VOGONS


First post, by keenerb

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I'd like to add high-density floppy support to this Tandy 1000TX I've found, but it looks like most of the 8-bit XT class floppy adapters are double-density only, and/or don't have a bios so I can boot from them?

Anyone have any suggestions on how to (relatively easily) add a HDD floppy controller?

Reply 3 of 15, by carlostex

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The easiest way is too use 2M-XBIOS on the DOS prompt, but if you need HD support at boot time there's no way around a ISA card with a BOOT ROM.

You can:

1- Get a floppy controller with a ROM BIOS;
2- Use a 16bit NIC with a socket for a ROM BIOS, keep in mind to configure the card first so that the ROM is placed at a bootable address;
3- Build an ISA ROM card yourself;

Last edited by carlostex on 2016-02-23, 16:07. Edited 1 time in total.

Reply 4 of 15, by konc

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If you really want to add and use an HD drive with HD capacity (format it to 1.44MB), people above me are 100% correct. I could even change that to "more difficult than you can imagine" and good luck with it.

But just making sure since from the context of your post, at least for me, it's not 100% certain what you're trying to achieve:
If you only want to connect a 3.5" HD drive (because the one it has now is broken for example) and you think it needs to be a DD one, then this is not the case.
You can connect a normal, brand new 1.44 drive (well, almost all of them) and it will just work as long as you make sure you use "DD" (HD with the hole taped) disks on it.
This is not applicable for 5 1/4" drives though.

Reply 5 of 15, by stamasd

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I've actually done exactly that - added HD floppy support to a XT clone. It's easier than you think.

There are 2 parts: the hardware, and the software.

1. The hardware: many, if not most 16-bit IDE+floppy cards work just as well when plugged in a 8-bit XT slot. The floppy controller will then work in DD mode (because that's all that the XT BIOS supports), and the IDE will not work at all (because the XT BIOS has no support for it) if that is all that you do. To make the FDD work in HD mode, and the IDE to work at all, you need #2

2. The software: as I said above, the native support is very limited. You can make the hardware work by adding software as BIOS extensions.
For the FDD, use a BIOS from a HD FDD card such as http://minuszerodegrees.net/rom/bin/Kouwell%2 … %20-%201987.bin
For the IDE, use the XTIDE universal bios https://code.google.com/archive/p/xtideuniversalbios/ configured for a 16-bit IDE controller in 8-bit mode. Yes it will be slower, but with the XT 8-bit bus that's all you can hope for.
What to do with the BIOS extensions? Write them to an EPROM and place the EPROM somewhere where it will be scanned by the startup code of the BIOS (any startup address on a 8kB boundary between C000 and F400 will work). See my thread at http://www.vcfed.org/forum/showthread.php?484 … omponents/page5 where I detailed how I did exactly that.

I/O, I/O,
It's off to disk I go,
With a bit and a byte
And a read and a write,
I/O, I/O

Reply 6 of 15, by alexanrs

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Just beware that using XTIDE with a regular 16-bit ISA multiIO is no sure way to get hdds going. For that to work the HDD itself must support working in 8-bit mode (the full XT-IDE card has additional logic to compensate for that), and they usually don't. I think CF cards are required to do so, though, so this is useful if you plan on using CF cards instead of HDDs.

Reply 7 of 15, by stamasd

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I used the setup successfully with CF cards as well as microdrives. Haven't tested on real IDE HDDs because, well, I don't have any. 😀

I/O, I/O,
It's off to disk I go,
With a bit and a byte
And a read and a write,
I/O, I/O

Reply 8 of 15, by alexanrs

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stamasd wrote:

I used the setup successfully with CF cards as well as microdrives. Haven't tested on real IDE HDDs because, well, I don't have any. 😀

Me too. My XT-class machine works with CF cards normally. I've tried IDE HDDs (even old sub-1GB ones) and none of them worked. For a 8088 machine unless you really want HDD noise you're better off using CF cards anyway.

Reply 10 of 15, by Jolaes76

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Just beware that using XTIDE with a regular 16-bit ISA multiIO is no sure way to get hdds going.

I have recently gone through such an ordeal. Even with a 16 bit controller such as the GoldStar Prime 2 (original) which has support for 8 bit IDE mode, regular ATA drives will not work. The port can be jumpered from 1F0h to 320h on the card, but you will still need a HDD that can do the "bitstream-splitting".
I do not have XTA HDDs either but have MFM controllers that work, naturally.

"Ita in vita ut in lusu alae pessima iactura arte corrigenda est."

Reply 11 of 15, by keenerb

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Thanks for all the feedback. It appears even more complicated than I initially thought, since I'm working with a Tandy 1000TX.

I've ordered a full selection of lo-tech XT expansion boards and will be spending the spring populating those. I've also got a WD1002A floppy controller on the way that supposedly the Tandy support (but only if booting from hard disk!)

In addition to all that, I've picked up a Gotek floppy emulator that multiple people report is compatible with the on-board controller, so that will be good enough for now until I get the XT-IDE card put together.

Reply 12 of 15, by stamasd

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Keep in mind that no matter what kind of floppy drive you attach, whether it's a classic mechanical one or a gotek emulator, you will not get more than DD format support unless you add a BIOS extension for HD format support. The BIOS of XT-class machines simply does not have HD floppy support.

I/O, I/O,
It's off to disk I go,
With a bit and a byte
And a read and a write,
I/O, I/O

Reply 13 of 15, by keenerb

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stamasd wrote:

Keep in mind that no matter what kind of floppy drive you attach, whether it's a classic mechanical one or a gotek emulator, you will not get more than DD format support unless you add a BIOS extension for HD format support. The BIOS of XT-class machines simply does not have HD floppy support.

I'm fine with that. My initial question was really just because I happen to have a bunch of high-density drives just laying around and didn't want to have to order any double-density drives.

Reply 14 of 15, by stamasd

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keenerb wrote:
stamasd wrote:

Keep in mind that no matter what kind of floppy drive you attach, whether it's a classic mechanical one or a gotek emulator, you will not get more than DD format support unless you add a BIOS extension for HD format support. The BIOS of XT-class machines simply does not have HD floppy support.

I'm fine with that. My initial question was really just because I happen to have a bunch of high-density drives just laying around and didn't want to have to order any double-density drives.

If that's all of your problem, you can connect a HD drive to a DD controller and it will work (as DD only obviously).

I/O, I/O,
It's off to disk I go,
With a bit and a byte
And a read and a write,
I/O, I/O

Reply 15 of 15, by keenerb

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stamasd wrote:

If that's all of your problem, you can connect a HD drive to a DD controller and it will work (as DD only obviously).

I figured that out over the weekend, actually!

I ended up just flashing a gotek drive though. Once I build my xt-ide card I'll be able to set up the high-density WD1002-WX1 I ordered off of ebay and all will be right with the world.