[TUHS] why is sum reporting different checksum's between v6 and v7

All, While working on the latest episode of my saga about moving files between v6 and v7, I noticed that the sum utility from v6 reports a different checksum than it does using the sum utility from v7 for the same file. To confirm, I did the following on both systems: # 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 There is no man page for the utility on v6, and it's assembler. On v7, there's a manpage and it's C: man sum ... Sum calculates and prints a 16-bit checksum for the named file, and also prints the number of blocks in the file. ... A few questions: 1. I'll eventually be able to read assembly and learn what the v6 utility is doing the hard way, but does anyone know what's going on here? 2. Why is sum reporting different checksum's between v6 and v7? 3. Do you know of an alternative to check that the bytes were transferred exactly? I used od and then compared the text representation of the bytes on the host using diff (other than differences in output between v6 and v7 related to duplicate lines, it worked ok but is clunky). Thanks, Will