I would use the 3.5" floppy as A drive, then add the 5.25". Why: My XT/3 has a 720k as A and the 360k as B so I can easily from any computer with a 1.44Mb 3.5" make bootable or other disks for it if needed.
If you use the 360k as A then you need another with good 360k drive AND good 5.25" floppies to do anything with it as far as creating bootable media >>> I tried it that way and it became to big a chore.
Just my thoughts....
Which scsi controller are you going to use ? I like the 8bit Data Cannons or any NCR based (Rancho Tech, Trantor 128, etc) ....

Thought XTs can't handle high-density at all.
I would go with 2 360K drives because that's how my XT used to be, so lots of XT software were built with that in mind. But if the machine had an HDD, typically they'd keep only one 360K drive.
3 or 4 floppy drives doesn't compute with me 😅 and I'd be surprised if any software can use that (besides DOS).

Hi, I'm not sure. Currently, I'm using a 5,25" 360KB drive as A: and a Gotek as B:.
A: is the real one because of booter games, etc. Booting from B: is possible through a special boot floppy, which has Boot_B program.
The XT can handle 3,5" 720KB format by using 2M-XBIOS driver.

wbahnassi wrote on 2024-04-21, 04:19:

Thought XTs can't handle high-density at all.
I would go with 2 360K drives because that's how my XT used to be, so lots of XT software were built with that in mind. But if the machine had an HDD, typically they'd keep only one 360K drive.
3 or 4 floppy drives doesn't compute with me 😅 and I'd be surprised if any software can use that (besides DOS).

XT can handle High -density drives if you have the right controller card with bios extensions.
Iam going use a 4 way one.

So two drives goes on primary IDC.

And drive 3 goes on the secondary IDC

What i also really want to know which is the best to do, when i have to look out for the drive interface cable length.

Interesting. I wonder how they do more than 2 drives on that card when the main chip only does 2.

Horun wrote on 2024-04-21, 01:35:

I would use the 3.5" floppy as A drive, then add the 5.25". Why: My XT/3 has a 720k as A and the 360k as B so I can easily from […]
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I would use the 3.5" floppy as A drive, then add the 5.25". Why: My XT/3 has a 720k as A and the 360k as B so I can easily from any computer with a 1.44Mb 3.5" make bootable or other disks for it if needed.
If you use the 360k as A then you need another with good 360k drive AND good 5.25" floppies to do anything with it as far as creating bootable media >>> I tried it that way and it became to big a chore.
Just my thoughts....
Which scsi controller are you going to use ? I like the 8bit Data Cannons or any NCR based (Rancho Tech, Trantor 128, etc) ....

The scsi controller adapter is a Seagate ST-02
I know that earlier scsi was proprietary too.
Its having a matching st- 296n to it. Needed a special tool to get these two coupled.

weedeewee wrote on 2024-04-21, 20:59:

Interesting. I wonder how they do more than 2 drives on that card when the main chip only does 2.

Maybe the main controller could do actually 4..
Yes 2 drives where the most used.
But with a IBM XT CLONE.. you have (if you use half height drives) 4 spaces to install drives in.

That changed when the IBM 5170 came to the market.. And only mostly had 2x 5.25 external, and sometimes with 1x 5.25 internal low above the bottom of the case.

I got the 4 way drive controller working.

The rule of tumb here is, you cant skip drive C: if you want the 1.44MB drive on the secondary IDC.

So you would have A: B: and D:
Its only possible to do A: B: C: so HDD would be probably D:
If you install a fourth drive.. HDD will be E:

Thought i had to install a driver for drive 3 and 4.. But that was not how it came out.

Drive A: and B: needs to be on the same cable on primary IDC.
Drive C: is on secundairy IDC.

Find out that you also can do this:

So the 3.5 inch 1.44 MB drive just cant work on a single drive cable in the middle before the twist comes?
Does these 3.5 inch 1.44MB drives also have termination and should it be possible to disable that?

wbahnassi wrote on 2024-04-21, 04:19:

Thought XTs can't handle high-density at all.
I would go with 2 360K drives because that's how my XT used to be, so lots of XT software were built with that in mind. But if the machine had an HDD, typically they'd keep only one 360K drive.
3 or 4 floppy drives doesn't compute with me 😅 and I'd be surprised if any software can use that (besides DOS).

If i dont use 3 floppy drives, i dont have nothing to fill the blank spaces with.
And i also have 2 other XT class systems here.. So propably most of the time would use the system as transfer / format / backup system.
So 3 drives would be very helpfull in any way.

Robin4 wrote on 2024-04-21, 22:28:

So the 3.5 inch 1.44 MB drive just cant work on a single drive cable in the middle before the twist comes?
Does these 3.5 inch 1.44MB drives also have termination and should it be possible to disable that?

Most 3.5" newer floppy drives are locked at second ID for "A" after the twist, some have jumpers that you can change to first ID and put it middle before the twist and be A drive.
Most newer are auto terminated, those with jumpers might have a Term enable jumper but most are auto....
added: Your Panasonic JU-257 should have jumpers or switches. If switches it is sw3 that sets the ID...only the ones with jumpers have a TM term enable/disable, the ones with switches do not.
I cannot find the exact JU-257T234

Horun wrote on 2024-04-22, 00:04:

Most 3.5" newer floppy drives are locked at second ID for "A" after the twist, some have jumpers that you can change to first ID […]
Show full quote

Robin4 wrote on 2024-04-21, 22:28:

So the 3.5 inch 1.44 MB drive just cant work on a single drive cable in the middle before the twist comes?
Does these 3.5 inch 1.44MB drives also have termination and should it be possible to disable that?

Most 3.5" newer floppy drives are locked at second ID for "A" after the twist, some have jumpers that you can change to first ID and put it middle before the twist and be A drive.
Most newer are auto terminated, those with jumpers might have a Term enable jumper but most are auto....
added: Your Panasonic JU-257 should have jumpers or switches. If switches it is sw3 that sets the ID...only the ones with jumpers have a TM term enable/disable, the ones with switches do not.
I cannot find the exact JU-257T234

Yes, thank you.. Thats a good one to remember.
I will look for something older.
I will report back when i found the solution or a other update.

Just mentioning there are two options to get three floppies in one full height/two-half height bays...

A two in one 3.5 and 5.25 drive... rare, gets you two drives in one half height package, I guess technically if you have hundreds of bucks to blow and a horseshoe up your butt you could find and buy two and have 4 floppies in the height of a full height bay.

Third height 5.25s, which exist for low values of exist, also quite rare, think they were for one of the Compaq portable. Third full height which makes them 2/3 half height. Maybe there are brackets obstructing a fitment across two half bays in some systems that make things difficult. Anyway, two of these types of 5.25s and 3.5 adapters are available where the 3.5 is at the bottom more or less, and it's all faceplate above the drive, which you'd have to trim down to make the 3.5 assembly also third height.

Then also For super7 and slot 1 and later systems, you may find you can get a 1.2MB 5.25 that is a bit more slimline behind the faceplate and squeeze a compact USB floppy into it also, either connecting with USB internally or by hacking it to take regular interface. There's also some slimline drives built into "media bay" 3.5" drives that have floppy and card readers, but it's kind of a shame to spoil one of those to hack the drive mech out of it, unless it's had some weirdly specific damage to the card reader part.

Horun wrote on 2024-04-22, 00:04:

added: Your Panasonic JU-257 should have jumpers or switches. If switches it is sw3 that sets the ID...only the ones with jumpers have a TM term enable/disable, the ones with switches do not.
I cannot find the exact JU-257T234

There's definitely quite a range in the JU-257 model numbers, the nice fully configurable old ones, to the ones that look like anything made in the 2000s, heavily cost optimised where they didn't even bother to put all the pins in the 34pin connector, like leaving off most of the grounds.

I thought about this question..

Is it true that the drives on the left side have to removed first before you can remove the units on the right side?

Also found out that the right side have more screw holes on the bottom.. (yes it was designed like so that the motherboard is otherwise in the way?

A also think that a heavyer HDD would be much more secured on the right side of the cage then on the left side..

So probably it would be better to have the two 5.25 inch drives on the left side..

Then on the right side on the the 5.25 inch bracket to 3.5 inch for mini floppy drive and on the bottom the half height HDD or HDD 5.25 inch to 3.5 inch bracket.