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Wang Electronic Calculators - Wang 370 Programmer




Wang 370 Programmer Keyboard/Display Unit
August, 1968.

The Wang 370 is an add-on console for the Wang 300-Series electronic calculator systems with special logic internal to the console that provides full programming capabilities to the calculator. The 370 connects to a minimum of one and up to four specialized Model 371 "bed of nails" punched card readers (not to be confused with the earlier Wang CP-1 and CP-2 punched card readers) that added very simple linear programming capabilities to the 300-Series calculators). The 371-Master and 371-Slave punched card readers can be daisy-chained together to provide up to 480 program steps. The program steps were read directly from the punched cards as programs are being executed. A single-step function, as well as the ability to display the step number and the program instruction located at that step on the punched card made program debugging a bit less arduous, although making changes if errors were found could lead to having to re-punch some or all of the program cards, which could prove rather inconvenient.

The 370 Programmer provides instructions for testing the sign of the number on the display, as well as determining if the number on the display is exactly zero. If a logic test is true, the next instruction on the card is skipped over, and if false the next step is executed, allowing for different actions to be taken depending on the result of the test instruction. An unconditional jump instruction to a different step on the same punched card for creating loops is provided. Another instruction provides for switching to the same step number on a different card reader is provided for use in cases where multiple card readers are connected to the 370.

The 370 also provides a group of instructions that allow communication with external devices plugged into the I/O port of on the back the 370. A fairly wide-range of peripheral devices became available for the 370 in time, including add-on memory systems (the Model 372 and 373 Data Storage units), the Model 379-5 IBM Selectric Output Writer, the Teletype Model 33ASR Input/Output Terminal interface (Model 377), and the Model 379 Graphic Storage Tube Display Interface.

The Wang 370 Programmer Console, combined with one of the higher-end Wang 300-Series calculator Electronics Packages, four Model 371 punched card readers(one master and three slaves), a Model 373 Data Storage unit, and a Model 377 Teletype Interface with a Wang-modified Teletype Model 33ASR data terminal made for a fairly capable computing system that in certain cases could out-perform entry-level minicomputer systems available at the time at significantly lower cost.