DOS ain't dead - DR FlexOS?

bocke

31.01.2013, 13:33

DR FlexOS? (Miscellaneous)

Hi, I just stumbled at some information about something called FlexOS.

What I can make out is that it was a successor to DR Concurrent DOS. It was a multiuser(? - at least it had a login facility)/multitasking OS that was first "published" (there has to be a better term) somewhere around 1986 (judging by the manuals) for 80286 based PCs. It was basically DOS-like. It used the same commands with some additions (not unlike OS/2 or Windows NT), but also provided some facilities like command piping, stderr redirection and similar.

It supported multiple "windows", something a sort of like Unix virtual consoles, so you could run several full screen tasks along each other. It came with GUI: X/GEM - a multitasking version of DR GEM; and networking: supporting ethernet and arcnet. It seems it could run CP/M and DOS executables from different architectures: 68xx CP/M, DOS x86, CP/M86, M/PM (from what I could make out, not completely sure).

As I see in Wikipedia, it was used mostly in industrial applications and was also used in some Siemens solutions.

Does anyone know what happened with FlexOS and why did it fail (if it did)? Was it ever offered as an OS for PCs or was limited only to industrial applications?

The list of features is impressive for the time (1986).

Arjay

02.02.2013, 12:45
(edited by Arjay, 02.02.2013, 13:12)

@ bocke

DR FlexOS? 2013 = PC death+year of Linux "tablet" desktop?

Post reply

> Hi, I just stumbled at some information about something called FlexOS.
I had heard of FlexOS but am not that familiar. It's existance interests me though in the evolution of operating systems and the various temporary side paths that occur like this.

> What I can make out is that it was a successor to DR Concurrent DOS.
I've a love hate relationship with Wikipedia.... but "according" to the Wikipedia Multiuser (Concurrent 286) DOS article: "These same limitations affected FlexOS 286 version 1.0, a derivation of Concurrent DOS 286."
The way I read that and the FlexOS article is they sort of brother/sister products which share a lot of common code base but were marketed for different uses.

Currently there is a dead link in the Multiuser Wikipedia page to a 2006 Les Bell technical article called "CP/M and Derivatives" which article appears to have been removed from the website. Unfortunately it was stored as a NSF (Lotus Notes File) which for anyone familiar with Notes can be described as almost one way data storage... so although a 2010 cache of LesBell.com is available via Archive.ORG the article appears to NOT be available.

It seems that it only recently disappeared offline? as the interesting RetroTechnology.com website by Herbert R. Johnson has a link to Les Bell's article from Herb's 2011 article "CP/M and Digital Research Inc. (DRI)".

> It was a multiuser (? - at least it had a login facility)/multitasking OS
Yup, I agree appears to have been from what I've read.

> It came with GUI: X/GEM
Ah yes that takes me back. I remember using it around 1987/1988 on an Amstrad 1512 which I had access to and GEM was much better than Windows at that time. (I uninstalled Windows on my first PC to free up space!)

> Does anyone know what happened with FlexOS and why did it fail (if it did)?
> Was it ever offered as an OS for PCs or was limited only to industrial
> applications?
Looks like it merged with MultiDOS to me? We need to do more reading....

> The list of features is impressive for the time (1986).
Yes and No. Yes, in the PC world at the time but No when you consider the Amiga launched in 1985 and the Archimedes in 1987, when you compare against them it makes you realise how behind PC's were.

Which has made me think more about the future or lack there of for our beloved traditional PC. I find the world is a funny place in that things often go fall circle in popularity and FlexOS has reminded me of just that, e.g.
Unix - CPM - DOS - Windows - Linux (Unix!)
Mainframes - midrange - PC's - Distributed cloud computing (= mainframes!)

Indeed in the early 1990's when it came to upgrading from my (Acorn) BBC Micro model B, I decided to ignore my Amiga/Archimedes friends and went down the unfashionable PC route for one simple reason, it was obvious the PC which I had first met in 1985 had won as the business office machine and I wanted to go into I.T - even back then I knew the PC's days were limited but I never thought that PC's would last for as long as they have. Still like most here I've have spent years evolving and upgrading along with PC's but also still keeping close to the continued expansion of the ARM architecture which was designed on the BBC B (and originally called "Acorn RISC Machine") which has now gained massive market share from PC's, to the point that this year PC's were finally recognised to be obsolete, e.g.
PC sales fall for first time in over a decade, PC sales fall 6.4% in Q4, worse than expected, PCs hit hard as mobiles and tablets overtake iPlayer viewing etc.

I'm afraid as much as I have nostalgia for PC's, we've gone full circle with hardware and their demise is going to continue to obviously happen hence why my recent new PC wasn't a PC! I feel anyone who believes tablets are a temporary thing is very much mistaken. I guess it could finally be argued that (2012) 2013 is finally the year of the Linux Desktop only it's the Linux Desktop on a ARM based tablet and NOT an Intel PC running Windows 8. I do however wonder what Windows 9 will bring and suspect that it won't be long before a new GUI via "revised" Windows 10 running some "revised" Intel hardware will come into existance. A bit like when Microsoft suddendly had to play catch up with Netscape and the Internet. I think we are kind of at that Windows 95 to Windows XP stage at the moment where the world has changed and several companies have just woken up to it the hard way.

Regardless IMHO I think the PC we've all loved is now finally dead (RIP) :-(

Rugxulo

Usono,
02.02.2013, 17:23

@ Arjay

DR FlexOS? 2013 = PC death+year of Linux "tablet" desktop?

Post reply

> > Hi, I just stumbled at some information about something called FlexOS.
> I had heard of FlexOS but
> am not that familiar. It's existance interests me though in the evolution
> of operating systems and the various temporary side paths that occur like
> this.

Dunno, but it sounds like "yet another" offshoot of CP/M-86 and DR-DOS.

> GEM was much better than Windows at that time.

But GEM didn't run any Windows apps, nor did it multitask DOS apps, nor provide DPMI. :-) But I guess back in pre-Win-3.x days, it might've been more useful. (I'm just saying, maybe I'm wrong, I know GEM has some apps, but it seems more like a glorified file manager than what Windows eventually became.)

> > The list of features is impressive for the time (1986).
> Yes and No. Yes, in the PC world at the time but No when you consider the
> Amiga launched in 1985 and
> the Archimedes
> in 1987, when you compare against them it makes you realise how behind PC's
> were.

Dunno, you probably have more perspective than I do. Compaq's 386s vs. IBM PC AT 286s (or PCjr) tried to fill a lot of gaps, though I admit software took a while to catch up. For whatever reason, gaming became a big focus of PCs, which I don't think was intended. (And that ignores networking, which would take longer to become ubiquitous but was/is huge.)

> Which has made me think more about the future or lack there of for our
> beloved traditional PC. I find the world is a funny place in that things
> often go fall circle in popularity and FlexOS has reminded me of just that,
> e.g.
> Unix - CPM - DOS - Windows - Linux (Unix!)
> Mainframes - midrange - PC's - Distributed cloud computing (= mainframes!)

I don't know if I'd call any of today's stuff a "traditional PC" anymore. Sure, it's got a BIOS, it's got x86, but even that is under attack, moreso from people who hate compatibility (yet have nothing 100% "better" to offer, IMHO).

> even back then I knew the PC's days were limited but I
> never thought that PC's would last for as long as they have.

In what way? BIOS + x86 compatibility? IBM? Microsoft? Or just home computing?

> Still like most here I've have spent years evolving and upgrading
> along with PC's but also still keeping close to the continued
> expansion of the ARM architecture, which has now
> gained massive market share from PC's, to the point that this year PC's
> were finally recognised to be obsolete

I don't think it's obsolete, but indeed, people would rather have something pocket-sized than a huge behemoth. Even laptops are "too big" for some people. However, honestly, the big drawback is battery life, laptops just don't compare to tablets, etc. (esp. for multimedia like Flash). But tablets are (usually) harder to type on, even though external keyboards exist. Still, there are efforts underway (ultrabook?) to combine the traditional PC with detachable forms for on-the-go use.

> I'm afraid as much as I have nostalgia for PC's, we've gone full circle
> with hardware and their demise is going to continue to obviously happen
> hence why my recent new PC wasn't a PC! I feel anyone who believes tablets
> are a temporary thing is very much mistaken. I guess it could finally be
> argued that (2012) 2013 is finally the year of the Linux Desktop only it's
> the Linux Desktop on a ARM based tablet and NOT an Intel PC running Windows
> 8.

There's still tons of legacy software that has to be used (moreso by big companies), so there's little chance of everyone abandoning Windows, Linux, OS X, x86, etc. any time soon. Esp. with all the love going into AMD64 (though AArch64 is on the horizon, will probably become quite popular though presumably only after a few years). I read about someone the other day buying 32 GB of RAM. I'm not aware of any phone, tablet, etc. that can use that much! (And I don't recall this being a server machine either, another area where portables can't compete.)

> I do however wonder what
> Windows
> 9 will bring and suspect that it won't be long before a new GUI via
> "revised" Windows 10 running some "revised" Intel hardware will come into
> existance. A bit like when Microsoft suddendly had to play catch up with
> Netscape and the Internet. I think we are kind of at that Windows 95 to
> Windows XP stage at the moment where the world has changed and several
> companies have just woken up to it the hard way.

Bah, MS always makes weird decisions. I don't envy them, esp. since I think they've overextended themselves (too many products, too many markets).

> Regardless IMHO I think the PC we've all loved is now finally dead (RIP)
> :-(

The main draw for the "IBM PC clones" was the openness, the competition, and the tons of standard software that still worked. In recent years, it's been adding more and more features but sometimes making things incompatible and harder to use (not to mention constantly fighting battles over patents, closed specs, and sometimes painfully poor driver support). If anything, it was already halfway "dead" due to this. Unfortunately, most companies just don't play nice, but at least it's still "mostly" working. 300+ Linux distros can't be wrong. ;-)

P.S. I'm no hardware guru, but it seems the most popular cpu hardware is covered by Debian and FreeBSD (and of course tools like GCC). Yet it's become fairly obvious that "top tier" always includes x86 as well as x64 these days, usually over all others. Why? It's cheap, powerful, and ubiquitous. I don't see those going away any time soon (or at least not the latter). If I didn't feel the immense pressure for them to maintain 32-bit, I'd have been more surprised they all didn't (stupidly) switch entirely to AMD64 (bad idea! some think it's wise, but ...).

Arjay

02.02.2013, 18:37

@ Rugxulo

DR FlexOS? 2013 = PC death+year of Linux "tablet" desktop?

Post reply

> Dunno, but it sounds like "yet another" offshoot of CP/M-86 and DR-DOS.
> > GEM was much better than Windows at that time.
> But GEM didn't run any Windows apps, nor did it multitask DOS apps, nor
> provide DPMI. :-) But I guess back in pre-Win-3.x days, it might've been
> more useful.
From my memory, it was a first since I remember seeing it support better applications, e.g. Ventura publisher however it was very quickly overshadowed by Windows 3.0.

> I'm just saying, maybe I'm wrong, I know GEM has some apps,
> but it seems more like a glorified file manager than what Windows
> eventually became.)
True, but remember that when the first versions of Windows came out that's effectively all they were: glorified file managers! There wasn't much for Windows and the reason I removed Windows 3.0 from my first PC in 1991 (a few years later) was I went "oh paint program" and .... erm ok. So I went back to using cshow and I think neopaint (or whatever was the equivalent then) which fitted up nicely on my 52megabyte harddrive and still allowed me to have room for other useful things like a word processor and battle chess. Whereas oh most of my harddrive (still large at the time!) went to the operating system (DOS) and operating environment (Windows!). Later Windows I discovered stacker and reading the Windows manuals (a lot) - so I removed some bits I didn't need. It was a few years later I continued that work....

I got a Windows 2.0 machine in around 1995 and believe me it's not great, cardfile, calendar. In fact I'll joke that I recon the reason Solitaire came so popular was there was nothing else installed to use back then ;-) heh

The different is GEM did it smoothly in comparism I think what started to kill GEM was Windows (3.0 DMPI over VCPI) and Windows 3.1 (drag drop) then Windows 3.11 (oh networking!) then Windows 95 when Microsoft documented the drag and drop functionality that already existed in Windows 3.1 added a slicker shell and the rest is history...

> Dunno, you probably have more perspective than I do. Compaq's 386s vs. IBM
> PC AT 286s (or PCjr) tried to fill a lot of gaps, though I admit software
> took a while to catch up. For whatever reason, gaming became a big focus of
> PCs, which I don't think was intended. (And that ignores networking, which
> would take longer to become ubiquitous but was/is huge.)
The original gaming was with null-modems. I remember PC networking taking off with Doom which supported IPX and lots of small home network cards were then sold there was a "personal netware" which I have installed for work in the past at the time and I remember seeing friends buy it for doom (which I used but never bothered to network myself - I was too busy with BBS's).

> I don't know if I'd call any of today's stuff a "traditional PC" anymore.
Well it's got the same heritage and until the last couple of years was pretty constant for years.

> Sure, it's got a BIOS, it's got x86, but even that is under attack, moreso
> from people who hate compatibility (yet have nothing 100% "better" to
> offer, IMHO).
Attack or just evolution. I'd say it's evolution but unfortunately the waters are being muddied by certain people who don't play well in the playground but there again it's always been like that. It's easy to go to Ralph Brown's interrupt list and look up all sorts of information but remember that the whole reason things like that came about was interrupts API calls were often closely guarded secrets.

> In what way? BIOS + x86 compatibility? IBM? Microsoft? Or just home
> computing?
I meant the IBM PC. When I saw and used the archimedes it blew me away, when I first played Lander in late 1988/early 1989 I was blown away. Incredible, remember PC's at the time didn't have sound cards and CGA/EGA was still common as the VGA only came out in 1987 - there was really nothing much out for it in 1988 (some MCGA stuff but mostly CGA/EGA). Lander was like seeing the future but like various things it became the betamax of it's time. A bit like when I used a touch screen HP computer (used light beams) to play cards in 1989 by touch - wow. Now that's common and it's what's the big deal. The deal is back then all of that stuff was incredible because it was a million miles away from what was common at the time. So I could see just from those experiences that the PC sucked and sucked bad. I still fell in love with it but it's been obvious that there would come a time when it died and I think that's now.

> I don't think it's obsolete, but indeed, people would rather have something
> pocket-sized than a huge behemoth. Even laptops are "too big" for some
> people. However, honestly, the big drawback is battery life, laptops just
> don't compare to tablets, etc. (esp. for multimedia like Flash). But
> tablets are (usually) harder to type on, even though external keyboards
> exist. Still, there are efforts underway (ultrabook?) to combine the
> traditional PC with detachable forms for on-the-go use.
Original laptops were called luggables for a reason. Likewise the original cell/mobiles were called "bricks" - I remember a friend having one in their parents car trunk/boot (yes they were well off) with a full DB25 on it - geez!
Anyway my point being that what you see now is the next step IMHO but needs more refinement but we've not just turned to a new page (e.g. Extensible Firmware Interface) but instead to a new chapter (tablets and multiple computers). The idea of a single large empty box of air is over. The next few pages will fix some of the issues that you refer to but I don't believe we are going back. In terms of power remember that the original PC needed things like negative voltages for moving parts, e.g. disk drives, cd-rom drives. We are now fully in the era of flash solid state hardware which doesn't need the juice that was needed previously. Flash? Isn't that some legacy video scripting text system? /sarcasm oh I admit I did recently have to stick a flash browser onto a device not supporting it... but flash is dead.
I remember I spending some money on tools for it to help a client, approaching it thinking it was programming and then quickly realising that Flash is just the modern day equivalent of FLIC files. As for keyboards I fully agree but on larger tablets I find them fine for a lot of tasks, e.g. reply to email and without the hassle of weight, opening up the laptop screen etc.

Over the coming years I recon we will see more multiple devices just talking to each other better and more things like GPU processing over traditional CPU.

> There's still tons of legacy software that has to be used (moreso by big
> companies),
Well. I've watched the changes inside those big companies as well.

> so there's little chance of everyone abandoning Windows, Linux,
> OS X, x86, etc. any time soon. Esp. with all the love going into AMD64
I agree but don't forget that both OSX and Windows have existed on RISC (ARM) cpu's for some time.

> I read about someone the other day buying 32 GB of RAM. I'm not
> aware of any phone, tablet, etc. that can use that much!
Lol. I remember this with 32k, 32MB and soon it will be 32TB. I always thought that 640k was enough for anyone personally!

> (And I don't recall this being a server machine either,
> another area where portables can't compete.)
I agree as I've just brought an external network drive to stick stuff on, it came with it's own battery and my phone/tablet talk to it absolutely fine.

> The main draw for the "IBM PC clones" was the openness, the competition,
I think your forgetting that there were lots of battles to get to that point, e.g. Compaq and others reverse engineering the IBM BIOS, AARD code, Galoob vs. Nintendo to name some examples.

> and harder to use (not to mention constantly fighting battles over patents,
> closed specs, and sometimes painfully poor driver support).
> If anything, it was already halfway "dead" due to this.
Nothing changes.

Unfortunately, most companies just
> don't play nice, but at least it's still "mostly" working. 300+ Linux
> distros can't be wrong. ;-)
Yup and IOS and Android being 2 well known examples on the mobile arena ;-)
The hardware changed the software hasn't if you see what I mean and that's my point here the IBM PC as we know it is I feel now dead. 1981-2013 (32 years!), ok it's still around a little bit longer (obviously) but it's death has started and give it a couple of years and firms will be shutting down the PC divisions.

> Why? It's cheap, powerful, and ubiquitous.
Cheap? Are you kidding me? It depends what your using them for, e.g. I have just brought a whole load of machines that for video play back kick completely over PC's and I got them for less than the price of a single PC.
It's why tablets are doing so well as for people who just want to send email, browse the web (e.g. the majority of people) they are absolutely ideal hence tablets have just stomped all over PC sales over Christmas for good reason.

> I don't see those going away any time soon (or at least not the latter).
I agree PC's will be around for a while but what I'm saying is they've started to well and truely die and this is the year that it's truely started.

RayeR

CZ,
03.02.2013, 18:43

@ Arjay

DR FlexOS? 2013 = PC death+year of Linux "tablet" desktop?

Post reply

I think there still will be a segment for powerfull workstations and gaming (consoles are here for many years but they was unable to kill gaming on PCs) where "classic" PC will do the best job. But it it will keep changing that way there will no remain any legacy PC comaptability like BIOS and x86. It will slowly transform to different architecture. Of course mobile segment will continue grow and PCs will decay so ARM will dominate also for home computing but there still will be some powerfull "PC" alternative...

---
DOS gives me freedom to unlimited HW access.

bocke

07.02.2013, 18:36

@ RayeR

DR FlexOS? 2013 = PC death+year of Linux "tablet" desktop?

Post reply

> I think there still will be a segment for powerfull workstations and gaming
> (consoles are here for many years but they was unable to kill gaming on
> PCs) where "classic" PC will do the best job. But it it will keep changing
> that way there will no remain any legacy PC comaptability like BIOS and
> x86. It will slowly transform to different architecture. Of course mobile
> segment will continue grow and PCs will decay so ARM will dominate also for
> home computing but there still will be some powerfull "PC" alternative...

Agreed. I also think PC will survive. But it will be limited to a specific niches.

bocke

07.02.2013, 18:34

@ Arjay

DR FlexOS? 2013 = PC death+year of Linux "tablet" desktop?

Post reply

I didn't look much in the neighbourhood. I was mostly looking at PC and CPM/DOS family of operating systems. :) There were also Unices for PC at the time. Xenix, Coherent and some others. There was also AT&T's own UnixPC(TM) which was based on Motorola 68000 family of CPUs.

Well, at the time I was still a kid, so you are more invited to talk about that era. But, I have some interest in ye ole' times, so I'm more informed than the other "kiddies" on the block. :)

Anyway, it was interesting for me to write a note or two about it, as it seems to have been more advanced than MS' and IBM's similar creations at the time. And DR generally seems to be one of the most underestimated companies in the industry (not counting the early success with CPM).

I couldn't access LesBell link. Did it contain anything interesting?

diasan

07.03.2013, 22:48

@ bocke

DR FlexOS?

Post reply

> Hi, I just stumbled at some information about something called FlexOS.

A few years ago (ending in1997) I worked for an equipment manufacturer which
made use of FlexOS in its products. So I have had experience in using it, and
programming for it.

> What I can make out is that it was a successor to DR Concurrent DOS.
Sort of - certainly some of the drivers and headers had references to CDOS.

> It was a multiuser
Yup. I never used the equivalent of setuid() / setgid() on in (it had both groups and users),
but the documentation seemed to imply that one needed to be 'root' userid to make either call.

We always used it as the 'root' like userid in the shipping product.

> (? - at least it had a login facility)
Which was optional, if not used the one would simply execute the start up config file as 'root'.

> /multitasking OS that was
> first "published" (there has to be a better term) somewhere around 1986
> (judging by the manuals) for 80286 based PCs.
The 286 version was the main one we used, though we also used the '386 version in development.
However, despite the 386 version having better MMU handling, we were never able to switch to it
for product as we still had 286 based shipped devices to support.

The 386 version could run COFF executables. Both the 286 and 286 versions supported forms of
shared libraries. The 386 version could run all 286 programs.

> It was basically DOS-like.
External - at the command.286 shell level it was.

Internally, it was quite different.

I've seen it described as being a bit VMS like in how most system APIs were available in asynchronous as well as synchronous forms. It sort of seemed like an interesting blend of VMS, unix, and DOS.

Programming abstractions included things like PIPEs and Shared Memory.

> It used the same commands with some additions (not unlike OS/2 or Windows NT),
> but also provided some facilities like command piping, stderr redirection
> and similar.

Yup.

> It supported multiple "windows", something a sort of like Unix virtual
> consoles, so you could run several full screen tasks along each other.

That was an optional installed program, more like the unix 'layers' scheme in that it
multiplexed the physical console across a number of virtual console.

> It came with GUI: X/GEM - a multitasking version of DR GEM;
An optional separately licensed piece (we did not have it), but the video (VGA, CGA) drivers were
scattered with bit of support for graphics modes. We always used it in text mode.

> and networking: supporting ethernet and arcnet.
Let's see - it has NetBIOS (over TCP), NetBEUI, and SMB support.
SMB came in two forms - one compatible with an early PC LAN version, and their own native
FlexNET form which was a cleaner version supporting their native filesystem APIs (together with
resource sharing: PIPE, FILE, DISK, DEVICES).

> It seems it could run CP/M and DOS
> executables from different architectures: 68xx CP/M, DOS x86, CP/M86, M/PM
> (from what I could make out, not completely sure).
Yes. It could run a subset of DOS programs, as it only provided a limited set of compatibility,
the 386 version having more support (V86 mode) but still a bit limited. We used to run
TurboC under it (as an alternate to the supplied MetaWare High C). Some DOS editors
could be run under it.

This was provided by a set of replaceable 'Front Ends'. Actually, I believe the 68xxx version
is available (as binaries) on the website where the old free'ed DR files may be found. e.g. it
is one of the pieces lumped in with the collection of old CP/M variants.

> As I see in Wikipedia, it was used mostly in industrial applications and
> was also used in some Siemens solutions.
Yup - ours was a quasi industrial use - Petrol Station Forecourt control systems,

> Does anyone know what happened with FlexOS and why did it fail (if it did)?
Novell bought DR, and supported it.
The ISI bought it, and eventually seemed to let it rot (I changed employers around that time).
The Wind River bought it (or ISI?) and killed it.

I don't know that it failed as such, it was just aimed at an embedded control market.
I know we started to look for replacements after Novell began to lose interest.

> Was it ever offered as an OS for PCs or was limited only to industrial
> applications?
Well the 286 and 386 versions ran on PCs. We used them a development and test machines
(self hosted development).

> The list of features is impressive for the time (1986).

Yeah quite nice, a 32 bit programming model despite running on 16 bit machines.
(Albeit segmented on the 80286). I've been tempted to re-implement a version of it
for private hacking. But in the last 15 years still haven't got around to it.

The native file system was also interesting. It was FAT (8.3) with extensions, supporting stuff
like pre-allocation of files, case sensitive names, slightly better globbing than on DOS, access
permissions (Read, Write, Execute, Delete) for World, Group, Owner

Actually, I think I've also seen PDF files containing scans of the various manual (including
programmers manual) online.

diasan 07.03.2013, 23:34 @ diasan	DR FlexOS? Post reply
	> Actually, I think I've also seen PDF files containing scans of the various > manual (including programmers manual) online. Found: http://bitsavers.informatik.uni-stuttgart.de/pdf/digitalResearch/flexos/

bocke

17.03.2021, 11:14
(edited by bocke, 17.03.2021, 17:37)

@ diasan

DR FlexOS?

Post reply

Heh. Sorry, I didn't see this at the time. It took me "only" a decade. But better ever than never: thank you very much for the additional information. :-)

Edit:

I just browsed through some of the docs from BitSavers.

Funnily enough, Flexos doesn't use CP/M syntax, but DOS syntax. With unixlike '/' as a directory separator.

Although there are also some differences. DEFINE is cross between SUBST and ALIAS (FREEDOS, on MS DOS you can use DOSKEY for this). ERASE instead of DEL (like in CP/M). Reserved logical names is kinda like special devices under DOS (LPT, AUX, CON, NUL), but it's not limited only to devices. Flexos shell also supports redirection and it seems to also support more thorough redirection similar to Unix. It also supports command chaining, but uses '!' instead of ';' in Unix.

It includes a visual editor (full screen editor), not CP/M ed or DOS edwin. It uses bindings similar to Wordstar. It's name is DR Edix and it supports up to 4 buffers (simultanous files)

Flexos Windows are kinda like GNU Screen, but for local processes. You get one virtual screen per process. And it seems fairly simpler.

Per docs, it needs a 286 CPU, 1,1 MiB RAM and CGA or EGA.

But Diasan's response mentions some other stuff like 386 and VGA, so the docs don't seem to cover the later versions. Also, Diasan said that a lot of stuff are optional, so it was probably pretty modular depending on specific needs.

Anyways, that was some great info. :)

I didn't find any info about X/GEM in user manual. But I've seen some other info out there in the web. X/GEM was supposed to be cross-platform. Beside Flexos, they also planned X11 (Unix) and VMS ports.

Although, it did mention VDI, which is an element of GEM. But here it seems to be used separetly. Kinda like GSX on CP/M (which it succedded).

Edit:

More info...

As Diasan mentioned it was indeed derived from Concurrent DOS 286. There is a bit more here (Retro Technology) and here (Beta Archive). Also this thread on VCEF contains a bit of info.

There is a tiny bit of GEM/X info in Atari pages. Like here (TOS.HYP) and here (GEM-DEV).

Edit:

More info on GEM/X from Dr. Dobbs Magazine archive at Archive.org:
Writing portable applications with X/GEM

More info on FLexos from Byte Magazine archive at Archive.org:
FlexOS's Muscle

Also, a version of FlexOS is used by Siemens in some of their industrial products: https://support.industry.siemens.com/cs/document/4...n-for-the-year-2000-update-?dti=0&lc=en-US.