Doubling the Memory for a Set of Programs in the “Promin” Computer

V. M. Reider

(Presented by the scientific seminar of the Computer Technology Department of the Research Institute of Electronic Mathematical Machines)

The electronic digital computing machine “Promin,” widely used in the national economy, has a substantial shortcoming—there is little memory for a set of programs. The literature [1] describes a circuit by means of which information can be read from two program matrices. However, this circuit does not allow logical control operations to be transferred from one program matrix to the other. It is clear that the class of problems solvable in this case is sharply limited.

Fig. 1.

In this paper a scheme is proposed that permits the use of the logical operations for transferring control of UPP1, UPP2, and BP when switching from one program matrix to another. As the additional program matrix, one may use either the program matrix of another “Promin” type machine or a separate program-matrix device with a complete set of readout amplifiers USCh 2.

Figure 1 presents a block diagram explaining the principle of operation with two program matrices. The feature determining whether the machine addresses its own matrix or another matrix is the state of trigger \(T_9\). When trigger \(T_9\) is in the zero state, one program matrix is addressed; when trigger \(T_9\) is in the one state, the program matrix of another machine is addressed. Permission and prohibition of addressing the program matrices are carried out by permitting and inhibiting the interrogation pulses of the program matrices \(I_1\), controlled by trigger \(T_9\). Information read from the program matrices PM1 and PMP is amplified by their own USCh 2 amplifiers and is fed to the common readout amplifiers USCh 1.

For implementing the logical operations for transferring control of BP,

Fig. 2

UP 1, UP 2 to another matrix and executing them within this matrix, the operation codes \(\sin \overline{OO}\), \(\cos \overline{OO}\), and \(\operatorname{tg}\overline{OO}\) were used, which are denoted in the circuit respectively as SBP, SUP 1, and SUP 2. Figure 2 presents a circuit implementing the execution of the functions:

\[ SBP = ``O" T_{\mathrm{op}} \land \sin \land \overline{OO}\, RA \]

\[ SUP1 = ``O" T_{\mathrm{op}} \land \cos \land \overline{OO}\, RA \]

\[ SUP2 = ``O" T_{\mathrm{op}} \land \operatorname{tg} \land \overline{OO}\, RA \]

Since the operation codes \(\sin\) and \(\cos\) with an address are used in the machine as the operations ChmRg and ZnRg, the feature “O” of the GOP is used to distinguish the logical operations SUP1 and SUP2. To exclude access to the microprogram matrix for the codes SBP, SUP1, and SUP2, the I2M pulse is blocked by the “O” level of RA (Fig. 2). The logical operations SBP, SUP1, and SUP2 are performed according to the same algorithms as the operations BP, UP1, and UP2. After execution of command number 99 of any program matrix, trigger \(T_9\) is switched to the opposite state, thereby preparing the interrogation of the other matrix from the zero command.

To implement the circuit described above, 1 trigger cell, 3 inverter cells, and 6 D9E-type diodes were installed. In addition, 2 previously unused U1 amplifier cells in the machine were employed, one U amplifier cell, and one input was added to each of the Usch.1 cells.

Thus, switching from the first program matrix to the second is carried out by the commands SUP1 and SUP2 when the logical conditions are fulfilled, and by the command SBP unconditionally. The reverse transition is possible when the logical conditions are fulfilled by the commands UP1 and UP2, and unconditionally by the command BP.

References

1. V. F. Litrinenko. Increasing the Number of Commands and the Library of Subprograms in the “Promin” Machine. Abstract collection “Instruments and Means of Automation,” issue 9. 1966, Moscow.