OS-9 was a multitasking operating system for the 6809 8-bit CPU. Level I was for systems without memory management and therefore both the OS and the user programs had to fit in 64 KB RAM. Level II gave an address space up to 2 MB. OS-9's overall structure was based on the UNIX operating system, and provided a remarkably similar user experience. You had a multi-level directory file system, background processes, redirection of input/output and even pipes. The standard library for the C language was almost identical to an early UNIX except for the fork and exec system calls, which were combined into one call.
The OS-9 operating system was sold for a variety of 6809 systems: TRS-80 Color Computer, Dragon 64, GIMIX, SWTPC, Smoke Signal Broadcasting etc. Only a few distributions still exist. The most popular one was for the Color Computer line and enthusiasts created NitrOS-9 when support ceased for OS-9.
What has survived?
The table below shows the six hardware platforms I have been able to find software for.
|TRS-80 Color Computer||Due to the large number of units sold, almost everything has been copied to disk images and can be found at the TRS-80 Color Computer Archive. The later systems had MMUs supporting up to 2 MB RAM.|
|Dragon 64||The Dragon 64 from Dragon Data Ltd, Eurohard SA and Tano was a clone of TRS Color Computer I. OS-9 software can be downloaded from The Dragon Archive.|
|Dragon 128||The Dragon 128 was an unfinished project at the time Dragon Data went bankrupt. It was designed to have from 256 KB RAM up to 768 KB, and run OS-9 Level II.|
|SWTPC||The kernel and device drivers are available in the Evenson Consulting Services SWTPC 6800/6809 Emulator. Most of the utilities on the embedded disk images come from the Color Computer distribution. The kernel, bootstrap code and device drivers can be created from the OS-9 Source code package, however.|
|GIMIX||The only material available is a single floppy disk for the GMX I computer, which can be downloaded from this page. It seems to be the only existing distribution where the utilities were assembled for 80 column terminals. The GMX I had no MMU, but later systems had one. It is unknown if it was compatible with the Color Computer. No software has survived for these later systems.|
|Commodore SuperPET||Super-OS/9 is an adaptation of OS-9 Level 1 for the SuperPET that was developed and sold by the Toronto PET Users Group. It is now available from Mike Naberezny's website.|
|Fujitsu FM-7||First released in 1982 and was sold in Japan and Spain for home computing. OS-9 Level I was available. The boot disk image was found on RetroWiki.es.|
|Fujitsu FM-11||A business computer announced by Fujitsu in November 1982. It ran OS-9 Level II. The boot disk image was found on VETUSWARE.COM.|
|Thomson MO5||In 2004 there was an attempt to port OS-9 to the MO5 - a French home computer from the eighties. The work status page can be seen at the OS-9/MO5 Homepage.|
- Assembler/Editor/Debugger for Dragon 64 with Y2k updates (assembler.vdk) (184,345 bytes)
- Contains asm, debug, edit and the defs-files.
- OS-9 Editor/Assembler/Debugger Manual (assembler.pdf) (379,888 bytes)
- OS-9 System Programmer's Manual (sysprog.pdf) (560,080 bytes)
- OS-9 User Guide (os9guide.pdf) (431,708 bytes)
- For Use with OS-9 Level One and OS-9 Level Two
- OS-9 source code package (OS-9_Source.tar.gz) (159,360 bytes)
- Microware sold source code for standard I/O drivers, and a "User Source Code Package" (on OS-9 format disk only) which contained source code to the Shell, INIT, SYSGO, device driver and descriptor modules, and a selection of utility commands which could be useful when moving OS-9 to a new target system. The device drivers in the package are for the SWTPC 6809 microcomputer.
- Y2K updates for OS-9 level I (y2k-updates.vdk) (184,347 bytes)
- Updates to fix year 2000 in OS-9 Level 1 for Dragon 64 computer. This disk contains changes to the utilities Date, Dir, Free, Login, Setime, Basic09 and Runb. It was the intention to provide the same user experience as in 1980. Therefore most utilities will still display a two-digit year except 'date', which shows the full four digits. Setime in particular still expects a two-digit year and will then adjust to the twenty-first century unless no date is entered. The sources are provided for your own assembly.