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Seagate 5.25 "vaporware" drives ST206 and ST278

chris_nh

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Forking this thread from the for sale forum: http://www.vcfed.org/forum/showthread.php?78515-Seagate-5-25-quot-MFM-hard-drive-boards

Was there really a 5MB version of the ST-212 (ST-206)? A quick google search reveals nothing and I’ve never seen it mentioned anywhere before. Didn’t know about the ST-278 either!

Glad to see someone else who collects these old drives too! They need to be saved just like the computers themselves do! I think having an old PC with a real MFM drive in it adds a lot of character.

So yeah, the ST206 was apparently one of the early models they worked on and it appears to not have made it out to the market. There's a mention of it here in this article: https://books.google.com/books?id=I...st206&hl=en#v=onepage&q=seagate st206&f=false

Also a few other mentions of it if you search books.google.com ... Here it is listed available for purchase, sortof: https://books.google.com/books?id=o...st206&hl=en#v=onepage&q=seagate st206&f=false

I found the same with the ST278 ... the Seagate ST11R tech document describe this model drive, but it does not appear to have ever made it out to market.


=============================================================
| Model | Formatted | R/W | Data | Sectors | Auto- |
| | MBytes | Heads | Cylinders | per Track | Park |
=============================================================
| ST137R| 32.7 | 4 | 615 | 26 | No |
-------------------------------------------------------------
| ST138R| 32.7 | 4 | 615 | 26 | Yes |
-------------------------------------------------------------
| ST157R| 49.1 | 6 | 615 | 26 | Yes |
-------------------------------------------------------------
| ST225R| 21.2 | 2 | 667 | 31 | No |
-------------------------------------------------------------
| ST238R| 32.7 | 4 | 615 | 26 | No |
-------------------------------------------------------------
| ST250R| 42.9 | 4 | 667 | 31 | No |
-------------------------------------------------------------
| ST277R| 65.5 | 6 | 820 | 26 | Yes |
-------------------------------------------------------------
| ST278R| 65.5 | 6 | 820 | 26 | Yes |
-------------------------------------------------------------
|ST4144R| 122.7 | 9 | 1024 | 26 | Yes |
-------------------------------------------------------------

Anyway, I'd love to find an ST206 or ST278 ... I would like to imagine that a few examples do exist, if Seagate built them at all. Anyone ever come across these?
 

chris_nh

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Another relatively unknown model might be the ST252 ... this one looks like it made it out to market, but I haven't yet found a picture of it.

Also, the ST296 which came out as SCSI, but could in theory be converted to RLL using a 6 head board

Also oddballs, the ST225R and ST250R are 3000rpm versions, either needing a 16-bit controller or ST11R as the only 8-bit controller I know of that can properly run these drives.
 

chris_nh

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Oh yeah, and I was going to mention that there were two 10mb drive models, ST212 and ST213. The ST212 is half-height version of ST412 and the ST213 is the 10mb version of the ST225 lineage.
 

krebizfan

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Some of the off by one model numbers are the same drive but in a different OEM mounting bracket so it is very unlikely to find one and even if one was found, the drive itself might not have a label indicating the special nature of the order.
 

krebizfan

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Only one I can find in a quick search is http://www.mfarris.com/hard_drives/seagate_technology/seagate_st252.html which is a ST-251 with a terminator that can't be removed. Same applies to the ST-278 which is a permanently terminated ST-277.

I think there was a half height drive in a full height bracket that got a special model number but I can't find a reference for it right now. I can't get to the Seagate FTP and see all the models listed.
 

chris_nh

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Well that is certainly a good explanation of the ST252 and ST278 ... I hadn't noticed that minor detail before, so thanks for pointing it out. Good stuff!

There is still no evidence that the ST278 ever made it to market ;)

Now, I wonder what is the benefit of a permanent terminator? Less flexibility for the end user I suppose, but maybe to simplify the product perhaps. I also wondered if the ST252 and ST278 were perhaps redesigns of the control board to address the reliability issues of those models. They are noted for higher failure rates.
 

compaqportableplus

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Some interesting stuff here! This is right up my alley! :)

I’ve got an old eBay pic of an ST-252 somewhere. Would you like me to try and find it?
 

Casey

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Also oddballs, the ST225R and ST250R are 3000rpm versions, either needing a 16-bit controller or ST11R as the only 8-bit controller I know of that can properly run these drives.

Isn't the ST225R the same as an ST238? As for 8 bit adapters, what about the Adaptec 2070a? It was (so I've been told) it was designed for the 238, and it's good enough to act as a reference controller.
 

chris_nh

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The ST225R is different, but the ST-225 MFM is basically the same drive as an ST-238R ... they do have different control boards, but I've formatted an ST-225 as an ST-238 before and it works OK. There are some differences in the platters, so data reliability is an issue if you have the lower density platter type of the MFM. The ST-225R/ST-250R are 3000 RPM drives ... normally 3600 on the better known models.

I don't know a lot about the Adaptec controllers, but I do know that every controller is basically unique and could be outfitted with different drive tables. Some cards are stuck with fixed parameters and others can be dynamic. I find that Speedstor command line "sstor /romlist" will usually output the drive table from the controller to show you what drives it can handle.


I think the ST-238R is the best and most reliable in my experience ... ST-238R had nice bearings and good platters, and is the model I find with the least failures. Even if you want to use it downsized as a regular MFM ST-225 equivalent, the extra margin will give you good reliability.
 

chris_nh

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Browsing some other lists, I uncovered a few more oddball models ... anyone heard of these?

ST-290A 5.25 half-height w/ IDE interface (81mb) ... quite possibly the only drive of this lineage with IDE interface? Would love to find one of these, wow!

ST-224N 5.25 half-height SCSI
 

compaqportableplus

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ST-290A 5.25 half-height w/ IDE interface (81mb) ... quite possibly the only drive of this lineage with IDE interface? Would love to find one of these, wow!

That’s likely a totally different designed drive than the ST-251-style units (like the 296N), as it’s listed as having 1023 cylinders, which means it’s likely voice coil and not stepper actuated. I’ve certainly never seen a stepper drive 1023 cylinders.

Probably similar in design to the ST-280A.

I’m loving this thread so far though! :)
 

chris_nh

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The ST-280A is listed as a WREN drive, so it is definitely different, agreed. The ST-290A, I've discovered, was not actually produced ... according to: http://bk0010.narod.ru/DRIVESPECS/SEAGATE/4051.txt

So... yeah, no IDE interface for these drives, BUT we did discover another model of vaporware ;) The ST-290A was likely to have been a WREN as well, but no confirmation of that. I guess we need to find the product announcement to find out more.
 

Al Kossow

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rll.jpg - Click image for larger version  Name:	rll.jpg Views:	0 Size:	119.4 KB ID:	1209440
Forking this thread from the for sale forum: http://www.vcfed.org/forum/showthrea...d-drive-boards



So yeah, the ST206 was apparently one of the early models they worked on and it appears to not have made it out to the market.

I found the same with the ST278 ... the Seagate ST11R tech document describe this model drive, but it does not appear to have ever made it out to market.

| ST277R| 65.5 | 6 | 820 | 26 | Yes |
-------------------------------------------------------------
| ST278R| 65.5 | 6 | 820 | 26 | Yes |
-------------------------------------------------------------


Anyway, I'd love to find an ST206 or ST278 ... I would like to imagine that a few examples do exist, if Seagate built them at all. Anyone ever come across these?

I have a drive labeled ST278R that I just put on the bench. It has 615 cyl and 6 heads. Pretty weird, actualy 'literally weird' I bought it at Weird Stuff in 2014 marked as not working.
I'll document it and put pictures up on bitsavers. Makes me think the 820 cyl stepper positioner drives never made it out.

Well, looking at the defect list, it goes up to cyl 729. Now I'm wondering if someone stuck a different head positioner microcontroller on the board at some point.

--

It looks like the cylinder problem may be the rev of firmware in my ST21R. I just was able to format the drive out to 820 cyls with a DTC controller. I have a later rev of firmware on another card, I'll have to try formatting it with that version.
 
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compaqportableplus

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That’s insane! I guess they actually exist.

Definitely don’t junk that drive, even if it doesn’t work!
 

Al Kossow

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That’s insane! I guess they actually exist.

Definitely don’t junk that drive, even if it doesn’t work!

It works. I also found an ST277R in my pile of drives but that one seems to have a head positioner problem.
Need to take pictures of them. I also wonder how the 277R differs from the 251, which was a common drive that is also 820cyl 6hd
A project for today is trying to format and test the 251 with RLL controllers.

I don't understand what is going on with the ST21M or R boards that I have. None of them work past 615 cyl and I've tested the drives
with a bunch of other controllers now that all work to 820 on the 278R and 251
 
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