...looking with a hex editor, it seems like there was still data on the drive - bigtime weirdness. And more data than just partition table, boot sector, and (mostly blank) NTFS metadata. I'll have to look a bit more into this.
Seems to confirm what the drive manufacturers say:
From Seagate (emphasis added - and note the "misnomer" comment
Does "somewhat" = "wrong"?)
What does "low level formatting" an ATA (IDE) drive mean?
Actually the term "low level" is somewhat of a misnomer. The low level process first used years ago in MFM hard drives bears little resemblance to what we now call a "low level format" for today's ATA (IDE) drives. The only safe method of initialising all the data on a Seagate device is the Zero Fill option...
Interestingly enough, Seagate discusses two different zero-fill options on their utility
Zero Fill Drive (Quick) will write over the beginning of the drive which includes the critical partition information, eliminating all partitions and information on the drive including the Master boot record. This is useful if you have a drive that has a corrupted partition, or that you wish to erase to reinstall a fresh operating system and new data.
Zero Fill Drive (Full) will write over the entire data area of the drive. This is useful if a drive has bad sectors that cannot be fixed by the operating system. This will also erase all the data on the drive, but it will take several hours.
I suspect the "full format" you ran would be similiar to Seagate's "Quick" option.
I guess the "easiest" way to get to the bottom of it would be to (1) fill the drive with something other than zeros first; (2)then format; (3)then do a "full format erase." After that you could examine it with a hex editor and see what's been left untouched. Be interesting to see if there was any difference if you repeated steps 2 and 3. If they're both the same you've nailed it.
I'll have to see if I have an old drive that wouldn't take an entire day to zero out and try it. Heck, if I have a 386-20 still floating around I'm bound to have a couple of old ST343's someplace back in The Tar Pit
. (And yes, the Northgate has now been up since yesterday. It must think it's an IBM System36 mini. Easy to do since it's almost big enough to be mistaken for one.)
I suppose you could also try to back into what the utility you're using is doing, but that kind of reverse engineering is beyond my technical abilities. Probably should have studied harder when I had the time.
In the meantime, I'd be interested in hearing what you find out.