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CF to IDE on my Tandy 1000HD

seaken

Veteran Member
Joined
Jun 20, 2016
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590
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Shokan, New York
I've been doing lot's of reading here and I am following another users thread on a similar topic. But I want to stop hijacking their thread and I still have more questions. I think I am close to uderstanding and @twolazy, @Trixter , and @CloudInMyHead have given me some good sources. I am reading here:


and I am almost ready to buy one of these cards since I think it will work for me. What I think I understand is that this card will work with regular full IDE hard drives and CF cards.

My concern is that I am trying to upgrade a Tandy 1000HD, which is one of the early models of the 1000. I know the early 1000's have some issues with some upgrades, such as VGA cards. As I understand I have a revision for RAM and DMA that will allow me to use this special IDE card. And my plan would be to remove the MFM HD and replace with a CF card. Do any of you disagree and would caution me not to buy this for use with the original version of the 1000?

My thinking is that if it doesn't work in the 1000HD it should work in some of my other XT or AT clones. So there is little risk. And I should just trust @twolazy and stop being so OCD about it. Just buy it already! Right? Sorry @twolazy for being such a loser. This is all new to me and I need reassurance. Thank you for your help.

Seaken (being a nervous nelly)
 
What I think I understand is that this card will work with regular full IDE hard drives and CF cards.

If you want the option of real spinning hard drives don’t buy the cheaper “XT CF” adapters like you linked to, get one of the more expensive “full” XTIDE cards. The difference between the two is the XTCF adapters save a lot of circuitry by implementing an 8-bit wide subset of the normally 16 bit wide IDE data bus; CF cards and those handy IDE-to-SD adapters (which technically emulate a CF card, the same chip is used in CF->SD adapters) are expected to be able to handle that, but it’s rare to find hard disks that do.

Anyway, one of these should work fine in a 1000HD; the very first original 1000 BIOS lacked support for detecting hard disk bios extensions, but the same fix that let the original controller work in your 1000HD will work for an XTIDE/XT-CF card. In fact, it wouldn’t even matter if you didn’t have DMA, the XT-CF works without it.
 
Thank you. I'm not sure what I want to do. I wish I understood this stuff better. But I think the only way to learn is to just jump in and learn from my mistakes. I do like the idea of using regular IDE drives but I am not sure that is necessary. If it works with a CF card that should be sufficient.

I was thinking that the HD version of the 1000 had the update as part of the Hard Drive setup. But I have been reading so many stories of other 1000 owners who have struggled with the BIOS and addressing with these cards and I'm never quite sure where my 1000HD fits. I think most of the issues are on models different from my 1000HD.

I will read up more on the difference between this card and the full XTIDE cards and make a decision.

Seaken
 
The adapter supports any ATA-2 compliant hard disk (almost all of which will be long defunct) but also microdrives, if you want something a bit unusal. CompactFlash is best for most people though as it's easy to plug them in to a modern PC for file exchange too (via a USB adapter).
 
There are some questions you should consider if you haven't already.

1. Do you want to be able to access/swap the CF card without opening the computer's case?

2. Would you be better off if you used a DOM or an actual IDE drive instead of a CF card? My understanding is that CF cards weren't really designed to be a hard drive replacement. Some work fine in this role and some don't work at all. Newer CF cards tend to be better at it.

3. Would you prefer to dispense with the IDE cable altogether and plug the CF or DOM directly into the XT adapter?

4. Do you want to get into running a master/slave setup with two devices? Unlike an actual IDE drive, a CF card has no user selectable master/slave option. That has to be selected by the cable or the IDE-CF adapter, but not both. Some IDE-CF adapters support this properly and some don't. Further, some "cable select" IDE cables are not properly marked as such.

From my experience, you should be prepared to mix/match/swap stuff around until you come up with a combination of parts that work together in the setup you want to have. I avoided some of the headaches and questions by starting with a set consisting of an XT-IDE adapter, IDE cable, IDE-CF adapter, and CF card that was guaranteed to work together by an ebay seller, then swapped components until I had the setup I wanted, with two CF cards exposed in the front of my 5160 that act as my C: and D: drives.

I ended up with two XT-IDE adapters. The first one is one of the Lo-Tech cards that came with the set I bought. It works just fine. The second one I bought is a Glitch Works Rev 3. that also works just fine.


Be advised that the proprietor of Glitch Works is a frequent flyer on this site.
 
the very first original 1000 BIOS lacked support for detecting hard disk bios extensions
An oft-repeated myth. but not true. I had an original Tandy 1000 with BIOS revision 01.00.00 and it had no trouble using MFM, RLL, and IDE-XT hard drive controllers. I didn't have an XT-IDE back then, but the basic principle of how the BIOS detects it is identical.
 
An oft-repeated myth. but not true. I had an original Tandy 1000 with BIOS revision 01.00.00 and it had no trouble using MFM, RLL, and IDE-XT hard drive controllers. I didn't have an XT-IDE back then, but the basic principle of how the BIOS detects it is identical.

Ah. That’s interesting, because it is oft repeated that it won’t work at all. This page, on the other hand, claims there was some kind of data corruption issue that cropped up with it sometimes?The Tandy 1000 FAQ explains that it’s an issue with how the original BIOS sets up the DMA controller, and it was bad enough that Radio Shack did offer an upgrade chip. It does say, however, the problem can be worked around in the controller BIOS, maybe that was common for controllers that were willing to run on IRQ2 to work around the 1000 sitting on the normal IRQ5.

Of course, none of the Tandy 1000 quirks matter for an XT-CF, it uses neither DMA nor an interrupt, so if the problem with the original BIOS is *not* “won’t detect BIOS extensions” then yeah, no problem.
 
I ordered the Lo-Tech XT CF adapter from the link above. I'll post back the results after it arrives and I can test it out.

Seaken
 
There are some questions you should consider if you haven't already.

1. Do you want to be able to access/swap the CF card without opening the computer's case?

2. Would you be better off if you used a DOM or an actual IDE drive instead of a CF card? My understanding is that CF cards weren't really designed to be a hard drive replacement. Some work fine in this role and some don't work at all. Newer CF cards tend to be better at it.

3. Would you prefer to dispense with the IDE cable altogether and plug the CF or DOM directly into the XT adapter?

4. Do you want to get into running a master/slave setup with two devices? Unlike an actual IDE drive, a CF card has no user selectable master/slave option. That has to be selected by the cable or the IDE-CF adapter, but not both. Some IDE-CF adapters support this properly and some don't. Further, some "cable select" IDE cables are not properly marked as such.

From my experience, you should be prepared to mix/match/swap stuff around until you come up with a combination of parts that work together in the setup you want to have. I avoided some of the headaches and questions by starting with a set consisting of an XT-IDE adapter, IDE cable, IDE-CF adapter, and CF card that was guaranteed to work together by an ebay seller, then swapped components until I had the setup I wanted, with two CF cards exposed in the front of my 5160 that act as my C: and D: drives.

I ended up with two XT-IDE adapters. The first one is one of the Lo-Tech cards that came with the set I bought. It works just fine. The second one I bought is a Glitch Works Rev 3. that also works just fine.


Be advised that the proprietor of Glitch Works is a frequent flyer on this site.
1. Yes, that would be preferrable. I ordered the cable and bracket and power adapter to go along with the ISA interface card.

2. I don't know what "DOM" is. I do have some IDE drives that may work. But I like the idea of using a CF card. I have never tried a CF card before so it will be a learning experience. (I have used CF cards in cameras and I have USB adapters and multi-drives that support them. But I have not used them as disks for an XT class machine before).

3. I decided to go with the extension cable and external bracket. I know it will take an extra slot but I don't have anything but the HD in there now.

4. At this point I only need the one "drive". A single CF card should work for me. However, I will probably branch out after this first attempt and try also the full XT-IDE setup.

Thanks for all the tips.

Seaken
 
2. I don't know what "DOM" is. I do have some IDE drives that may work. But I like the idea of using a CF card. I have never tried a CF card before so it will be a learning experience. (I have used CF cards in cameras and I have USB adapters and multi-drives that support them. But I have not used them as disks for an XT class machine before).
DOM-Disk On Module (see below). I've had mixed success with them, generally better with 486's/pentiums than with older systems, but your mileage may vary.

 
Honestly, when it comes to DOMs I’m in the “don’t bother” camp unless you can get one cheaper than the same size CF card plus an adapter. Modern DOMs are literally just pre-adapted CFs, if you spread the datasheets they literally use exactly the same controller chips they put in the cards.
 
Thank you @T-R-A , now I know what that is.

I looked for my CF Cards today but couldn't find them. I know I have a couple that I used with an old camera. But it's been so long since I've used them I have lost track fo where they were stored. I'll probably find them someday when I'm not looking for them. In the meantime I'll look to buy one on the internet.

TexElec was out of stock on the CF card they suggest for use with the XT CF adapter.

Where is a good place to shop for CF cards that will work best in an old XT. Will it matter if they are more than 2Gb or 4GB? I was thinking of something like 256MB or 1GB. I'll look around.

Seaken
 
I found the card recommended at TexElec here, and ordered two. I hope they work!

 
I started out with a small stack of cards from my son's old camera bag. Mostly 128mb and 256mb cards. Some famous brands and some not. I added a few "cheapos" from Ebay in the 1gb to 2gb range. Based on that purchase, I would suggest you avoid that route. I also bought 2 each of 2gb Sandisk Ultra's from one of the "big box" stores. Then the fun began. I found that whether the card would work was more a function of how old it was. I'm guessing that CF card makers got better at complying with IDE requirements as they went along. The Chinese ebay cheapos turned out to be recycled overlabeled cards of various makes and sizes that didn't come close to matching their labels. Even at $10.00 each they were overpriced IMHO. Of the two Sandisk Ultras I bought, one worked and one didn't, but the store took back the dud so no loss there. Some things I learned:

1. That a card worked fine for years in a DSLR (Nikon D70) does not guarantee it will format and boot DOS.
2. A newer (as in more modern, not less used) card is more likely to format and boot than an older one.
3. DOS maxes out at a 2GB partition. I haven't managed to fill any of my 128mb cards. So cards bigger than 2GB with multiple partitions seem like overkill.
4. Stay away from really cheap stuff. The sellers know what their merchandise is worth. Sorting the wheat from the chaff is not worth your time.
5. When all else fails "FDISK /MBR" might do the trick. If it doesn't, the card belongs in the trash or back in the camera bag.
6. A card that has been successfully formatted, and has files on it, might not even be readable by another XT-IDE adapter. Be careful swapping cards between machines.
 
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I tested over a dozen cards of various sizes between 128MB and 2GB in my XT-CF controllers. Slightly less than half worked completely; the definition of success is not only taking a format, but being able to run the “media test” function of this DOS disk tester without errors:


Compatibility seems to be a significant problem with CFs and XTIDE; the cards that failed would inevitably work perfectly fine on a “real” IDE port. (I tested them with a USB PATA adapter, plugged into the same ide to CF adapter.

These shenanigans are why I don’t use CF anymore, I use those inexpensive PATA to SD adapters and SD cards. Those adapters are based around a chipset which was actually designed to emulate the full CF card specification (they make CF-shaped cards containing it to use SDs in older cameras), and in my experience they’re 100% reliable. Some people say their luck hasn’t been that good, and I’ll allow that maybe there are varieties of these adapters that have bad firmware or something floating around, but in my experience *if* you get a good adapter then you don’t need to worry about memory card compatibility anymore, I’ve tried quite a few SD cards and they all work.

(That said, use a new, high quality card. A modern Samsung is a lot faster on the IOPS test then an ancient 16MB digital camera refugee…)
 
Thank you guys. That's all very informative. I guess I won't know until I try the CF cards. It will be a fun learning experience.

I do have some old IDE hard drives also so maybe if the CF cards don't work as expected I can fall back on an actual hard drive.

Seaken
 
I don't own any Tandy's but i have the Lo-tech ISA XT CF adapter and Sandisk Ultra II 2Gb CF cards and have had no problems, I also have several old hard drives which are supposedly ATA 2 compatible but none of them were recognized when connected to the Lo-Tech ISA XT CF adapter, Likewise none of my SD card adapters are recognized.
 
Likewise none of my SD card adapters are recognized.

I still find that baffling. My CF adapters have their address decoding implemented inside of a GAL instead of discrete components but functionally they're a straight copy of this Lo-Tech product. The SD adapters worked so well on the prototype (which *did* use discrete components) that I built the units with 44 pin 2mm pitch PATA connectors so I can hang the laptop versions of the adapter directly off them with no cable.
 
My parts box has brands like SanDisk. Verbatim, Kingston, PQI Industrial, some Seagate Microdrives too, ranging from 32MB to 8GB and all work fine. I haven't had a non-working card so don't know for sure what it is about them that is the problem. It is though worth noting that CompactFlash is a CMOS standard operating at either 3v3 or 5v and this is why the Lo-tech cards are specified with HCT components.
 
I still find that baffling. My CF adapters have their address decoding implemented inside of a GAL instead of discrete components but functionally they're a straight copy of this Lo-Tech product. The SD adapters worked so well on the prototype (which *did* use discrete components) that I built the units with 44 pin 2mm pitch PATA connectors so I can hang the laptop versions of the adapter directly off them with no cable.
That's the adapter i have, Neither the SD adapters or ATA 2 compliant hard drives i have are recognized, I dunno why but it's not high on my priority list as I've stopped buying CF and my preference has been SD adapters and ISA - USB for a long time now.
 
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