UniFlex

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UniFlex

Company/ developer:	Technical Systems Consultants (TSC)
OS family:	Unix-like

UniFlex is Unix-like operating system developed by Technical Systems Consultants (TSC) for multitasking, multiprocessing for the Motorola 6809 family. It was released for DMA-capable 8" floppy, extended addressing hardware, Motorola 6809 based computers. Examples included SWTPC and GIMIX. On SWTPC machines, it also supported a 20 MB, 14" hard drive (OEM'd from Century Data Systems) in 1979. Later also larger 14" drives (up to 80 MB) were supported, also 8" hard drives and 5-1/4" floppies.

Due to hardware limitations main memory requirements for the UniFlex kernel had to stay below 56 KByte (code + data). This was achieved by a 100% assembly language implementation and by stripping of a few classical Unix features, like group permissions for files. Otherwise UniFlex was much similar to Unix Version 7, only its commands were named slightly different. There was no technical reason for this. By renaming the commands "Unix Look & Feel" could be established, though due to memory limitations the command line interpreter (shell) was still less capable as the Bourne Shell known from Unix Version 7.

TSC never bundled a C compiler with UniFlex for the 6809, but in the early 80's a C language implementation became available as 3rd party product ("McCosh Compiler"). That way source-level compatibility with Unix Version 7 was achieved, i.e. a number of Unix tools and applications could be ported to UniFlex - if size allowed: Unix on a PDP 11 limited executables to 64 KByte of code and another 64 KByte of data, the Uniflex limit was apx. 56 KByte for both, code and data together.

In the mid 80's a successor version for the Motorola 68000 was announced. Though this would have removed all the pressing space limitations, it was not commercially successful as it had to compete with source-code ports of original Unix.

See also: FLEX.