IBM 608
| Company type | Product |
|---|---|
| Industry | Computer hardware |
| Predecessor | IBM 604 (prototype all-transistor adaptation) |
| Founded | December 1957 |
| Defunct | April 1959 |
| Successor | IBM 7070 |
Key people | Robert A. Henle (principal circuit designer), Tom Watson (IBM CEO) |
| Products | Transistorized calculator |
| Parent | IBM |
The IBM 608 Transistor Calculator was IBM's inaugural commercially marketed calculator to utilize transistor technology exclusively, eliminating the need for vacuum tubes. This plugboard-programmable device, recognized as the first fully transistorized calculator available on the market, was announced in April 1955, launched in December 1957, and discontinued by April 1959.
History
Robert A. Henle, who later gained recognition for his work on emitter-coupled logic (ECL) circuits, served as the principal circuit designer. The 608 succeeded a prototype all-transistor adaptation of the IBM 604, which had been demonstrated in October 1954 but never entered commercial production.
To promote the integration of transistor technology, IBM's CEO Tom Watson imposed a deadline that prohibited new vacuum tube-based products prior to the 608’s introduction. This directive encouraged IBM’s product managers to transition to transistors, resulting in the transistorized follow-up to the IBM 650, known as the IBM 7070, which was IBM's initial transistor-based stored-program computer.
Functionally, the 608 resembled the vacuum tube-powered IBM 604 released roughly ten years earlier. Despite delivering performance approximately 2.5 times greater than its predecessor, the IBM 607, only a limited number of units were produced before subsequent IBM models made it obsolete.
Overview
Incorporating more than 3,000 germanium transistors, the 608 represented a significant technological advancement from earlier IBM calculators. Its transistor components facilitated a reduction in physical size by half and decreased power consumption by 90% compared to vacuum tube equivalents. While programmed through a plugboard, it utilized magnetic core memory for data storage.
The primary memory capacity included storage for 40 numbers of nine digits each, alongside an accumulator capable of holding 18 digits. The calculator could execute 4,500 addition operations per second; multiply two nine-digit numbers producing an 18-digit product in 11 milliseconds; and divide an 18-digit number by a nine-digit divisor yielding a nine-digit quotient within 13 milliseconds. It supported programming sequences of up to 80 steps.
Additionally, the system was equipped with a type 535 card reader/punch device featuring its own control plugboard.