Coherent OS

https://en.wikipedia.org/wiki/Coherent_(operating_system)

by Jaruzel • 7 years ago

82 48 7 years ago

en.wikipedia.org

_bxg1• 7 years ago

Did Linux deal with any of the same legal scrutiny?

hobo_mark• 7 years ago

Yes, for years...

https://en.m.wikipedia.org/wiki/SCO–Linux_disputes

msla3• 7 years ago

SCO was a farce. Microsoft used a company called BayStar to fund SCO's lawsuits, which had absolutely nothing to them; SCO wouldn't even release the evidence it claimed to have proving code copying for a suspiciously long period of time, and when the evidence was released, it was nothing of the sort. Ultimately, the legal merits of the case wouldn't have mattered, in that a bad lawsuit can still drown an opponent. What mattered was that Microsoft waited too damn long to try it: One of the players on the other side was IBM, which by then had a serious business in Linux on mainframes, and a two-bit nuisance suit jumped up with some venture capital wasn't going to sink the damn Nazgul.

https://www.computerworld.com/article/2547289/baystar-exec-s...

cowmix• 7 years ago

Coherent was a great option in and around the 1990-92 timeframe. It was a great UNIX clone for $99 (with a great manual to boot). What killed it is they, for some reason, spent time and treasure port XWindows to it instead of working on a TCP/IP stack. It would have been the perfect Internet OS.

anyfoo2• 7 years ago

Just from memory, I can sort of see how they could have mistaken those priorities. Windowing systems (with which X11 was synonymous on unixy systems) were a big deal at the time, while TCP/IP, even networking in general, was still emerging in what probably was Coherent's target market.

Coherent did have UUCP, didn't it? In a lot of cases, that got you much further in small to mid scale environments than TCP/IP. I wouldn't even be surprised if Novell Netware would have been considered more important.

teh_klev3• 7 years ago

I wouldn't even be surprised if Novell Netware would have been considered more important.

Speaking as a field engineer from the UK from days of yore... Up until around 1995 IPX/SPX, Novell's default networking stack at that time, was hugely prevalent in corporate and governmental environments. I didn't start bumping into TCP/IP in any serious way until around 1992 in my job as a field engineer. The general kinda setup was groups of departmental Novell Netware 386 servers (I was a Netware engineer since around '87) with loads of DOS and Windows 2/3.x clients running Novell's IPX/SPX stack atop NE2000 compatible NIC's.

Around '95 things changed. Novell Netware 4 (as did NT 3.51 - NT done properly) shipped and the default stack became TCP/IP...the rest is history.

ecksii4• 7 years ago

Coherent had Taylor UUCP. The most enthusiastic users were doing Usenet News delivered via UUCP. Coherent ran into big issues due to a nasty bug in the ATA disk driver. The users who got hit the worst were the ones running C news.

wildduck• 7 years ago

Yeah but back then you got all kinds of stuff like Token ring, Novell as alternative to TCP/IP. Seems they have gone with other ones.

nils-m-holm5• 7 years ago

It did have UUCP, I used to run a USENET leaf node back in the days.

ecksii4• 7 years ago

The decision was before my time but it was based on a user survey. I have to admit that my vote was also for X11 rather than TCP/IP. I don't think people realized how tightly X11 was bound to networking. This blinded them to the the extra effort required to port X Windows to an OS without TCP/IP.

nigel_bree4• 7 years ago

What killed it is they, for some reason, spent time and treasure port XWindows to it instead of working on a TCP/IP stack

Just to be clear, there's a whole heaping helping of really big work required to get there either way, since Coherent was still essentially a 16-bit OS that started out as a V6 clone on the PDP-11 and hadn't really kept up during the 1980's with any of what was happening in the wider UNIX world beyond, oh, the Seventh Edition.

The key starting point for Coherent 4.x was essentially a single piece of work (almost all of it provided in a single .c file) that let a 3.x kernel boot into 386 protected mode and provided a system call handler that more-or-less emulated the call sequence specified in the Intel iBCS specification and mapped the iBCS system calls to the original 16-bit Coherent 3.x ones, and a very basic loader for statically linked SVR3 COFF files.

[ See https://en.wikipedia.org/wiki/Intel_Binary_Compatibility_Sta... which essentially formalized a subset of what the SCO port of System V did. Note, that omitted a number of system calls; I'm fairly certain that the iBCS manual didn't include any of the socket-related system calls anyway, so the public spec for what people took to mean "will run SCO binaries" left a lot to be desired. ]

Everything else around that was still, essentially, 16-bit code that was written around some variation of Sixth Edition or Seventh Edition, not System III/ or System V (so to be iBCS compliant the bible was the System V Interface Definition, aka SVID), let alone any of the things that were being added to POSIX.1 or POSIX.2

So, the work required for releasing the V4.x series of Coherent included a massive number of upgrades of almost everything, along with all kinds of awkward technical compromises to a) not break any existing things from the 16-bit userland, which stayed 100% supported, b) navigate between SVID and POSIX because while we on the one hand wanted to be able to run SCO binaries (hence, do things per the SVID) while we had all kinds of enthusiasts really wanting to use the ability to 32-bit code to run various shar archives of GNU project code unmodified.

So, I'd just note about that 16-bit userland from Coherent 3.x was that virtually everything on the (nominally 32-bit) version 4.x install floppies - all the standard utilities, pretty much everything that could be - still was built as 16-bit a.out binaries to keep the install size down. Pretty much everything we did in terms of C libraries and such had to be, and had to stay, buildable both 32-bit and 16-bit from the same source since both subsystems were needed. At some point we could conceivably have (at a technical level) cut over to all-32-bit, but just from the point of view of media duplication, doing that and still staying at a $99 price point wouldn't fly, and also the resulting increased memory footprint wouldn't have made existing customers happen since the kernel didn't have any support for demand paging, at a time when lots of people had just 1-2Mb (or 4Mb for a relatively beefy system) of RAM.

[ So for all the work required to let /bin/sh able to run successfully run multi-megabyte autotools scripts that tried relying on POSIX.1 shell features? Yup, everything involved in POSIX.2 support was all done with code that stayed 16-bit. ]

Without getting too much into the weeds of all the other various challenges involved getting a system like this out, for TCP/IP specifically the question was what kind of TCP/IP stack to pursue and most critically of all the question of where were the NIC drivers going to come from. There was not going to be any plausible way we could work with third-party SCO driver binaries, which were the most common type of UNIX driver that NIC vendors did provide at the time; SVR4.2, however, had STREAMS and the DDI/DDK so there was a plausible, reasonably portable driver model which seemed like a realistic future, but just licensing Lachmann and trying to bolt that into the kernel wasn't realistic at the $99 price point (and at the time, there weren't much of any third-party NIC drivers either).

To make 4.x happen we had to come from a very very long way behind, and getting to where we needed to go while staying within the constraints of a small staff and that $99 price point just made for an incredibly tight set of constraints. None of the resulting tradeoffs were fun to make. We did our best.

Annatar2• 7 years ago

On top of all of that you had to compete with Sun Microsystems selling a fully boxed set of Solaris 2.5.1 for the i86pc for $50 USD. There was just no way to compete with them.

nils-m-holm5• 7 years ago

You could run KA9Q NOS under Coherent, which provided TCP/IP over serial line. Not many people used it, though. Most used UUCP. Personally, I cared neither about X11 nor networking and I know I was not the only one, so the decision may have been solid back then. Of course this changed very quickly in the following years. Bad timing, I guess. The shutdown of MWC was really sad, Coherent was my favorit OS, and I still have a few VMs running 3.2 (286).

anyfoo2• 7 years ago

This is only based on playing around with it in a VM and poking at its source code after it was open sourced with a BSD license in 2015, but to me, Coherent seemed like a quite well put together system. Enough that it made me a bit sad that it's now an OS of the past.

simonblack2• 7 years ago

Coherent's misfortune was that it was released at the same time that Linux was.

All through the 90s as I progressed from Coherent to AT&T Unix to Novell's Unixware to Sun's Solaris, I used to to look at Linux every six months or so. I was always gobsmacked at how quickly Linux (actually Gnu/Linux) was moving ahead in leaps and bounds.

By the time that 2001 rolled around, it was time for me to put away my Solaris and switch to Linux fulltime.

ecksii4• 7 years ago

While Linux would have certainly killed Coherent eventually, that's not quite the case. First Coherent was out long before Linux. Coh was around long enough for AT&T to have sent Dennis Ritchie to Chicago to inspect the code and evaluate it for copyright claims. Coherent ran on the PDP11 and on the 80286. Linux became a real force in the Unix market around 1998. MWC went out of business in Feb 1995. The first round of layoffs at MWC happened in Oct, 1994.

A perfect storm of several things killed Coherent The two biggest problems were:

The customers dinging Mark Williams Company in the newsgroup mainly complained about the lack of TCP/IP networking. This happened because MWC had done a customer pole to see what big feature should come next? TCP/IP or X11. X11 won.

The real or perceived drop in quality of the product. This one is hard to explain. Coherent 3.10 and 4.0 had been solid V7 Unix clones with V7 sensibilities. When 4.2.05 shipped it included a really nasty disk driver bug that basically destroyed your file system beyond the ability of fsck to fix. The bug was triggered when your drive when into a very common thermal recalibration mode. This mode was rare or hadn't existed during the days of MFM/RLL/ESDI drives but became common with ATA drives especially as the market got flooded with cheap 504MB drives. While the bug was fixed somewhere between 4.2.10 and 4.2.14, the damage to Coherent's reputation was done.

teh_klev3• 7 years ago

Back in the day (early 1991) just before Linux appeared I convinced my company to pay for a copy of Coherent and they agreed. It was $99 and I learned a decent amount of Unixy basics on my el-cheapo clone 386 PC. In summary it was a pretty decent learning tool. I managed to get it to connect to my ISP and get some basic text based internet kinda things done.

I eventually filched a copy of SCO Unix from a customer (which is what I had to support way back then - along with SCO Xenix) with a license key and ran that for a bit and once Linux became a bit more stable (for me it was Slackware circa 1994/1995) I started running that instead.

I kinda wonder what would have happened if MWC had open sourced Coherent back then (provided they owned all their own code, or the third party code was compatible with GPL/MIT/et-al)?

EvanAnderson• 7 years ago

Fun fact - The Mark Williams Company[1], who made Coherent, was founded by Aaron Schwartz father, Robert Schwartz [2].

A couple of friends and I drooled over an AT&T Unix manual that our public library had in 1990 - 1991. Unix seemed really cool but we could never afford a real Unix machine. We talked about pooling our money and buying a copy of Coherent but we never did. Then Linux came on the scene and Coherent was forgotten.

[1] https://en.wikipedia.org/wiki/Mark_Williams_Company

[2] https://en.wikipedia.org/wiki/Aaron_Swartz

simonblack2• 7 years ago

Coherent was my entrance to the wonderful world of Unix back in 1991. Thanks to Coherent's introduction I never ever had to endure Windows as my everyday personal desktop environment.

tyingq• 7 years ago

I remember the magazine ads for it: http://2.bp.blogspot.com/-vfzVzVxKynE/To2Hu97jlLI/AAAAAAAAAD...

icedchai• 7 years ago

I ran this on a 386SX for while in 1991. It came with a very comprehensive "Unix" manual. A couple years later I switched to Linux...

Foroldhack44• 7 years ago

in 1990, while working for an insurance company, we were looking for what UNIX to port a multi user database to, We looked at SCO, Microport, Cohernet and Sperry. The company chose Microport, and the Sperry went back, so I got to keep SCO and Coherent. Loaded and ran both, liked SCO a tiny bit more because of it successfully compiling a few programs, and heard about the UNIX Copyright controversy.

Coherent installed, and ran, but had a few incompatibilities with our software, but ran solid as hell. The documentation was very good too.

wstrange• 7 years ago

This brings back a lot of memories.

I was an intern an Inetco sytems in Vancouver (circa 1989?). They developed switching software for ATMs that used Coherent running on Intel PCs.

My task was to extend the Coherent shell (a clone of the standard Unix sh) with BSD csh features (history, etc.). I had nothing to go on except the csh man page.

I have since lost the source code (it was called the "wsh"), but I suspect I would cringe looking at it now.

Coherent was definitely my gateway drug into Unix.

bifrost• 7 years ago

I remember using Coherent along with Xenix around the same time. I think I tried everything I could get my hands on :) I even used 386BSD heh.

Mountain_Skies• 7 years ago

Almost bought it after seeing the stunningly low price. $99 for a Unix like OS? It seemed too good to be true. At the time my housemate and I ran a small multiline BBS we wanted to make into something bigger. Coherent would have been to run Picospan after seeing how well M-Net worked. Someone we contacted at the Mark Williams Company said they didn't think Picospan would work with Coherent's memory model. No idea if that was correct but we went with MajorBBS instead for our big upgrade. Still thought about buying it to play with but Linux showed up before I had the spare money for Coherent.

nineteen999• 7 years ago

These days (as another poster has already pointed out) it is under an Open Source license.

The author of this page:

https://www.autometer.de/unix4fun/coherent/index.html

previously worked for MWC and has put some quite detailed notes on setting up various aspects of Coherent running under Virtualbox there.

luismedel• 7 years ago

I met about Coherent thanks a small article in the spanish edition of ComputerWorld[1]. I was 13 y/o and all my computer knowledge was about Basic, Pacal, DOS and Win3.1. Good times. I still remember the accompanying picture in the article, showing the windowing system with an astronaut picture in a window, some terminals and a file explorer. I think that picture inspired my view of what operating systems should be, more than everything I've seen since then.

Also, I recently stumbled upon Idris[2], which, as far as I know, predates Xenix and Coherent in the PC scene.

[1] https://www.computerworld.es/archive/omega-anuncia-coherent-... [2] https://en.wikipedia.org/wiki/Idris_(operating_system)

tass• 7 years ago

My dad (or maybe his work) bought Coherent for him to learn UNIX and we had a setup in the garage with serially-connected VT100-like terminals.

It was my only time knowingly using a UNIX-like OS until a few years later when I installed Slackware.

nils-m-holm5• 7 years ago

In case somebody did not know yet: Coherent is officially free software now. You can download disk images with the whole system, including full, self-replicting source code, here:

https://www.autometer.de/unix4fun/coherent/ftp/vms/

Udo's Coherent pages in general are worth a visit:

https://www.autometer.de/unix4fun/coherent/

MarkMMullin• 7 years ago

Ran this on the Ithaca Intersystems Z-8000 based rig in the early/mid '80s - it was remarkably command compatible with V7 for the basics, even built a MicroAngelo based 3D graphics system on it.....the biggest problem the box had wasn't Coherent, it was the fact the socketed logic on the custom MMU S100 card kept trying to walk out of the sockets because of thermal issues

Coherent OS

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