Oops, *sorry Gilbert*, I looked at this thread again, and it was *your* position on checksums that I'm supporting. Maybe I have some bad/failing Chinese capacitors in my head. :)
Hartmut W Sager - Tel +1-204-339-8331
On Fri, 31 Jul 2020 at 08:44, Hartmut W Sager hwsager@marityme.net wrote:
TCP checksums aren't perfect, and with very large transfers, there is a statistically significant probability of errors getting through,
I think they are 32-bit checksums in TCP? Yes, between the
lower layer checksums and TCP my gut says errors should be rare. Maybe the math will spell differently though on really junky connections... However short of wireless, no one should really have that junky a connection anymore.
If those "32-bit checksums" are truly just checksums, i.e., sums mod 2^32, then my math knowledge definitely agrees with Trevor. A simple bit-flip of two bits in the same bit position throughout the entire file would cancel each other and go undetected. And for a large file, that probability is very significant. As for the unlikelihood of "really junky connections" nowadays, well, that's what checksums, CRCs, etc., are for, as a "just in case" the unlikely event does occur, in addition to the occurrence of the more likely events.
Hartmut W Sager - Tel +1-204-339-8331
On Fri, 31 Jul 2020 at 04:11, Trevor Cordes trevor@tecnopolis.ca wrote:
On 2020-07-30 Gilbert E. Detillieux wrote: