If you haven't figured it out yet, I'm not particularly good at analog circuitry... But that doesn't prevent me from being interested in its potential uses!

An ongoing "thing" has been: what can be done with hard-disks...? And, another ongoing-thing has been: how can I actually *see* the data on a hard-disk...?

Something like that, anyways.

I've checked for datasheets on nearly every read-head-amplifier chip I've found from nearly every hard disk I've taken apart for as long as I can remember, with no luck... until recently.

So here we've got a chip marked:

VTC 100

VM355830FVSL

9714 AN

I can't recall *exactly* what I searched for, this time, that resulted in a match... But it was probably "VM355830"

There's a pretty thorough data-sheet on this guy's family, woot!

No idea *what* I'll do with it, but it's nice to know I finally have something that'll convert those *tiny* magnetic signals into something I can see with my 'scope...

One interesting discovery: This chip has a "Servo Mode" which writes the same data to every read/write head... I *think* this is for positioning the voice-coil... and, if so, then that suggests there's a certain data-pattern written to each "platter" in order to detect the position of the read/write head...

I haven't quite pieced it together... This particular voice-coil is attached to three r/w heads. (Why wouldn't they put a fourth on the other side of that second platter...?).

Then, does that mean that one platter contains a "servo" pattern, and the other platters are used for data *in that same track*, or does it mean that all platters are written with a servo-pattern, and the data is written *slightly off* from it... (kinda like a CD, maybe?). Or does it mean the "servo" pattern is written to all platters, then data is written *over* it in some sort of pattern that assures it's always toggling even if the data itself is all zeros...?

The second case is a bit elusive... If the data is written in a track *slightly* off from the servo-pattern, how does the servo keep on that non-servo-marked track? It looks to me like the r/w heads are all two wires apiece, so it's not like there's one sensor slightly off that's used for servoing and another that's used for R/W...

I dunno. Anyways, it's an interesting thing nonetheless.