There is a wonderful article in ArsTechnica that summarizes the story of OS/2, the competitor to Windows at it's infancy. I'll have something to say about the article later.
The article made me pull out a draft I had kicking around on old-school tech. I had written on old-school tech like PCGEOS and TFS before but this article reminded me of on another legacy technology that is no longer around: memory managers and the unintended competitor one memory manager spawned.
When PCs still ran DOS (or command line to you younger guys), it had a big weakness: DOS programs can't use more than 640kb of memory. As programs got bigger, there was a need to use memory above that limit. Then programs got weird, they wanted to stay running in memory while you ran another program. These were called TSR (terminate and stay resident). There were programs that displayed alarms or provided a function that could be called on at any time. These programs caused more memory to be used.
The memory manager was born. They allowed more memory to be used by swapping blocks of memory from under the 640kb limit with blocks of memory above the limit, fooling DOS into thinking it's still using 640kb of memory. The gory details of DOS memory management can be found here. The best memory manager was QEMM. It allowed more programs to run at once simply be making more memory available. But it soon took that to another level with a companion product called DESQView.
Before DESQView, a program had to be programmed to be able to become a TSR. But with DESQView, any program can become a TSR. This allowed for the ability to switch to another application and then switch back, without stopping the first application. There were other programs that could provide that function. But DESQView also allowed DOS applications to run within something called "windows". This meant that applications that were programmed to run full-screen could now run in a smaller virtual screen or better known as a window. Some graphical applications could run inside a window, too. The picture shows 2 full-screen applications, WordStar and Lotus123, running at the same time. The top blue window shows other programs that are ready to run.
Quarterdeck, the company behind both programs, upped the ante with DESQView/X. This was a program simply too far ahead of it's time. It integrated an X Windows server with
DESQView. Not many people could fully wrap their heads around what that meant. It was mainly marketed as a GUI interface for DOS and a Windows alternative. It also provided a tiled interface to launch DOS applications. With some applications that used smaller fonts, it allowed them to run on-screen at the same time with programs using normal-sized fonts. It even allowed graphical applications, like AutoCAD, to run in a window alongside normal text-based DOS programs. Some pictures in magazines even showed MSWindows running within DESQView/X. Although it wasn't virtualization, that feature did seem like it was, mainly because MSWindows was essentially a graphical DOS program.
What blew people's mind was that because it was an X Windows server running on DOS, a PC running DESQView/X could serve DOS programs to X Windows workstations (XWindows terminals still needed a start-up system for booting, IP management etc). If you are not familiar with X, the concept allows for Unix workstations to run DOS programs because they were running on the PC's CPU. Unfortunately, it didn't blew that many people's minds. The fact that the configuration meant bypassing some licensing restrictions also meant that if it was ever popular, it would have been shut down anyway.
If you are interested in old technology and want to experience how it was done in the old days, there are now sites that give guides and clues as to how to rock it old school. Apparently, you can get QEMM and DESQView from here. Quarterdesk was bought by Symantec but I'm not sure what they did with the technology they bought. My guess is that they bought it for patents.
Some additional thoughts. The ArsTechnica is a good read. In fact, there are business lessons to learn from it, some of which are still applicable today. I don't won't spoil it other than to add that the next time you see a BSOD (blue-screen of death) at an ATM, curse the idiot who thought that Windows is stable operating system. There is no justification to put Windows as an ATM operating system. Just because you know or am familiar with Windows, it is not the only operating system in the world. The reason because "it's what everybody uses" is just masking your laziness to think. Windows is not stable because of it's working design. I've tried Windows since version 3 and worked on NT when it came out (NT was the exception when it came to stability, so much so that Microsoft had a hard time getting banks to upgrade away from them). Even Windows for devices, Windows Embedded screwed royally. To these people, I hope your washing machine runs on Windows one of these days.
Sorry about that rant.
The article made me pull out a draft I had kicking around on old-school tech. I had written on old-school tech like PCGEOS and TFS before but this article reminded me of on another legacy technology that is no longer around: memory managers and the unintended competitor one memory manager spawned.
When PCs still ran DOS (or command line to you younger guys), it had a big weakness: DOS programs can't use more than 640kb of memory. As programs got bigger, there was a need to use memory above that limit. Then programs got weird, they wanted to stay running in memory while you ran another program. These were called TSR (terminate and stay resident). There were programs that displayed alarms or provided a function that could be called on at any time. These programs caused more memory to be used.
The memory manager was born. They allowed more memory to be used by swapping blocks of memory from under the 640kb limit with blocks of memory above the limit, fooling DOS into thinking it's still using 640kb of memory. The gory details of DOS memory management can be found here. The best memory manager was QEMM. It allowed more programs to run at once simply be making more memory available. But it soon took that to another level with a companion product called DESQView.
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| DESQView running DOS programs in windows |
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| If it run xeyes, it's XWindows. |
DESQView. Not many people could fully wrap their heads around what that meant. It was mainly marketed as a GUI interface for DOS and a Windows alternative. It also provided a tiled interface to launch DOS applications. With some applications that used smaller fonts, it allowed them to run on-screen at the same time with programs using normal-sized fonts. It even allowed graphical applications, like AutoCAD, to run in a window alongside normal text-based DOS programs. Some pictures in magazines even showed MSWindows running within DESQView/X. Although it wasn't virtualization, that feature did seem like it was, mainly because MSWindows was essentially a graphical DOS program.
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| That's right, Tiled GUI and Windows-within-a-window circa early 1990s |
If you are interested in old technology and want to experience how it was done in the old days, there are now sites that give guides and clues as to how to rock it old school. Apparently, you can get QEMM and DESQView from here. Quarterdesk was bought by Symantec but I'm not sure what they did with the technology they bought. My guess is that they bought it for patents.
 |
| DESQView also allowed cut and paste between DOS applications |
Sorry about that rant.
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