JPH05303836A - Magnetic disk device - Google Patents

Abstract

PURPOSE:To make a read gate signal active and to read data without getting the adverse effect by a write splice or the like which is generated in the head portion of a formating medium in the data reading of a magnetic disk device. CONSTITUTION:Two outputs of an index signal generating circuit 11 and a sector signal generating circuit 12 are delayed by going through delaying circuits 21 and 22. The two output signals and the delayed signals are selectively outputted by two input.one output selectors 31, 32, respectively. And other than during a formatting, delayed index signals and sector signals are outputted and a write splice or the like, which is generated during a formatting, are avoided and read gate signals are instantaneously made active without putting a waiting time in read gate signals during a date reading.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention detects an index signal or a sector signal, writes data on a recording medium when a write gate signal becomes active, and writes data from a recording medium when a read gate signal becomes active. The present invention relates to a magnetic disk device for reading data.

[0002]

2. Description of the Related Art The operation of a conventional magnetic disk device will be described with reference to the time chart shown in FIG. In FIG. 4, the write gate signal and the read gate signal are active at a low level.

First, in order to enable writing or reading of data to or from a magnetic disk device, a recording medium of the magnetic disk device (hereinafter, referred to as a minimum unit called a sector starting from an index signal or a sector signal) is used. It is necessary to divide the medium). Data can be written / read by writing address information or the like in each sector, that is, by formatting. To write this format or data, the write gate signal is activated. Further, it is necessary to activate the read gate signal for reading data.

At the time of formatting, the magnetic disk device normally detects that the index signal or the sector signal is active and activates the write gate signal. Then, when the write gate signal becomes active, the format data starts to be written on the medium. When the write gate signal becomes active on the medium, indefinite data called a write splice is written until the signal goes low, and then format data is written.

When reading data, the magnetic disk device first detects that the index signal or the sector signal has become active. Then, wait a time long enough to avoid the write price portion formed during formatting, and then activate the read gate signal to start data reading.

[0006]

The above-described conventional magnetic disk device detects the index signal or the sector signal during formatting and activates the write gate signal, and when the write gate signal is activated, the medium is transferred to the medium. Since the data writing of No. 1 is started, there is a disadvantage that there is a wasteful portion from the rising edge of the index signal or the sector signal to the beginning of the format data on the medium.

Further, in order to avoid a write splice portion which occurs on the medium during data reading, there is a drawback that the active of the read gate signal must be intentionally delayed after detecting the index signal or the sector signal. ..

An object of the present invention is to eliminate a useless portion on a medium immediately after detection of an index signal or a sector signal,
Another object is to provide a magnetic disk device that activates a read gate signal without delay.

[0009]

According to a first aspect of the present invention, there is provided a magnetic disk device including an index signal generating circuit for generating an index signal, a sector signal generating circuit for generating a sector signal, and delaying and delaying the generated index signal. A first delay circuit that outputs as an index signal, a second delay circuit that delays the generated sector signal and outputs as a delayed sector signal, and the index signal and the delayed index signal are input and either one is selected. And a second 2-input / 1-output selector for outputting, and a second 2-input / 1-output selector for inputting the sector signal and the delayed sector signal and selecting and outputting either one of them.
The first and second 2-input / 1-output selectors output the index signal and the sector signal respectively when the recording medium is formatted, and output the delayed index signal and the delayed sector signal when unformatted. The feature is that each is output.

The magnetic disk device of the second invention is
An index signal generation circuit for generating an index signal, a sector signal generation circuit for generating a sector signal, a first 1-input / 2-output decoder for inputting the generated index signal and switching to one of the outputs, and generation A second 1-input / 2-output decoder which inputs the sector signal and switches and outputs the sector signal, and one of the first 1-input / 2-output decoder which delays and outputs as a delay index signal A first delay circuit, a second delay circuit for delaying one output of the second 1-input / 2-output decoder and outputting it as a delayed sector signal;
OR gate for receiving the other output of the 1-input / 2-output decoder and the delayed index signal, and the other output of the second 1-input / 2-output decoder and the delayed sector signal A second OR gate, wherein the first and second 1-input / 2-output decoders respectively output the index signal and the sector signal when the first and second OR gates execute formatting of a recording medium. It is characterized in that the delay index signal and the delayed sector signal are respectively output during non-formatting.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing a first embodiment of the present invention. In FIG. 1, 11 is an index signal generation circuit, 12 is a sector signal generation circuit, 21 and 22 are delay circuits, and 31 and 32 are 2-input / 1-output selectors. Further, a signal for switching between execution and non-execution of the format (hereinafter referred to as a format mode signal) is a control signal for switching the inputs of the selectors 31 and 32, and this format mode signal indicates the execution of the format. Becomes active when you do.

Next, the operation of the first embodiment of the present invention will be described with reference to FIG.

First, the index signal generated by the index signal generation circuit 1 and the sector signal generation circuit 1
The sector signal generated by 2 includes a delay circuit 21, a 2-input / 1-output selector 31, and a delay circuit 22.
And two input / one output selector 32. Then, both signals sent to the delay circuits 21 and 22 are delayed by the time from when the index signal or the sector signal becomes active until the light splice on the medium can be detected, and their outputs have two inputs respectively. -Sent to the other input of the one-output selectors 31 and 32.

The 2-input / 1-output selectors 31 and 32 are
When the format mode signal is active, the index signal generation circuit 11 output and the sector signal generation circuit 12 output are selected and output. Then, when the format mode signal is inactive, that is, when normal data is read, the outputs of the delay circuits 21 and 22 are selected, and the delay index signal and the delayed sector signal are output.

Here, when the magnetic disk device performs formatting, the format mode signal becomes active, so that the index signal and sector signal without delay are output. The magnetic disk device detects these signals and activates the write gate signal. Then, the light splice and the format data are written on the medium.

When the magnetic disk device reads data, the format mode signal becomes inactive, so that the delay index signal and the delayed sector signal are output. Since the delay index signal and the delayed sector signal are output after passing through the portion where the light splice exists on the medium, there is apparently no wasted portion before the first format data on the medium. Also, since there is no write splice, the read gate signal can be activated immediately after detecting the index signal or the sector signal. When reading data, the delay index signal and the delayed sector signal are detected to reduce the waiting time. The read gate signal can be activated and data reading can be started without providing.

Next, a second embodiment of the present invention will be described with reference to FIG. In FIG. 2, 11 is an index signal generation circuit, 12 is a sector signal generation circuit, 21 and 22 are delay circuits, 41 and 42 are 1-input / 2-output decoders, 51 and 52 are OR gates, and the decoders 41 and The control signal for switching the input of 42 is a format mud signal.

In this embodiment, both the index signal generated by the index signal generation circuit 11 and the sector signal generated by the sector signal generation circuit 12 are first input to the 1-input / 2-output decoders 41 and 42. To be done. Then, the 1-input / 2-output decoders 41 and 42
Is an output of the index signal generation circuit 11 and a sector signal generation circuit 12 when the format mode signal is active.
The output is sent to one input terminal of each of the OR gates 51 and 52. At this time, the signal lines to the delay circuits 21 and 22 are fixed to the low level, so that the delay circuits 21 and 22 are
The output is also low level. Therefore, the output of the OR gate 51 becomes the output of the index signal generation circuit 11, and
The output of the OR gate 52 becomes the output of the sector signal generation circuit 12. That is, the index signal and the sector signal without delay are output.

Next, when the format mode signal is inactive, the output of the index signal generating circuit 11 is input to the delay circuit 21 and the output of the sector signal generating circuit 12 is input to the delay circuit 22. The output of the index signal generation circuit 11 sent to the delay circuit 21 and the output of the sector signal generation circuit 12 sent to the delay circuit 22 are the same as those in the first embodiment. After activation, there will be a delay before the light splice on the medium can be detected, and their outputs are sent to the other inputs of OR gates 51 and 52, respectively. Then, the inputs of the OR gates 51 and 52 of the outputs of the 1-input / 2-output decoders 41 and 42 are fixed to the low level at this time. Therefore, the output signal of the delay circuit 21 is sent from the OR gate 51, and the output signal of the delay circuit 22 is sent from the OR gate 52. That is, the delayed index signal and the delayed sector signal are output respectively.
This allows the circuit of FIG. 2 to produce the same output as in the first embodiment. Therefore, a delayed index signal and a delayed sector signal are output at the time of reading data, and these signals are output after passing through a portion where the write splice written by the detection of the index signal without delay and the sector signal at the time of formatting exists. Therefore, the useless portion of the medium is apparently eliminated, and the read gate signal can be immediately activated.

[0021]

As described above, in the magnetic disk device of the present invention, the read gate signal at the time of reading data is used in order to apparently eliminate the useless portion formed on the medium immediately after the detection of the index signal or the sector signal at the time of formatting. Has the effect that it can be activated without delay.

[Brief description of drawings]

FIG. 1 is a block diagram showing a first embodiment of the present invention.

FIG. 2 is a block diagram showing a second embodiment of the present invention.

FIG. 3 is a time chart showing signal waveforms in the main parts of FIGS. 1 and 2.

FIG. 4 is a time chart showing a signal waveform of a conventional magnetic disk device.

[Explanation of symbols]

 11 index signal generation circuit 12 sector signal generation circuit 21, 22 delay circuit 31, 32 2 input / 1 output selector 41, 42 1 input / 2 output selector 51, 52 OR gate

Claims (2)

[Claims] 1. An index signal generation circuit for generating an index signal, a sector signal generation circuit for generating a sector signal, a first delay circuit for delaying the generated index signal and outputting it as a delayed index signal, A second delay circuit for delaying the sector signal and outputting it as a delayed sector signal; and a first 2-input / 1-output selector for inputting the index signal and the delayed index signal and selecting and outputting one of them. , A second 2-input / 1-output selector that inputs the sector signal and the delayed sector signal and selects and outputs one of them, and the first and second 2-input / 1-output selectors include: Outputs the index signal and the sector signal respectively when the recording medium is formatted, and delays when the non-format is performed. A magnetic disk device characterized in that it outputs an index signal and the delayed sector signal, respectively. 2. An index signal generation circuit for generating an index signal, a sector signal generation circuit for generating a sector signal, and a first first input / input 2 for inputting the generated index signal and switching the output to either one. An output decoder, a second 1-input / 2-output decoder for inputting the generated sector signal and switching to one of the outputs, and a delay index for delaying one output of the first 1-input / 2-output decoder A first delay circuit for outputting as a signal, a second delay circuit for delaying one output of the second 1-input / 2-output decoder and outputting it as a delayed sector signal, and the first 1-input / 2-output A first OR gate for receiving the other output of the decoder and the delay index signal, the other output of the second 1-input / 2-output decoder and the delay sector A second OR gate for inputting a signal and the first and second one-input / two-output decoders, wherein the first and second OR gates have the index signal and the index signal when the recording medium is formatted. A magnetic disk device, wherein a sector signal is output, and the delay index signal and the delay sector signal are output during non-formatting.