>From time to time I do something similar - writing to log files with FILETOSTR() / STRTOFILE(), writing separate log entries in rapid succession. I have never seen any of those operations fail, and I've never had to check the return value of STRTOFILE(). The log files have ranged in size up to about 150KB.

I've found that size doesn't matter if you append to the file. This is from my logger class:

STRTOFILE(c+0h0d0a, THIS.cFile, 1)

The third parameter is the kicker.