Wang 700 Calculators
The featured machine is a Model 700A, serial 811122 with internal datestamps from June 1970. It represents the basic model and capabilities at the introduction of the 700 series.
The 700 series was actually an effort to catch up with Hewlett Packard, whose HP9100 which had been released in 1968. Wang had not been intending to replace the 300 series but HP’s unexpected announcement of the 9100 had rendered the 300 series obsolete. Wang had been developing a new microcode-based logic architecture which was intended for a small word processing computer. The power of microcoding is demonstrated by the ability to take hardware that had been intended for a word processor and instead create an advanced programmable calculator with features including:
- Full floating point arithmetic with 12-digit mantissa and 2-digit exponent
- 24 digits of precision were available if required
- 8k bits of magnetic core RAM, providing 120 storage registers, or 960 program steps
- Programmability, with loop, branch and subroutine capabilities
- Magnetic tape drive for load and store of programs
- Peripheral interface connection for printer, plotter and data input/output
The 700 came in three models:
- 700A two levels of subroutine, no support for 702 plotter, block I/O, binary decisions or Learn+Run mode
- 700B five levels of subroutine, support for 702 plotter
- 700C five levels of subroutine, block I/O transfers, binary decisions, Learn+Run mode
700A and -B have the same hardware and differ only in microcode. The 700C has three 700C-specific circuit boards as well as its own microcode.
The 700 series user interface was an improvement over the 300 series but was still somewhat uncompromising and obscure, in the Wang tradition. Basic functions were more intuitive than the 300 series but obscurity returned when using storage registers - the register addresses are formed by flipping switches to form codes which are combined with whatever keyboard key is pressed next. This particular interface goes right back to the LOCI machines of the early 1960s.
The two most important advances of the 700 series were ample internal storage and programmability, with loop and branch constructions. Good-sized data sets could now be loaded and have complex processing applied. The tape drive allowed easy storage and distribution of software libraries and also allowed data to be stored and reloaded.
It is also interesting to see interface connectors, similar to the original LOCI machines. Hard copy output to a typewriter or plotter was of general use while data input/output facilities allowed the 700 machines to be used for data acquisition, processing and control. External tape drives and even disk drives were available, the tape drives are well known but to date there has been no account of a disk drive in use.
The 700 Series Operator’s Manual is available in the Wang Data pages.