Hi Frank

 > A CRC applies a polynomial which is calculated to minimise the
 > probability of a change to the file ending up with the same CRC.

I got the file that Bob recommended, and learnt all about polynominals.
Remembering it al is another matter though :-)


 > NP> I just use a checksum of the ascii value of each byte of the file.

 > Not as effective as a CRC. A simple change like say 2 bytes being
 > swapped will result in the same checksum for example. There was some
 > commercial software I used once which must have used that or a similar
 > approach for the user's registration details. rFakn was as valid a user
 > as Frank. :-)

I can see that now you have pointed it out.
I have got a pice of software that must be done even worse, as upper or
lower case on any letter is still acceptable.


 > I've just coded the 32-bit CRC which PKZIP & ARJ use in (very) fast asm.
 > It takes 6 minutes to calc the CRC of 5400 files, 220meg, on one of my
 > hard disks. Also did the 16-bit CRC which all the other archivers use,
 > and the 16-bit XModem one but didn't bother timing those.

Is the 32 bit code available in an EXE file ??????

Cheers
Niels Petersen

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