How you do stop a large file becoming un managable

Question

This simple program will create a file filled with sequencial 8 digit hex codes seperated by commas, ie.. (AA0AAAAA, AA0AAAAB, AA0AAAAC etc...)
The problem I have is when running this program, the more values are added to the file, the slower the program runs... I hope to itterate this approximatley 100'000 times.
The first 500 values are placed in the file quickly, but each subsiquent value takes longer and longer. I assume this is because the file is taking longer and longer to access... Does anone know what route would be the best was around this crippling perfomance issue?
Many thanks, Alec
Attachments:
keygen.jpg ‏68 KB

Answer 1

Hi Alec,
in addition to smercurios tips I would:
- collect data to a reasonable string size of (let's say) 4kb instead of writing 9 bytes in each loop iteration
- use "format into string" with format string of "%08x," and one "write to file" instead of your formatting function and two writes to the file
- get rid of that sequence structure, it's not needed here!
If the computer is a modern one you can also create the string in RAM and just write once to disc (100.000 times 9 bytes gives a file of ~900kb size - quite easy to handle nowadays).
Message Edited by GerdW on 01-10-2008 04:16 PM
Best regards,
GerdW
CLAD, using 2009SP1 + LV2011SP1 + LV2014SP1 on WinXP+Win7+cRIO
Kudos are welcome