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kishy
May 10th, 2010, 01:17 PM
Hi,

I've obtained a "Conner 2MB Floppy Controller" which is 8 bit ISA. It appears to have a BIOS chip on it and thus may support high density floppies on nonsupporting systems...yay?

That's not the question, however. It has a bank of jumpers, clearly labeled, but I need to know what to set them to. The card is being used in a typical XT clone mobo, no integrated features, but I am using a VGA graphics card.

The floppy card provides these options:

IO Address: 1, 2, 3, 4
IRQ: 3, 4, 5, 6, 7, 9
DMA: 1, 2, 3

Randomly guessing at these settings could take forever and the number of power cycles in quick succession to each other to accomplish that could damage the equipment. Can anyone offer a couple "highly likely to work" combinations for this setup? It does not seek either a 3.5" high density or 5.25" high density drive with no jumpers installed, and my random guess of 3/5/2 (IO, IRQ, DMA respectively) also didn't cause the drives to seek.

Thanks in advance!

Chuck(G)
May 10th, 2010, 01:40 PM
If this is replacing your original controller, use I/O address 1, IRQ 6, DMA 2.

vwestlife
May 10th, 2010, 01:45 PM
The default for a floppy controller is IRQ 6 and DMA 2. If this is going to be the computer's primary floppy controller, you should use those settings.

The default I/O address for a floppy controller is 3F0-3F7h. I'm not sure which jumper this maps to on your controller. Perhaps "1" for the primary controller.

Chuck(G)
May 10th, 2010, 02:39 PM
Is this the half-length card with two headers at the top, one labeled for 2.88MB drives? If so, not only do I have the card, but I think I've also got documentation on it if you get stuck.

kishy
May 10th, 2010, 03:01 PM
If this is replacing your original controller, use I/O address 1, IRQ 6, DMA 2.

There is no original to speak of, but it will be the only controller. Thanks, I'll give these a try.


The default for a floppy controller is IRQ 6 and DMA 2. If this is going to be the computer's primary floppy controller, you should use those settings.

The default I/O address for a floppy controller is 3F0-3F7h. I'm not sure which jumper this maps to on your controller. Perhaps "1" for the primary controller.

Thanks for confirming it :) Always nice to get multiple people in agreement on something like this, keeps life easier.


Is this the half-length card with two headers at the top, one labeled for 2.88MB drives? If so, not only do I have the card, but I think I've also got documentation on it if you get stuck.

Nope, just one header. It's a very tiny card, I'll get pics in here later when I report back with progress. Just says "2MB floppy controller", which I suspect indicates support for high density 3.5" since the "real, unformatted" capacity of one of those disks is approximately 2MB.

kishy
May 10th, 2010, 03:30 PM
Alright, so...good news and bad news.

The suggested settings of 1/6/2 work because the first drive seeks after POST. However, it isn't booting from my high density media.

Photo: 3585

It also isn't booting from a true 720K floppy formatted on my desktop which has a high density drive.

All I own are high density drives...

What's going on here?

MikeS
May 10th, 2010, 03:31 PM
http://www.vintage-computer.com/vcforum/archive/index.php/t-16274.html

Sound familiar?

kishy
May 10th, 2010, 03:42 PM
http://www.vintage-computer.com/vcforum/archive/index.php/t-16274.html

Sound familiar?

D'oh!

I Googled the part number and found nothing...figured maybe I stumbled upon a great find. Fortunately it was extra cheap, I won the auction at $0.99 and it shipped USPS First Class so a small loss, if a loss at all.

The thing is, it definitely IS seeking the first floppy drive, and it waits until after the seek to report "boot disk failure". Presumably it is a floppy controller and can be used with floppy media (the silkscreening sure says it can)...just a very picky setup, perhaps?

Raven
May 10th, 2010, 04:08 PM
I have a question/point.. DMA? This is an XT.. they don't have DMA... or am I wrong..?

Chuck(G)
May 10th, 2010, 04:35 PM
I have a question/point.. DMA? This is an XT.. they don't have DMA... or am I wrong..?

Let's see--pop the top of your 5160. See a 40-pin DIP labeled 8237A (or Am9517A)? That's a DMA controller. 5170s have two of them.

Raven
May 10th, 2010, 06:21 PM
Let's see--pop the top of your 5160. See a 40-pin DIP labeled 8237A (or Am9517A)? That's a DMA controller. 5170s have two of them.

I read somewhere that the PCjr doesn't have DMA and I thought XT class machines did not either.. I learned something! :P

vwestlife
May 10th, 2010, 06:40 PM
I read somewhere that the PCjr doesn't have DMA and I thought XT class machines did not either.. I learned something! :P
The original Tandy 1000 series (with the non-standard keyboard that is missing Scroll Lock) also does not have DMA on the motherboard, however if you install Tandy's memory upgrade card, then it includes the DMA chip.

southbird
May 11th, 2010, 06:49 AM
Other things to consider at this point are mismatched drive selects... it could be that it sees your floppy as the second drive and can't find a primary.

kishy
May 11th, 2010, 09:45 AM
Other things to consider at this point are mismatched drive selects... it could be that it sees your floppy as the second drive and can't find a primary.

It's seeking the drive though :/
And only the one, the LED on the other one doesn't even come on.

Raven
May 11th, 2010, 09:48 AM
Is it seeking really short? If so it might just be checking the drive, which it would do even if not trying to boot from it. My 5160 has two floppy drives and will only boot from the first one - both seek on boot, however, for a short period.

Chuck(G)
May 11th, 2010, 11:59 AM
It's seeking the drive though :/
And only the one, the LED on the other one doesn't even come on.

Kevin, try grabbing a copy of Anadisk and run it in SECTOR mode. See what it sees. Right now, we don't know if it's your drive configuration, the controller or the BIOS.

Old Thrashbarg
May 11th, 2010, 01:42 PM
Despite what the silkscreening may indicate, that Conner card is strictly for floppy-interface tape drives. The 2MB denotes the speed, rather than the capacity.

That's why those are so cheap on eBay... they don't work with regular floppy drives.

Raven
May 11th, 2010, 01:53 PM
I have some of those tape drives.. and I've been trying to get them to work on normal floppy interfaces (at least I have in the past) to no avail.

Chuck(G)
May 11th, 2010, 02:52 PM
Despite what the silkscreening may indicate, that Conner card is strictly for floppy-interface tape drives. The 2MB denotes the speed, rather than the capacity.

That's why those are so cheap on eBay... they don't work with regular floppy drives.

Hmmm, I have a couple of those, but not Conner brand. They actually do use a floppy controller to function, but I've never tried to make one work that way. For one thing, mine have 48 MHz XCOs on i82078 controllers, so coding for them would be a little non-standard. At least one is ISA PnP (16 bit ISA connector, but only an 8-bit data path).

Still, if they're really cheap and plentiful, it might be worthwhile to work out some DOS drivers for them to run floppy drives--if all of the floppy control lines have be brought out to the connector.

Just one of those things I started to check out and never finished.

Old Thrashbarg
May 11th, 2010, 04:05 PM
It would be nice if they could be made to work, and it should be doable with a bit of know-how, since it is the same basic interface. However, as you found, there are some issues to address. Actually, I don't even recall the Conner/CTC cards being bootable, though it's been awhile since I've messed with one. (It stands to reason, though... not often you'd want to boot from a backup tape drive.)

As for the tape drives themselves, some of them would work on a regular floppy controller, but they were quite picky at best... they wouldn't work on just any controller. I still have one of the proper Conner drives to match OP's controller, but I never bothered trying it on anything else.

kishy
May 11th, 2010, 04:11 PM
Kevin, try grabbing a copy of Anadisk and run it in SECTOR mode. See what it sees. Right now, we don't know if it's your drive configuration, the controller or the BIOS.

I don't really have a test environment able to support that ATM...while I do have an XT-IDE I don't have a drive currently set up with a decent version of DOS or any of that. I don't have ANY way of booting the system from a floppy currently, that's what this card would have hopefully accomplished.


Despite what the silkscreening may indicate, that Conner card is strictly for floppy-interface tape drives. The 2MB denotes the speed, rather than the capacity.

That's why those are so cheap on eBay... they don't work with regular floppy drives.

Interesting...it's almost like it tries to work though. Are floppy and tape technologies really similar enough that a floppy drive would seek media on boot if the card is for tape drives only?


It would be nice if they could be made to work, and it should be doable with a bit of know-how, since it is the same basic interface. However, as you found, there are some issues to address. Actually, I don't even recall the Conner/CTC cards being bootable, though it's been awhile since I've messed with one. (It stands to reason, though... not often you'd want to boot from a backup tape drive.)

As for the tape drives themselves, some of them would work on a regular floppy controller, but they were quite picky at best... they wouldn't work on just any controller. I still have one of the proper Conner drives to match OP's controller, but I never bothered trying it on anything else.

I think someone in the thread MikeS linked to earlier had said they could get it to begin booting DOS off a floppy connected to this type of card but it would lock up (forget what they said now, would need to read it again). Something about beginning to boot DOS and not completing it.

Old Thrashbarg
May 11th, 2010, 04:47 PM
Are floppy and tape technologies really similar enough that a floppy drive would seek media on boot if the card is for tape drives only?

Yeah, it's a really simplistic and specific interface... I mean, you can just look at the pinout of the 34-pin connector and see exactly how the whole thing works. But that also means that anything connected to that interface has to operate in pretty much the same way. Of course, there's still room for little variations, hence the incompatibilities of the tape drives/controllers, but the basic operation has to be the same.

digger
May 13th, 2010, 01:09 AM
I read somewhere that the PCjr doesn't have DMA and I thought XT class machines did not either.. I learned something! :P


The original Tandy 1000 series (with the non-standard keyboard that is missing Scroll Lock) also does not have DMA on the motherboard, however if you install Tandy's memory upgrade card, then it includes the DMA chip.

And I didn't know that a DMA controller could even be added to a Tandy 1000 as an upgrade. So I learned something as well. ;)