not that amazing when you realize all this MCU does is most likely just handling 'buffered stepping' by counting pulses

I missed posts, replied on vogons, gonna repeat here - do NOT try formatting IDE (even xt ide) disks with MFM formatting tools.
all the low level tools had warnings about this back in the day.
there were briefly tools promising low level format of some specific early ID drives, like ISPFMT (cant find it anymore, dont have it on hdd to quote its readme) and SGATFMT
https://www.uselesssoftware.com/download/sgatfmt3-zip
sgatfmt4 https://www.vogons.org/viewtopic.php?p=1192929#p1192929

Michele, the platter swap is impressively methodical, but I'd suspect the LLF trouble lies with the servo/index track rather than the donor surfaces. Stepper drives like the WDI-325 still depend on a fixed index pulse and the original sector geometry written at the factory. Since you moved platters between a 325 and a 387, the track-to-head alignment and the recorded index reference won't necessarily match the new stack. Check whether the drive sees a stable INDEX signal and whether the controller expects a specific head/sector map. The controller's low-level format routine may also be gated on a valid defect table or geometry table burned into ROM.

Well, of course that's the case, anything that's left on those platters is not actually usable by the WDI-325. And as the drive was already partially demagnetizing with age, a lof is for sure just garbled mess. That's why I want the drive to blindly treat these platters like blank one fitted during the production process.

Michel, the transplanted platters raise the layout question you already flagged: servo and low-level format info differ between a 325 and 387 even if the coating looks identical, so the controller may not find valid track data and refuse to format. On stepper drives the LLF usually needs the right cylinder/head count and interleave set in the controller, plus a valid defect map. Does the PS/2 setup utility expose those parameters, or does it assume the original drive geometry? That would explain why it stops short. Keep the original platters labeled so you can backtrack.

It doesn't expose any parameter, but I don't know if it just assumes that the drive is a 20 MB 615/4/17 CHS or if it asks the integrated drive's controller for that. I think that it asks the controller, because for the PS/2-30 there are the options for 20 (WDI-325) or 30 (WD-336) megabytes hard drive. But it could well just ask the drive for its model and then select the appropriate geometry between the two variants. There is no information on how the Advanced Diagnostic utility works internally.



Of course the geometry is entirely inappropriate for the drive. But the original platters, as it can be seen in the photos, are in a totally rough and unusable state. The plastic powder chemically embedded itself to the platters' surface and it can't be removed. And rotating at high speed those rotten and contaminated platters under the heads would mean grinding them to death. I have no other option than transplanted platters here. By the way, in the meantime I demagnetized the "new" platters because I want the drive treating it like totally blank ones that still have to be initialized. Anything that was on those platters was useful anyway.

And in this regard, unless some other information about an hypotetical "factory mode", where the drive can initialize totally blank platters from scratch, would pop up, the only option I see here is to come up with a custom firmware that can be put in place of the original one to blindly low-level format the disk without any sanity check in place. In the last days, with the help of Google's AI (sorry folks, I don't know i8031 assembly so I had to rely on big brother's tools, even if I'm not actually fond of AI and the whole vibe coding thing) I, naively I admit, made the robots slopify me some assembly source code to put together a sort of "factory restore" firmware, of which I thoroughly outlined the specifications. I gave to the AI the hex dump of the original IBM's firmware to make it extract from the IBM's code all that's needed to handle all the hardware and the low-level format routine itself, which appears to be actually present into the original code, and to build over it the custom firmware. But of course, it doesn't yet work, not that I expected different results anyway. Today I spent all the afternoon at it but I got no results, mostly because of my lack of skills with 8031's assembly and in general low-level, close to the metal programming. That was the stuff "cooking in the pan" that I talked about in my last post but at this point I even couldn't had got the recipe itself right. I still have a lot of learn in this regard.

If you want I can share the code, my specifications and some other stuff that came out during the conversations with Terminator... ehmm I mean, Google's AI. Of course, for all of you that know 8031's assembly, don't expect good code here.

afaik in soft sectored early stepper drives index was generated by optical/hall sensor or motor driver
here for example chip doing it for Seagate 125 https://github.com/schlae/HardDriveInfo ... 647-502.md
and on a diagram https://github.com/schlae/HardDriveInfo ... _20629.pdf



afaik also too early for defect tables handled by disk

now index track is another matter and I agree disk fails to get ready because it most likely cant find its index track. Seagate uses special track -1 (or -2?) for this purpose, no idea how WD handled it.



Google's toasters arent the best for this. I havent seen anyones RE success stories using google crap. Claude toaster on the other hand sometimes pulls rabbits out of its ass one-shotting exotic firmwares. What Im trying to say is you are going to need a bigger boat.




I havent seen a firmware for an IDE drive so I dont know how it looks like internally and how much is handled by controller chip (chip directly connected to IDE port) and how much still goes thru micro. If its anything like old SCSI drives then micro is the brains of everything - selects heads, controls head assembly arm movement, sends commands to actual controller Asic, even controls rotation speed. Here micro is at least directly controlling head stepper.

For WD drive start with making robot produce annotated disassembly to the point it can name functions. Im you will need:

Trace which 8031 IO connect to two TEA3717 pins 7 8 9. Thats between 3 and 6 IO taken care of.
Trace which 8031 IO go to big IBM chip - this one incorporates

Capture all 8031 IOs, if you dont have 40 IO LA capable of storing couple seconds at >12mhz you will need to kludge = https://sigrok.org/wiki/Lcsoft_Mini_Board would be barely fast enough at 12MHz considering cycle times of 8031. Capture all 8031 IOs in groups of P0, P1, P2, P3. In 16 channel mode at least grabbing one of the ports + pin 9 reset (and trigger on that) / 16 wr / 17 rd / 29 psen + P0.0-P0-4 for syncing. Lets say 5 seconds from reset. AI will be able to cobble python script gluing all the captures into one correlated log.

give that to AI + as much pinout as you can gather. Dont mix two boards you have Pick just one and stick to it, AIs are stupid and easily confuse when given too much choice.

The questions that interest us most are
- How and when does it know its on track 0? waiting for some IO port or maybe reading something from controller? waiting for specific pattern decoded by ENDEC? this one is crucial and should be easy as its somewhere at the beginning of initialization. - - does it sync with Index pulses? Which IO it uses to do it? logic capture should show it as one of the pins will steadily pulse at ~50Hz.

Finally in separate session you can try https://github.com/yyzkevin/COMrade https://github.com/jdredd87/DOSBridge one of those to let Toaster control PS/2 with drive connected and ask it to determine whats the status of connected XT-IDE drive. Try it with Seagate first since its almost working. Ask it to low level format it too, knowing how AIs operate it will cobble together custom made programs to attempt this. It will find IO ports on its own, determine command structure etc.