After a copy, the Finder does minimal checking to see if any errors were
logged during the copy or verify. It doesn't do a checksum, or any
byte-for-byte comparisons of the file.
As for file comparisons, the Hard Disk Jockey disk utility from FWB lets
the user copy and verify (among other things) files on disk.
The Macintosh Programmer's Workshop (MPW), available from APDA, comes with
two utilities for comparing files:
* Compare compares the lines of two text files and writes their
differences to standard output. Options are provided to compare a
specific column range in each file, to ignore blanks, and to ignore case.
* ResEqual compares the resources in two files and writes differences in
type, identifier, size, or contents to standard output.
To locate a vendor's address and phone numbers, use vendor name as a search
string.