Time Machine Help, Need to go back to the future

Sorry about the title I could not resist.
I would like to know, if time machine works by ghosting a whole hard drive for backup or does it just save the registry and user files?

All the information - data, files, documents, registry… whatever - is kept into the snapshot.

So this would be a ghosted copy?
Therefore if I had a 30gig hard drive I would have a 30 gig snapshot backup?

Then what’s the difference between this and comodo backup

Comodo backup uses file backup (backup to a file).
CTM uses snapshotting technology over the free space of the disk. It’s not a backup tool but it is an advanced system restore one. Should I say “was” as it is not being developed anymore.

really? awwhh that’s a shame I guess I will stick with comodo backup then.
Good looks.