The diskette drive has an internal switch to detect diskette changes. You may need to disassemble the drive to see if there's a problem or if it needs to be cleaned.

Are you sure it's in the drive?

I've built a system around an IBM PS/1 motherboard with absolutely no original components other than that board and the CPU. Yet I experience the same, even with a Gotek instead of a regular floppy drive. That suggests it's in the BIOS or something...

Have you checked the FDD cable? The disk change signal is at one side, and maybe that wire is damaged.

Zup wrote:

Have you checked the FDD cable? The disk change signal is at one side, and maybe that wire is damaged.

In my case: definitely not the cause. Have tried three different cables with same result on the PS/1 motherboard but all three working normally on any other system. Of course it could be a damaged pin/trace on the motherboard, but hearing someone else with an IBM from the PS/x lines having exactly the same issue makes me doubt that.

That said, I had an IBM PS/2 model 70 back in the day and this certainly was not an issue back then - and I would have noticed as that was years before CDRoms or other mass storage was available, so all installs had to be done from (frequently multiple) floppies. But the 70 was a real dinosaur, much older than my 1994-era PS/1 board and even older than zzgus's 55SX

I also think its the drive, remember to had a similar problem once.

What happens if you type DIR at the A:\ prompt, then change the disc, and do the DIR again? Does it still show the content of the 1st disc?
I remember its possible to force the disc change by doing a CTRL-C at the A:\ prompt. But this doesnt help you when running a game installer.

The disk change is usually triggered monitoring changes in pin 34 of the floppy drive (see that pinout scheme). AFAIR, that pin is called "Disk Change/Ready" because in some floppies it means "Disk Change" (active when disk has been changed) and in others is "Ready" (active when disk is ready, i.e.: loaded and the latch closed in a 5.25 FDD).

So, some things to try:
- Checking/changing the cable (as you did). Being the last pin, the wire is somewhat exposed.
- Checking if your FDD is original. I don't know what kind of signal do you need, but maybe your FDD is providing the motherboard with the opposite. If you have replaced the FDD, note that some FDDs behaviour can be selected via jumpers or modded to fit your needs.
- Checking the internal change disk switch, maybe is non functional.
- Clean the cable and the motherboard contacts with cleaning fluid. Some dirt can make signals unreliable.
- Trying with another FDD (can a modern FDD work with a PS/2? IBM throw propietary stuff everywhere).

Predator99 wrote:

I also think its the drive, remember to had a similar problem once.
What happens if you type DIR at the A:\ prompt, then change the disc, and do the DIR again? Does it still show the content of the 1st disc?

Yes.

I remember its possible to force the disc change by doing a CTRL-C at the A:\ prompt. But this doesn't help you when running a game installer.

Good catch, if I do a CTRL+C and change the disk now the content is being refreshed for what I assume is not the cable.

AlaricD wrote:

The diskette drive has an internal switch to detect diskette changes. You may need to disassemble the drive to see if there's a problem or if it needs to be cleaned.

I Will now disassemble the drive to see if I find the switch.

Thankyou
Gus

The truth is that I have no idea of where to start to search...

Zup wrote:

- Checking if your FDD is original. I don't know what kind of signal do you need, but maybe your FDD is providing the motherboard with the opposite. If you have replaced the FDD, note that some FDDs behaviour can be selected via jumpers or modded to fit your needs.

All floppy drives and controllers are compatible with the original specifications, so the age of the drive won't be the problem.