|See your thread about the proprietary CD drive for a new post from me. |
I think every version of DM I have has the manual mode available.
Did you use a space between dm and /m? You must for DM!
If in doubt, you should always use a space between a command and a command line switch (e.g. /m), and between multiple switches, on the command line.
Some newer commands will work anyway without the spaces, but for older commands/software you must use spaces.
I haven't found any MFM /RLL ribbon cables yet but I'm sure I have a few somewhere because I remember being surprised I still have some, after I had gathered up those pieces that are now lost.
I haven't found any MFM/RLL controller cards so far........
" Interestingly, the number of cylinders, heads, and sectors detected by DM changes ever time I reboot the computer."
That NEVER happened in my cases. That's sounds like the controller card is having the problem.
"(essentially the fatal track 0 problem, caused by an internal stop moving and making the drive not be able to find track 0)"
Did you add this part yourself?
"...caused by an internal stop moving and making the drive not be able to find track 0"
I don't know why you're fixated on thinking the drive has problem with a mechanism inside it.
As far as I know I had zero problems with the mechanisms inside the drives.
If DM or whatever did not find track 0 on a MFM or RLL drive, or on an IDE drive for that matter, the problem is many times more likely to be caused by the drive developing bad sectors in that critical area, or it could be a false error generated by a faulty controller card but I never had any indication of that with the MFM/RLL drives (that has happenened with IDE drives because of a faulty board on the drive) .
If the controller circuits or the circuits on the drive's board are faulty, it can certainly seem like there's something wrong with the mechanisms inside the drive, but as far as I know I've never encounted such, on any hard drive that has failed.
In many cases with IDE drives it was obvious there was something wrong with the drive's board circuits, because one or more chips on it got too hot to keep a finger tip on - a drive that had that usually made loud thrashing sounds, once the chip got hot enough.
About your ribbon cables.
If there is something wrong with their connection(s), it can appear there is something wrong with the controller / the drive.
- According to what I remember.....
- one of the two ribbon cables has 34 pin connectors. You have to connect that and the ribbon cable with fewer wires to each drive.
- If there are two connectors on the 34 pin cable, it's for a single drive, and some of the wires flip positions between connectors.
- If there are three connectors on the 34 pin cable, some of the wires flip positions between the middle and end drive connectors - a single drive goes on the end connector after the flipped wires. If you have two drives the second drive connects to the middle connector - a single drive won't work or won't work properly connected by itself to the middle connector (it probably won't be detected at all) .
It's easy to confuse floppy data cables with those for MFM/RLL drives.
Floppy drive data cables use the same 34 pin connectors, BUT the wires that flip positions, between two connectors, or beteen the middle and end connectors on athree connector cable, are DIFFERENT ones from those flipped on the MFM/RLL data cables. A single MFM or RLL drive cannot work properly connected to a floppy data cable!
There is one header for the 34 pin ribbon cable, and usually two headers for the one with fewer wires. The proper header with fewer pins must be connected to the drive - one is for a single drive, the other is for a second drive if you have two drives - it probably won't work, or won't work properly, connected to a single drive that is by itself.
The striped side of the ribbon cables should be on the pin 1 end of the row of pins on both ends. The drive can't work properly if one end is on the header backwards, or if it's misplaced on the pins. If any pins are bent, you may need to staighten them in order to get a good connection. If any connector is loose when on the pins, you may need to try another cable that doesn't have such.
If the drive and/or controller stopped working properly on the PS/2 without you having fiddled with the ribbon cable connections previous to that, then it's quite likely something went wrong with the controller card or the drive - but if you did fiddle with them, or in any case, your problem could be caused by a problem with the ribbon cable connections.
I never had a problem with the controller cards, and other than maybe one or two, I never had a problem with the drives, at least not when I used DM, but I did have problems with some of the ribbon cables as I recall.
I composed this for IDE data cables, but the same applies to any ribbon cable:
It is common to un-intentionally damage IDE data cables, especially while removing them - the 80 wire ones are more likely to be damaged. What usually happens is the cable is ripped at either edge and the wires there are either damaged or severed, often right at a connector or under it's cable clamp there, where it's hard to see - if a wire is severed but it's ends are touching, the connection is intermittant, rather than being reliable.
Another common thing is for the data cable to be separated from the connector contacts a bit after you have removed a cable - there should be no gap between the data cable and the connector - if there is press the cable against the connector to eliminate the gap.
80 wire data cables are also easily damaged at either edge if the cable is sharply creased at a fold in the cable.
Try another data cable if in doubt.