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4x disk drives on a 5150 via 2x HxC2001's is a go !

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voidstar78

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I can't remember the last time I made a cable - been decades. So pardon I'm a little excited. And it works, 37-pin to 34-pin adapter to the external connector of the floppy disk controller. I couldn't find a supplier of these anywhere.

This is with 2x HxC2001 floppy emulators. I'm using a Molex to 4-pin Y splitter of one of the physical 5.25" drives to power them (presently hanging out the case just to verify that the cabling all works)..

Only thing to remember: if you boot PC-DOS before v3.2, you can only use 360KB disks images or less. v3.2 or later, you can use 720KB images (and the 5150 stock controller won't support over 720K, but the HxC can if you use some newer controller).


Attached is CheckIt 1.10 reporting the drives (along also with the XT-IDE E: drive - and verified they all 4 work without the XT-IDE, or with the XT-IDE then just pushing E on startup let the XT-IDE boot from the CF as E:). [CheckIt says XT, but this is really a 5150 later model B configured with the onboard 256KB RAM @ stock 4.77mhz 8088]


If you boot with PC-DOS 2.10 and set the HxC to 720KB images (that 2.10 doesn't support), then you get funny results when doing DIR (see attached).


The cable is kind of easy to make, but you do need a couple parts and tools, so it's not completely trivial. It's a bit late in the day now, but I'll try to post a write up somewhere about it tomorrow (the notes at minueszerodegrees.net are good, but not quite a step-by-step tutorial).



The next thing I want to verify is if I can just use the external drives by themselves -- and if so, do I need to still leave it as 4-drives in the dip settings or can I leave it as 2-drives? What I'm trying to get at is: if someone has a bone stock 5150 model A, and absolutely didn't want to open it - but they wanted a little extra disk space to work with (or couldn't find physical disk media for some software they wanted to try, or didn't have a slot open for an XT-IDE, etc.), then they could just attach an HxC to the external port (but I'm not sure if they can boot from it). You'd still have to open the case at least once, to probably set it to 4 disk drives. Or if you leave it at 2 drives and just remove the internal edge connector, maybe you can boost from the external connections? We'll see, ran out of time today to try. [ but without the case open, then you'd have to find a 4-pin power connector for the external drives - USB to Molex to Berg maybe? ]


And the 63W handles this just fine.
 

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Thanks, the notes there do indicate that we won't be able to boot from the external drives (BIOS limitation).


And, I didn't need to load DRIVER.SYS . Is that needed only if you don't adjust the dip-switches? Or is it needed on the earlier BIOS revisions (of a 5150 model A)?


The cable to start with from Amazon is:
"uxcell IDC Wire Flat Ribbon Cable DB37 Male to FC-40 Female Connector 2.54mm Pitch 20cm Length"
10 bucks is a lot, should be plenty to be found at the right places. But in any case, that's what you're looking for (nice 37-pin connector side -- and it's a 37-wire ribbon cable, silly they put on a 40-pin connector). Disregard the 3 wires starting from the "red" side, and crimp on one of these: "34 Pin Dual Row IDC Socket - Female"
https://www.showmecables.com/34-pin-...AaAvSnEALw_wcB
Can find at a lot of vendors, but some have minimum orders (of like 50!).

I'm maintaining a set of draft notes here: (for my overall 5150 setup, so years later I can remember what the heck I did!)
https://voidstar.blog/ibm-pc-5150-notes/
 
voidstar78 said:
And, I didn't need to load DRIVER.SYS . Is that needed only if you don't adjust the dip-switches? Or is it needed on the earlier BIOS revisions (of a 5150 model A)?
Click to expand...

Speaking from the experience of cramming 3.5" floppy drives into a lot of 5150/5160s back in in the day: the deal with DRIVER.SYS (an alternative for non-IBM versions of MS-DOS 3.2 and later is the DRIVPARM built-in config.sys directive) is you usually only really need it if you want to format 3.5" disks at the proper size of 720k. DOS versions post-2.x store a description of the individual floppy's geometry on the disk itself so if you boot a 5150 without DRIVER.SYS/DRIVPARM set up and insert a 720k disk into your floppy drive it'll read and write to it just fine, the geometry written to the disk will override DOS'es assumptions based on the BIOS. (The only difference between a 360K disk and a 720k one is the latter has 80 tracks of data instead of 40, they use a compatible number of sectors per track, controller density, etc, so the BIOS driver will be able to step to track zero and read the boot sector where the geometry is stored without a problem.)

The issue comes if you want to format a disk: obviously a blank disk has no "geometry" coded on it so this is when BIOS defaults kick in. So without one of those patches a 5150 with a 3.5" disk drive connected to the stock controller will format blank disks to 360k instead of 720k. If you're just using disk images in an emulator you may never care about formatting a disk, so you may not need to care about DRIVER.SYS/DRIVPARM.

Re: PC-DOS 2.1 being unable to read your 720k disks, that may be a quirk specific to that version. Tandy's DOS 2.11 shipped with early Tandy 1000 models doesn't seem to have that problem. I mostly ran DOS 3.2 or higher back in the day so I don't think I ever tried a 5150 with a 720k drive in it under 2.1.
 
Actually, I guess one other note, since it seems like maybe this needs more clarification:

voidstar78 said:
And, I didn't need to load DRIVER.SYS . Is that needed only if you don't adjust the dip-switches? Or is it needed on the earlier BIOS revisions (of a 5150 model A)?
Click to expand...

As Exceter said in his post, the other thing DRIVER.SYS can do is act like an "enabler" for drives that BIOS doesn't enumerate. In his config he's using it not just to set the size of the floppy drive to 720k, he's also using it to tell DOS that there's a drive there at all because he left the motherboard switch settings set to 2 drives. Per a link in his post there *is* apparently an issue with the XTIDE BIOS that makes it screw up autoboot when the switches are set for three or four drives. If you used driver.sys instead you'd avoid this problem: the extra floppy drives would show up *after* the hard drives instead of in front, so your hard disk would remain C: and the extra floppy drives would be D: and E:. Personally that sounds like a better idea as long as you're willing to spend a few hundred bytes of RAM for DRIVER.SYS to be resident.
 
I'm still playing around with the 4 drive configuration. Including also having two hard drives on the XT-IDE. Which there are different variations of the XT-IDE, I got the XT-IDE Deluxe with the 32K EEPROM (boot menu). But having 6 total drive letters works, but indeed not always predictable on how the drive letters will play out. [ kind of funny to me, in all these years I never really heard of anyone running out of drive letters - I think the most I ever used at once, with including like mapped drive letters, was maybe about 18; I wonder how hard "two letter drive letters" would be to add to any DOS ]

Not being able to boot from the external connector is unfortunate.

Configured down to 64KB RAM, I could boot up to PC-DOS 3.00 (but 3.20 won't, it gives a message "Configuration too large for memory").

For the price, there's kind of no reason NOT to get an XT-IDE. It's the most practical way to get files onto a 5150 system. Only reasons not to use an XT-IDE that I can imagine is if the 5 expansion slots are filled already.

But before I had the XT-IDE, I had no physical 5.25" floppy disks. I ended up getting the floppy emulators before I got the XT-IDE. With just 160/180KB images, you run out of space quickly. The two external drives gives some "breathing room", like having a compiler on (disk) C: and source/data on D: (with the OS on A: and extra reference files on B).


Just exploring some scenarios where the external drives would be handy. Like: can keep 2 physical drives A: B: (if ever handling physical disk media), have XT-IDE, then use external drives to introduce new files via SD-card (if don't want to remove the XT-IDE CF card, like maybe it was internal and didn't want to open the case-- and didn't have a NIC).

Also just verifying the BIOS support to handling the 4 drives.
 
voidstar78 said:
I'm still playing around with the 4 drive configuration. Including also having two hard drives on the XT-IDE. Which there are different variations of the XT-IDE, I got the XT-IDE Deluxe with the 32K EEPROM (boot menu). But having 6 total drive letters works, but indeed not always predictable on how the drive letters will play out. [ kind of funny to me, in all these years I never really heard of anyone running out of drive letters - I think the most I ever used at once, with including like mapped drive letters, was maybe about 18; I wonder how hard "two letter drive letters" would be to add to any DOS
Click to expand...

Sanity check: Do you have a LASTDRIVE directive set in your Config.sys? I believe in most versions of DOS post-3.0 it defaults to “E:”; I think it’s supposed to increment that to be one more than the number of disks BIOS detects but pretty sure that means “physical” disks only, not hard drive partitions. So things might get weird if you have four floppy drives set up in the BIOS and then start partitioning up your HD.

Out of curiosity did you ever try that HFE format disk image of DOS 1.0 I posted in your 8-sector thread in your HxC?
 
Eudimorphodon said:
Out of curiosity did you ever try that HFE format disk image of DOS 1.0 I posted in your 8-sector thread in your HxC?
Click to expand...

Ah, yes I did. I got distracted with the tape cassette for a bit, and did forget to report about the DOS 1.0.

That HFE did boot just fine (in the HXC2001). But, I couldn't open it either winImage or the HXCImage editor (hmm forget what they call it, from the HXC site). Which means, I can't add files into it. So for instance, if I make a copy of that HFE and just call it BLANK.HFE and just want to clear it out (make it a "blank disk"), I couldn't open it at all (to add or remove files).

So aside from running the BASIC samples, there wasn't a whole lot to do with it (and most of those same samples are in PC-DOS 2.10, although on a separate disk 2).
 
voidstar78 said:
Ah, yes I did. I got distracted with the tape cassette for a bit, and did forget to report about the DOS 1.0.

That HFE did boot just fine (in the HXC2001). But, I couldn't open it either winImage or the HXCImage editor (hmm forget what they call it, from the HXC site). Which means, I can't add files into it. So for instance, if I make a copy of that HFE and just call it BLANK.HFE and just want to clear it out (make it a "blank disk"), I couldn't open it at all (to add or remove files).
Click to expand...

I did a little experimentation and, yeah, you're right, the disk browser in the HxC software package has no idea how to parse a DOS 1.0 disk. (And of course ImageDisk is going to have *no idea* what to do with an HFE. What happens if you convert back to raw, does that also fail?) But the point is made that using HFE you *can* get the hardware emulator to accept 8-sector disks. You could always do transfers by using a later DOS version as a middleman, and it also shows you can make workable images of existing raw images by loading them into the HFE software and exporting them out as HFE.
 
Thanks Eudimorphodon for the heads up about DRIVER.SYS, I think I get it now.


With a single XT-IDE and single partition CF (128MB), with the dip-switches set to 4 drives, I get letters: [ A B C D ] Floppies then [ E ] HDD. I can access any of [ A B C D ] fairly instantly (just type the drive letter). But on booting, I have to mash E all the time to force XT-IDE to boot from E:. Then a lot of installs (and even the PATH, CONFIG.SYS paths etc,) will likely still reference C: instead of adjusted boot drive of E:.



With a single XT-IDE and single partition CF (128MB), with the dip-switches set to 2 drives, I get letters [A B ] Floppies then [ C ] HDD. I can't access the other Floppies with D: or E: (even though they are attached to the external port). To resolve, the CONFIG.SYS must contain the
DEVICE=\DOS\DRIVER.SYS /d:2 /t:80 /s:9
Once for each desired drive [ D and F ], so twice. Then, at least with DR DOS 3.41, when I go to those drives [ D or F ] for the first time, I have to press a key and wait awhile (as prompted by DOS). (maybe that first time access is resolving the geometry?)




EDIT/NOTE: I do have the 2nd (CF) HDD, but was just trying it out to make sure it worked with the XT-IDE. But taking it out (for now) since I don't have an available expansion slot. SB/Joystick, NIC, Serial/Parallel, CGA or VGA, FDC. (don't really need the FDC since can just FTP files into the system via the NIC or remove the CF card itself - but still like to play with some HXC images)
 
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