huh? those combo drives are meant to be used as the only device on the cable, you set jumpers to pick one as A and the other as B

Indeed.
It's possible to have more than two floppy drives - https://www.seasip.info/VintagePC/floppies.html
...but those dual 5.25+3.5 drives aren't of any help here.

This is one of those "It deepends" not a typo, just possible if you're willing to go off the deepend. I think Grzyb's link there is a fairly comprehensive overview.

maxtherabbit wrote on 2021-11-20, 15:05:

huh? those combo drives are meant to be used as the only device on the cable, you set jumpers to pick one as A and the other as B

Guess it should work fine on a secondary controller with your driver. What do you think?
Isn't this combo drive in fact just two drives on one cable with the twist somewhere inside the circuitry?

Bondi wrote on 2021-11-20, 16:31:

Isn't this combo drive in fact just two drives on one cable with the twist somewhere inside the circuitry?

Yes.

Bondi wrote on 2021-11-20, 16:31:

maxtherabbit wrote on 2021-11-20, 15:05:

huh? those combo drives are meant to be used as the only device on the cable, you set jumpers to pick one as A and the other as B

Guess it should work fine on a secondary controller with your driver. What do you think?
Isn't this combo drive in fact just two drives on one cable with the twist somewhere inside the circuitry?

yeah it is, and would

Wait a min... I think I've missed something...

Is there some new driver for >2 FDDs?

Not that I really need one...
Once upon a time, I tried to install two generic multi-I/O cards, one jumpered for primary FDC address, the other for secondary - but it didn't work, even the drive connected to the primary ceased to work... probably IRQ and/or DMA conflict, and no jumpers to select different IRQ/DMA.
So I ended up purchasing one of those 4-floppy controllers with its own BIOS.

Just do what is described in the article linked above.
It works fine, I did this already in the mid 1980s to connect 4 drives.
Nothing more needed than driver.sys and drivparm.
And uniform and/or xenocopy if your intent is to transfer from other systems' diskettes.
You just have to make sure that you either don't use castrated drives without DS jumpers or mod these to a particular DS.

retardware wrote on 2021-11-20, 17:32:

Just do what is described in the article linked above.
It works fine, I did this already in the mid 1980s to connect 4 drives.

But what exactly do you mean?
There's many scenarios described in that article...

Also, in mid-80s... wasn't that with an XT-style, DD-only controller?
I need HD, of course!

Grzyb wrote on 2021-11-20, 17:07:

Wait a min... I think I've missed something... […]
Show full quote

Wait a min... I think I've missed something...

Is there some new driver for >2 FDDs?

Not that I really need one...
Once upon a time, I tried to install two generic multi-I/O cards, one jumpered for primary FDC address, the other for secondary - but it didn't work, even the drive connected to the primary ceased to work... probably IRQ and/or DMA conflict, and no jumpers to select different IRQ/DMA.
So I ended up purchasing one of those 4-floppy controllers with its own BIOS.

Yes, there is this driver https://www.vcfed.org/forum/forum/technical-s … ver=#post919840
But you need a proper secondary controller which allows to set alternative port and IRQ/DMA or handles sharing correctly. Adaptec AHA1542CF worked for me fine. AHA1542B I'm sure will do as well.

BTW nothig described in that article worked for me.

Grzyb wrote on 2021-11-20, 17:39:

Also, in mid-80s... wasn't that with an XT-style, DD-only controller?
I need HD, of course!

Controller (765 core) is same, it's just a better data separator.
Recently there was some talk about FDD controller, mentioning that the AHA-1542 FDC is one of the best ones available, also works with 2.88MB disks.

Of course, disable mobo onboard FDC, it's almost always inferior.

My only quad floppy controller is a GRC with an IDE Bios onboard, has its own setup program and everything

3rd and 4th floppy drive letters end up interesting if you have a hard drive and cd

Bondi wrote on 2021-11-20, 17:58:

Yes, there is this driver https://www.vcfed.org/forum/forum/technical-s … ver=#post919840
But you need a proper secondary controller which allows to set alternative port and IRQ/DMA or handles sharing correctly. Adaptec AHA1542CF worked for me fine. AHA1542B I'm sure will do as well.

Fantastic! This is the first driver I managed to get working with a 3rd floppy drive on Adaptec AHA1542CF, thank you very much for the link!

crvs wrote on 2021-11-22, 14:37:

Bondi wrote on 2021-11-20, 17:58:

Yes, there is this driver https://www.vcfed.org/forum/forum/technical-s … ver=#post919840
But you need a proper secondary controller which allows to set alternative port and IRQ/DMA or handles sharing correctly. Adaptec AHA1542CF worked for me fine. AHA1542B I'm sure will do as well.

Fantastic! This is the first driver I managed to get working with a 3rd floppy drive on Adaptec AHA1542CF, thank you very much for the link!

The thank you goes to maxtherabbit, who wrote the driver. (:

crvs wrote on 2021-11-22, 14:37:

Bondi wrote on 2021-11-20, 17:58:

Yes, there is this driver https://www.vcfed.org/forum/forum/technical-s … ver=#post919840
But you need a proper secondary controller which allows to set alternative port and IRQ/DMA or handles sharing correctly. Adaptec AHA1542CF worked for me fine. AHA1542B I'm sure will do as well.

Fantastic! This is the first driver I managed to get working with a 3rd floppy drive on Adaptec AHA1542CF, thank you very much for the link!

That's great. Using a 1542 as a secondary FDC is actually what motivated the project

maxtherabbit wrote on 2021-11-22, 16:37:

That's great. Using a 1542 as a secondary FDC is actually what motivated the project

Thank you a lot for your effort, both on the driver and sharing the details. There is suprisingly few information on this topic, basically just a page mentioned above, but none of its solutions had worked for me (I didn't try only 4-floppy controller, just couldn't find one).

crvs wrote on 2021-11-22, 17:52:

maxtherabbit wrote on 2021-11-22, 16:37:

That's great. Using a 1542 as a secondary FDC is actually what motivated the project

Thank you a lot for your effort, both on the driver and sharing the details. There is suprisingly few information on this topic, basically just a page mentioned above, but none of its solutions had worked for me (I didn't try only 4-floppy controller, just couldn't find one).

Every IBM 5150 has a quad floppy controller but it only supports up to 720kb drives, would need to wire the external floppy connector back inside to use it most effectively (unless you like enclosures)

Not supportting HD drives is a deal killer

I like enclosures

There are a good handful of 4 drive controllers out there that support 500kHz too