The presumption in this is that tracks are like magnetic grooves (as on old LPs), in a longitudal fashion. This was true with MFM drives.
This is no longer the case. Back in 2005 we already had 133 Gbit/in2 with perpandicular recording. Now we have perpendicular double-layer media, and some even talk about recording longitudal and perpendicular and double layer… That is 4 layers in a single track…
Because of the nature of the writing all heads use side shielding, and read through Hilbert filters.
An other way - It is like staring at a handful of dry spaghetti at the tip, and trying to guess the length of each strand of dry noodle. The only thing you are going to see is their end, not their length.
There is no 0.5 track.
If you've ever turned up the volume on a tape player and were still able to listen to music you'd already erased, you experienced the information sitting between tracks. And that was with the play head still in the middle of the track. Yes - HDDs heads are much more discrete - but …
Anyone who used a "cats eye" and tools to set up tracking on an IBM full sized disk drive will have a clear physical picture of the idea of setting track 0 to be 0.5 - either physically, or in firmware.
If I were, let's say, someone wanting to get data off an erased drive, I'd set the firmware to make track 0 = 0.5 and start reading.
I've discussed this approach with folks from several "3 letter" agencies, and had neither a confirmation, nor a denial of the validity of the approach - only a couple of smiles.
There's a reason why the procedure in some of the labs near me is to physically take out the platters, scape them, then shred the whole thing, then bury it on site.
I'm more of the multiple pass persuasion - at least. My own drives? Gutman wipe, then the "Thor" process …
Oh, sure. Take the easy way!
Unless you do it for the government. mrgreen
Yes, which is why I specified venting . . .
No, no. If you're so foolish as to not vent the gases, it's a safety concern.
If you vent the gases, it's now an environmental concern. Some government agencies might take issue with you venting the gases to the outside.