[comp.sys.ibm.pc] Help! Writing TSR program

beatyr@pur-ee.UUCP (06/08/87)

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O.K. Here goes...
  I am writing a TSR program (or at least trying to), in Turbo Pascal.
Basically it is a LAN over the serial port. I have no trouble getting
the serial ISRs running and doing what I want, but I cannot find the
location of the CGA TEXT screen memory. I know the graphics, but I want
to save the text so when I pop-up I can restore it after I leave.
  On that same note, I need to know how to make a Turbo program TSR.
I am familiar with ISRs and the fact that I need to intercept the keyboard
interrupt vector to check for the hot key, but where can I find out
exactly what I need to do?
  On a last note, I need to output to LPT1: INSIDE in ISR. Is this possible
due to the non-reentrant nature of DOS, or is this possible?
  In closing then, I need help with:
  1) How do I make a Turbo Pascal program or routine TSR?
  2) How do I intercept the keycodes so that I can pop-up my TSR?
  3) Where is the CGA text screen memory located, so I can save it?
  4) Can I output to LPT1: inside an ISR?

  Thanks for all the help/pointers/examples/code sections that all of you
can give me on this project.

				Bob B.
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