected to the capstan motor 15 and supplies a drive signal, and
A capstan control device 13 connected to this servo circuit 14 for supplying a control signal, a reverse travel distance control circuit 11 connected to this capstan control device 13 and supplying a reverse travel distance control signal, and this reverse travel distance A positioning counting circuit 12 connected to the control circuit 11 for counting the number of repositioning operations, an instantaneous speed fluctuation detection circuit 17 connected to the read head 19 for detecting instantaneous speed fluctuations of the magnetic tape, and detecting data block errors. an error detection circuit 18 that is connected to the instantaneous speed fluctuation detection circuit 17 and counts the number of occurrences of instantaneous speed fluctuations in the data block; and an error detection circuit 20 that is connected to the error detection circuit 18 and counts the number of errors. An instantaneous speed fluctuation circuit is connected to the counting circuit 21, the instantaneous speed fluctuation detection circuit 17, and the error detection circuit 18, and counts the number of times instantaneous speed fluctuation detection and error detection occur simultaneously.
and an error counting circuit 22.

The operation of the embodiment of the present invention configured as described above will be explained. The reverse travel distance control circuit 11 has a reference distance β. Initially, the capstan motor 15 is operated through the capstan control circuit 13 and the servo circuit 14. The read head 19 supplies read data signals from a running cartridge tape to an instantaneous speed fluctuation detection circuit 17 and an error detection circuit 18.

The error detection circuit 18 detects the presence or absence of an error in the read data block and supplies the detected data to the error counting circuit 21 . The error counting circuit 21 counts the number of errors N in the data blocks processed after beam positioning.

Similarly, the instantaneous speed fluctuation detection circuit 17 detects the occurrence of instantaneous speed fluctuation from the read data block and supplies it to the instantaneous speed fluctuation counting circuit 20. Instantaneous speed fluctuation counting circuit 2
At 0, the number M of occurrences of instantaneous speed fluctuations in data blocks processed after beam positioning is counted.

On the other hand, the repositioning counting circuit 12 counts the number of times P of repositioning operations. Further, the instantaneous speed fluctuation/error counting circuit 22 counts the number of times Q that instantaneous speed fluctuation detection and error detection occur simultaneously in the data block processed after repositioning. The reverse travel distance control circuit 11 uses the capsun control circuit 1 based on the above count value.
The value of reverse distance given to 3 is I! Change from o to β.

-For example, if ->K (reference value) then ! >fa□〈K (reference value), then l ku βO In this way, by changing the reverse travel distance depending on the frequency of occurrence of instantaneous speed fluctuations of the cartridge tape, the repositioning time is optimized, and the best method is obtained for data processing on the tape. can provide throughput.

In this embodiment, after the repositioning operation is completed, the number of errors N and the number of occurrences of instantaneous speed fluctuations M of the data block to be processed next are counted, and the reverse traveling distance during repositioning is determined by the ratio to the number of repositioning operations P. For cartridge tapes that have a low frequency of instantaneous speed fluctuations, the reverse travel distance between B and E in Figure 2 can be shortened (by shortening the time required for repositioning, the throughput can be significantly increased). It can be improved.

〔Effect of the invention〕

As explained above, according to the present invention, throughput can be significantly improved by changing the acceleration during positioning using the cartridge tape.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention. FIG. 2 is a diagram showing beam positioning operation. DESCRIPTION OF SYMBOLS 11... Reverse travel distance control circuit, 12... Repositioning counting circuit, 13... Capstan control device, 14... Servo circuit, 15... Capstan motor, 17... Instantaneous speed fluctuation Detection circuit, 18... Error detection circuit, 19... Read head, 20... Instantaneous speed fluctuation counting circuit, 21... Error counting circuit, 22
. . . Instantaneous speed fluctuation/error counting circuit, 25 . . . Block for forward direction (By), 26 . . . Block for reverse direction (BM), 30 . . . Block for forward travel (Bll+1).

Claims (3)

[Claims] (1) Error detection circuit (18) into which the read signal of the cartridge magnetic tape operating in streaming mode is input.
and repositioning means (11, 12) for stopping the running of the magnetic tape, causing the magnetic tape to run in reverse, and further stopping the running of the magnetic tape in accordance with the detection output of the error detection circuit. A running control device for a magnetic tape, comprising: a circuit (17) for detecting instantaneous fluctuation; and wherein the repositioning means includes means for increasing or decreasing the distance for reverse running from a standard value in accordance with the detection output of the circuit. (2) The magnetic tape running control device according to claim (1), wherein the repositioning means includes means for increasing or decreasing the distance of reverse running according to the number of times of detection by the error detection circuit. (3) The repositioning means includes means for increasing or decreasing the distance for reverse travel according to the number of times the detection output of the instantaneous variation detection circuit and the detection output of the error detection circuit occur simultaneously. ) The magnetic tape running control device according to item 1.