JPS6136284B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a recording inspection method for a magnetic storage device.
In particular, the present invention relates to a recording inspection method for a magnetic storage device that inspects the writing state of information and the occurrence of noise in a magnetic medium.

Conventionally, as a method for inspecting the writing state of information in a magnetic storage device, such as a magnetic tape device, information on the magnetic storage medium, such as a magnetic tape, is erased in advance, new information is written, and immediately after that, the new information is read. A method that checks whether the output level of the read signal is above a certain level and checks that new information has been reliably written (Read After Write).
method). However, with this method, if incomplete erasure of old information occurs due to improper installation or failure of the erase head, or if low-level noise introduced during erasing and writing is recorded on the magnetic medium. However, since the detection level of the read signal is set to a high level, these noises cannot be detected, and therefore, the writing state of information cannot be properly inspected.

An object of the present invention is to focus on the fact that the output level of the read signal of noise including the erased residue is relatively low, while the output level of the read signal of information is relatively high. When reading an unwritten portion, the detection level of the read signal is set to a low level to detect noise that exceeds the low level and includes unacceptable erasure. When reading a portion where information is written, by setting the detection level of the read signal to a high level, the writing state of information higher than the high level is detected. The object of the present invention is to inspect the writing state of information recorded on a magnetic medium as well as the noise generation state to more appropriately test the writing state of information recorded on a magnetic medium, thereby solving the problems in the conventional method described above.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block circuit diagram of an apparatus for performing a recording inspection method for a magnetic storage device as an embodiment of the present invention. In FIG. 1, a time sense unit 10 detects the generation of a write command pulse from a magnetic storage control device that controls a magnetic storage device, and a delay unit 20 detects the generation of a write command pulse after a certain period of time from the end of the write command pulse. The detection level selection unit 34 selects the detection level in the read signal inspection unit 35 that inspects the read analog signal, and the detection level has two levels in advance:
That is, a high level and a low level are set. Further, "0" is always applied to the set input S of each flip-flop 13 and 33.
The operation of the apparatus shown in FIG. 1 will be explained below.

2a to 2h are for explaining the operation of the device of FIG. 1 and show the signals appearing in the device of FIG. First, as step 1, the read signal inspection before the start of the write operation will be explained. A magnetic storage controller, such as a magnetic tape controller 1, sends out a drive signal a shown in FIG. 2a and a clock signal c shown in FIG. 2c. As a result, the magnetic medium 44 of the magnetic medium write/read section 40 moves in the direction of the arrow 45, and the information on the magnetic medium 44 is erased by the erase head 41. Also, the clock signal c
Therefore, counter 12 and flip-flop 3
3 is in the operating state, in this case the drive signal a is applied to the clear input CLR of the flip-flop 33, and the output signal g becomes "1" as shown in FIG. 2g.
becomes. As a result, the detection level selection section 34 selects a low level, and the read signal inspection section 3 accordingly selects a low level.
5 sets the detection level to a low level and inspects the read signal from the read head 43. For example, the second
As shown in Figure h, the read signal is at a low level because there is no write operation, but there is noise (second
(corresponding to X in Figure h) may exceed the low detection level shown by the dashed-dotted line. In this manner, when inspecting a read signal that does not involve a write operation, the detection level is set to a low level to detect noise including erased residue.

Next, the read signal inspection during the write operation will be described as a step. First, the magnetic tape controller 1 sends out a write command pulse b shown in FIG. This write command pulse b is applied to the preset input PR of the flip-flop 33 through the AND gate 31, so that the output signal g of the flip-flop 33 becomes "1" as shown in FIG. 2g. As a result, the detection level selection section 34 selects a high level, and in response, the read signal inspection section 35 selects the detection level as shown in FIG.
to the high level shown by the dashed line. Therefore, by checking the level of the reproduced information, it is checked whether the information has been reliably written. Further, the generation state of the write command pulse b is monitored by the time sense section 10. That is, in the time sense section 10, when the drive signal a and the write command pulse b are present, the counter 12 is kept in a clear state by the output signal of the AND gate 11, but when the write command pulse b ends, the counter 12 is kept in a clear state. AND gate 11 is closed and therefore counter 12 begins counting clock signal c. When the counted value of this counter 12 exceeds a certain value, a count over signal is sent to the reset input R of the flip-flop 13, and the flip-flop 13 is reset. Therefore, the output signal d of flip-flop 13 rises. This corresponds to Y in FIG. 2d. In this manner, the read signal during the write operation is inspected by setting the detection level to a high level in accordance with the size of the write data, thereby determining whether the write state is good or bad.

Next, as a step, inspection of the read signal after the write operation is completed will be described. Write head 4
The write operation according to 2 ends with the end of write command pulse b. As mentioned above, this end is detected by the time sense section 10, and the signal d becomes "1".
become. Furthermore, this signal d becomes a starting signal for the delay section 20. That is, the signal d becomes the countable signal E of the counter 22, and the counter 22 becomes the countable signal E of the counter 22.
QTP obtained at 1/4 timing of the speed response pulse (tacho pulse) of the capstan that moves the
(Quarter Tacho Pulse) is started to be counted through the AND gate 21. When this count value reaches a certain value, the counter 22 outputs a count over signal e.
As a result, "1" is applied to both inputs of the AND gate 32. Therefore, the flip-flop 33 is reset and the output signal g becomes "1".
become. As a result, the detection level selection section 3
4 selects a low level, and the read signal inspection unit 35 sets the detection level to a low level as shown by the dashed line in FIG. Note that the counter 22 is cleared in advance by the clock signal c. Further, the constant value set in the counter 22 is set by the time it takes for the magnetic medium 44 to pass the distance D from the write head 42 to the read head 43, thereby determining the information written on the magnetic medium 44. The detection level for testing the read signal changes from a high level to a low level after it has been completely read.

In the above embodiment, a magnetic tape device is shown as the magnetic storage device, but it can also be a magnetic disk device having a read-after-write function.

According to the present invention, when reading a portion of a magnetic medium where no information is written, the detection level required for inspecting the read signal is set to a low level, and when reading a portion where information is written, the detection level is set to a low level. By setting the detection level to a high level and inspecting both the written state of information and the state of noise generation including erasure, it is possible to perform a more appropriate inspection of the information recorded on the magnetic medium. This is useful for solving problems in conventional methods.

Further, according to the present invention, since the detection level of the read signal is changed from a low level to a high level at the same time as the start of the new information write operation, the signal written to the write head can be read by the read head. The detection level remains at a high level even during the period until the write head is erased, so that there is so-called field-through (leaking magnetic flux from the write head that is unrelated to the noise stored on the magnetic medium including the erased residue). The reading head does not detect even the noise signal caused by the noise (detected by the scanner), and troubles caused by this can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a block circuit diagram of an apparatus for performing a recording inspection method for a magnetic storage device as an embodiment of the present invention.
Figures 2a-2h are timing diagrams of signals appearing in the apparatus of Figure 1. Explanation of symbols, 1...Magnetic tape control device, 10...
Time sense section, 12... Counter, 13... Flip-flop, 20... Delay section, 22... Counter, 3
3...Flip-flop, 34...Detection level selection section, 35...Read signal inspection section, 40...Magnetic medium write/read section, 41...Erase head, 42...Write head,
43...reading head, 44...magnetic medium.

Claims (1)

[Scope of Claims] 1. A recording inspection method for a magnetic storage device in which information on a magnetic medium is erased in advance, new information is written, and immediately after that, the new information is continued to inspect the recording state of the new information, The detection level of the read signal is checked for noise including erased residue while the detection level of the read signal is at a low level, and the detection level of the read signal is changed to a high level at the same time as the start of the writing operation of the new information to record the new information. A recording inspection method for a magnetic storage device characterized by inspecting the state. 2 After a certain period of time after the new information writing operation is completed,
2. The method according to claim 1, wherein the detection level of the read signal is changed to a low level to check for noise including erased residue.