JPH01286175A - Magnetic disk device - Google Patents

Abstract

PURPOSE:To improve the universality of a magnetic disk device by enabling the appropriate signal format of output data to be selected corresponding to the constitution of a host device by switching the setting of a conversion circuit by a control means. CONSTITUTION:Recording information on a magnetic disk 11 is inputted to a variable frequency oscillator VFO16 via a magnetic head 12, a read amplifier 14, and a pulse detector 15. The VFO16 oscillates a square wave following the fluctuation of read data due to the fluctuation of the rotating speed of the disk 11, and forms an output signal synchronizing with the wave, and sends it to the conversion circuit 17. In the circuit 17, a read clock is inverted, and is frequency-divided to a double frequency by a frequency divider 23, and is converted to a window signal, and also, the read data is converted to the read data with narrow width via the output of a monostable multivibrator 22 and an AND gate 21. By setting a switch 18 appropriately, the output data with a format suitable for the disk controller of the host device is transferred via an output driver 19.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a magnetic disk device, and particularly to a magnetic disk device that reads data from a rotationally driven magnetic disk using a magnetic head and outputs the data to the outside using a predetermined signal method. It is.

[Prior Art] Magnetic disk devices as described above have been known as external storage devices for host devices such as personal computers and word processors. In this type of device,
The analog signal read from the magnetic disk is converted into serial digital data by a pulse detector using a comparator, etc., and then output to the host device. A plurality of formats are known as output signal formats at that time. This is because the formats of output data accepted by host device side disk controller ICs currently available on the market are different. Figures 4(A) and 4(B) show two typical different conventional output data formats; Figure 4(A)
, (B), the output data is expressed from two signals. Here, read data in the MFM method is shown.

In FIG. 4(A), symbol C indicates clock data inserted for each data bit, and data bits of 1 or O are inserted before and after this clock data as shown. In FIG. 4A, the output data consists of read data and a read clock, and the read data is a pulse having a pulse width twice that of the read clock. Here, l data is shown by high level, and 0 data is shown by low level. When there are consecutive 0's, there is clock data in between. The rising timing of the read clock is synchronized so that it passes through the center of the read data pulse, so the disk controller on the host device reads the read data level at the rising timing of the read clock to read the read data and clock. Can be detected.

On the other hand, in FIG. 4(B), read data and window signals are used as output signals. In this case as well, the read data represents 1 data by a high level and 0 data by a low level, but the pulse width of the read data is smaller than the pulse width of the window. In FIG. 4, the window identifies read data by the presence or absence of a high level on the read data side during a high level period, and the valid period for data acquisition is indicated by the high level.

The polarity of the window may be reversed in some cases.

[Problems to be Solved by the Invention] As described above, since different output signal formats are defined for each disk controller IC, conventionally, a magnetic disk device that can be used in one host device cannot be used at all in another host device. However, there was a problem in that a magnetic disk device with different specifications had to be provided for each host device.

An object of the present invention is to solve the above problems and provide a highly versatile magnetic disk device.

[Means for Solving the Problems] In order to solve the above problems, the present invention provides a magnetic disk device that reads data from a rotationally driven magnetic disk using a magnetic head and outputs it to the outside using a predetermined signal method. A configuration is adopted that includes a conversion circuit that converts data read from the magnetic disk into a plurality of signal formats, and means for controlling the output signal format of this conversion circuit.

[Operation] According to the above configuration, by switching the settings of the conversion circuit by the control means, the signal format of the output data can be selected according to the configuration of the host side.

[Example] Hereinafter, the present invention will be described in detail based on the example shown in the drawings.

FIG. 1 shows the configuration of a magnetic disk device employing the present invention.

In FIG. 1, a magnetic disk 11, such as a floppy disk or a hard disk, is rotated by a drive system (not shown), and a magnetic head 12 is positioned at a predetermined track position along the radial direction of the magnetic disk. Information is magnetically recorded and reproduced through the magnetic disk. The magnetic head 12 includes a known write circuit 13 for recording information.
is connected. The writing system is well known.

A detailed explanation will be omitted here, and the configuration of the readout system will be shown below.

A read amplifier 14 is connected to the magnetic head 12 , and the read amplifier 14 amplifies the analog read signal output from the magnetic head 12 at a predetermined amplification factor and inputs the amplified signal to the pulse detector 15 . The pulse detector 15 is configured using a comparator or the like, converts the read analog signal into serial digital pulses, and inputs the serial digital pulses to a VFO (variable frequency oscillator) 16.

The VFO 16 is provided to prevent the timing of output data from varying due to the influence of jitter in the rotation drive system of the magnetic disk. The VFO 16 oscillates a square wave that follows fluctuations in read data due to fluctuations in the rotational speed of the magnetic disk 11, and forms an output-data signal synchronized with this. The VFO 16 has a known circuit configuration, as shown in FIG.
), two signals (read data and read clock or window signal) in one of the signal formats shown in (B) are output.

Conventionally, the output signal of this VFO 16 is sent to the output driver 1.
In this embodiment, a conversion circuit 17 is provided between the VFO f6 and the output driver 19. The configuration of the conversion circuit 17 is as follows:
Depending on which output signal format shown in FIG. 4(A) or FIG. 4(B) is used, the output signal may be as shown in FIG. 2 or 3, for example.

When the VFO 16 has the output format shown in FIG. 4(A), the conversion circuit 17 is configured as shown in FIG. 2, and converts the output format shown in FIG. 4(A) to the output format shown in FIG. 4(B). . On the other hand, VF
When O16 has the output format shown in FIG. 4(B), the conversion circuit 17 conversely converts the signal format from FIG. 4(B) to (A). It can be activated or deactivated by 18. When the conversion circuit 17 is deactivated, no conversion operation is performed and V
The output of the FO 16 is output as is via the output driver 19. The switch 18 is a jumper wire or dip switch provided on the control circuit board of the magnetic disk device.
It consists of a manual switch installed on the back of the device.

When converting the signal format from the read clock method shown in FIG. 4(A) to the window method shown in FIG. 4(B), the conversion circuit 1
7, as shown in FIG.

As shown in the figure, the read clock output from the VFO 18 is input to the monomulti 22 as it is, and is inverted and input to the frequency divider 23. The output of the monomulti 22 is input to the AND gate 21 together with the read data output from the VFO 16. Read data and a window signal in the format shown in FIG. 4(B) are output from the AND gate 21 and the frequency divider 23, respectively.

The operation of the circuit shown in FIG. 2 is as follows. That is, the read clock shown in FIG. 4(A) is inverted, frequency-divided by the frequency divider 23 to have a double period, and converted into a window signal as shown in FIG. 4(B). On the other hand, Fig. 4 (A)
The read data is input to the AND gate 21,
By inputting the output of the monomulti 22, which has the same output pulse width as the read data shown in FIG. 4(B), to the other input terminal of the computer controller 21, the output as shown in FIG. 4(B) is generated. Read data with narrow pulse width can be created.

On the other hand, when converting a signal from the window method shown in FIG. 4(B) to the read clock method shown in FIG. 4(A), the conversion circuit 1
7 is composed of monomultis 24 to 26 and an OR gate 27, as shown in FIG. The window signal output from the VFO 16 is input to the mono multi 24 as it is, and is inverted and input to the mono multi 25.
The output of 25 is input to an OR gate 27. On the other hand, read data is input to the monomulti 26. or gate 2
7 and the monomulti 26 output the read clock and read data shown in FIG. 4(A).

The operation of the circuit shown in FIG. 3 is first-order. That is, the monomultis 24 and 25 are activated by the rise and fall of the window signal output by the VFO 16, respectively, and output pulses having half the pulse width of the window signal. As a result, the read clock obtained via the OR gate 27 is converted into the read clock shown in FIG. 4(A) having exactly twice the frequency of the window signal. On the other hand, the read data is processed by the monomulti 26 set to the pulse width of the read data shown in FIG. 4(A).
The pulse width is expanded as shown in A).

A conversion circuit 17 configured as shown in FIG. 2 or 3 is provided depending on the format of the VFO 16, and by setting the switch 18 appropriately, the format suitable for the disk controller of the host device is converted via the output driver 19. Output data can be transferred.

Therefore, unlike in the past, it is not possible to transfer a magnetic disk device for one host device to another host device, and there is no need to supply a different magnetic disk device for each host device, increasing the versatility of magnetic disk devices. be able to. In addition, signal format conversion can be carried out at low cost by simply adding a simple circuit as shown in FIGS. 2 and 3 without modifying the VFO or the like.

Although the circuit for activating or deactivating the conversion circuit 17 is not shown above, the two input/output signal lines of each of the circuits in FIGS. 2 and 3 are directly connected to the switch 18 (comprising a multi-contact circuit). It may be bypassed by using an analog switch or the like.

Alternatively, when activating or deactivating the conversion circuit 17, the switch 18 is not used, and a predetermined signal is manually inputted from the host device side via the bar and fa 30 as shown in FIG. This allows the output data format of the magnetic disk device to be selected by software processing on the host device side.

[Effects of the Invention] As is clear from the above, according to the present invention, in a magnetic disk device that reads data from a magnetic disk that is driven once by a magnetic head using a magnetic head and outputs it to the outside using a predetermined signal method, The configuration includes a conversion circuit that converts the read data into multiple signal formats and a means for controlling the output signal format of this conversion circuit, so it can be configured to suit the configuration of the connected host device. This has the advantage that the signal format of the output data can be selected, greatly improving the versatility of the magnetic disk device.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a magnetic disk device adopting the present invention, FIGS. 2 and 3 are block diagrams showing different configurations of the conversion circuit of FIG. 1, and FIGS. 4 (A) and (B). 5 is a timing chart diagram showing different data output formats, and FIG. 5 is a block diagram showing the configuration of a magnetic disk device different from that in FIG. 1. 11... Magnetic disk 12... Magnetic head 13
...Write circuit 14...Read amplifier 16.
・・VFO17・・Conversion circuit 18・・Switch 21・・And gate 2
2.24-26... Monomulti 23... Frequency divider 27... OR gate 30
...Input buffer C- ≠ Beni suffering

Claims (1)

[Claims] 1) In a magnetic disk device that reads data from a rotationally driven magnetic disk using a magnetic head and outputs it to the outside using a predetermined signal method, a conversion circuit that converts data read from the magnetic disk into a plurality of signal formats; 1. A magnetic disk drive comprising means for controlling an output signal format of a conversion circuit.