Quote:
Originally Posted by HarryT
What could you do with it that you can't do with the command prompt in Windows?
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You could run just a small handful of carefully selected programs and have all the computer resources for yourself. With the newer operating systems you have obscene numbers of things running that you can't do anything about [without lots of work].
I used to run a SCADA HMI system on a 486 on DOS with Windows 3.11 interface. The only things running were mouse driver, network card driver (very simple, because the very expensive card took care of most of communication stuff), driver for communication with special PLC communication hardware, and of course said SCADA HMI (database, communication, event manager, operator interface screens, logging system, alarm processing ...).
Several [PC] generations later on an XP you needed magnitude more memory and magnitude faster processor to run similar visualization and the screens with hundreds of updates had markedly slower response time, because everything had to run through additional layers, like OPC server, every single animation on the screen was an OLE object that had to go various hops to display value from PLC memory block ...
So, in the good old times you had much better control over what runs on your computer. You can do similar things today, it is just *much* more hassle to configure things and switch off boatloads of stuff you do not want and do not need.
I know, much of stuff you hear on the net is just nostalgia (people forget the bad stuff and only remember the good bits and even that is seen unrealistically).
When you have to go in and actually *use* a very old system (like an old, but still running SCADA HMI system on a 486 computer, where loading of 100MB of stuff from a ZIP drive connected to LPT port takes 60 minutes) you appreciate how much hardware moved forward.
You would simply kill any old PC (DOS or WfW era stuff) if you tried to use it with a large Calibre library or have a look at an SD card with 1000 20megapixel photos on it.