JPS6212594B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a defect information storage method for a major-minor magnetic bubble memory device having a boot loop, and particularly to its format.

Recently, devices using magnetic bubbles that use magnetic bubbles to store information, perform logical operations, etc. are nonvolatile, have high storage density, have low power consumption, and are solid-state devices that do not contain any mechanical elements. It has extremely high reliability. The element configuration of such a magnetic bubble memory includes a serial loop system in which the bubble propagation path 1 is an endless loop as shown in FIG. 1, and a major line 2 and a plurality of minor loops 3 _-1 to 3 _{- as} shown in FIG. There is a major minor loop method with _o . For large-capacity memory, the major-minor loop method is used, which is advantageous in terms of quick access. However, due to the manufacturing process of the crystal substrate of the magnetic bubble memory, defects in the crystal lattice and defects occurring in the propagation path cannot be avoided. Therefore, in the major minor loop method, a certain number of bad loops are allowed from the beginning, and these bad loops are not used. Information about this defective loop is stored in a specific page of each minor loop, and after reading this information, necessary information is read or written. However, the reading method of the major minor loop method is as shown in Figure 2, where each minor loop 3 _-1 to 3 _-o
The bubbles 4 at the same position on the page are transferred to the major line 2 all at once, and the bubbles lined up on the major line 4 are sequentially read out by the detector 5. When this page is finished reading, the bubbles on the next page are transferred to the major line. Then, they are read out sequentially in this manner. If reading is performed in this manner, reading may take a long time depending on where on the minor loop the page storing the defective loop information is located. As a countermeasure against this problem, as shown in FIG. 3, a boot loop 6 that can be serially written and read out is sometimes provided as a special loop for storing defective loop information. When storing defective loop information in this boot loop, there are two main methods: Part 1 stores only one block of defective loop information in the boot loop. The second method is to store multiple blocks of defective loop information in the boot loop. However, in the case of 1, it takes a maximum of one round to read the defective loop information, and in the case of 2, if there is only one header mark, it is the same as 1, and if a header is added to each block, With information such as the conventional header (#$FE), the block length becomes long, making it difficult to store many blocks. SUMMARY OF THE INVENTION An object of the present invention is to eliminate such drawbacks and provide a method for storing defective loop information in which a large amount of defective loop information can be stored in a boot loop and accessed quickly.

Therefore, in the present invention, in a defective loop information storage method for storing defective loop information in the boot loop of a magnetic bubble memory equipped with a boot loop, a header mark is attached to the defective loop information,
The number of bytes of the header mark is N, and the number of acceptable minor loops of the magnetic bubble memory is n,
It is characterized in that N>n/m, where m is the number of "0"s included in one byte.

Hereinafter, the defective loop information storage method of the present invention will be explained in detail.

Generally, the format of defective loop information is in the form |header mark|address|defective loop information|, with a header mark and address information attached.

If you want to provide bad loop information in a format that gives "0" to bad loops and "1" to good loops, set the allowable number of bad minor loops to n and 1 byte to 8.
Bit, N or more #$00 shown by n/8<N, where N is an integer (#$00 means 0, 0, 0, 0,
The information (in the format 0,0,0,0) does not appear in the bad loop information. Therefore, in a format in which N or more #$00s are used as header marks and no more than N #$00s appear in other parts, the minimum header mark is a line of N #$00s. For example, when n=60, in the worst case, there may be 60 consecutive "0"s. This is 60/8<
Since N is 8, the header mark has 8×8=64 consecutive “0”s.
If such a header mark is used, it becomes possible to distinguish it from defective information.

In addition, #$00 in the above is just one example; if #$00 cannot be used as a header, for example, if "0" continues as a remainder after defective information, numbers such as #$01, #$02, etc. It is preferable to use "00000001" for #$01 and "00000010" for #$02, each containing "1"). In this case, the number of bytes of the header mark should be n/7<M (integer) bytes because the number of "0"s in which the defect information is "00000001" or "00000010" are repeated is n or more. It turns out.

You can also directly address the location of the bad loop, e.g.
When storing in 2 bytes like 0000, 0001, if there are consecutive 0's, it takes less than 4 bytes like 0000, 0001 in the example, so it is possible to configure the header mark with even fewer bytes. can.

As explained above, the magnetic bubble memory defective loop information storage method of the present invention allows the allowable number of defective loops to be n.
When the number of bytes of the header mark is N>
n/m (where m is the number of "0"s included in one byte), it is possible to identify defective information with a short block length. A plurality of pieces of bad loop information can be stored, and the bad loop information can be accessed quickly.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of an example of a serial loop configuration of a magnetic bubble memory, Fig. 2 is an explanatory diagram of an example of a major-minor configuration of a magnetic bubble memory, and Fig. 3 is an explanatory diagram of an example of a major-minor configuration of a magnetic bubble memory with a boot loop. FIG. 2 is an explanatory diagram of an example of a memory. 2... Major line, 3 _-1 to 3 _-o ... Minor loop, 4... Bubble, 5... Detector, 6... Boot loop.

Claims (1)

[Claims] 1. In a defective loop information storage method in which defective loop information is stored in the boot loop of a magnetic bubble memory equipped with a boot loop, a header mark is attached to the defective loop information, and the number of bytes N of the header mark is determined based on the allowable number of the magnetic bubble memory. A magnetic bubble memory defective loop information storage method characterized in that, where n is the number of defective minor loops and m is the number of "0"s included in one byte, Nn/m is set.