View Full Version : Coherent?

October 19th, 2009, 11:14 PM
I was thinking about tinkering with Coherent. Coherent (http://en.wikipedia.org/wiki/Coherent_%28operating_system%29) is an old UNIX clone for the IBM PC (just like Linux, except Linus was just a little kid when they first released it). It runs on systems Linux won't run on, the 808(6/8), 286, and so on.. I was wondering if any of you have any experience with Coherent.

I tried running it on VPC, but it panicked. I've heard that people have had success with running it under QEMU.

Not quite a surprise when the developers of Coherent (Mark Williams Company) went out of business in 1995.

October 21st, 2009, 05:31 PM
I was one of the last employees of Mark Williams Company (Jim Leonard, check your manual on the employee page), but all I can remember about Coherent at this point is historical information and not necessarily technical details (although if I sat down in front of it I'm sure a lot would start to come back to me). Working with Coherent, even from a tinkering standpoint, is very frustrating in today's world because there was never an official TCP/IP stack written for it. Without networking, unix becomes somewhat useless... Also, it had no virtual memory.

What *was* interesting about Coherent 4.x was that, without virtual memory, the entire OS was optimized for size, including the compiler. Some of the COFF executables were absolutely minuscule for their functionality.

The 286 version of Coherent (version 3) was very interesting in that 1. it was unix for a 286 and 2. it supported up to 16M of memory in 286 protected mode. You could only allocate memory in 64K segments, but you could allocate up to 16M of it :-)

I can't give you tech support since MWC folded in 1995 (I got out in 1994) :-) but I could try if you had specific questions.

I will say this: If you have the 808x version of Coherent from the 1980s, I would REALLY love to get disk image copies. I've only ever worked with the 286 and higher versions.

October 25th, 2009, 04:09 PM
I'm pretty certain that at some point I had it working under Bochs, but then again that was several years ago so I may be mistaken.

The good part is that the kernel source is available, so it may be patched to work in emulator if it needs to be. If someone knows how to build it that is.

If that is of any help I have a scanned manual available on http://www.tenox.tc/docs/

April 7th, 2010, 05:19 AM
See comp.os.coherent, in e.g. dejanews or Google. You will find more information and links to a maintained copy of the last release of Coherent there.