12 Dec
2015
12 Dec
'15
1:38 a.m.
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.