Microware OS-9/6809

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.

Diskette label
OS-9 Diskette label for Dragon 64

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 hardware platforms I have been able to find software for.

TRS-80 Color ComputerDue 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 64The 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 128The 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.
SWTPCThe Southwest Technical Products Corporation was a primary vendor of FLEX and OS-9.
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 SuperPETSuper-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-7First 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
Fujitsu FM-11A business computer announced by Fujitsu in November 1982. It ran OS-9 Level II. The boot disk image was found on VETUSWARE.COM.
Motorola EXORciserA development system for Motorola's 6800/6809 CPUs.
CMSCreative Micro Systems - High-performance 6809 processor cards for the Motorola EXORbus.
Positron 9000A British made computer intended for multiuser use.
Thomson MO5In 2004 there was an attempt to port OS-9 to the MO5 - a French home computer from the eighties. The work status page is no longer online.
"The Mill" An Apple II co-processor card containing a 6809 processor. By Stellation Two, ran OS-9 Level One. For more information see HACK Z APPLE (French).
Assembler/Editor/Debugger for Dragon 64 with Y2k updates (assembler.vdk) (184,345 bytes)
Identical to original Dragon 64 disk with asm, debug, edit and the defs-files. The utilities dir and free have Y2K updates.
OS-9 Editor/Assembler/Debugger Manual (assembler.pdf) (379,888 bytes)
OS-9 Interactive Debugger User's Manual (OS-9 Interactive Debugger Users Manual.pdf) (2,430,861 bytes)
OS-9 Level Two System Designer's Guide (OS-9 L2 System Designers Guide.pdf) (5,346,751 bytes)
From the website of David C. Wiens:
OS-9 System Programmer's Manual Revision F-1 (OS-9 System Programmers Manual 1983-01.pdf) (15,050,500 bytes)
Scanned from paper.
OS-9 System Programmer's Manual Revision H (sysprog.pdf) (567,551 bytes)
OS-9 User Guide (os9guide.pdf) (431,708 bytes)
For Use with OS-9 Level One and OS-9 Level Two
OS-9 User's Manual January 1983.pdf (OS-9 Users Manual 1893-01.pdf) (10,614,398 bytes)
For Use with OS-9 Level One and OS-9 Level Two. Scanned paper manual.
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.dsk) (184,320 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. The disk is 40 tracks, 18 sectors/track.

It is possible to read OS-9 DSK images with ToolShed.

Source files

Some of the systems listed above have hardware specific source files as well.