Re: Making the present code run faster

[Tom Droege <tdroege@veriomail.com>]

Arne and all,

At 09:20 AM 1/29/01 -0700, you wrote:
 From Michael's description in the troubleshooting notes,
it sounds like he was reading the CCDs in reasonable time,
but taking five minutes instead of one minute to _write_ the
image to disk.  So I think Tom's request to speed up the
reading loop is the wrong one to fix.  Michael, is
this right?

My request was to speed up the disk write operation, that is what is 
between the ********* lines in my example.

   Then it is not a question of CPU speed, but rather disk
speed or some interaction between the BASIC code and disk
writing.  It is often better to just upgrade the computer


I think that is is not clear where the bottleneck is.


than play with these problems.  Remember: Tom's BASIC program
is just there for testing things, not to run the Mark IV
in a production mode.

Yep, but until someone starts using new code, we will have to make do with 
what I have written.

   Regarding Andrew's tests:  using Pascal or any other
language for reading or storing is fine, as long as it
can be linked to BASIC or shelled from BASIC.  Rewriting
Tom's entire BASIC code is not the proper way to proceed,
as Tom needs to make changes and doesn't want to learn
a new language.  I'd say at most a program needs to be
written that, after the BASIC program has detected a block
done, is started and reads the memory card and writes a
primitive FITS file before returning to BASIC.  You could
get a little more complex and have the new program read
the log file to get temperature, exposure times, etc.,
but you soon run into handshaking problems that are probably
not worth solving at this point.

This is just what I requested.  There are just 27 lines of QBasic code to 
be written and compiled in some faster running language.  Actually a little 
more to do than that if arguments are passed from the QBasic.  Best is to 
then come out with .fts files and save the RawToFts translation that I have 
to do now.  This could make a big difference in the present speed of 
operation.  Andrew has reported to me disk write speeds on a 486 that are 
faster than those of my 600 MHz Athelon.

Tom Droege


Arne