JPS59201271A - Magnetic disk device - Google Patents

Abstract

PURPOSE:To prevent user's data from being destroyed by mistake during maintenance diagnosis by permitting data to be written to a track where a magnetic head is positioned only when CE area identification information is read out and a write permit signal is supplied. CONSTITUTION:Data read out of a servo surface 5 by a servo head 4 is supplied to a sink data detecting circuit 6. The circuit 6 extracts sink data from the the servo data and converts it into a digital value, which is supplied to an area identification circuit 7. The circuit 7 decodes the pattern of the sink data to identify the position where the servo head is positioned and supplies the result to a write permission/inhibition decision circuit 8. The circuit 8 is supplied with a control signal A. Then, writing by the magnetic head is permitted only when the signal A shows a write permit state and the circuit 7 identify that the servo head is on a CE track.

Description

[Detailed description of the invention] [Technical field of invention] The present invention relates to improvements in magnetic disk drives.

[Technical background of the invention]

When positioning the magnetic head in a magnetic disk drive using the servo data method, servo data is written on the recording medium as an information source for positioning the servo head, in addition to the data that the user reads and writes arbitrarily. . This servo data is written on the servo surface (formed on a servo disk separate from the data disk on which the user writes data) during the manufacturing process of the disk device, and will not be rewritten by the user thereafter.

FIG. 1 is a diagram illustrating an example of this servo data.

As shown in the figure, the servo byte consists of a sync bit part as a clock information source and a position bit part as a position information source. The sync bit portion further includes a sync clock portion and a sync data portion. Here, although the sync clock part always exists, the sync data part may be omitted due to the field 'jr on the Boobo surface. By decoding this sync data, the index mark and the zone or area in which the head is located are identified.

Figure 2 is an example of dividing areas on a recording medium. Theory 1↓IJ
This is a diagram. Data Zone 1 is read by the user!
The guard band 2 indicates the limit position txt of the area where data can be recorded and is used to detect abnormalities and annotate the reference initial position of the head (RT
Z time). Further, the landing zone 3 is an area where the head flies and stops. 1. To determine the position of the magnetic head on the data surface of the data disk,
- When reading and writing from row 1 based on the position bit information called from the servo surface on the servo disk by the revo head (・Recording medium (disc)
It is positioned on a concentric circle (trunk) with n, ij axis in the radial direction of. The reading operation by the user is limited to the data zone 1 described above.

1□1'Problems with Keigi SotoJ] Here, on the data surface of the recording medium, a dedicated area (CE track) is reserved for maintenance personnel to use when maintaining and inspecting the disk device. There is. However, conventionally, this CE rack is not distinguished from other tracks, and normally the outermost (inner) track is simply assigned to a trunk that is prohibited for use by users. In this way, conventionally, it is determined whether the rack is a CE) rack based only on the trunk number, so during maintenance, a truck other than the CB) rack may be mistakenly used for diagnosis, resulting in the user's data being accidentally destroyed. Sometimes I end up doing it.

[Purpose of the invention]

The invention was made in view of the above-mentioned shortcomings of the prior art, and it clearly distinguishes between the CE rack used by maintenance personnel and the truck used by users, so that the user's data is not accidentally destroyed during maintenance or diagnosis. It is an object of the present invention to provide a magnetic disk device that does not suffer from failure.

[Summary of the invention]

In order to achieve the above-mentioned object, the present invention also provides servo data read out by the servo controller from the central area) to the Cl area. 3) A method for detecting separate information (written in advance on the servo surface corresponding to CE) and a maintenance staff using a magnetic disk device Only when the CI'2 area identification information is read out and a write permission signal is given is a means for outputting a word and a write permission signal given, the magnetic head is moved to the 1st position and then to the 0°C track: The present invention provides a magnetic disk@value having means for enabling 6-inclusion.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described with reference to FIG.

FIG. 3 is a block diagram showing the configuration of the same embodiment. Servo data read from the servo surface 5 by the servo head 4 is provided to a sync data detection circuit. The sync data detection circuit 6 takes out the sync data from the surf 3 vector, converts it into a digital value, and supplies it to the area identification circuit 7. The area high side circuit decodes the zone of the sync data, identifies the position where the GT servo head is present, and provides the result to the write suitability determination circuit 8.

Here, the write suitability determination circuit 8 is given a control signal PER from a control means (not shown). Then, writing from the magnetic head is enabled only when the control means number A indicates a write permission state and the area identification circuit 7 identifies that the servo head is present in the rack CE). .

Here, the specific configuration of the control means (not shown) is as follows. First, a unique switch is installed, and when maintenance personnel turn on this switch during maintenance, the CE
) A control signal A indicating a write permission letter 7J to the rack is generated. The second is to use the write protect switch in common, and when the write protect switch is OFF, only writing to the data zone is valid, and when the write protect switch is ON, only writing to the CE track is valid. Third, by connecting a tester used during maintenance to 1'', it is possible to automatically enter and write the CE track.

Next, please refer to Fig. 4 for the Bh production of the embodiment shown in Fig. 3. (
I will explain it to you. MS4 diagram is area 'li\'
; This section 1 explains how to identify the CEI-rack and other zones (tracks) using a 4-bit pattern. In the figure, the sync bit part (consisting of sync clock a and sync data b) (Positions shown only)
j”;”=Minutes are omitted. As shown in the figure (, in the data zone, the combination of 4 bits of sync data (1111
'C' in the area of ``Touchi'', Gauchai, and the outer guard band.
fl-'C1t(10], O) + (10], 1
) ノ:r-') 7"ff ('￥+l or allocation skin. In this case, the area information request for (1001,) is set in the data zone and Gartband songs) guess

When the servo head 4 reaches the CE) rack position (100
The area 'Iff 'i'υ of 1) is read out, converted into a digital signal Z1 by the sync data detection circuit 6, and then applied to the area product η specific circuit 71C.

When the detected area/message is (1111), the servo head 4 is in the data zone. Therefore, when the control signal A indicates that the device is being used by the user, writing by the servo head 4 is enabled. On the other hand,
The signal indicating that control signal A is under maintenance is
A write inhibit signal B is generated from the write suitability determination circuit 8, and the writing by the magnetic head is inhibited.

If the read area information is (1001),
The magnetic head is on the CE track. Therefore, when control signal A indicates that the user is in use,
A write inhibit signal B is generated from the write suitability determination circuit 8, and writing by the magnetic head is prohibited. On the other hand,
When control signal A indicates that maintenance is underway,
It is possible to enclose it using a magnetic head.

〔Effect of the invention〕

As described above (according to the present invention, CE of the servo surface on the medium)
The part corresponding to the rack has its own CE area identification information, and there is a means for detecting this CE area identification information from the servo data read by the servo head, and maintenance personnel use the device. Next, a means for outputting a write permission signal is provided, and only when the CE area identification information is read out and a write permission signal is given, it is possible to mow on the track where the servo head is in the first position ( - Since the magnetic disk drive is equipped with a scraping means, it is possible to clearly distinguish between the CE rack and other areas, and to obtain a magnetic disk device that does not accidentally destroy user data during maintenance or diagnosis.

[Brief explanation of the drawing]

FIG. 1 is a diagram for explaining an example of boobo data, FIG. 2 is a diagram for explaining an example of dividing areas on a recording medium, FIG. 3 is a circuit diagram of an embodiment of the present invention, and FIG. It is a figure explaining the operation of the example of a figure. ]...Data zone, 2...Gart band, 3...
・Landing zone, 4...Servo head, 5...
・Servo surface.

Claims (1)

[Claims] Data zones used by users and maintained by maintenance personnel,
In a magnetic disk drive that has a recording medium with a CE) rack used during inspection and positions the magnetic head using the servo data method, the servo data read by the servo head is used to determine the position of the CE) rack in advance. means for detecting CE area identification information written on a servo surface to be used; means for outputting a write permission signal when a maintenance person is using the magnetic disk device; 1. A magnetic disk drive comprising means for enabling a magnetic head to write to a track on which it is located only when identification information is read and the change location permission signal is given.