OPD Mini Processor
| Company type | Product |
|---|---|
| Industry | Word processing, Computer hardware |
| Predecessor | IBM Mag Card Selectric devices |
| Founded | January 1977 |
| Successor | IBM Displaywriter |
| Headquarters | Austin , United States |
Area served | Large enterprises, centralized word processing departments |
| Products | OS/6 word processor, 9-inch CRT display console, daisy wheel and IBM 46/40 inkjet printers (IBM 6640) |
| Parent | IBM |
OS/6 (also known as Office System/6 or System 6) is an independent word processor created by IBM's Office Products Division (OPD), which debuted in January 1977. It was succeeded by the IBM Displaywriter in 1980.
Overview
The system includes a console equipped with a keyboard, a 9-inch CRT character display, and supports either a daisy wheel or the IBM 46/40 inkjet printer (later renamed the IBM 6640). Documents are saved on 8-inch floppy diskettes and magnetic stripe cards, maintaining compatibility with IBM's earlier Mag Card Selectric devices. The display operates in a pre-WYSIWYG mode, presenting embedded formatting codes that users can edit by navigating with arrow keys.
Developed prior to the personal computer era, OS/6 was designed for centralized word processing departments within large enterprises. It provided capabilities such as mail merge, high-resolution printing with diverse formatting options, and printers equipped to handle envelopes or sheets from two separate drawers (for letterhead and additional pages). Data transfer to IBM 5110 and 5120 machines was possible through third-party applications.
Under the hood, OS/6 is powered by IBM's exclusive 16-bit OPD Mini Processor, a single-chip FET microprocessor engineered by Richard Vrba. This processor features a 16-bit little-endian instruction set built upon an internal 8-bit architecture and utilizes sixteen general-purpose registers organized as a 32-byte register window functioning like a stack for operand referencing.
History
The development of OS/6 occurred within IBM's "Rio" project based in Austin, Texas. Following the decision not to upgrade the video display of the Selectric Mag Card II, IBM announced in 1977 that Mag Card II users could enhance their systems with an added communications option to interface with System 6.
In 1977, the System 6 series consisted of models 6/430, 6/440, and 6/450; by the next year, models 6/442 and 6/452 were introduced. The system's hardware components included a monitor, keyboard, magnetic card reader, inkjet and daisy wheel printers, as well as a floppy disk drive.
IBM broadened its product offerings in 1978 by releasing the 6/420 Information Processor—a standalone CPU unit that did not include magnetic card or printing capabilities.
In 1979, IBM launched the communication-capable laser printer and photocopier combination device known as the IBM 6670 Information Distributor. That same year, IBM's General Systems Division unveiled the IBM 5520 systems, which shared some features but were distinct from System 6.
Ultimately, OS/6 was phased out in favor of the IBM Displaywriter in 1980.