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Comment by orionblastar | Hacker News Reader

OS/2 2.X was superior to Windows 3.0 but lacked the apps and marketing to compete with it. IBM Client Access/400 for DOS ate into the 640K layer and OS/2 used Extended RAM to keep more of the 640K for WIN-OS2 and DOS programs. Once Microsoft released Visual BASIC for 16-bit Windows, IBM had nothing for OS/2 mode like Visual BASIC. Borland had Delphi and Turbo C++ for Windows 3.0 but not for OS/2.

OS/2 started as Advanced DOS at Microsoft and IBM, by the way. An open-source project called OSFree (OS/3) wants to write OS/2 from scratch: https://osfree.org/

At my employer, I had to downgrade OS/2 2.X systems to MS-DOS 6.2 and Windows for Workgroups 3.11 before OS/2 Warp 3.0 and Windows 95 came out. Microsoft also had affordable license fees for DOS, Windows, and Office. We had to have everyone on the same OS for compatibility reasons and OS/2 lost out.

You can still buy the OEM version of OS/2 here: https://www.arcanoae.com/arcaos/

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> IBM Client Access/400 for DOS ate into the 640K layer and OS/2 used Extended RAM to keep more of the 640K for WIN-OS2 and DOS programs.

Nah.

OS/2 1.x was a native 80286 OS and it used one big block of 16-bit RAM. It did not have the concept of "Extended memory" (XMS) -- that was a DOS and Windows 3.x thing.

I was working with this stuff at the time, too. :-)

Extended Memory is just the name for memory above 1MB that could be accessed by the 80286 in protected mode. The 286 was still a 16bit processor, still had segments (although descriptors in protected mode) and "one big block of 16-bit RAM" is 64KB.

The single DOS session available on OS/2 1.0 still ran in real mode.

AFAIK the split into conventional/base and extended memory is largely a DOS concept.

It's of course based on the 8086 real mode being fundamentally limited to 1M and the 286 protected mode not being limited to that.

But if you divorce yourself from the DOS memory model, I don't think there's a fundamental need in protected mode to treat 0 to 640k (or <1M) differently from >1M, or for protected mode to have a concept of extended memory.

"One big block of 16-bit RAM" probably means the entire RAM (accessible in protected mode) addressed in 16-bit segments. If you wrote an OS that uses 286 protected mode and don't care about the DOS memory model, that's what you'd have, and there would be no need for distinguishing between "base" and "extended" memory once you've entered protected mode.

I'm not really that familiar with OS/2 so I don't know how exactly it handled the switch to real mode for the DOS session or what it did about keeping the rest of the memory separate from the <640k of the DOS session.

But in general the base vs. extended memory split is a DOS memory model thing.

Many PC BIOS implementations also reported base and extended memory separately in POST output for a long time but I think even that's just following conventions based on the DOS memory model.

The original comment was about running DOS programs under OS/2 1.0. The comment I replied to seemed to be under the impression that OS/2 didn't care about the DOS memory model, but of course it did, because it ran DOS programs in real mode.

But really calling memory above 1MB Extended Memory was just to differentiate it from Expanded Memory which was memory that was banked into the address space above 640k.

> The original comment was about running DOS programs under OS/2 1.0.

No, it didn't: it specified OS/2 2.0, but I missed that just as you did.

« OS/2 2.X was superior to Windows 3.0 »

« I had to downgrade OS/2 2.X systems »

> "one big block of 16-bit RAM" is 64KB.

Without large model or something, one segment was a block of 64kB and me, I'd call that an 8-bit block of RAM.

OS/2 1.x allocated all the computer's RAM as its RAM, with no conventional/extended split -- unless or until you ran a DOS box. The handful of times I used it, it was a fileserver with 3+Open and those never ran DOS boxes.

Slight correction - there were some Borland tools for OS/2, but after the split MS stopped putting out new tools; but IBM did have some interesting compiler stuff too.

https://en.wikipedia.org/wiki/VisualAge

> In 1992, Apple and IBM cofounded Taligent, based upon Pink, an operating system with a mass of sophisticated object-oriented compiler and application framework technology from Apple. Pink became CommonPoint, the partnership was dissolved, and CommonPoint was absorbed into VisualAge starting with the Compound Document Framework to handle OLE objects in VisualAge C++ 3.5 for Windows. In February 1997, the first mass release of Taligent technology came in the form of the Open Class within VisualAge C++ 4.0 ... The original prototype which led to VisualAge was an attempt "to make something like the NeXT interface builder" within the Smalltalk/V development environment.

What eventually made it out of VisualAge into the wider FOSS world was Eclipse.

https://wiki.eclipse.org/FAQ_Where_did_Eclipse_come_from%3F

Eclipse is the FOSS version of the C/Java rewrite of Visual Age SmallTalk -- which is still on sale as VAST.

https://www.instantiations.com/company/history/

Fun 40-year incarnation history page!

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