تدقيق المذاكر الآلي - تدقيق الالواح الآلي - صنع الحاسبات .. الحاسبات تعمل

Automated checklist - Automated checklist -
Making computers .. Computers work

Automated checklist

Computer checklists usually consist of either magnetic rings or semiconductor circuits, and form an essential part of the computer. The computer is used to check the different types of checklists.

The rings are arranged in a matrix and each ring is penetrated by several wires. If the current flows in one of these wires in a specific direction, it creates a magnetic field, so the ring becomes magnetized in a specific direction and remains so after the current is cut off. If the direction of the current is reversed, the direction of magnetization is reversed: The ring magnetized in one direction is considered to store bit "1" and the ring magnetized in the other direction is considered to store bit "0" • The bit is read by passing a current through one of the wires and examining the voltage excited in a special wire for the probe.

The memo usually consists of hundreds of thousands of rings that all look similar but must differ somewhat in the intensity of the current that magnetizes or demagnetizes the ring, and the intensity of these two currents varies with temperature. Since this information is of great interest to computer designers, and obtaining it manually is a tedious and monotonous matter, the computer is used for this purpose.

(The computer checks the elements of other computer memos)

The computer adjusts the selection currents of each ring in the memo it is examining, until the current fails to magnetize a ring in one of the two directions. The computer also measures the probe current, thus determining a limit of the operating limits.

This process is repeated, and for different temperatures, so that engineers obtain the information necessary to use this memo to the fullest extent in all operating conditions.

As for semiconductor memos, they are basically integrated circuits in which the storage cell is repeated once for each bit stored. The computer plays a fundamental role in the manufacture of integrated circuits, including semiconductor memos. In the design phase, the computer simulates the circuit's performance and modifies its design until it obtains the required performance. The computer is used to optimize the arrangement of circuit elements, prepare the masks necessary for the various manufacturing stages, control production, and examine circuits after they are manufactured.

Automated board checking

Integrated circuits and their accessories are assembled from electronic components on printed circuit boards as previously mentioned. A computer is used to check each board after it is manufactured to ensure the integrity of its connections and the proper operation of the circuits it contains.

Since boards usually perform logical functions, they generate electrical signals when a specific set of signals enters them, and do not generate any signal if this input set differs. Boards are checked by a computer that enters specific voltages into the board's inputs and checks the resulting output voltage. This process is repeated for other sets of input voltages, in the correct sequence, until all the necessary input sets are tested to ensure the integrity of the board. If the output signals are correct for all input sets, the board is considered sound. If not, the computer indicates that the board is rejected.

Rejected boards are checked to identify the defective parts in them and replace them, then checked again to ensure their proper operation.

The computer checks itself

Computers are most often checked by diagnostic programs that are executed on the computer to detect any malfunctions.

The diagnostic notebook program, for example, checks each location in the notebook by entering all the numbers that may be stored in the location.

The program starts by entering the number "1" in each location and then reads all the locations to see if the number has been changed in any of them. Then it enters the number "2" in each location and the process is repeated until the largest number that can be stored in the location.

(A microcircuit enlarged to ten times its actual size)

At the end of the check, the program issues a list of the locations where the numbers stored differ from those entered into them, and the extent of these differences. The diagnostic program is usually executed at different temperatures to ensure that the notebook operates properly under all operating conditions.

The diagnostic instruction program checks the basic set of computer instructions to ensure that they perform as they should. The program examines each of these instructions in turn to see if they perform the required logical functions. For example, it applies the "add" instruction to a set of different numbers and compares the result of the operation in each case with the correct sum. If the instruction performs the required function, the program moves on to another instruction, such as the "multiplication" instruction, and so on until the program has completed the entire set of instructions. The computer produces a list of failed instructions and details of their failure. Other diagnostic programs are used to check the various parts of the computer system, such as the disk storage, the printer, the card reader, and others.