486 problem

was

MFM

were

I didn't know they did that too. It was a neat way to turn their 20MB drives into 32MB for sure.

connect

connector

Not disgareesing with you just brought a few memories back.

I'm curious that you said MFM controllers didn't work in 486s though due to speed issues. The speed of the AT expansion bus was still 8MHz as long as you didn't tweak it.

Graham

That was one way, but there were programs from several hard drive manufacturers that did the low level format, verified the surface area, followed by the high level format. It put the system files on the drive, asked for the Volume Label, and exited with a bootable C: drive. Then you installed DOS, Drivers and the programs you wanted. it could take eight hours of inserting floppy disks before the job was done.

Might be easier just to get a machine designed to run with the mfm card. Some 486s had no onboard IDE so you've got a fair range of obsolete kit to choose from.

NT

Both 486's I had required separate IDE interface cards, the second being a VLB type.

Graham

On Sat, 10 Feb 2007 01:22:26 -0800, meow2222 Has Frothed:

If you guys like me, like to browse through vintage computer junk, give this site a try. It has some interesting links.

Does anyone have a good 16 bit MFM HDD/floppy controller thy would wish to part with? I suspect that mine may be bad and I've called everyone in the local Yellow pages. Thanks. Lenny.

On Thu, 15 Feb 2007 16:39:00 -0800, snipped-for-privacy@yahoo.com Has Frothed:

I'll have a look in the attic. I know I have a couple Connor drives and a big old Seagate up there along with a couple IBM ps/2 machines and some other old junk.

those are the wrong people, businesses wont have that kind of stuff. Post a wanted notice somewhere to find the enthusiasts that have historic junk sat in the loft. Some newspapers let you do this free.

NT

Typically I would try a computer recycler. You might get one for free since they are not desired nowadays.

If you can spend around $20-$25, there are a bunch on ebay. Computer stores aren't likely to have anything that old. You need to find a surplus electronics place. Andy Cuffe

snipped-for-privacy@gmail.com

I'll look around. I should have a few. (dozen)

You could also try driving around on trash pickup day, if you still have one in your community, and see what folks are putting out on the curb. This can often be an excellent source for parts and repairable items.

tomh

" snipped-for-privacy@yahoo.com" wrote in news: snipped-for-privacy@l53g2000cwa.googlegroups.com:

Disable the onbard IDE, the BIOS likely will see the MFM card.

innews: snipped-for-privacy@l53g2000cwa.googlegroups.com:

This one guy is telling me that because my original controller was a WD 300 operating my Seagate drives and the drives were possibly set up with that controller, that controller is the only one that I can use to get into my drives. He says that even the Seagate controller which I borrowed from someone and i have been trying to use will not work. Does this sound reasonable?

innews: snipped-for-privacy@l53g2000cwa.googlegroups.com:

I have run into problems like that before, it's been years since I've messed with MFM though so I'm a bit hazy.

it is true that sometimes your drive will not work with a different controller...the only way to know without having unavailable info is to try it...beware as in many cases if you are trying something, do not do anything like chkdsk since then you are not only trying, you are changeing

the reason is that the low level format program is on the bios of the controller ... when you set up a disk you use the debug comand to run the controllers "setup" program which low level formats the drive and i guess the partition is set too... then it is ready to do the regular high level format with DOS ... different controllers had slightly different parameters sometimes so you can't just switch and expect to read the drive set up on another type controller

the thing is that these drives lose the low level format over time ... that is where spinrite allows you to redo it without saving the data and putting it back

WD 300 ... does not ring a bell ... WD1003 does

and your drives are double spaced or single spaced, whatever one was the little used format ... that does complicate things ... again info that is in the past as far as my brain goes ... sorry

again ... SpinRite is the killer ap ... it low level formats or "renews" the disk without hurting data ...

innews: snipped-for-privacy@l53g2000cwa.googlegroups.com:

that is very possible, i remember years ago having problems like that. you can get a controller with a different bias that was updateable and if you formatted the drive with it, it's possible that would be the only controller that would work on that drive. how ever, I found that most of the time, if you had the same model controller, and set up the same it would work fine.

innews: snipped-for-privacy@l53g2000cwa.googlegroups.com:

Boy, this topic sure brings back dusty old memories! Yes, if you're running MFM or RLL drives, you need to use the same brand & model controller. Most of the time, a controller with the same chipset will work, but you can't count on it. As long as you're careful not to write (best to cut the *WR_EN line on the cable, as insurance) to the drive you're trying to recover from, there's no harm in trying other controllers. The other problem in those days was that there was no standard way for the drive to tell the controller or BIOS what heads/cylinders/sectors numbers to use, which was often a real nightmare if that data was lost from the CMOS memory. I always used to write it on the case of the drive itself, so that it could easily be found if the CMOS battery went bad. If you're lucky, so did the person who installed the drive on this machine.

innews: snipped-for-privacy@l53g2000cwa.googlegroups.com:

There was no standard for 8 bit HD controllers, even with the same manufacturer. 16 bit HD controllers were more compatible, as long as they were for the same type of drive. You had MFM, RLL, SCSI, and a few other interfaces/formats. The standard MFM or RLL card supported a pair of drives and all you had to do was pair it up with the right class of card. One BIG problem was that some 386 and most 486 motherboards were too fast to support the MFM or RLL controller cards. The fact that the motherboard has an IDE port makes it very likely that it can not support a MFM or RLL drive, unless you set the CPU speed as low as possible. Even then, it may be too fast. I keep a couple old 286 computers around to transfer the data to IDE drives, and can be used in faster computers. The early IDE controller cards gave you a choice of several base addresses so you could add them to older computers without a conflict. There was a great website called "The Ref (tm)" with a lot of mirrored sites, but I can't find any of them that still exist.

Another reference is the "Pocket PC Ref" from Sequoia publishing:

that has a LOT of data on older drives. You have to know the number of cylinders, heads and sectors to set up a MFM drive. There were a few standard sizes in the BIOS, but most drives required a custom configuration.