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Tandy 8-bit IDE series (TL, RL): Do CF adapters work?

Trixter

Trixter

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(Having hosted the Tandy 1000 FAQ for many years, and able to use search engines, you'd think I'd be able to find the answer to this... but after 30 minutes of searching, I figured I'd just ask people who have been through this already:)

I have a functional Tandy TL/2 with a semi-functional WD-93044-X. It works, but it takes several minutes of warming up and operation to allow reading without errors. Since it's an 8-bit IDE interface, can I assume that replacing it with a CF card+adapter should work ok, or does the built-in controller only recognize certain models?

If the latter, should I resign myself to adding an XT-IDE once the original drive fails? With DOS in ROM (which I don't ever want to disable), is there room for the XT-IDE's XUB anyway?
 
A CF adapter attached to the built in disk port is a no go. “XTA” is electrically vaguely similar to an 8-bit ATA subset like CF but isn’t compatible with it at all “API-wise”. Short of rearranging the wiring and replacing the driver in ROM it’s a nonstarter.

(There’s a thread on the forum where someone actually does that to some other machine with an XTA port, but I can’t imagine it’d be easy on the Tandy between its massive ROM and extensive use of ASICS.)

There is room in the peripherals extension area for an XTIDE but, yes, it’s pretty crowded on those models. The DOS in ROM is paged in the E-area, I think? (My vague recollection is that those have a total of 512k of ROM?)
 
My attempts with XT-IDE on a Tandy 1000 RLX all failed.

I have not found any reference to success with XT-IDE in a Tandy 1000 RLX, but there is a youtube you can find where someone did it on a RL.
 
I have another XT-IDE card on the way that I'm hoping to use in a TL/3. I can try it in the TL/2 as well, and report back on how things fare. Presumably, it should work in either system, but may yet require use of a "late initialization" XUB version. We'll see...

lafos said:
My attempts with XT-IDE on a Tandy 1000 RLX all failed.

I have not found any reference to success with XT-IDE in a Tandy 1000 RLX, but there is a youtube you can find where someone did it on a RL.
Click to expand...
So, the RLX is another story, but I'm booting-from and using an XT-IDE card in an RLX-B variant, as demonstrated here:


For reasons that have yet to be determined, the XUB on the XT-IDE card will fail to initialize unless a 3.5" XTA hard-drive is also plugged into the system's motherboard header. It seems like there ought to be a fairly simple XUB code fix for this, especially where other bootable solutions pose no problem in this system at all, but at this point, I'm not even sure who to ask to look into the problem.
 
I’ve been using an XT-IDE in my TL/3 for years. I can boot to both the XT-IDE and the internal HD without issue from the boot menu.
 
Here's an account of an XT-IDE being used in a TL/2 with the internal drive disconnected, and with the latest XUB. Looks like he's using an earlier XT-IDE variant that doesn't natively provide a CC00h address option, and consequently required padding of the XUB.
 
Trixter said:
I have a functional Tandy TL/2 with a semi-functional WD-93044-X. It works, but it takes several minutes of warming up and operation to allow reading without errors.
Click to expand...
Did you try oiling the stepper motor? This trick worked great with the WD IDE-XT drive in my Zenith eaZy PC:

 
I've nursed the drive back to full health, but the option for a replacement remains. The drive isn't going to last forever.

Cloudschatze said:
Here's an account of an XT-IDE being used in a TL/2 with the internal drive disconnected, and with the latest XUB. Looks like he's using an earlier XT-IDE variant that doesn't natively provide a CC00h address option, and consequently required padding of the XUB.
Click to expand...

Luckily for me, I have no plans to install VGA in a Tandy (heresy!), so C000 is open for me. So, unless I run into this late-init thing, it should work.
 
So, I'm happy to report having no trouble at all with an XT-IDE in the TL/3 @ CC00h, using the "XTPlus," r602 BIOS, and with the internal drive completely absent.
 
I've got a TL/2; a XT-IDE's my plan B when the internal drive beefs it. Ran the idea by Glitch a ways back and he made it sound like there shouldn't be any issues. XTA sure is an odd beast!
 
All you fancy fellas and your overcooked Tandys! A simple TL or SL doesn't need any of this "late initialization" muck. :p

As I understand it, the XT-IDE Universal BIOS can instruct a CF card to initialize in 8-bit mode instead of standard IDE-compatible 16-bit mode. Of course if you use a fully featured XT-IDE, you do not need this initialization step, it can handle the 16-bit CF/IDE data bus by latching the low byte followed by the high byte and presenting the bytes to the 8-bit ISA data bus sequentially.

XTA on the other hand is essentially the MFM hard drive interface with the electronics on the drive. The ports used are from 0x0320-0x0324 instead of 0x01F0-0x01F7. The BIOS must interact with an XT hard drive very differently from an AT hard drive.

The ideal solution would be for a BIOS extension to translate XT ports to AT ports for a CF card or an adapter with a microcontroller that puts the CF card into the 8-bit mode and handles the translation. Of course, the BIOS of these machines only recognize a few disk drive geometries, so there would have to be more translation for that too.
 
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