CRC Check Option

[CG]

When I really want to make sure that files are identical, I use the CRC check after the file copy process is done. While that will ensure that they are identical, it takes forever to complete when copying a large volume of data. I've seen suggestions about doing multithreaded checks which would help, but here's an idea for a CRC check that would make it extremely likely that the files were identical.

In ViceVersa there is an option to do a CRC comparison and allow it to look at X number of bytes. The idea being that you are checking a much smaller amount of data in most cases. While this is a good idea, in some cases the files will be identical at the beginning but changes or additions are at the end. A database file that has a new table might be a good example. Nothing changed except for a new table at the end of the file.

Here's my idea - give an option to perform the CRC check with x number of bytes from the beginning AND end of the file. So if I say 10,000 bytes, I'd really be getting a CRC on the first 10,000 AND last 10,000 together - 20,000 bytes total comparison between the target and source. You're much more likely to catch a problem than only looking at the beginning of a file.

Unless I had critical data that I absolutely needed to guarantee it be identical, I'd use this type of check much more often than a full CRC because you'd get great performance and a much higher likelihood of the two files being identical without a full CRC check.

This option could be used both for comparing Source to Target files - but also verifying that the copy process completed successfully.