
"...doesn't support CRC transfers, but I've not had any trouble with checksums"
				-- an lucky fool

"Death to Checksums!" -- me

For some reason, many of the binaries for Macintoshes that we receive here in
the mn area from Usenet have crc errors when we try to unpack them.  Upon
inspecting one of these files (it was a font, so easy to check visually!),
I noticed DOUBLE BIT ERRORS.  These puppies occur when somebody transfers
over a noisy line using only a checksum protocol.  In fact, if you EVER (even
rarely), see errors while transmitting, eventually you will get a double bit
error, which will not be detected by a checksum.

To encourage the use of CRC's, I am posting a FAST crc calculator.  It is
set up to calculate the CRC used by the popular XMODEM protocol.  This routine
is at least 5 times as fast as the one used by rb, a recectly distruted XMODEM 
program for unix.

