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Fire-Flare
May 4th, 2017, 10:59 AM
I need to make a system that can transfer data between different size (physical and capacity) floppies.

From what I've gathered already, the system should run Windows 98SE, have ISA and PCI slots, onboard IDE and dual floppy controllers, and if possible USB.

I'm sure I can find the components, but I have a question: Is it possible to run ALL floppy sizes in one machine at the same time with additional floppy controllers?

If not, are there drives that can reliably write more than one type of floppy?

Chuck(G)
May 4th, 2017, 11:31 AM
Depends on the utility and the programs and the floppy controllers. I have a 6-floppy system using Micro Solutions Compaticard IV boards--each CCIV is capable of running up to 4 drives. Some low-level utilities don't like to use alternate I/O port, interrupt and DMA, however.

Buf if you're asking if it's possible to set up a system with 2 drives, one 3.5 and one 5.25" HD, well, of course it is.

SomeGuy
May 4th, 2017, 11:40 AM
Exactly what types of machines/drives will you be inter-operating with?

The main issue with disk and drive compatiblity is between 360k and 1.2mb drives. 1.2mb drives can not reliably write 360k disks (there are ways to make them "work"), and obviously 360k drives can't do anything with 1.2mb disks.

Ideally, one would usually want a 1.44mb drive (writes 720k disks fine), a 1.2mb drive, and a 360k drive.

But you will probably have to pick two.

Most motherboards and controllers only support two floppy drives. There are some rare 8-bit ISA controllers that support 4. In theory, changing the I/O address of an ISA floppy controller might let you use two additional drives, but would require a special BIOS or installing a device driver. Most don't have that option. No idea how those would work inside Windows.

One, probably less troublesome, option is to have two "tweeners" one with a 360k and another with a 1.2mb.

Another option is to have a 360k and 1.2mb internal and use a USB 1.44mb drive (you will want to hunt down one that supports 720k). But USB can not handle oddball formats or copy protection.

Also, keep in mind that with a tweener you are still limited to MFM (and FM if you are lucky) encoded disks such as those used by the IBM PC. If you wish to use Apple II, Commodore, or such, then you will need a Kryoflux and/or SuperCard Pro.

Fire-Flare
May 4th, 2017, 11:47 AM
Depends on the utility and the programs and the floppy controllers. I have a 6-floppy system using Micro Solutions Compaticard IV boards--each CCIV is capable of running up to 4 drives.

That's what I wanted to hear. Thanks!

Fire-Flare
May 4th, 2017, 11:55 AM
Exactly what types of machines/drives will you be inter-operating with?

Just PC-Compatibles. I have a few disks already but they're not too reliable.

I like your idea of using a USB floppy for the 3.5" disks. Thanks!

lutiana
May 4th, 2017, 12:01 PM
My Tweener has a 1.44 and a 1.2Mb drive in it. It seems to write data to 360k floppies with no issue, however it cannot format 360k at all, so I just format that on one of my old machines with a 360Kb drive. And obviously I am limited to IBM formats with this.

That said, one of the things I always try to do is get a 1.44 or 720kb drive working in the old machine. Much easier to work with.

Stone
May 4th, 2017, 12:14 PM
IMO, a tweener should run DOS, primarily, not Windows. Many of the operations you will be performing are more DOS friendly than Windows friendly. Most of the programs you will be using will be DOS programs. Dropping to DOS in Windows to perform DOS operations will not always leave you with a smile on your face.

lutiana
May 4th, 2017, 12:43 PM
IMO, a tweener should run DOS, primarily, not Windows. Many of the operations you will be performing are more DOS friendly than Windows friendly. Most of the programs you will be using will be DOS programs. Dropping to DOS in Windows to perform DOS operations will not always leave you with a smile on your face.

Mine is Windows 98 with a fully configured DOS Mode. This allows me to work with Winimage in Windows as well as networking to get data to and from it from my server and main workstation. If I need to do things in pure dos, then I just restart in DOS Mode. Works for me and I've not run into any major problems doing this.

lafos
May 4th, 2017, 01:24 PM
Mine is a dual-boot WinXP/Win98SE machine with the ability to boot in DOS mode. My internal drives are 360K and 1.44 MB. I have a 1.2MB drive on rails installed, where I simply move the cable from one of the other drives. Since I am a TRS-80 guy, 1.2MB floppies are not often used, except when I need them on the PC itself.

Xacalite
May 4th, 2017, 02:23 PM
In theory, changing the I/O address of an ISA floppy controller might let you use two additional drives, but would require a special BIOS or installing a device driver.
I tried it with a few "multi I/O" cards, and failed.
Yes, there's plenty of such cards with option to select secondary FDC address, but IRQ and DMA remain the same, and the cards I tried obviously fail to share those resources.

So I'm using one of those 4-floppy cards, with its own BIOS.

Formulator
May 4th, 2017, 02:55 PM
I use two different systems, mostly a 386 with 1.44"/1.2" drives, and an XT turbo with 720k/360k drives. For some reason I just prefer to format DD disks on DD drives (even though I don't really have to).

MikeS
May 4th, 2017, 03:20 PM
There's also the option of using a simple switch or two to select which two drives out of three or more are active.

Stone
May 4th, 2017, 03:42 PM
I use two different systems, mostly a 386 with 1.44"/1.2" drives,...I know you didn't really mean this. :-)

Caluser2000
May 4th, 2017, 04:03 PM
I need to make a system that can transfer data between different size (physical and capacity) floppies.

From what I've gathered already, the system should run Windows 98SE, have ISA and PCI slots, onboard IDE and dual floppy controllers, and if possible USB.

I'm sure I can find the components, but I have a question: Is it possible to run ALL floppy sizes in one machine at the same time with additional floppy controllers?

If not, are there drives that can reliably write more than one type of floppy?Having it hooked up to a network is also handy.

glitch
May 4th, 2017, 04:25 PM
I use an industrial PICMG chassis with a 1 GHz P3 single board in it. It dual boots DOS 6.22 and Slackware Linux. Internal IDE hard disk, but no floppy drives in it -- I always hook something up external when I need it. I've got an Adaptec 1522 for writing single density floppies and dealing with old SCSI devices (I find it does better than newer controllers, especially if I'm trying to recover data from a dying drive).

The machine spends most of its time in Linux mode, but I do use DOS for my EPROM programmer (ISA based) and ImageDisk.

Obviously a PICMG/industrial system isn't anywhere close to essential, but they're nice in that you can change out the CPU card and have a different system. I usually drop a no-features 486 card in when I'm testing MFM/RLL/ESDI disks, since the controllers often don't seem to like the P3's BIOS. If you're going with a standard consumer PC, I'd say go for as fast of a P3 system as you can get, cram as much RAM in as is reasonable (some of them choke on more than 384 or 512 MB).

KC9UDX
May 4th, 2017, 04:57 PM
If I ever build one, it'll be an Amiga with an A2386 Bridgeboard. There's no disk format that I can think of that I couldn't read and write with that configuration that I could read and write with any other 'tweener' setup. Ethernet, USB, and RS232 all work perfectly well. SCSI, IDE, MFM, you name it. Can run any version of MacOS and Windows up to 95 (at least, I never tried anything newer) very well in an emulator, anything you can run on an 80386/16 AT clone natively on the Bridgeboard. Unix and Linux run natively on the Amiga and/or Bridgeboard. Add a PCI bus, and a PC-on-a-PCI card, and I really don't know what else you could want.

Chuck(G)
May 4th, 2017, 05:08 PM
For years I used a 386/20 "tweener" that had a 9GB SCSI 5.25" hard drive, a 1.44M 3.5"; a 1.2M 5.25" and a 360K 5.25" installed in an AT-styled desktop case. Inside was a DTC SCSI controller that supported up to 4 floppies (on the same cable), also a Deluxe Option board and a separate wire-wrapped WD2793 controller for an external drive.

I haven't fired the thing up in a long time, however.

KC9UDX
May 4th, 2017, 07:10 PM
Four floppies on one unit number, I presume. That means theoretically with one SCSI controller and that hard drive, you could have had 20 floppy drives just on the SCSI bus.

I yoosta have a bunch of SCSI floppy drives (one per unit number) and had five in one machine in addition to the four connected to the stock floppy controller. If I'd had some four-pers, I woulda set up a whole case full of floppies. :)

zombienerd
May 4th, 2017, 07:47 PM
I do this with my IBM Thinkpad 390 + Parallel Backpack 1.2mb Floppy. I haven't tried tossing a 360kb drive in the backpack, but I don't see why it wouldn't work. Works great with Win 98 SE. Has USB, WiFi capable (with my PCMCIA card), and works as my "I need to move X to Y, and wouldn't mind it on Z as well" machine.

Chuck(G)
May 4th, 2017, 07:59 PM
Four floppies on one unit number, I presume. That means theoretically with one SCSI controller and that hard drive, you could have had 20 floppy drives just on the SCSI bus.

I yoosta have a bunch of SCSI floppy drives (one per unit number) and had five in one machine in addition to the four connected to the stock floppy controller. If I'd had some four-pers, I woulda set up a whole case full of floppies. :)

The floppies aren't SCSI at all. Plain old legacy SA450 interface. The controller has the DTC-labeled verson of the National DP8473. This controller can drive 4 floppies directly. DTC thought to bring out the drive selects (with jumpers) so the cabling is "old style"--1 motor enable and DS0, DS1, DS2, DS3 for each the floppies. Flat cable.

There are variations on this--Ultrastor did a similar thing with some of their controllers, except that they brought out only a third drive select through unused pins on the cable (e.g. pin 4). It requires a rather peculiar twisted cable but you get motor control on each of the drives.

Some Future Domain controllers could be operated in this way with a simple wire patch on the board.

I've posted about this before.

KC9UDX
May 4th, 2017, 08:22 PM
Technically the SCSI ones I had (still have one somewhere) weren't SCSI either, but they had an adaptor board that bolted to the bottom of the drive and plugged into the pin header. The drivers were almost SA-450 as well (they had an extra signal for either eject or sense, don't recall which), which is why I don't have them anymore. I repurposed them as Amiga drives and ended up selling them as such eventually. I may have the SCSI adaptors yet, somewhere.

Chuck(G)
May 4th, 2017, 09:55 PM
The problem with SCSI (and USB) floppies is that the supported formats are pretty much hard-coded into the controller. Remember that SCSI disks are addressed by relative block, not CHS.

KC9UDX
May 4th, 2017, 10:04 PM
For my purposes at the time, they worked great. I was able to fool the tape backup utility I was using at the time into thinking the floppy drives were tape drives. Newer versions of the same utility had provisions to use them without any trickery, but by then I was done backuping my system to 200 floppies. :)

pcdata76
May 4th, 2017, 10:42 PM
I would install 360k and 1.2M 5 1/4" drives to the floppy controller and one IDE LS-120 drive, which supports 1.44M and 720k disks also. With this setup, your PC has the ability of supporting all common floppy formats (except 2.88M, which is actually quite uncommon) including 120M LS-120 as a bonus by using only one FDD and one IDE controller.

I'm using LS-120 drive in my daily computer (core i5) to transfer data from/to the vintage PC's in addition to the network. Performs quite reliable on both 720k and 1.44M formats.

Chuck(G)
May 5th, 2017, 09:34 AM
Currently, I use a bunch of drives mounted in PS/2 (4869) external drive boxes. When I need a specific drive, I just plug it into the machine I'm using and I'm set to go. This allows me to handle things like 3.0 inch CF floppies as well as 100 tpi 5.25" formats.

Malc
May 5th, 2017, 09:48 AM
My 'Tweener' is a Pentium MMX 166 with PCI and ISA slots, USB, CD-ROM, 360K and 1.44Mb floppy drives, If i need a 1.2Mb i either use a backpack or another machine but i mainly use 360k. DOS flies :-)

Stone
May 5th, 2017, 11:06 AM
Malc, yours is not too different from mine which has a 233MHz CPU and like you said, DOS really flies. :-)

Xacalite
May 5th, 2017, 11:56 AM
LS-120
It has the same problems as USB and SCSI FDDs:
- no support for non-standard diskette formats
- no support in software which directly accesses the FDC

So I prefer regular FDDs connected to a 4-floppy controller card.
And some day I'm going to build a modern PC with 1.44+1.2+360 FDDs controlled by KryoFlux. Yes, it's inconvenient when you want to just copy a few files, but it's the ultimate tool for diskette imaging.

jamesbeat
May 5th, 2017, 12:09 PM
Exactly what types of machines/drives will you be inter-operating with?

The main issue with disk and drive compatiblity is between 360k and 1.2mb drives. 1.2mb drives can not reliably write 360k disks (there are ways to make them "work"), and obviously 360k drives can't do anything with 1.2mb disks.

Ideally, one would usually want a 1.44mb drive (writes 720k disks fine), a 1.2mb drive, and a 360k drive.

But you will probably have to pick two.

Most motherboards and controllers only support two floppy drives. There are some rare 8-bit ISA controllers that support 4. In theory, changing the I/O address of an ISA floppy controller might let you use two additional drives, but would require a special BIOS or installing a device driver. Most don't have that option. No idea how those would work inside Windows.

One, probably less troublesome, option is to have two "tweeners" one with a 360k and another with a 1.2mb.

Another option is to have a 360k and 1.2mb internal and use a USB 1.44mb drive (you will want to hunt down one that supports 720k). But USB can not handle oddball formats or copy protection.

Also, keep in mind that with a tweener you are still limited to MFM (and FM if you are lucky) encoded disks such as those used by the IBM PC. If you wish to use Apple II, Commodore, or such, then you will need a Kryoflux and/or SuperCard Pro.


Since this is a dedicated machine for handling floppies, could you get around this by having switches to control which drives are receiving power?

What I mean is, connect all the drives, but tap into the power cable for each drive so that it can be switched on or off.
The data cable could remain connected, because that wouldn't matter if the drive isn't receiving power.
Mount the switches neatly in a blanking plate so they are easy to access.

Then, simply throw the switches for the two drives you happen to want to use at the time and boot the machine.

Depending on how many different drives you want, it might mean making or modifying some custom ribbon cables, but that's not particularly difficult to do.

krebizfan
May 5th, 2017, 12:16 PM
Could you get around this by having switches to control which drives are receiving power?

What I mean is, connect all the drives, but tap into the power cable for each drive so that it can be switched on or off.
The data cable could remain connected, because that wouldn't matter if the drive isn't receiving power.
Mount the switches neatly in a blanking plate so they are easy to access.

Then, simply throw the switches for the two drives you happen to want to use at the time and boot the machine.

It might mean making or modifying some custom ribbon cables, but that's not particularly difficult to do.

Take a look at http://www.seasip.info/VintagePC/floppies.html partway down shows how to have a switch and 3 floppy drives with only 2 being available at a time.

jamesbeat
May 5th, 2017, 01:00 PM
Take a look at http://www.seasip.info/VintagePC/floppies.html partway down shows how to have a switch and 3 floppy drives with only 2 being available at a time.

For a dedicated machine for handling floppies, it would be cool to put it in a server case with loads of drive bays and then have two of every type of drive with switches.

MikeS
May 5th, 2017, 01:02 PM
Take a look at http://www.seasip.info/VintagePC/floppies.html partway down shows how to have a switch and 3 floppy drives with only 2 being available at a time.
It can be even simpler without any cable mods; a SPST switch, common to DS1 from the controller on one of the drives and the other two to DS1 in of each drive; With a DPDT switch you could also control the motor.

jamesbeat
May 5th, 2017, 02:43 PM
Wouldn't it be simpler still to just have the switch cut power to the drive via the Molex connector?

If you bought some male and female power connectors, you could even make some pigtails with switches so you wouldn't even need to alter the wiring permanently.

It's a lot easier to modify power connecters than mess around with the ribbon cable.

I do this with hard drives all the time.
Whenever I install a new OS, I always disconnect the power from all hard drives except the one I'm installing the OS on.
Makes it impossible to accidentally format the wrong drive.
I leave the data cables attached when I do this and it works fine. I assume floppy drives would be the same.

MikeS
May 5th, 2017, 03:03 PM
Just on principle I'd be reluctant to have a live drive in parallel with an unpowered one, but I suppose it could work.

No need to make or modify any special cables though; just three single-pin connectors to plug on to the drive select pins (assuming they're available, of course... ;-) ).

KC9UDX
May 5th, 2017, 03:59 PM
Yeah, an unpowered drive might not be harmed in most cases but is not safe to assume in every case.

I'm guessing though no matter how you switch them, that putting 6 or more unpowered drives on one bus unbuffered is not a good idea either.

Plasma
May 5th, 2017, 07:10 PM
I would install 360k and 1.2M 5 1/4" drives to the floppy controller and one IDE LS-120 drive, which supports 1.44M and 720k disks also. With this setup, your PC has the ability of supporting all common floppy formats (except 2.88M, which is actually quite uncommon) including 120M LS-120 as a bonus by using only one FDD and one IDE controller.

I'm using LS-120 drive in my daily computer (core i5) to transfer data from/to the vintage PC's in addition to the network. Performs quite reliable on both 720k and 1.44M formats.

This is what I do. In the rare instance a 3.5" disk is a non-standard format, I can use teledisk on an older computer. Programs that write directly to the floppy like WinImage work fine with LS-120 drives. An added benefit is LS-120 is 2 to 4x faster.

Fire-Flare
May 9th, 2017, 06:34 PM
Thank you all for your advice. I can't be too picky on parts as my budget for this project is practically non-existant, but so far I've pulled the following from my job's scrap piles:

A working ATX motherboard that has ISA slots.
A case with 4 external 5.25" drive bays and two external 3.5" bays and a 350w PSU.
360kb and 1.2MB 5.25" drives.
A NIB 3.5" floppy drive that claims to be capable of reading and writing 720kb and 1.44mb floppies.
A 500GB IDE HDD.

And from Ebay I bought a quad-floppy controller (no IDE or SCSI to worry about) and Windows 98SE.

I still need a 720kb 5.25" drive and a 360kb 3.5" drive, but those will have to wait as I can't find any at a price I'm willing to pay.

Caluser2000
May 9th, 2017, 06:41 PM
I still need a 720kb 5.25" drive and a 360kb 3.5" drive, but those will have to wait as I can't find any at a price I'm willing to pay.Do they even exist?

Formulator
May 9th, 2017, 06:56 PM
I still need a 720kb 5.25" drive and a 360kb 3.5" drive, but those will have to wait as I can't find any at a price I'm willing to pay.

Sometimes you get lucky. Just check regularly.

http://www.ebay.com/itm/182502710048

krebizfan
May 9th, 2017, 06:59 PM
Do they even exist?

Yup, they do exist. Shugart SA-300 is the classic 360kB 3.5" drive and Teac 55FR and 55FV are some examples of quad-density 5.25" drives. Scarce and expensive these days. Neither is really needed. 360kB on a 3.5" drive is generally* a single sided format and can be produced by any floppy drive capable of doing 720kB double sided formats. 5.25" high density drives can be used to write 720kB formats with special drivers.

* There is also the original IBM JX format which is double sided but only writes the first 40 tracks.

Fire-Flare
May 10th, 2017, 11:47 AM
Something's not working right. I've assembled all the components and installed Windows and drivers, but I'm unable to see the 360kb 5.25" drive in Windows.

Maybe it's the controller? This is the manual for it: http://www.minuszerodegrees.net/manuals/Kouwell/Kouwell%20KW-530F%20-%20configuration.pdf

I've tried jumpering the connection to make it the secondary floppy controller and moving the cable to the second header, but I still only see the motherboard's floppy drives...

If this is IRQ related, someone's going to have to walk me through it. I don't know anything about those. :(

Chuck(G)
May 10th, 2017, 12:27 PM
Does the BIOS setup in your system allow you to disable the (on board) floppy controller? If so, do that--you should still be able to set the A and B drive types in the BIOS. Also, is the FDC BIOS showing that it's loaded? (I'm assuming that it's U2 on your FDC board) If not, you probably have an addressing conflict.

Also, forget about secondary addresses--most FDC BIOS-in-ROMs only work with IRQ 6, Port 3FxH and DMA 2.

Rick Ethridge
May 10th, 2017, 01:40 PM
Later versions of Windows don't support 360K 5.25 inch floppies. Won't even run in a DOS window.

Stone
May 10th, 2017, 01:48 PM
Something's not working right. I've assembled all the components and installed Windows and drivers, but I'm unable to see the 360kb 5.25" drive in Windows.What happens when you boot from the floppy drive?

jamesbeat
May 10th, 2017, 02:18 PM
Yup, they do exist. Shugart SA-300 is the classic 360kB 3.5" drive and Teac 55FR and 55FV are some examples of quad-density 5.25" drives. Scarce and expensive these days. Neither is really needed. 360kB on a 3.5" drive is generally* a single sided format and can be produced by any floppy drive capable of doing 720kB double sided formats. 5.25" high density drives can be used to write 720kB formats with special drivers.

* There is also the original IBM JX format which is double sided but only writes the first 40 tracks.




Yes, the drive that was originally in my Atari ST was 360K, and that just meant that it was single sided.

Most commercial software came on single sided disks so as not to exclude people with the single sided drive.

ST Format magazine even came up with some clever format so that people with single sided drives would at least be able to access half of the stuff on their cover disks.
People with double sided drives could click the folder called 'side 2' to access the rest of the stuff.

My best friend had a double sided drive in his, and I was very envious.

I eventually scraped together the money for a double sided drive, which opened up a whole new world of cracked menu disks :)

My point is that a 360K disk is just one side of a 720K disk, so a standard drive should be able to do both.

Edit: just to be clear, I'm talking about 3.5" drives here. No clue about other sizes.

KC9UDX
May 10th, 2017, 02:23 PM
That's good to know. I had no idea that the Ataris came with single sided 3.5s. I thought that was limited to Apples and Japanese machines.

Fire-Flare
May 10th, 2017, 02:37 PM
Does the BIOS setup in your system allow you to disable the (on board) floppy controller? If so, do that--you should still be able to set the A and B drive types in the BIOS. Also, is the FDC BIOS showing that it's loaded?

I disabled the onboard FDC, and got a floppy error until setting the onboard drives to disabled. The card does not appear to have its own BIOS during startup.

Chuck(G)
May 10th, 2017, 02:47 PM
I think it's worse than that--normally, you can pop in a floppy card set to Port 3fx, IRQ 6 DMA 2 and disable the on-board integrated floppy--even if you don't have a floppy BIOS and it should work. After all, a floppy controller hasn't changed much at all from the 5170 days.

So, next question: What is your motherboard--and do we have a data sheet on it? Some later motherboards permanently reserved IRQ6 DMA2 for the integrated floppy and didn't bother to make them available for ISA peripherals. In particular, many P3 and later boards did this.

When did Windows stop supporting 360K floppies? I can still format, read and write them in XP.

Fire-Flare
May 10th, 2017, 02:48 PM
What happens when you boot from the floppy drive?

When set as drive A on the integrated controller and enabled in BIOS, it boots my DOS disk.

Fire-Flare
May 10th, 2017, 02:55 PM
I think it's worse than that--normally, you can pop in a floppy card set to Port 3fx, IRQ 6 DMA 2 and disable the on-board integrated floppy--even if you don't have a floppy BIOS and it should work. After all, a floppy controller hasn't changed much at all from the 5170 days.

So, next question: What is your motherboard--and do we have a data sheet on it? Some later motherboards permanently reserved IRQ6 DMA2 for the integrated floppy and didn't bother to make them available for ISA peripherals. In particular, many P3 and later boards did this.

When did Windows stop supporting 360K floppies? I can still format, read and write them in XP.

My motherboard is an Asus P2B rev 1.10


When I was installing Windows, I noticed that the third floppy drive would light up when the first floppy was active. Perhaps they were both configured as drive A?

Chuck(G)
May 10th, 2017, 03:07 PM
Hmmm, the P2B is a 440BX chipset--generally thought of as one of the more compatible ones. Heck, I've probably got a P2B around here somewhere. I definitely have a P2A (SS7) and it works just fine with an add-in controller--just disable the in-board controller. Boots to DOS just fine--which is what you're going to want to do if you want a real "tweener".

I suspect that you might have the cables for floppies 1+2 and 3+4 swapped. Otherwise, there'd be no reason for drive 3 to get selected.

Fire-Flare
May 10th, 2017, 03:17 PM
I suspect that you might have the cables for floppies 1+2 and 3+4 swapped. Otherwise, there'd be no reason for drive 3 to get selected.

I think both were configured as the first drive on their respective controllers. If there was a conflict it make sense to me that they'd both try to be active.

Chuck(G)
May 10th, 2017, 03:40 PM
Well no, not really. The motor control/select register is a simple latch. The layout is something like this:

WXYZ EE AB

WXYZ = bits 7-4, motor control for each drive.
EE - Enable for IRQ/DMA
AB = binary select code for 1 of 4 drives

Note that this register is outside of the general NEC 765 internals. So if you write 4E, to port 3F2, you'll select drive A: and turn the motor on. Since this is a write-only register, any number of these can be present at the same I/O port address. So if you're getting the third floppy selected when the BIOS accesses drive 0, you've got your cables swapped. I can't think of any other explanation.

jamesbeat
May 10th, 2017, 05:01 PM
That's good to know. I had no idea that the Ataris came with single sided 3.5s. I thought that was limited to Apples and Japanese machines.

I believe it was very early on in the production of the 520STFM - mine must have been one of the first ones made, because they moved over to the double sided drives very quickly.

It was nice of the software houses to continue to cater to the single sided folk out there. I guess there must have been quite a few of us out there to make it worth their while (they sometimes had to supply two disks instead of one).

So, if you ever had an ST game that came split across two disks and had to keep swapping them, you can thank us single sided drive owners :D

Actually, I could only put up with it for a short while before I begged and pleaded with my parents to lend me the money for a double sided drive, so I didn't have to put up with it for long.

This was my first ever computer upgrade.
I remember that the new drive was slimmer than the old one.
From memory, I believe it was the same size as a standard floppy drive - the old one was deeper.

This left a gap along the entire top of the drive.
I filled this with a strip of beige plastic that I cut from one of the dividers out of my floppy disk storage box - I just glued it into the inside of the case above the drive.

I suspect most other people performed the same upgrade, which makes me wonder how much business sense it really made for the software houses to keep supporting the single sided drives.

KC9UDX
May 10th, 2017, 06:07 PM
The same thing happened with Amiga software. Nothing was ever published on 1.76M disks that I'm aware of, even though most people buying software had 1.76M drives.

Fire-Flare
May 11th, 2017, 09:25 AM
Well no, not really. The motor control/select register is a simple latch. The layout is something like this:

WXYZ EE AB

WXYZ = bits 7-4, motor control for each drive.
EE - Enable for IRQ/DMA
AB = binary select code for 1 of 4 drives

Note that this register is outside of the general NEC 765 internals. So if you write 4E, to port 3F2, you'll select drive A: and turn the motor on. Since this is a write-only register, any number of these can be present at the same I/O port address. So if you're getting the third floppy selected when the BIOS accesses drive 0, you've got your cables swapped. I can't think of any other explanation.

Update: I'm able to access the first two floppy drives using the add-in controller by disabling the internal controller but leaving the size and capacity settings for the onboard controller the same as the add-in board's switches.

Disabling the integrated floppy controller and setting its drive types to "none" shows an unusable 180Kb 5.25" drive in Windows. (I know my 3rd floppy is a 360Kb from Googling the model number.)

You mentioned IRQ 6 and DMA 2, but those aren't available in the motherboard's BIOS.

Is there still a way I can get the two controllers to work independently the same time?

Chuck(G)
May 11th, 2017, 12:32 PM
Perhaps, but you'll need drivers that can be so configured to use non-standard port addresses.

If you disable the integrated controller, you're freeing up the DMA, port and IRQ resources for use by the add in board.

Some utilities, such as ImageDisk can be made to work with non-standard configurations, but they're not general-purpose drviers.

Fire-Flare
May 12th, 2017, 12:44 PM
I've decided to just use the integrated controller and swap the connector and settings, but I've run into another hurdle: The programs I've installed to write downloaded floppy images in 98 either 'expect a newer version of Windows' or 'perform illegal operations' when attempting to write.

What program (and version) do you guys use?

Caluser2000
May 12th, 2017, 01:10 PM
First tell us what software you are attempting the use.

Look for old versions of winimage or you should be able to run dos based programs.

Stone
May 12th, 2017, 01:26 PM
I have WinImage 8.00 and 8.50 and they both work with WIN9x.

Fire-Flare
May 12th, 2017, 03:37 PM
I was using WinImage 8.1 as it's the most recent version that states it has 9x support.

WinImage 8.5 won't install because it expects a newer version of Windows, and 8.0 also performs an illegal operation.

The image I'm trying to write is the Corona Data Systems DOS 1.25 (Bios 1.07) https://winworldpc.com/product/ms-dos

krebizfan
May 12th, 2017, 03:46 PM
WinImage will not work with DOS 1.x created disks. ImageDisk probably can. http://www.classiccmp.org/dunfield/img/index.htm

Chuck(G)
May 12th, 2017, 03:55 PM
Be sure to run IMD under DOS, not Windows. You can shut down Win9x to MS-DOS command prompt mode (very different from just opening a DOS prompt window).

Fire-Flare
May 15th, 2017, 11:39 AM
Finally wrote the disk. Thanks guys!