The OS-9 family was popular for general-purpose computing and remains in use in commercial embedded systems and amongst hobbyists. Today, OS-9 is a product name used by both a Motorola 68000-series machine language OS and a portable (PowerPC, x86, etc.) version written in C, originally known as OS-9000.
In 1983, OS-9/6809 was ported to Motorola 68000 assembly language and extended (called OS-9/68K); and a still later (1989) version was rewritten mostly in C for further portability. The portable version was initially called OS-9000 and was released for 80386 PC systems around 1989, then ported to PowerPC around 1995. These later versions lack the memory mapping facilities of OS-9/6809 Level Two simply because they do not need them. They used a single flat address space that all processes share; memory mapping hardware, if present, is mostly used to ensure that processes access only that memory they have the right to access. The 680x0 and 80386 (and later) MPUs all directly support far more than 1MB of memory in any case.
As a consequence of early pervasive design decisions taking advantage of the easily used reentrant object code capabilities of the 6809 processor, programs intended for OS-9 are required to be reentrant; compilers produce reentrant code automatically and assemblers for OS-9 offer considerable support for it. OS-9 also uses position independent code and data because the 6809 also supported it directly; compilers and assemblers supported position independence. The OS-9 kernel loads programs (including shared code), and allocates data, wherever sufficient free space is available in the memory map. This allows the entire OS and all applications to be placed in ROM or Flash memory, and eases memory management requirements when programs are loaded into RAM and run. Programs, device drivers, and I/O managers under OS-9 are all 'modules' and can be dynamically loaded and unloaded (subject to link counts) as needed.
OS-9/6809 ran on Motorola EXORbus systems using the Motorola 6809, SS-50 and SS-50C bus systems from companies such as SWTPC, Tano, Gimix, Midwest Scientific, and Smoke Signal Broadcasting, STD-bus 6809 systems from several suppliers, personal computers such as the Fujitsu FM-11, FM-7 and FM-77, and many others.
The best known hardware (due to its low price and broad distribution) was the TRS-80 Color Computer (CoCo) and its clones such as the British Dragon series. Even on the CoCo, a quite minimalist hardware platform, it was possible under OS-9/6809 Level One to have more than one interactive user running concurrently (for example, one on the console keyboard, another in the background, and perhaps a third interactively via a serial connection) as well as several other non-interactive processes.
On a computer like an SS-50, machines which had more memory (for example, those from Gimix, Southwest Technical Products, etc.), and I/O controllers that did not load the CPU as did the CoCo, multiple users were common, even with only 64 KB of RAM (i.e., Level One). With hardware supporting memory management circuits (that is, address translation) and OS-9 Level 2, GUI use was successfully routine, even on the minimal resourced CoCo. This was several years prior to successful GUIs on the 16-bit IBM PC class machines, and many years prior to properly working multi-tasking, multi-user, access-controlled operating systems on IBM PC type machines or on any of Apple's machines.
OS-9's multi-user and multi-tasking capabilities make it usable as a general-purpose interactive computer system. Many third-party interactive applications have been written for it, such as the Dynacalc spreadsheet, the VED text formatter, and the Stylograph and Screditor-3 WYSIWYG word processors. TSC's nroff emulating formatter was ported to OS-9 by MicroWay, as well.
In mid 1980s, OS-9 was selected for the CD-i operating system. Around the same time, Microsoft approached Microware for acquisition of the company primarily because it was attracted by CD-RTOS, the CD-i operating system. The negotiation failed and no deal was made; Microware decided to remain independent.
In late 1980s, Microware released OS-9000, a more portable version of the operating system. The vast majority of the operating system kernel was rewritten in C leaving a handful of hardware-dependent parts in assembly language. A few "more advanced features" were added such as tree-like kernel module name space. OS-9000 was initially ported to the Motorola 680x0 family CPUs, Intel 80386, and PowerPC. The OS-9000/680x0 was a marketing failure and withdrawn very quickly probably because few customers wanted to try the fatter and slower operating system over the existing OS-9/680x0 proven record of stability. That the Motorola 680x0 family and VME board computer system vendors were nearing their end of life might have affected the unpopularity of OS-9000/680x0. Microware later started calling all of its operating systems including what had been originally called OS-9000 simply OS-9 and started shifting its business interest towards portable consumer device markets such as cellphones, car navigation, and multimedia.
In late 1980s and early 1990s, the Character Generators computers used in Broadcast Systems used OS-9 and OS-9000 extensively. The now defunct Pesa Electronica used OS-9 on their CGs such as CG 4722 and CG4733.
In 2000, Radisys purchased the nearly bankrupt Microware to acquire the Intel IXP-1200 network processor resources. This acquisition infused Microware with needed capital and allowed Microware to continue OS-9 development and support. As of 2008, OS-9 is still supported by Radisys and Microware.
When compared with more modern operating systems such as Linux, however, OS-9 lacks many features used extensively in today's applications.
Strictly speaking, OS-9 is a very soft real-time operating system for many reasons.
An operating system similar to OS-9, but with less functionality and
special features designed to soak up excess memory, disk space and CPU
time on large, expensive computers.
This entry was, curiously, removed in the version 3.0 manual.
The OS-9 shell had an easter egg in its command history function, invoked by CTRL-A. Upon a fresh boot, the command history was supposedly empty, but if the user typed a single space followed by a backspace, then hit CTRL-A, the names of the authors would be displayed: 'by K. Kaplan, L. Crane, R. Doggett'.
X-Window package provides user interface for embedded real-time applications. (Microware Systems Corp.'s OS-9/ X-Windows program development software) (product announcement)
Apr 25, 1991; OS-9 real-time operating-system users can add X-Window-based graphical user interfaces to their 68000-based embedded...
Development tool set eases OS-9 network-software programming. (Microware Systems Corp.'s Fastrak) (Product Announcement)
Apr 15, 1993; A new software-development tool set, called Fastrak, from Microware Systems Corp aims to make life easier for programmers who...
Development tool set eases OS-9 network-software programming. (Microware Systems Corp.'s Fastrak software development tool) (Product Announcement)
Sep 16, 1993; A new software-development tool set, called Fastrak, from Microware Systems Corp aims to make life easier for programmers who...