Hardware control of the computer. fundamentals of building hardware control

Hardware control of the computer. fundamentals of building hardware control

Type of operation in a computer
Main
Building an automatic control system
Control of information transfer codes and their types
Code Correction Capability

All operations in the computer are divided into 3 classes
When transmitting information, the computer word is represented in space-time, thus the control over the transfer of information storage consists in comparing the input and output words, if they match, then the storage transfer is performed without error

Logical transformation is the formation by the logical rules of the original binary words of the output word, also the length of binary symbols in each digit of the output word depends on the value of the signals of the nth output digit and does not depend on the symbol values ​​in other digits of the input word
Arithmetic transformations consist of the corresponding algorithm of arithmetic operations of the resulting output word, and diagnostic symbols for the veins of the output word bits depend on the values ​​of the upper and in the other bits of the input words

From these operations, it follows that to build an automatic control system, it is sufficient to have a scheme for controlling the transmission of information and the correctness of arithmetic operations.

The basis of the construction of an automatic diagnostic monitoring system is the principle of redundancy, that is, when using additional equipment, information of time compared to devices operating without control.
Temporary redundancy is an additional cost of time to perform control operations.

Hardware redundant consists in applying additional hardware to implement control
Arithmetic redundancy is the solution of the problem according to different algorithms and comparison of the results obtained. Information redundancy is the use of code with additional digits to provide commands and data.
The ideal case of control is the control of the performance of each micro-operation and the transition to the next one after the signal of the correct previous one. But this reduces the performance.
In practice, the control procedure is implemented in parallel with the main processes and with a slight delay of 12
When controlling and transmitting information, information redundancy methods are most widely used, that is, used for discharge to control information

A code is a set of characters with the help of which information is displayed on a computer using binary codes of 0 units.
If the code length is 1 digit, this binary code can provide 2 degrees of N different words.

If all bits of the code is used to display information, this code is called simple unrealizable and is repeated by re-entering

What hour of digits is used to provide Information and the rest are control called redundant N equals n + K

Absolute redundancy
r = n / m

Relative redundancy
r = k / m

All redundant codes are divided into error detecting and corrective error detecting.

Requirements Kadam coding procedure should be simple and fast.

The cat should detect the most common errors.

The specified degree of error detection should be achieved with a minimum number of check bits.

The use of corrective codes complicates the hardware and applies where appropriate.

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The ability of a code to detect and correct errors is determined by the minimum code distance; the code distance between two combinations is the number of digits that the corresponding characters do not match.

1011
1001
1110

The minimum code distance is the minimum number of binary digits that are sufficient to change to obtain other information.

A simple code has a Yes code distance equal to 1 for redundant codes q greater than 1
For codes, the minimum code distance detecting for an error is determined by the formula

Dmin> = T + one
Where t is the error rate

Minimum code distance is determined for correction codes.

D min> = 2t + 1