[HN Gopher] DOS/4GW and Protected Mode (2021)
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       DOS/4GW and Protected Mode (2021)
        
       Author : atan2
       Score  : 19 points
       Date   : 2022-11-20 21:19 UTC (1 hours ago)
        
 (HTM) web link (pikuma.com)
 (TXT) w3m dump (pikuma.com)
        
       | dusted wrote:
       | So cool to finally read about this.. I remember wondering about
       | this when I was a kid, starting games..
        
         | hericium wrote:
         | And nowhere to search for info on it!
        
       | lizknope wrote:
       | I first learned C in 1991 on a VAX running VMS and also on an IBM
       | AIX machine. If I went outside the array bounds I might get a
       | crash or segfault and could use a debugger to load the crash dump
       | and see where it died.
       | 
       | When I tried using my roommate's DOS PC and C compiler I crashed
       | the entire machine so many times. There was no memory protection
       | of any kind. Write something outside the array bounds and you
       | could overwrite critical DOS data structures and lock up the
       | whole machine. Hard reboot so many times.
       | 
       | Then my roommate tried to explain near and far pointers. I never
       | understood it until I looked it up a few years ago. It was all
       | related to the 16-bit vs 32-bit segmented vs flat memory models.
       | Everything just seemed so much easier and faster on the VMS and
       | Unix systems. But the also cost 10 to 100 times as much.
       | 
       | I also thought it was really pathetic that I could only run one
       | program at a time. On the VAX and Unix systems 10 to 200 people
       | could be logged on at the same time all doing there own thing and
       | it was very difficult to accidentally bring down the whole
       | machine.
       | 
       | It all made me NOT want my own PC because DOS/Win 3.1 was so
       | limited. It wasn't until Linux in 1993 that I wanted my own PC.
        
       | JayGuerette wrote:
       | "... a terminate-and-stay-resident program (or TSR) was a
       | computer program running under DOS that uses a system call to
       | return control to DOS as though it has finished, but remains in
       | computer memory so it can be reactivated later. Needless to say,
       | this was extremely unreliable."
       | 
       | There were very likely some hacky TSRs that caused problems, but
       | in my experience most were extremely reliable. We used an off-
       | the-shelf TSR to enhance a motion control system that laser
       | scribed ceramic vacuum checks for silicon wafer fabrication.
       | Those things cost $5k in 1990, and took ~20h of processing,
       | increasing their value to $15k; we wouldn't screw around with
       | something that was inherently "extremely unreliable".
        
       | jmclnx wrote:
       | Very interesting article. My objects were always written for real
       | mode on DOS, by the time I would have wanted to use these
       | extenders, Coherent and then Linux came out.
        
       | forgotmypw17 wrote:
       | https://archive.ph/SpUm4
        
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       (page generated 2022-11-20 23:00 UTC)