WINOS2/DOS Question

[Raven]

I've not used OS/2 except in a VM as of yet. I am aware that Warp 3 (perhaps pushing it with 20MB of RAM in the particular system in question) can run on a 486, and that it has WinOS2 and DOS compatibility features. I'm not, however, an OS/2 expert, and I don't know how these compatibility layers work.

Basically, what kind of performance can one expect from these things? Is it like bare metal execution but with a GUI, i.e., similar to running DOS/Win3x apps from Win95?

Is it emulation, or partial emulation? In this case it would only really be viable on a newer machine.

 

[Chuckster_in_Jax]

I've not used OS/2 except in a VM as of yet. I am aware that Warp 3 (perhaps pushing it with 20MB of RAM in the particular system in question) can run on a 486, and that it has WinOS2 and DOS compatibility features. I'm not, however, an OS/2 expert, and I don't know how these compatibility layers work.

I'm not sure what you mean when you say you are running OS/2 in a VM. OS/2 is the program that has complete control over the computer after boot-up just as say Linux or Windows do. When a WinOS2 session is launched, OS/2 launches Windows 3 code and manages it in a window. It does the same with DOS using DOS code. So both OS/2 and Windows code are running at the same time.
It does remarkably well running the major applications that came out at that time. However, while it was good to have the ability to run Windows and DOS code, a flaky Windows program could easily crash OS/2. DOS was handled much better as I remember. When running only native OS/2 applications you had the more stable system.

Basically, what kind of performance can one expect from these things? Is it like bare metal execution but with a GUI, i.e., similar to running DOS/Win3x apps from Win95?

It actually performed well. Having SCSI drives gave a considerable performance boost, so you may consider that if you are setting up a 486 computer

Is it emulation, or partial emulation? In this case it would only really be viable on a newer machine.

OS/2 runs fine on a 486 machine. You have to make sure you have the drivers for your system. You shouldn't have any problems running it on a PS/2.

Hope this helps some. Others may disagree on some of my explanations.

Chuck

 

[Chuck(G)]

OS/2 has a PM API very like Windows. You'd recognize the similarity immediately if you are familiar with Win16 API interface. So much of WinOS2 is translating the Windows API calls into OS/2 PM calls.

No emulation per se.

 

[krebizfan]

Most programs will run at between 90% and 150% of the speed on the baseline hardware if sufficient memory is available. The higher speeds are thanks to improved caching that a Dos machine could not match. If you have lots of excess memory, it is possible to seperate each WinOS/2 session so if any one crashes, the others will generally manage to continue running.

However, many programs won't run at all. These include all non-DPMI dos extended programs and even some DPMI extended programs; windows programs that used Win32, WinG, or vxds often won't work.

There were a number of compatablity settings that were needed to make programs work. A list that covers a couple hundred DOS games is in the games21j.zip archive at http://hobbes.nmsu.edu/h-browse.php?dir=/pub/os2/info/faq

One other slight benefit to OS/2 is the ability to boot into other real mode operating systems (like different DOS versions) which means all the really old games that required booting on a floppy could instead be in a VDM under OS/2. The VDM will magically go away instead of forcing a system reboot.

 

[Raven]

SNIP

By "in a VM" I mean on my 64-bit modern PC in a virtual machine. As for the "what kind of performance" question, I meant what kind of performance can I expect from WinOS2 and DOS under OS/2, not OS/2 itself - krebizfan answered this. When asking about emulation at the end, this was in regards to the Windows and DOS compatibility - Chuck(G) answered that well.

Thanks - I will try OS/2 on my other Presario 425 at some point.