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WTB: MFM controller for 5150
- Thread starter JNZ
- Start date
Stone
10k Member
I've got a Western Digital WD1002-27X RLL 8-bit card and a Seagate ST-238R drive that's paired with it for sale.
I only intend to see if the MFM drive I have now will work, so I just need a controller. I'll use a CF card for a more reliable hard drive, but this one might have interesting things on it, and I'd like it to be usable if possible.
modem7
10k Member
It will be an XT-class MFM controller going into your 5150.
In case you are unaware, be aware of the information at [here]. Additional info at [here].
Variations of that result in hit-and-miss.
If you want to use all of the capacity of your hard drive, you will need an XT-class MFM controller that supports the cylinder/head geometry of your drive. For potential controller suppliers, what is the make and model of your drive?
In case you are unaware, be aware of the information at [here]. Additional info at [here].
The only way to guarantee (repeat: guarantee) that you can do 'plug and play' with previously used 'MFM' drives (i.e. connect controller and drive, then watch drive boot, then list existing drive contents) is to use the same make and model of controller that was used before (what is now missing). In some cases, even the same revision of the controller's BIOS ROM may be required.
Variations of that result in hit-and-miss.
After the hardware set up, you would low-level format the drive, followed by partitioning, followed by a high-level format.
If you want to use all of the capacity of your hard drive, you will need an XT-class MFM controller that supports the cylinder/head geometry of your drive. For potential controller suppliers, what is the make and model of your drive?
Stone
10k Member
The only way you'd be able to access the data on that drive is if you ran it with the same controller it was initially used in conjunction with.
MFM LLFs were different among various controller brands and generally not interchangeable. So, unless you have or get the same controller you'll not be able to see anything on the drive. IOW, if you connect it to a controller which is not the one it was initially used with it will appear to be... unformatted.
Thanks for the information. I'm surprised by the level of incompatibility between controllers. What was it about their design that made them like that? Something about the precise placement of the head or the encoding?
The HDD is a WD25 IBM HDD, with apparently no information on the drive about its geometry. I believe this is the original type of drive that comes with the computer, and might be considered "type 13" for the BIOS.
According to the sticker on the back of the computer, it has a 200W PSU
The HDD is a WD25 IBM HDD, with apparently no information on the drive about its geometry. I believe this is the original type of drive that comes with the computer, and might be considered "type 13" for the BIOS.
According to the sticker on the back of the computer, it has a 200W PSU
Chuck(G)
25k Member
There was a bit of jealous IP concerning ECC on the early ST506 controllers. I suspect that that's most of the cause.
Since 5150 didn’t come with hard drives, it would be hard to say what card was used when the drive was added, but since it’s an IBM drive there is a good chance it was an ibm card too, I’d guess. Or is there a chance this is actually a 5160?
Where are you located? Maybe someone local could help. I’ve got the later style card mentioned here: http://minuszerodegrees.net/ibm_xebec/ibm_xebec.htm
Where are you located? Maybe someone local could help. I’ve got the later style card mentioned here: http://minuszerodegrees.net/ibm_xebec/ibm_xebec.htm
I'm in Utah, but I'm not aware of that many retro computing enthusiasts here.
The machine is a bit unusual in that it's a 5150 but it has a Microsoft Mach 10 "supercharger" card, which gives it an 8086, making it equivalent to an XT, I believe.
It sounds like a reasonable bet to say it used a HDD and controller out of a 5160, but I suppose there's no way to know for sure now. I suspect it had a floppy drive too, but that bay is missing, as are any FDD controllers.
Maybe the Mach 10 had some compatibility information that'd give me a clue? It's hard to find information on it. (Other than this review: https://books.google.com/books?id=o...ECAkQAQ#v=onepage&q=microsoft mach 10&f=false)
Stone
10k Member
I think there is a Utah vintage group on Facebook.
There is always a chance the drive is no good also. Did it get parked before the controller was removed? I have a 5170 that had a bad RAM chip in bank 1 when I bought it. It got shipped all over the country and I’m pretty sure that’s why the ST-225 is very questionable now, since it wouldn’t post it couldn’t be parked before moving it.
There is always a chance the drive is no good also. Did it get parked before the controller was removed? I have a 5170 that had a bad RAM chip in bank 1 when I bought it. It got shipped all over the country and I’m pretty sure that’s why the ST-225 is very questionable now, since it wouldn’t post it couldn’t be parked before moving it.
modem7
10k Member
There is another way to recover contents of drives without the original controller. http://www.pdp8online.com/mfm/. Probably overkill for just reading one drive.
The head positioning is handled by the drive so that doesn't effect the controller. Its mostly changes to the sector header format and CRC/ECC codes.
From what I have seen for formats most of it looks to be the standard we want to do our own thing. Some was driven by desire to add additional capability such as jumperless configuration, handling of bad sectors by the controller, and ECC codes to allow recovery from some read errors. Adaptec went their own way with LBA addressing. Others by not planning ahead. Format in the ST-506 manual only allocated one byte for cylinder which wasn't enough for their next drive the ST-412. The non PC controllers are much worse than PC controllers for weird formats.
The head positioning is handled by the drive so that doesn't effect the controller. Its mostly changes to the sector header format and CRC/ECC codes.
From what I have seen for formats most of it looks to be the standard we want to do our own thing. Some was driven by desire to add additional capability such as jumperless configuration, handling of bad sectors by the controller, and ECC codes to allow recovery from some read errors. Adaptec went their own way with LBA addressing. Others by not planning ahead. Format in the ST-506 manual only allocated one byte for cylinder which wasn't enough for their next drive the ST-412. The non PC controllers are much worse than PC controllers for weird formats.
Thanks for all the information. I'm going to try a Xebec rev. 3 to start with. I'm almost tempted to find someone who has a card that can back it up like that, as this is an old work computer...But given the age of the computer it's unlikely to have any fun older versions of code.
Stone
10k Member
Keep in mind that it's not uncommon for MFM drives to fail from age alone, even while sitting on the shelf for years. I've had lots of them go south that way. Track zero problems are not unusual either and that's a nonstarter.