MFM drive on a 386 IDE motherboard - Page 1
Forum section: electronics / general

author: LittleFrog
author_rank: Contributor
timestamp: February 21, 2025, 05:46:40 pm
content: Hi,I would be grateful for any thoughts/input on the following;I have 5 different MFM drives and I'm trying to get one or more of them working. I have MFM controller cards that are NOT the ones used with the drives which I understand could be a show stopper from the get-go. My host computer is a very old 386SX motherboard the BIOS of which does not seem to understand about MFM drives (but it does allow you to specify the geometry of IDE drives which might be useful).My question is; is there any way of getting an operating system (e.g. FreeDOS) to recognise the presence of the MFM controller and attached MDM HD's in this environment?In a perfect world, I'd like to reformat an MFM drive and attempt to use it in a non-DOS environment (actually a 68K VME based system) but this is way off down the line.My 386 system is as follows;386SX motherboard which has the outline/chip positions of a JETPRO INFOTECH MB-3A (MB-333SXA) with an ALI-1217-40 glue chip, 8Meg of RAM and AMIBIOS dated 1992Pine Technology PT-606 Multi I/O card. This card can disable the HD controller if requiredSeagate ST-3660A IDE HDD loaded with FreeDos 1.3Gotek FDD emulator3COM 3C509B-TP network card which is connected to my LAN using 10BaseT. This card has an EPROM fitted which is loaded with XTIDE Universal BIOSTrident VGA card with 1024megThe MFM HDD controller cards I have are;Western Digital WD1003-WA2, 16 bit ISA slot interfaceWestern Digital WD1002-WX1, 8 bit ISA slot interfaceSo far I have;Disabled the IDE interface on the Multi I/O cardFitted one of the MFM cardsBooted the machine into FreeDos from floppyLoaded "CheckIT" from floppy to see what resources are claimed by the MFM card under testTried verious DOS commands to see if there's any way that the MFM HDD can be seen by a program/DOS. This has always totally failedFound that none of the resources (e.g. INT, I/O bus devices) I'd expect to be claimed by the MFM controller have been claimedFiddled around with jumpers on the MFM Controller cardsWritten a posting on this forum because I have run out of ideasWith the above in mind, I have a couple of other thoughts/questions;For DOS to see the MFM HDD, does the BIOS have to recognise the MFM controller for you to stand any chance of it working? Or can a driver be loaded along with DOS that brings it to life?I've not managed to find any diagnostics programs for the MFM HDD Controller cards. Are there such things? Maybe that don't even need DOS to be running first? Maybe that's too much to hope forAs I said before, I have 5 different HDD's but I've done most of the testing described above with a Seagate ST-251 42Mb MFM HDD which I believe is working and loaded with MS-DOS 6.22. This has been powered by a SM PSU with plenty of power to make the HDD run.As I say, I'd be really grateful for any thoughts / ideas.Thanks for your attention.Dave

author: Algoma
author_rank: Frequent Contributor
timestamp: February 21, 2025, 05:56:46 pm
content: Seems to be some discussion over on Reddit in R/vintagecomputingSo much of this is nearly lost knowledge, 386 systems were really limited in support for hardware that was greatly improved upon with i486 and beyond. most embedded Industrial systems I've come across are at least 486 based.https://www.reddit.com/r/vintagecomputing/comments/128uvx1/read_data_from_mfm_hard_disk/

author: LittleFrog
author_rank: Contributor
timestamp: February 21, 2025, 06:24:53 pm
content: Good evening Algoma (well it's evening in the UK),Thanks for very prompt reply. Your Reddit tip is a good one; I'll follow it up.With reference to 486/386, I picked on an old 386 board because (for some reason) I thought this was the right age of technology for an MFM drive; maybe that's way too simple in thinking. In fact I've just realised that I should be Googling for BIOS's that support MFM....Anyway I am grateful for your responses; thanks.Dave

author: Algoma
author_rank: Frequent Contributor
timestamp: February 21, 2025, 06:49:26 pm
content: Most compute systems of that period maintained backwards compatibility, simply become faster with more cache.newer 486 and 586 systems had much better support for expansion I/O cards and drive controllers. and introduced plug and play technology for the bios to scan hardware addresses instead of relying on manual configuration of every specific BIOS setting and moving a forest of jumper settings around on each card.MFM drives were a competing technology, and often relied on dedicated controllers configured for that specific drive. If all you need is storage the go for a more standard IDE drive / controller that became the mainstream well through the Pentium era. I'm not familiar enough with MFM drives to give specific directions.

author: Algoma
author_rank: Frequent Contributor
timestamp: February 21, 2025, 07:07:20 pm
content: A bit more research appears that the MFM controllers were often pre-configured to be the only controller in the system, and often used the same defaults that the system IDE controllers did.The IRQ and and Address settings overlap, and required disabling, removing or reconfiguring the competing Primary IDE controller to get the MFM controller to be identified first.generally only use one drive controller card, or they will conflict, if not reconfigured.That WD1003-WA2 should be able to run the entire system on its own, its got all the required interfaces for MFM, IDE and Floppy. You shouldn't even need that PT-606

author: Kleinstein
author_rank: Super Contributor
timestamp: February 21, 2025, 07:17:31 pm
content: Chances are that the old motherboad's bias would still support MFM discs and the MFM controller card. 1992 looks reasonable old with a good chance to still support MFM. One should see if MFM discs are still supported in the bios setup. There one should be able to set the disc type and if needed the number of cylinders and sectors.

author: nctnico
author_rank: Super Contributor
timestamp: February 21, 2025, 07:47:00 pm
content: If the motherboard has on-board IDE controllers, you probably have to disable these as they may conflict with the addresses of the MFM controller. AFAIK IDE sits at the same address as the MFM controller and the IDE hard disk has the MFM controller on board. IDE stands for 'integrated drive electronics' and the IDE bus is nothing more than a cut down ISA bus.

author: joeqsmith
author_rank: Super Contributor
timestamp: February 21, 2025, 10:05:49 pm
content: Are you just trying to test the drives?I have an old 68000 based VME chassis scope that uses MFM. You can't just use any old drive with it. Even if the drives have the same settings, they won't work. I hacked an old Seagate 225 drive to replace the dead Mini-scibe drives.I still have my old IBM 286 which uses MFM. I had ran some old Quantum Q2080 8" platters on that PC back in the day.Some of the old controllers for the first PCs had all the support built onto the board. Our first Corvas (SP?) external drive for the IBM PC was like that. The low format was in the board's BIOS. Seems you had to use Debug to run it.Then you had the RLL controllers. Somewhere around I have an old Perstore card that was another RLL compression board that they claimed would double the capacity. Then we got those monster Maxtor drives and had to run special software to format them...****Just to add, I was not using FDISK towards the end of the MFM era. I had some other software that could low format the drives and run pattern tests on them to map out the errors. That software supported large capacity (LOL) drives that were not supported by the IBM AT's BIOS. I can't remember the name of that software but there were several available back then.****And here it is. Someone actually archived it.https://www.minuszerodegrees.net/software/Storage%20Dimensions/speedstor.htmVideo showing an old wirewrap board I made for the AT. When the PC boots, you can see it load that SpeedStor driver for the larger MFM drives.

author: coppice
author_rank: Super Contributor
timestamp: February 21, 2025, 10:16:55 pm
content: Quote from: joeqsmith on February 21, 2025, 10:05:49 pmThat take me back. Don't those things have mains powered spindle motors?

author: joeqsmith
author_rank: Super Contributor
timestamp: February 21, 2025, 10:24:56 pm
content: Quote from: coppice on February 21, 2025, 10:16:55 pmI don't think so. The only reason I say that it the chassis had a big (BIG) transformer for the linear supply. It seems like the startup current draw to get the platters spun up pushed that supply to its limits. They used something like an SA1000 bus or something. It was very similar to the PC's MFM. I picked up the technical manual from Quantum and made an interface for them. The two bay chassis was as large as the PC. I think I was the first person in my small circle of engineers to break 100M of storage on a PC. 20M was common back then.

author: joeqsmith
author_rank: Super Contributor
timestamp: February 22, 2025, 01:59:24 am
content: Couldn't find the service manuals for the Quantum drives but I did find my low format software.***Runs under a DOSBox. Not useful but interesting to see how far we have progressed.

author: amyk
author_rank: Super Contributor
timestamp: February 22, 2025, 06:15:02 am
content: HDD controllers should have an option ROM which gets executed by the BIOS during boot up, and hooks int 13h to provide disk access services, but some very early ones relied on the BIOS to itself have that code.Looking athttps://www.minuszerodegrees.net/manuals/Western%20Digital/WD1002-WAH%20and%20WD1002-WA2%20and%20WD1003-WAH%20and%20WD1003-WA2%20-%20Users%20Guide.pdfit's not clear whether that's the case.

author: m k
author_rank: Super Contributor
timestamp: February 23, 2025, 08:30:08 am
content: Quote from: LittleFrog on February 21, 2025, 05:46:40 pmNo, MFM is MFM, controller or drive.QuoteIt does, no doubt.QuoteDon't do that.QuotePossibly.QuoteSomething must be running first.QuoteThat will do just fine.Disable other HDD controllers.Put MFM controller jumpers to their default positions.Set BIOS disk parameters to 820 cylinders, 6 heads and 17 sectors.One predefined setting is most likely just that.Wide cable and drive select must match.Straight cable and first drive select.Twisted cable and second drive select.If DOS is there it will boot.If not then initialize the drive, FDISK is DOS tool for that.Next Format the drive.System files to empty disk for DOS can be copied with command SYS.If COMMAND.COM is missing it can be copied using regular COPY.Now it will boot if partition is made active.

author: coromonadalix
author_rank: Super Contributor
timestamp: March 04, 2025, 03:58:45 pm
content: you had in the past controller cards with all the management needed for the drives, mfm rll esdi .... some had floppy controller on them, Western Digitali had an 387meg 5.25" full size to play with, man this bring souvenirs lollas written, it was a matter to access them thru debug c800:5 or else, you could partition them etc ...and in dos too you could partition them, system them make partition active too etc ...normally theses controller needed to be alone, no recent ide controller activated, but some could work even with some ide controller, it was an matter of ressources taken to do it, irq's, adress ranges .... thoses controllers had higher priorities in the bios, like some scsi controllers too ...and yes as written some bios had what it needed and other card had their own bios too,Promise had an ide controller with it's own bios to help migrate from theses old era drives ... to slightly more modern drives, while keeping the old computer system ...now if it is a matter of recovering some old drive contents ... that's another story, you needed the drive specs heads, cyls, sectors, normally written on it .... or be lucky to get it's controller who was used with it ...and yes you had speedstor and ontrack softwaresthe provided speedstor link give good infoshttps://www.minuszerodegrees.net/software/Storage%20Dimensions/speedstor.htmhttps://www.os2museum.com/wp/whence-identify-drive/https://www.os2museum.com/wp/identify-esdi-drive/

author: David Hess
author_rank: Super Contributor
timestamp: March 05, 2025, 01:32:30 am
content: IDE drives have the MFM, or RLL, or whatever controller build into the drive and present the ISA bus from that controller to the computer. The IDE controller on the computer just has to buffer the ISA bus. One can be built with 1 or 2 8-bit bus transceivers and some address decoding logic.So the 386 motherboard sees the same thing whether an MFM controller is installed, or an IDE controller is used, and they use the same control address and structure and commands, but the control addresses must not overlap if multiple controllers are in the system, which will normally mean disabling any built in IDE port if an MFM controller is installed.

author: joeqsmith
author_rank: Super Contributor
timestamp: March 05, 2025, 09:15:21 pm
content: Link showing my Perstor card. Seems at one time, I had a 486DX PC with SCSI, MFM and IDE controllers all running together. Horror stories of trial and error jumper and DIP switch settings trying to find a reliable combination.https://www.eevblog.com/forum/vintage-computing/old-ibm-compatible-pcxtat-cards/msg1425017/#msg1425017

author: m k
author_rank: Super Contributor
timestamp: March 11, 2025, 03:22:11 pm
content: Any info of different colors and other types of simple name tags on top of old Seagate pre IDE drives?I think 225 and 238R had some variations, maybe 251 also.I'm quite sure I've seen at least all basic colors and added 'R' stickers.

author: Oliv_Bricol-2
author_rank: Contributor
timestamp: March 12, 2025, 07:32:59 am
content: Hello, as Coromonadalix reminds us, there were "intelligent" controller cards, capable of directly managing the disk, without going through the bios, typical of old Bull micral based on 8080. I'll see if I have any documentation on the subject, from memory everything is to be configured according to the disk, which indicates on the label the necessary information. The noise of these disks is often used in science fiction films. I love it

author: Oliv_Bricol-2
author_rank: Contributor
timestamp: March 13, 2025, 08:14:34 am
content: Depending on the brand and type or designation of the HDD, there are only ST506/ESDI/SCSI or IDE controllers. Based on this information, I may be able to provide the elements for the settings.

author: CaptDon
author_rank: Super Contributor
timestamp: April 17, 2025, 03:24:44 am
content: You were given a bit of mis-information. MFM may be MFM but different controller cards act differently and you can take a fully functional working MFM drive and computer and swap the controller card with a different one and the drive may and probably will be unreadable. Remember, these old drives must be low level formatted first usually read in from a floppy, THEN they need to be dos formatted. In other words the HDD must be initiallized first then dos formatted. RLL works the same way but you get 1.5 times more storage from the same number of heads and cylinders IF the drive is RLL certified. A few MFM drives could be used with RLL controller cards. Most RLL drives can work with MFM controller but you lose storage capacity. Restated Some 20MB MFM drives could work as a 30MB RLL drive. Almost all 30MB RLL drives could be used as a 20MB MFM drive. I would have to look at my floppies to remember which low level formating program I used to use. I did use Spinrite a lot on MFM drives to detect bad areas which were very common back then.

author: Algoma
author_rank: Frequent Contributor
timestamp: April 17, 2025, 04:55:34 pm
content: https://www.grc.com/sr/spinrite.htmI second the use of this, it was one of the best low level software I remember using frequently with drives from 20-30 years ago. Actually quite a few programs from GRC.

author: edpalmer42
author_rank: Super Contributor
timestamp: April 17, 2025, 06:22:23 pm
content: I was trying to excavate info from the tarpit that I call a brain regarding MFM etc. Then I realized that was a lost cause.Here's what you need:https://archive.org/search?query=upgrading+and+repairing+pcsGrab one of the older ones. It should have lots of info on MFM, RLL, etc.Also grab the "Micro House Technical Library". I don't remember if that version has controller cards or not, but if it does, it'll have info on jumper settings. It could be interesting (aka painful) to get it running on a new PC.