Xref: news2.mv.net comp.os.msdos.djgpp:2197
From: gfedor AT lerc DOT nasa DOT gov (Gregory Fedor)
Newsgroups: comp.os.msdos.djgpp
Subject: Learning to use DPMI?
Date: 27 Mar 1996 14:06:12 GMT
Organization: ADF Inc. / NASA Lewis Research Center
Lines: 39
Message-ID: <4jbi0k$6hj@sulawesi.lerc.nasa.gov>
NNTP-Posting-Host: gfedor.lerc.nasa.gov
To: djgpp AT delorie DOT com
DJ-Gateway: from newsgroup comp.os.msdos.djgpp

I am a novice to the world of DPMI.  The only exposure I've had is 
using (not necessarily understanding) Pharlap's DOS extender with 
Borland C++.  I inherited that application and have been struggling 
with it ever since.  I would like to learn how to use (and 
understand:) DPMI with DJGPP.  I'm also on the beginning of the DJGPP 
learning curve.

The application I'm working on has a timer interrupt occuring every 
millisecond.  It occurs in real mode, however when it triggers I need 
to collect data from many A/D channels.  This can quickly consume a 
large amount of memory, hence the need for protected mode operation to 
store the data somewhere.  The current app appears to simply increment 
a counter at the interrupt.  The main body of the app sits in a loop 
until that counter reaches a value defining the data collection 
iterval.  It then goes collects the data and stuffs it into memory.  
Later after the time period is over for data collection, the data is 
read from memory, processed, and written to disk.

Ideally I'd like to simply declare a large array to hold the data:

unsigned int hires[30000][120]; // 30000 readings, 60 chnls @ 2 bytes 
unsigned int lowres[300][80];   // 300 readings, 40 chnls @ 2 bytes

Two questions:

   1) What is the best way and/or place to learn this?  Are there
      any materials on the net I can look at to learn more?

   2) Does anyone have any suggestions on how to best handle the
      application I described?

I freely admit I'm totally green on this subject.  Thanks in advance.
Gregory

-------------------------------------------------------------------------------
Gregory A. Fedor                          ADF Inc. / NASA Lewis Research Center
Computer Engineer                               Microgravity Experiments
    work: gfedor AT lerc DOT nasa DOT gov  http://sven.lerc.nasa.gov/~gfedor (216)977-1247
personal: gfedor AT en DOT com         http://www.en.com/users/gfedor