SU733028A1 - Read only memory - Google Patents

Description

one

The invention relates to computing, namely, storage devices.

A permanent storage device is known that contains a numeric block that is characterized by a large number of communication elements.

However, a large number of communication elements leads to uneven load on the address buses and large power consumption 1.

The closest technical solution to the invention is a permanent storage device containing a drive with defective storage elements, connected to the address register and the word register, the check bits register, the check bits information recovery block, the inputs of which are connected to the corresponding outputs of the check register bits, and the outputs - to the inputs of the register word and control unit J - LJ 20

The disadvantage of this device is the inefficient use of storage capacity with defective storage elements, since a large number of additional bits (redundancy) are needed for error correction.

The aim of the invention is to simplify and increase the reliability of the device.

The goal is achieved by the fact that the device contains NOT elements and AND elements, the first inputs of which are connected to the outputs of the address register, the second inputs - to the first output of the control unit, the outputs of one of the AND elements are connected to the first inputs of the word register, the outputs of other AND elements are connected the elements are NOT to the second inputs of the word register, the third inputs of the word register are connected to the second and third outputs of the control unit.

FIG. 1 shows a block diagram of the proposed device; in fig. 2 - matrix used when recording information into the device.

The permanent storage device contains the address register 1 having inputs 2, elements 3 and, drive 4 with defective storage elements, having inputs 5 and outputs 6, register 7 words, elements 8 NOT, control unit 9. The first inputs of elements 3 and are connected to the outputs of register 1, the second inputs to the first output of control unit 9. The outputs of one of the elements 3 are connected to the first inputs of the register 7 words, the outputs of the other elements 3 AND are connected via the elements 8 NOT to the second inputs of the register 7 words, the third inputs of the register 7 words are connected to the second and third outputs of the control unit 9.

Permanent storage device operates as follows.

In order to ensure data storage without storage in storage 4 with defective storage elements during recording, the recording information is matched with the defective storage elements by changing part or all of the digits of the recorded numbers to opposite ones. This is done as follows. The information to be written to the drive 4 with defective storage elements is represented as a matrix. An inversion code is selected for each column of the matrix (similar to Hamming codes). Each inversion code corresponds to a group of addresses that have a “1 in the junior category.

When writing information to the drive 4 with defective storage elements, the column bits (in accordance with the inversion code) are inverted.

When read from a signal from control unit 9, inputs 2 of register 1 receive the address of the cell in which to turn. The same address is supplied to elements 3 AND, at which the corresponding address bits are compared. For example, for a column that has an inversion code of 101010, the address group is XXI, therefore, "1 is compared with the logical bits of the incoming address code on the ZI elements. If there is a coincidence, then the inverting signal is sent to the counting inputs of the corresponding register register .7 word. If there is no match, the TO information on the corresponding cell and the corresponding column column is read into register 7 of the word without change. If the selected inversion code of column 0000000, then from block 9 of control, the signal "Logic O is received and the information in the corresponding bit of register 7 of the word is not inverted. If the inversion code of the column is 1111111, then the signal "Logic 1 from block 9" inverts the corresponding bit in register 7 of the word. As a result, at the output of the register 7 words, the information is obtained. Let it be necessary to write the matrix below into the device:

10,100

001 00011 010

information 10010 011

Address codes 00101 100 and matrix 10100 101 10111 PO 10110 111

An inversion code is selected for each column.

1. 1010101 2. Logical About

3,0001111

4.01100 and

5.0101010

The first inversion code corresponds to the address group XXI, the second one - 000, the third one - IXX, the fourth one - XIX, to that - XXX (through the elements NOT).

When writing to a drive with defective

certain storage elements

matrix bits (according to the inversion code) are inverted, i.e.

we get

00100001

00000010

Information 00000011

on the matrix OOOOO100 Address codes

00000101

10,000 PPO

OOOOO111.

Suppose it is necessary to read the contents of the storage location of drive 4 with address 101. This makes a comparison; for the first column “1 (XXI) with a lower-order address code (101), i.e.“ 1

1 + 0,.

the match has place, therefore this bit is inverted when read;

for the second column, by the signal "Logic O from the local control unit, no inversion is performed;

for the third column (IXX), compares "1 with the preceding address code bit

1 +, i.e., inversion is performed;

for the fourth column (XIX), compares "1 with the mean bit code of the address ad1-f 0 1,.

no match, read is done without Invert;

for the fifth column

0 + 1 1

no match In this case, the reading is done without inverting.

Thus, in the drive at address 101 information is recorded LLC. When reading, we get 10100.

The proposed device has the following advantages: there is no need for additional bits, which simplifies the drive, as well as improves the manufacturability of the drive (increases the degree of integration); there is no need for an information recovery unit consisting of a decoder and multi-input OR elements, on the basis of which an encoder for correction codes is implemented, which simplifies the device; The described inversion codes for columns allow you to "mask all possible combinations of" single and "zero failures in the places where the column codes of the information matrix are written, i.e. if there are defects. in the places where the columns are written, regardless of the values of the recorded information, it is possible to process the information so that these defects do not affect the recording.

Claims (2)

Invention Formula A permanent storage device containing a drive with defective storage elements, connected to the address register and word register, and a control unit, characterized in that, in order to simplify and increase the reliability of the device, it contains NOT elements and AND elements whose first inputs are connected to the outputs of the address register, the second inputs are to the first output of the control unit, the outputs of one of the elements are connected to the first inputs of the register of the word, the outputs of other elements AND are connected through the elements NOT to the second inputs of the register and the words, the third inputs of the register of the word are connected to the second and third outputs of the manager unit. Sources of information taken into account in the examination 1. USSR author's certificate No. 371616, cl. G 11 C 17/00, 1971. 2. USSR author's certificate No. 504247, cl. G 11 C 17/00, 1974 (prototype). S Sh    7 I I And it FIG. Through items (NOT F (r. 2