Improve file copy (fcopy()) performance by more than an order of magnitude.
Using a 256KB read buffer for copying files (rather than one byte at a time). Apparently calling fread() is not the same as a bunch of calls to fgetc() after all. Or maybe it was the many calls to fputc() being replaced with fwrite(). Or maybe it was both. Anyway, decreased the time to copy a 1GB file from and to a Samba share over a Gb Ethernet network from 13 minutes to less than a minute. This matters when sbbs is backing up your data/mail base and the files are big. The mail base is locked while being backed up and the longer it takes to back up, the longer the mail base is locked and no mail can be received, read or sent during that time.