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 | | From: | johnsold | | Subject: | Re: How can I add new values only to a column of a spreadsheet? | | Date: | Wed, 19 Jan 2005 10:40:17 -0600 (CST) |
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 | I think your three loops solution is probably better than putting different=
kinds of functions into one loop. Keeping data acquisition/generation sep=
arate from file i/o is usually better because the OS can interfere with tim=
ing on the file operations.
If you pass the data to the file loop vi=
a queues, place the data into shift registers, and only write to the file w=
hen you have equal amounts of data from each generator you should be able t=
o keep things synchronized. You can write larger or smaller amounts as nec=
essary to keep pace with the generators. If one of the generators gets way=
ahead of the other, you have to decide how to deal with that issue.
>Writing to the second column of a three column spreadsheet can be tricky. =
It involves keeping pointers to the portions written and not written, read=
ing the entire file into memory and overwriting the cells where new data go=
es and rewriting the entire file. This can get very slow for large files. =
If the file and data structures are simple enough it might be feasible to =
read only a portion of the file and overwrite it with new data, but that ap=
proach has lots of risks to the data.
Wait until next ms multiple is=
only reliable if the wait interval is sufficiently longer than the executi=
on time (including random OS delays) of each loop. Look at the synchroniza=
tion functions such as notifiers to synchronize your loops.
If you s=
till have problems, post a simplified version of your program and someone w=
ill probably be able to suggest solutions.
Lynn
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