Screen update speed of 8088 PC

[Chuck Guzis]

On 3/15/2006 at 8:43 PM Jim Leonard wrote:

>Poll?  How did you do this, and why was it necessary?  I've written 
>screen capture programs before and I just dump straight to a file...

If you're working off a keypressed interrupt, you could never be sure that
DOS was in a reentrant state.  So you save the capture information, check
the "INDOS" flag.  If it's clear, go ahead and write.  Otherwise, hook the
timer interrupt and try again in 55 msec.

>> They were panicy about the CGA snow!  They were worried about whether it
>> was damaging the monitor, etc.
>> So, I told them that it was just the "flash" from taking the picture,
and
>> that it was a "FEATURE", to show whether the image had been successfully
>
>Oh my :-)

One problem I had with my screen capture programs was seeing if they were
actually doing anything. The snow would have been helpful, but you don't
get that on MDA :).  So I just disabled the video during the capture,
resulting in a nice visible "blink".  That would have also taken care of
the CGA snow issue.

Cheers,
Chuck