JPS6052973A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To execute positioning of a head easily and at a high speed by storing periodically servo-information written intermittently to a track, in a freely rewritable memory, and controlling a head positioning mechanism. CONSTITUTION:Servo-information 23, 24 is written intermittently in a servo-information pattern part 22 at every (n), (n)+10, etc. of 10 tracks of a data track part 21 of a rotary disk. Such information is reproduced by a recording and reproducing head and stored periodically in a freely rewritable RAM through a microprocessor. Basing on this stored contents, the microprocessor calculates a position of the track (n)+(m) having no information 23, 24, etc. in accordance with an expression {(a)+(b)}X(m)divided by 10, and controls a head positioning mechanism. In the expression, (a) and (b) denote positions of the tracks (n), (n)+1. Accordingly, it is unnecessary to read the servo-information of each track, and the head can be positioned easily and at a high speed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to head positioning of a magnetic recording and reproducing apparatus, and more particularly to a magnetic recording and reproducing apparatus that can perform head positioning based on control data stored in a rewritable memory (eg, RAM).

The purpose of the present invention is to provide a system that enables faster head positioning! It's all about providing.

Conventionally, for example, in a 5.25-inch rigid disk device, the number of tracks per inch of the disk surface (TP
If the servo information is around 200 to 300, there is no need to print servo information on the entire disk surface, and an oven loop step motor is used to position the head. However, in recent years, there has been an increasing demand for higher TPI, and a so-called closed servo system has been used in which head positioning is performed based on servo information written on the disk surface. One of these servo methods is a servo surface servo method, in which a specific de-coupled surface is used as a servo surface. Although this method has high positioning accuracy and can perform head positioning at high speed, it requires a dedicated disk surface and a dedicated servo information reading head, leading to high costs. It is also not suitable for replaceable disk cartridges. The second servo system is an embedded servo system in which servo information is written between sectors of each data track. Therefore, unlike the servo method, servo information is obtained intermittently, and as a result, when the head crosses a track, it does not necessarily cross over the servo information, making it impossible to accurately count the number of moving tracks and track identification. Gray code is recorded as information.

In the above two methods, a voice coil motor is usually used as the head positioning mechanism, and the head positioning speed is high. However, it is necessary to write servo information for every track, which leads to high costs. Furthermore, these types of cartridge disks are very expensive. As an improvement measure, there is a method in which servo information is written once for each track by partially marking the track index mark. In this case, a step motor is used as the positioning mechanism, but the servo information is obtained only once per disk rotation, and assuming that the servo information is fed back twice, the disk rotation speed is 36.
00 Orpm requires about 35 milliseconds of fine adjustment time. Incidentally, the time required for this fine adjustment of the track position is several milliseconds for the servo-face-to-face system.

The present invention basically requires a step motor for all phases in the head positioning mechanism, but any motor that can perform step feed and fine adjustment feed may be used. Here, the fine adjustment feed by the step motor refers to microstep feed due to unbalance of current in the excitation phase.

In general, head positioning errors are caused by angular static errors and hysteresis of the step motor itself, errors due to changes in each mechanical part and parts over time, and the biggest factor is temperature caused by the difference in thermal expansion coefficient between the disk and the mechanical part. There is an error. In the servo method, the head position is controlled by reading servo information for each seek operation, so precise head positioning is possible regardless of temperature, step motor error, etc. However, in the conventional method, after a seek command (step pulse input), the head position is controlled while reading servo information on the disk surface, so devices that use a step motor for the head positioning mechanism have the disadvantage that the seek time is long. There is.

When using an apparatus, there is always a time period when the head does not seek, and furthermore, changes in each mechanical part over time or temperature changes within the apparatus remain almost constant over a short period of time. Therefore, during times when there is no seek operation command from the host computer, the seek operation is performed under the control of the microprocessor inside the device, and the control data for the head positioning mechanism is stored in the RAM using the track where the servo information is written. Then, if there is a seek operation command from the host computer, the control data in the RAM is input to the microstep controller under the control of the processor inside the device and the head position is determined without reading the servo information on the disk surface one by one. can be controlled.

The present invention utilizes the above idea to reduce the head positioning time and the cost of the apparatus, which are disadvantages of the conventional servo system using a step motor, and will be explained in detail below with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of the present invention, and only portions related to head positioning are described.

1 is a microprocessor, 2 is a microstep controller that fully controls the fine rotation of the step motor, 3 is a positioning mechanism using a step motor, 4 is a recording/reproducing head, 5 is a recording/reproducing circuit, 6 is a servo circuit, 7 is a RAM, 8
9 is a step pulse corresponding to the number of tracks to be fed, 9 is a direction signal that determines the direction of track feeding, and IQ is a signal that reads and controls servo information on the disk surface or RA
This is a RAM control signal that selects whether to control using the data in M.

FIG. 2 shows a data track 21 and a servo information section 22 used in the embodiment of the present invention, and servo information 23 and 24 that are written intermittently, in this case every 10 tracks. Figure 2 (bl represents the magnetization pattern of the part 23 or 24, 27 is the magnetization reversal part for the synchronous clock, 2B and 29 are the head positioning mechanism by comparing the way the head comes out at this reversal part) The present invention is used for fine adjustment control to the outer or inner track, and is used to create fine positioning control data.The details of the present invention will be described based on the above general description.

For example, after the previous seek operation command from the host computer and its recording or reproduction are completed, the reception of the next seek operation command becomes possible (READY), and then the cycle is periodically cycled by inputting the next seek operation command. The control data is stored in the iRAM every time T. If a seek operation command is input within 1 hour after the power is turned on, the servo information on the disk surface is directly used to position the head for all rows. If the RAM control terminal is at a high level as a normal usage state, when control data is to be stored in all RAMs, the RAM control terminal is at a low level. When servo information is written intermittently on tracks as in the embodiment shown in FIG. 2(a), 10) control data for each rack is stored in RAM, but for other tracks There is no data. Therefore, for example, if the control data 75E of track n is finely adjusted outward by a micron (plus a), it will be 1. If the control data of track n+10 is finely adjusted inward by 5 microns (minus b), then the track between n and n+IQ will be finely adjusted. n-1-m is (a-b
)xm÷1o micron fine adjustment is sufficient. This can be easily calculated using a microprocessor. As described above, according to the present invention, head positioning is performed based on the control data in the RAM immediately after a seek operation command from the host computer, and there is no need for feedback using servo information on the disk surface as in the conventional method. Hidden and high-speed head positioning is possible. For example, if all the servo information of the present invention is applied to a servo system in which a portion of the track index mark is written, the time for fine adjustment of the head position can be reduced by about one order of magnitude compared to the conventional method. Since there is no need to write servo information for all tracks, the cost of the drive can be reduced. In the embodiment, intermittent servo information is provided every 10 tracks, but it is possible to change the information arbitrarily by taking into account all the specifications and characteristics of the drive. The stored servo information pattern is not limited to the 21st yen + ('b), but any pattern that allows fine adjustment of the head position may be used.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of the present invention. FIG. 2(a) is a diagram showing part of a data track section and a servo section according to an embodiment of the present invention. No. 216(1)) is a diagram showing a servo pattern according to an embodiment of the present invention. 1...Microprocessor 2...Microstep controller 3...Head positioning mechanism 4...Recording and reproducing head 5...Recording and reproducing circuit 6...Servo circuit 7...I (AMC random access memory )8...
- Step pulse signal 9...Direction 10...RAM control signal 21...Data track section 22...Servo information pattern section 23.24...Servo information 27--Magnetization inversion section 28 for synchronous clock .29... Magnetization reversal unit for fine adjustment of head position. Figure 1 2/22 (61) 31. ''' No. 21x1

Claims (2)

[Claims] (1) In a magnetic recording and reproducing device that records and reproduces data on a rotating disk, a control data meeting for head positioning is performed periodically under microprocessor control using tracks on which servo information is written. A magnetic recording/reproducing apparatus characterized by storing control data in a rewritable memory IJ- and controlling a head positioning mechanism based on the stored control data. (2) - The magnetic recording and reproducing device according to claim 1, wherein the ribo information is written intermittently on the track.