Mailinglist Archive: opensuse (3394 mails)

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Re: [SLE] Minimum install still uses 14meg memory
  • From: Chris.Smith@xxxxxxxxxxxxxx (Chris.Smith@xxxxxxxxxxxxxx)
  • Date: Thu, 23 Mar 2000 15:48:27 +0000
  • Message-id: <002568AB.005B3CDF.00@xxxxxxxxxxxxxxxxxxxxx>



Hi,

** Thanks a bunch. This is on a really old 486, so I am going to try and
** make do with the hardware already on the machine. Would I be better
** off using another existing port, such as a mouse port, com port, or
** even keyboard port for the timings? I need just 4 possible wires,
** plus a ground to make this work.

You probably could get away with using the PP if you turn off all the
buffers and set it in bog-standard bi-directional mode. You might have to
manually tinker with the port registers, but that shouldn't be too painful
with a datasheet or two.

It would _have_ to be IRQ driven though because I assume the events would
be triggered as positive pulses and the probability of a process picking
one of these up in a loop of checking the PP status would be very low if
it's a fast process event. The kernel time overhead might screw this over
and you might miss laps :-)

Personally, I think DOS might be better for this as once the program is
running, the system is all yours. You can still use the DJGPP version of
GNU C/C++ to compile any existing code you have. See
http://www.delorie.com (I think). It works just as well once you've got
past DOS :-) DOS also doesnt have as much overhead.

I have done very similar things using embedded systems and operating
systems generally just get in the way. IRQs are the key to timing sucess!
It's still a pity that PCs don't have a 'geek-port' as standard like the
old Acorn BBC computers.

HTH

Chris.


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