JPS6289273A - Magnetic disk device - Google Patents

Abstract

PURPOSE:To easily know a track address when a writing action is interrupted and to shorten greatly the data recovering time, by using a rewritable nonvolatile memory circuit to store a cylinder address and a head address when a writing instruction is received together with the receiving state of said instruction. CONSTITUTION:A writing state memory circuit 61 stores a cylinder address 23 and a head address 42 at the leading of a writing instruction 53. Here the circuit 61 consists of a CMOS memory element backed up by a battery, for example, and an electronic erasion type memory element. When a writing action is through in a normal state, a magnetic disk controller delivers a clear instruction 63 to clear the contents of the circuit 61. If a subsystem for magnetic disk has the abnormality of a power supply during a writing action, this writing action is interrupted and no instruction 63 is delivered as well. Thus the contents of the circuit 61 is kept in storing the track address that received a writing instruction.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a magnetic disk device, and more particularly to write control in a magnetic disk control device and a magnetic disk subsystem including the magnetic disk device.

2. Description of the Related Art Conventionally, this type of magnetic disk device has at least a cylinder address register, a seek control circuit, a head address register, and a read/write circuit, and write control has been performed by the magnetic disk control device. That is, when writing data to a certain record, the magnetic disk control device sends the cylinder address where the corresponding record exists to the magnetic disk device, and the magnetic disk device performs a seek operation to the given cylinder address.
When the seek operation to the target cylinder is completed, a seek operation completion signal is sent to the magnetic disk control device. When the magnetic disk control device detects the completion of the seek operation, it selects the head where the corresponding record exists and performs a record search operation. The magnetic disk control device sends a read command to the magnetic disk device, reads the address field, and when the address matches the address of the corresponding record, writes data to the data field.

Therefore, if a power failure occurs while the magnetic disk device is writing a record, the writing operation will be interrupted.
The record becomes unreadable. In such a case, it is necessary to read all the records in the magnetic disk device after the power failure is restored, detect unreadable records, and recover the data. However, in a large-scale computer system in which a large number of large-capacity magnetic disk drives are connected, this data-storing work has the drawback of consuming an enormous amount of time. SUMMARY OF THE INVENTION An object of the invention is to provide a magnetic disk drive which solves the above-mentioned drawback, that is, when a power failure occurs, it takes a huge amount of time to detect unreadable records and recover data.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention provides at least a cylinder address register, a seek control circuit, a head address register, a read/write circuit, and a cylinder when receiving a write command. This configuration employs a rewritable nonvolatile memory circuit that stores an address, a head address, and a state in which a write command has been received.

Operation Since the present invention is configured as described above, the cylinder address is stored in the cylinder address register under the control of the magnetic disk control device, the seek operation is performed by the seek control circuit, and then the head address is stored in the head address register. Head selection is performed by the read/write circuit, and writing is executed by the read/write circuit in response to a write command to the track.

At the same time, this write-in command causes the nonvolatile memory circuit to store the cylinder address, head address, and the state in which the write command has been received.

When the write operation normally ends, the contents of the memory circuit are cleared by a clear command.

Therefore, if a write operation is interrupted due to an abnormality in the power supply, the contents are stored as they are in the nonvolatile memory circuit without a clear command being sent out.

Example Next, embodiments of the present invention will be described with reference to the drawings.

Referring to FIG. 1, which shows a block diagram of a write operation portion of an embodiment of the present invention, the magnetic disk device of the present invention includes:
Interface section 10 connected to a magnetic disk control device
a cylinder address register 21 and a head address register 41 connected to this interface unit 10 via an address bus 11; a seek control circuit 31 that receives a cylinder address from the cylinder address register 21;
It is connected to a read/write circuit 51 that receives the head address from the head address register 41, the cylinder address register 21, and the head address register 41, receives a write command 53 from the interface section, and reports its status 64 in the event of a power failure. The write state storage circuit 61 is also provided.

Next, using FIG. 1, we will explain the write operation of this embodiment.
I will clarify. First, in order to perform a seek operation to the target cylinder,
After the cylinder address is stored in the cylinder address register 21 along with the cylinder select 22 through the address bus 11, when a seek start command 32 is given, a seek operation is started under the control of the seek control circuit 31, and when the seek operation is completed. , the seek control circuit 31 sends out a seek completion signal 33. When the magnetic disk control device receives the seek completion signal 33, it selects the head.
The head address is transmitted along with the head select 43 through the entire address bus 11. The head address is stored in the head address register 41, and the read/write circuit 51
The signal is applied to the read/write circuit 51 to select the desired head, and is applied to the read/write circuit 51 to select the desired head. A track write operation is executed when a write command 53 is given to the read/write circuit 51.

The write state storage circuit 61 stores the cylinder address 23 and head address 42 at the rising edge of the write command 53. The write state storage circuit 61 is composed of, for example, a battery-backed CMO8 type O8 element or an electronic erasable type storage element.

When the write operation is completed normally, the magnetic disk controller sends a clear command 63 to clear the contents of the write status storage circuit 61.

If a power failure occurs in the magnetic disk subsystem during a write operation, the write operation will be interrupted and the clear command 63 will not be sent, so the contents of the write state storage circuit 61 will continue to store the track address that received the write command. be. After the power supply abnormality is recovered, the contents of the write storage circuits 61 of all the magnetic disk devices connected to the system are read by the system utility program. This makes it easy to determine whether writing was in progress when the power supply abnormality occurred.

According to the present invention, which has been explained and explained above and beyond the effects of the invention, when a write command is received, the cylinder address, head address, and state of receiving the write command are stored in a rewritable non-volatile memory circuit. By doing so, it is possible to easily know the track address at the time of writing interruption, which has the effect of significantly shortening the time for data recovery.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a write operation portion in an embodiment of the magnetic disk device of the present invention. 10... Interface section, 11...
Address bus, 21... Cylinder address register, 22... Cylinder select, 23...
... Cylinder address, 31 ... Seek control circuit, 32 ... Seek start, 33 ... Mark.
Seek complete, 41... Head address register, 42... Old... Head address, 43... Head select, 51... Group read/write circuit, 52...
... Read command, 53 ... Write command, 61 ... Write state storage circuit, 62 ...
...Status read command, 63... Clear command. Agent Patent Attorney Kuri 1) Yu Haru 1

Claims (1)

[Claims] A magnetic disk device includes at least a cylinder address register, a seek control circuit, a head address register, and a read/write circuit, and starts a write operation upon receiving a write command from a magnetic disk control device,
A magnetic disk device comprising a rewritable nonvolatile memory circuit that stores a cylinder address, a head address, and a state in which the write command was received when the write command was received.