JPS6013390A - Method for detecting defective address of magnetic bubble memory - Google Patents

Abstract

PURPOSE:To detect a defective address of a magnetic bubble memory easily without using a specific measuring device and a testing device by detecting the defective address on the basis of a normal address. CONSTITUTION:A storage device 1 is driven and address data are successively sent to an address data reading line 11. If address data stored in a magnetic bubble memory (BM) 10 are defective, the compared result of the address data by a comparator 12 are inconsistent, so that a CPU 2 decides that the address data are defective and changes the specified address data to an address specification line 13. When address matching information is obtained, the CPU 2 sends the address (A+1) to the address specification line 13 on the basis of the current address A to decide whether the corresponding address of the BM 10 is correct or not. If a defective address is detected, the CPU 2 reads out the defective address data from the BM 10 through an address data transfer line 15 and compares the read out data with the specified address data sent to the address specification line 13 to detect a defective bit.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a defective address detection method for magnetic bubble memory.

A conventional storage device using magnetic bubble memory has a built-in comparator. The method for checking the address match of the magnetic bubble memory in the storage device is to check the address specified by the address designation line from the central processing unit and the address data sequentially read out on the address data readout line by the rotating magnetic field of the magnetic bubble memory. The comparator compares the addresses, and when an address match is found, the address match information is passed to the central processing unit via the address match information line. □If the address data stored in the magnetic bubble memory is defective, it is said that an address match cannot be established forever. If the address data in the magnetic bubble memory is not returned, the control determines that the address data in the magnetic bubble memory is defective.

However, with the above control alone, there is no way to detect a defective address, let alone detect a defective bit in the address data, so if the address data in the magnetic bubble memory is actually destroyed, it will take a lot of effort to repair it. The drawback was that it required a lot of man-hours.

An object of the present invention is to eliminate the above drawbacks by providing a storage device with a function of detecting a normal address, a function of detecting a defective address based on the normal address, and a function of detecting a defective bit in the defective address. Another object of the present invention is to provide a method for detecting a defective address in a magnetic bubble memory, which makes it possible to easily detect a defective address without using a special measuring device or tester.

According to the present invention, means for detecting a normal address when address data stored in a magnetic bubble memory becomes defective, and means for detecting a defective address based on the normal address from the normal address detection means. and means for detecting a position of a defective bit within the defective address.

Next, the present invention will be explained with reference to the drawings.

The figure is a block diagram showing an embodiment of a method for detecting a defective address in a magnetic bubble memory according to the present invention. In the figure, a storage device (hereinafter referred to as MEM) 1 is a magnetic bubble memory (hereinafter referred to as BM).
) 10, the BMI O and address data read line 11
To,! It includes a comparator (hereinafter referred to as CMP) 12 which is connected in parallel. The CMP 12 inputs a designated address from the central processing unit (hereinafter referred to as CPU) 2 through an address designation line 13, and sends address match information through a CPU 2 match information line 14. Read address data on address data read line ll is transferred to CPU 2 via address data transfer line 15 connected to address data read line 11.

Next, the operation of this embodiment will be explained.

When an address is specified by the CPU 2 via the address specification line 13, the MEMl drives a rotating magnetic field (not shown) of the BMlo, and sequentially sends out address data to the address data readout line 11.

The CMP 12 compares the specified address data from the address designation line 13 and the address data from the address data readout line 11 using a generally known method, and when the two match, sends address match information to the 9 CPU 2 via the address match information line 14. will be sent to notify that the address has been matched.

Here, if the address data stored in the BMIO is defective, the address data comparison in the CMP 12 will not match, so the CPU 2 determines that the address data is defective by not receiving address match information within a certain period of time. Thereafter, the CPUz arbitrarily changes the designated address data to the address designation line 13 and starts MEM1 (this operation is repeated until address match information is obtained). When address match information is obtained, the CPU
In 2, the specified address at that time (temporarily assume address “A”)
Based on the specified address of address A+1”, address line 1
3, and determines whether the address data at address A+1'' of BMIO is acceptable.

If the judgment result is OK, further address address ``A+1+1'' is specified, and the acceptability of that address data is determined in the same way.Similarly, the specified address is changed to +1 address, and defective address data (address match information is not returned).
We will explore the following.

Next, when a defective address is detected, the CPU 2 reads the defective address data of fiBMlo via the address data transfer line 15;
A defective bit is detected by comparing it with the specified address data sent to the specified address data.

As is clear (from the above explanation), according to the method for detecting a defective address in a magnetic bubble memory of the present invention, a defective address in a magnetic bubble memory can be easily detected without using a special measuring device or tester. Even if the address data in the bubble memory is destroyed, the effect is that it does not take much time to restore it.

[Brief explanation of drawings]

The figure is a block diagram showing an embodiment of a method for detecting a defective address in a magnetic bubble memory according to the present invention.

Claims (1)

[Claims] means for detecting a normal address when address data stored in the magnetic bubble memory becomes defective; means for detecting a defective address based on the normal address from the normal address detection means; A method for detecting a defective address in a magnetic bubble memory, comprising means for detecting a defective bit position in a magnetic bubble memory.