From mboxrd@z Thu Jan 1 00:00:00 1970 From: random832@fastmail.com (Random832) Date: Sat, 12 Dec 2015 00:38:03 +0000 (UTC) Subject: [TUHS] why is sum reporting different checksum's between v6 and v7 References: <566B6467.5060703@gmail.com> Message-ID: On 2015-12-12, Will Senn wrote: > # echo "Hello, World" > hi.txt > # cat hi.txt > Hello, World > > Then on v6: > # sum hi.txt > 1106 1 > > But on v7: > # sum hi.txt > 37264 1 Interestingly, I can get both results on OSX: % echo "Hello, World" | cksum -o 1 37264 1 % echo "Hello, World" | cksum -o 2 1106 1 Or Ubuntu: % echo "Hello, World" | sum -r 37264 1 % echo "Hello, World" | sum -s 1106 1 Both of these define the one you got in v7 as a "BSD" algorithm. So it looks like v7's new algorithm didn't make it into USG Unix, rather it uses the same one as v6. (According to the OSX manpage, System V eventually grew a "-r" option to use the newer algorithm). The second number is the size in blocks, which is 512 for the "System V" algorithm and 1024 bytes for modern implementations of the "BSD" algorithm, *but* BUFSIZ (512) for v7.