KR890001951B1 - Track servo and information read logic circuit - Google Patents

Abstract

The Logic circuit for magnetic disk drive helps head search and trace the desired track exactly. Flip-flop output terminal (Q) and servo data head selection multiplexor (10) are connected to read servo or data and to select a servo head if necessary. Spindle pulse generator (1), designed to generate 1 pulse according to 1 rotation of disk, is attached to clock pulse terminal of flip-flop (CK).

Description

Track servo and information reading logic of magnetic disk drive

1 is a state diagram showing whether or not information is written in any form of a servo disk of a magnetic disk drive.

2 is a logic circuit showing when and how to read the servo information.

3 is a spindle pulse waveform diagram that appears when the magnetic disk is rotated.

4 is a pulse timing chart for explaining the operation of the present invention.

* Explanation of symbols for main parts of the drawings

2: servo information area 4: pulse generator

F / F: Flip-Flop 10: Servo / Data Head Select Multiplexer

11: microprocessor 12: counter

N ₁ : Nand Kate

The present invention relates to a track servo and an information reading logic circuit of a magnetic disk drive that enables the head to accurately search for a track to be searched for in the magnetic disk drive.

Conventionally, there has been a dedicated Servo (En beddbd Servo) method, but in the former case, the magnetic head can search a track by using a specific surface of the disk as a servo data recording surface. At this time, the information on this page is read to confirm that the track position is correct.

However, this method uses one side of the disc as a servo data recording surface, which causes a problem in that data recording capacity decreases when the same number of discs is used.

In the latter case, the servo information is recorded in the gaps between the sectors and the sectors in each track on all the discs, and when the magnetic head searches the tracks, the servo information recorded between these sectors is read to confirm that the correct track is located. Done.

But. This method also has a problem in that the user cannot arbitrarily adjust and format the sector length because the length is fixed between the sector and the sector.

In view of the above problems, the present invention can accurately search a track that a head wants to visit from a magnetic disk drive, and read the servo information on the track when accurate track cannot be tracked due to thermal expansion of the disk. In order to accurately search the track, it will be described in detail with reference to the accompanying drawings.

Fig. 1 shows the servo information on any of A, B, C, and D sides when the servo information is recorded on the A side of the A, B, C, and D surfaces when two discs are used. Enters the recorded area 2, interrupts the microprocessor, reads the recorded servo information by the operation of the logic circuit as shown in FIG. 2, and heads the correct track with the read servo information. It is configured to position.

Referring to the effects of the present invention configured as described above are as follows.

As shown in FIG. 1, one spindle pulse SP is generated by the pulse generator 4 installed adjacent to the spindle motor 3 once in one rotation of the disk rotating about the disk drive shaft 1. This pulse is applied to the clock terminal CK of the flip-flop F / F in FIG.

In this state, the servo / data head select multiplexer 10 returns to the position of the contact point 1 when the output terminal (Q) signal state of the flip-flop (F / F) is low. When it is high, it switches to the position of the contact point 2. As shown in FIG.

)가 한계 입력될때 각 포인트의 신호의 타이밍 챠아트는 제4도에 나타낸 바와같다.At this time, the counter 12 performs a counter operation (usually 200 µsec) at a predetermined time period T shown in FIG. Therefore, Spindle Pulse (

The timing chart art of the signal at each point when) is input as shown in FIG.

The period of the spindle pulse appearing at the time of rotation of the magnetic disk is as shown in FIG.

If a spindle pulse occurs due to disk rotation while the drive is reading data from or writing data to the disk, this pulse causes the interrupt request line (Interrupt Request LINS) to operate as shown in FIG. An interrupt is applied and the servo / data head select multiplexer 10 is automatically placed in position 2 to open the servo head channel.

At this time, when the microprocessor 11 receives the interrupt, it reads the servo data immediately to determine how much track offset has occurred and to preserve it.

)에는 드라이브 고장(Drive Fault)상태의낸드 게이트(N₁)의 일특 입력단에 접속되어 서어보 구간내에서는 디스크면에 써넣기를 할 수 없도록 써넣기 인에이블(

)을 폴스(False)로 한다.At this time, the output terminal (

) Is connected to a special input terminal of the NAND gate (N ₁ ) in the drive fault state, and the write enable (

) To false.

경과후에 카운터(12)에 의하여 플립플롭(F/F)은 클리엉 상태가 되고, 출력단자(Q)가 로우상태로 되면 헤드는 다시 데이타 헤드로 선택되어 계속 데아타의 읽기/써넣기 동작을 수행하게 되는 것이다.after

After the elapse of time, the flip-flop F / F is cleared by the counter 12, and when the output terminal Q becomes low, the head is again selected as the data head to continue reading / writing the data. Will be done.

The present invention operated as described above has the effect of extending the data storage capacity when applied to a magnetic disk drive or a floppy disk drive.

Claims (1)

The pulse generator 1 is connected so that one spindle pulse SP, which is generated when the disk is rotated once, is applied to the clock pulse terminal CK of the flip-flop F / F, and the flip-flop F A magnetic disk characterized in that the servo / data head selection multiplexer 10 is connected to the output terminal Q of the / F) to read the servo and the data, so that the servo head can be selected when necessary. Drive treasurer and information readout logic.

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