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Seagate 5.25" ST-277R "Frankendrive"

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chris_nh

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So, going further with explorations of the 5.25" half-height Seagate drive models, here are today's vintage hard drive shenanigans ... I attempted to convert an ST-277N (scsi) to ST-277R (rll) using a donor board from an ST-251. Will it work?

 
Spoiler for anyone who doesn't want to watch a long video - it seems to work.

I would still want to run some kind of pattern test after all of that to thoroughly test things.

It makes sense the logic boards would work. I have what I believe is a later model ST251 here that formats and tests fine using RLL (also what may be an earlier revision that is not happy with RLL at all.). So chances are, at least with later models they used the exact same logic board but marked them differently based on the quality of the hardware assembly.

Clearly a ST-277N and ST-277R would be the same hardware assembly with different logic boards.

Although, I am curious if a ST-277N would successfully low-level format after having been wiped/formatted with a ST-277R board.
 
Yes, it works, haha.

Yes, you could run your spinrites and things to pattern test this drive if you want to be re-assured ... I will probably do that in a follow-up in a few days anyway to show that the drive is reliable. This one, I am confident it will be reliable because the ST-277R is literally the same drive with the ST-251 control board ;) The SCSI version also uses RLL encoding, so this is technically an RLL spec drive anyway. Not all of the SCSI drives are like this, some use MFM encoding and aren't RLL spec.

Yes, this can converted back to SCSI. I might demonstrate this in a follow-up as well, but I only have one SCSI controller versus many MFM/RLL controllers. SCSI is too new and fancy for my tastes ;) I bang rocks together in my cave at night ;)
 
I should give ESDI a try ... I do have a few ESDI controllers but haven't played with those yet. Might be fun to try out. Maybe try a speed comparison between the different interface types on the same drive or something. Hmmm
 
So, yes the "frankendrive" turned out to be a nice one, and here's a follow-up to give a little more info and to answer a few questions, including SomeGuy's question about going back to SCSI. Made the video quicker this time.
 
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Very good to know. So, these Seagate SCSI drives do in fact fully implement the SCSI low level format command.

That also means that if someone really needed or wanted a SCSI interface they could possibly use a hardware assembly from an MFM or RLL version.
 
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