JPH041976A - Magnetic disk device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

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

[Conventional technology]

3 and 4 show the main parts of a conventional magnetic disk device, FIG. 3 is a block diagram of a signal processing circuit, and FIGS. 4(a) to 4(d) show write fault (WRITE)
FAULT) is a timing chart showing input and output waveforms of the signal processing unit with the horizontal axis as a common time axis. In FIG. 3, (1) is a controller which is a control means,
A first write gate (WRITE G) has an output terminal (11) and an input terminal (12), and receives a data recording instruction from a computer (not shown) and instructs writing.
ATE) signal *WGT1 goes to a low level (LOW LEVEL) at time t1 as shown in FIG. 4(a).
) and is transmitted from the output terminal (11). ■ is a write (WRITE) abnormality detection means that checks whether there is an abnormality in the writing circuit (not shown) for writing data to a disk (not shown) that is a record carrier, and if there is no abnormality, the writing is started. Figure 4(b) shows the unsafe signal WUS.
As shown in , the output level is outputted from the output terminal (21) as a low level at time t1. (3) is a signal generation circuit, and is an input terminal (31).

(32) and output terminals (33) and (34), and the input terminal (31) is the output terminal (11) of the controller (1).
The first write gate signal *WGT1 is received from the input terminal (32), and the write unsafe signal WUS is received from the write abnormality detection means port, so that both the first write gate signal *WGT1 and the write unsafe signal WUS are input to the input terminal (32). As shown in FIG. 4(c), the second write gate signal * W G T 2 is set to low level at time t2, slightly after time t1, and sent from the output terminal (33) to the write circuit. Output and enable the write circuit to write. When the write unsafe signal WUS from the output terminal (21) of the write abnormality detection means (2) inputted to the input terminal (32) is at a low level (indicating a normal state), the signal generation circuit (3) Output terminal (3
4) Write fault (WRITE F
AULT) signal *WFAULT level is shown in Figure 4(d)
is maintained at a high level as shown in , and therefore at time t
1 and t2 are at a high level, and the data recording operation continues. When an abnormality occurs in the write circuit, for example, at time t3 in FIG. 4(b), an abnormality occurs such as a short circuit or disconnection of the head coil, or a write current does not flow, the output terminal (21) of the write abnormality detection means U.
The write unsafe signal WUS output from is shown in Figure 4 (
The signal generating circuit (31) changes from low level to high level at time 3 in b), and the signal generating circuit (31) changes from the low level to the high level at time t3, as shown in FIGS. output terminal (3) at time t4.
3) Second write gate signal output from * W G
The write fault signal *WFAU is output from the output terminal (34) to the controller (1) while setting T2 to a high level and putting the write circuit in a write-inhibited state.
Change LT to low level.

When the write fault signal *WFAULT changes to low level, the controller (1) immediately releases the write instruction based on this, interrupts the data recording operation, and issues an alarm.

[Problem to be solved by the invention]

Since the conventional magnetic disk drive is configured as described above, noise may be mixed into the write unsafe signal WUS inputted to the input terminal (32) of the signal generation circuit (3), and chattering may occur due to switching contacts. occurs,
For example, as shown in FIG. 4(b), when noise A as shown in the figure is mixed in at time t5 during data writing, the signal generation circuit 131 outputs the output terminal (
33) second write gate signal output to W G
T2 is set to a high level as shown in B in FIG.
34) Write fault signal output to *WFAULT
Since the level of the controller (1) is set to a low level as shown in C in FIG. 4(d), the controller (1) cancels the write instruction.

Therefore, even though the write circuit is normal, the data recording operation is interrupted, causing problems such as hindering the operation and, in some cases, causing data to be lost.

This invention was made to solve the above-mentioned problems, and aims to prevent malfunctions of the signal generation circuit G) and provide a highly reliable magnetic disk device.

[Means to solve the problem]

A magnetic disk device according to the present invention writes information to a record carrier based on a first write gate signal from a control means for instructing a write operation and a write unsafe signal from a write abnormality detection means for detecting an abnormality in a data writing circuit. A write unsafe signal input to the signal generation circuit which issues a second write gate signal to the write circuit that prohibits writing of data and also issues a write fault signal which cancels the write instruction to the control means is passed through a low-pass filter. It is configured so that it passes through and is input.

[For production]

In this invention, the noise mixed in the write unsafe signal is removed by the low-pass filter and then input to the signal generation circuit, so there is no risk of the signal generation circuit generating a write fault signal due to noise. Therefore, it is possible to prevent data writing from being interrupted due to erroneous cancellation of the write instruction.

[Embodiments of the invention]

1 and 2 show the main parts of an embodiment of the present invention, FIG. 1 is a block diagram of a signal processing circuit, and FIG.
a) to (e) are timing charts showing signal waveforms of each part. In Figure 1, (4) is a low-pass filter, which is composed of a reactor (41) and a capacitor (42) connected in parallel between the ground and its input terminal (43).
) is the output terminal (21) of the light abnormality detection means port, and the output terminal (44) is the input terminal (32) of the signal generation circuit (3).
It is connected to the. Therefore, the write unsafe signal WUS from the output terminal (21) of the write abnormality detection means (2) is input to the input terminal (32) of the signal generation circuit (3) after passing through the low-pass filter (2). Since the other parts are the same as those in the conventional example shown in FIG. 3, the same reference numerals are given to the parts corresponding to 5, and the explanation thereof will be omitted.

With the above configuration, when noise A is mixed into the write unsafe signal WUS transmitted from the write abnormality detection means (2) at time t5 as shown in FIG. In the output signal WUSI of the output terminal (44) of the filter (A), the noise A is reduced to below a predetermined level as the noise a shown in FIG. 2(C). Therefore, the signal generation Circuit (3
), and the second write gate signal *W is output from the output terminal (33) and the output terminal (34).
GT2. Write fault signal * W F A U L
As shown in FIGS. 2(d) and (e), the signal level of T does not erroneously change as shown in B and C due to noise A. Therefore, it is possible to prevent the write instruction from the controller (1) from being canceled due to the noise A.

Note that, in addition to the case where the write unsafe signal WUS is contaminated with noise, the second write gate signal *WGT2. It is possible to prevent the signal level of the write fault signal *WFAULT from changing erroneously.

Further, the low-pass filter may be configured by a combination of a resistor and a capacitor, or may be configured in a π type or other shape.

〔Effect of the invention〕

As described above, according to the present invention, since the write unsafe signal is input to the signal generation circuit after passing through a low-pass filter, a malfunction due to noise etc. may interrupt the data writing operation. , and there is no risk of data loss due to this.
A highly reliable magnetic disk device can be obtained.

[Brief explanation of the drawing]

1 and 2 show essential parts of an embodiment of the present invention, FIG. 1 is a block diagram of a signal processing circuit, and FIG. 2(a)
~(e) is a timing chart showing signal waveforms of each part,
3 and 4 show a conventional magnetic disk device, FIG. 3 is a block diagram of a signal processing circuit, and FIGS.
(d) is a timing chart showing signal waveforms of each part. In the figure, (1) is the controller, (2) is the write abnormality detection means, B) is the signal generation circuit, (A) is the low-pass filter, *WGT1 is the first write Kate signal, WUS is the write unsafe signal, *W G T 2 is a second write gate signal, and *WFAULT is a write fault signal. Note that the same reference numerals in each figure indicate corresponding parts. Agent Patent Attorney Masuo Ookimi

Claims (1)

[Claims] a control means for emitting a first write gate signal for instructing a write; a write abnormality detection means for detecting an abnormality in a write circuit for writing data to a record carrier and emitting a write unsafe signal; the first write gate signal and the above; a signal generation circuit that issues a second write gate signal to the write circuit that prohibits writing data to the record carrier based on the write unsafe signal, and also issues a write fault signal to the control means that cancels the write instruction. What is claimed is: 1. A magnetic disk device comprising: a write unsafe signal input to the signal generating circuit via a low-pass filter;