Thanks for the clarification.

On my system, especially considering the EOL of XP, the main issue is just backing up a 'boot partition', that is, a hard disk partition that is bootable, that has the usual XP directory tree, and that otherwise has as little as possible. For everything other than a boot partition, I have a workable system based on WinZip and DVDs. A 3TB external hard disk with some suitable software, maybe just XCOPY, would be better.

Since I have two XP bootable partitions, I could boot one of the two and get a backup of the other, bit for bit, if I could find or write a utility such as the one you mentioned for Unix.

But, then, much of this backup interest is recovering after a hard drive failure, and if I replace a hard drive then the new one will no doubt have to be larger than the old one in which case I wonder if the bit for bit, or record for record, copy I have would boot if copied to the new drive.

That NTBACKUP will backup a live system is convenient but not essential. What is important about NTBACKUP for me is that, finally, I got it to work, all the way, from backup to restore.

I also have a copy of Acronis which likely I should unwrap, study, work with, and use.