Announcement

Collapse

Forum Rules and Etiquette

Our mission ...

This forum is part of our mission to promote the preservation of vintage computers through education and outreach. (In real life we also run events and have a museum.) We encourage you to join us, participate, share your knowledge, and enjoy.

This forum has been around in this format for over 15 years. These rules and guidelines help us maintain a healthy and active community, and we moderate the forum to keep things on track. Please familiarize yourself with these rules and guidelines.


Rule 1: Remain civil and respectful

There are several hundred people who actively participate here. People come from all different backgrounds and will have different ways of seeing things. You will not agree with everything you read here. Back-and-forth discussions are fine but do not cross the line into rude or disrespectful behavior.

Conduct yourself as you would at any other place where people come together in person to discuss their hobby. If you wouldn't say something to somebody in person, then you probably should not be writing it here.

This should be obvious but, just in case: profanity, threats, slurs against any group (sexual, racial, gender, etc.) will not be tolerated.


Rule 2: Stay close to the original topic being discussed
  • If you are starting a new thread choose a reasonable sub-forum to start your thread. (If you choose incorrectly don't worry, we can fix that.)
  • If you are responding to a thread, stay on topic - the original poster was trying to achieve something. You can always start a new thread instead of potentially "hijacking" an existing thread.



Rule 3: Contribute something meaningful

To put things in engineering terms, we value a high signal to noise ratio. Coming here should not be a waste of time.
  • This is not a chat room. If you are taking less than 30 seconds to make a post then you are probably doing something wrong. A post should be on topic, clear, and contribute something meaningful to the discussion. If people read your posts and feel that their time as been wasted, they will stop reading your posts. Worse yet, they will stop visiting and we'll lose their experience and contributions.
  • Do not bump threads.
  • Do not "necro-post" unless you are following up to a specific person on a specific thread. And even then, that person may have moved on. Just start a new thread for your related topic.
  • Use the Private Message system for posts that are targeted at a specific person.


Rule 4: "PM Sent!" messages (or, how to use the Private Message system)

This forum has a private message feature that we want people to use for messages that are not of general interest to other members.

In short, if you are going to reply to a thread and that reply is targeted to a specific individual and not of interest to anybody else (either now or in the future) then send a private message instead.

Here are some obvious examples of when you should not reply to a thread and use the PM system instead:
  • "PM Sent!": Do not tell the rest of us that you sent a PM ... the forum software will tell the other person that they have a PM waiting.
  • "How much is shipping to ....": This is a very specific and directed question that is not of interest to anybody else.


Why do we have this policy? Sending a "PM Sent!" type message basically wastes everybody else's time by making them having to scroll past a post in a thread that looks to be updated, when the update is not meaningful. And the person you are sending the PM to will be notified by the forum software that they have a message waiting for them. Look up at the top near the right edge where it says 'Notifications' ... if you have a PM waiting, it will tell you there.

Rule 5: Copyright and other legal issues

We are here to discuss vintage computing, so discussing software, books, and other intellectual property that is on-topic is fine. We don't want people using these forums to discuss or enable copyright violations or other things that are against the law; whether you agree with the law or not is irrelevant. Do not use our resources for something that is legally or morally questionable.

Our discussions here generally fall under "fair use." Telling people how to pirate a software title is an example of something that is not allowable here.


Reporting problematic posts

If you see spam, a wildly off-topic post, or something abusive or illegal please report the thread by clicking on the "Report Post" icon. (It looks like an exclamation point in a triangle and it is available under every post.) This send a notification to all of the moderators, so somebody will see it and deal with it.

If you are unsure you may consider sending a private message to a moderator instead.


New user moderation

New users are directly moderated so that we can weed spammers out early. This means that for your first 10 posts you will have some delay before they are seen. We understand this can be disruptive to the flow of conversation and we try to keep up with our new user moderation duties to avoid undue inconvenience. Please do not make duplicate posts, extra posts to bump your post count, or ask the moderators to expedite this process; 10 moderated posts will go by quickly.

New users also have a smaller personal message inbox limit and are rate limited when sending PMs to other users.


Other suggestions
  • Use Google, books, or other definitive sources. There is a lot of information out there.
  • Don't make people guess at what you are trying to say; we are not mind readers. Be clear and concise.
  • Spelling and grammar are not rated, but they do make a post easier to read.
See more
See less

TRUE IDE 8-bit XT (XTA) Hard Disk Replacement

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

    TRUE IDE 8-bit XT (XTA) Hard Disk Replacement

    For those interested in it, i have finally managed to replace an old 8-bit IDE interface with a CompactFlash driven by a “XT-IDE Universal BIOS” inserted in it's original BIOS. The trick is forcing the CF in 8bit mode and using the existing (but sligtly modified) XTA 40 pin connector.

    The machine is an Olivetti PC1 HD (a NEC V20 pc). It's very compact and have an internal power sopply plus RBG video out.

    The mod can be useful for every configuration that have internal XTA interface (i.e. Tandy 1000 models (1000RL, RLX, TL/2 and TL/3)). Because in not an Industry Standard (like AT-IDE) pinout may differ from mine. XTIDE Universal Bios made the difference overpassing original BIOS routine (you must have a free ROM space). The advantage is no ISA slot wasting (in effect the olivetti PC1 has NO internal ISA slot) and also a REAL QUIET, fast, compact, fanless PC clone.

    I have made a guide for the mod at my facebook page:
    http://www.facebook.com/OlivettiProdestPC1

    if you want to see it in action:
    http://youtu.be/KDL7-1kHT8Y?list=UUp...U5y9ZF2Q9bBNYw

    Any suggestion/feedback will be appreciated. thank you.

    #2
    I read your thread title and I said to myself 'surely not", but then I noticed that in the body of your message you stated that the XT-IDE universal bios was being used.

    What brought up my objection was that the XTA software interface is very different from the IDE. But I see that you've solved that one with a new BIOS.
    Reach me: vcfblackhole _at_ protonmail dot com.

    Comment


      #3
      Yes, a new bios and a couple of lines that was lacking. Instead of removing existing XTA bios software, i ADDED the XT-IDE Universal BIOS! The advantage was that it support already 8 bit operations. That is very similar to XTA lines but I/O ports has very different use.
      It's very fast for an XT, because I used 80186 instruction set! And the entire thing is surely very quiet!

      Comment


        #4
        Yes, years ago on this forum, I touched on the possibility of re-deploying XTA hardware for use on an ATA interface, but since I had no immediate application for it, the topic sort of died.

        Another place for your modification might be the IBM PS/2 Model 25 and 30, which uses a very similar interface:

        http://ps-2.kev009.com/ohlandl/misc/IBM_IDE.html
        Reach me: vcfblackhole _at_ protonmail dot com.

        Comment


          #5
          And Commodore PC20-II and PC20-III have XTA too. What puzzles me is that you ADDED another BIOS. Does that imply that it will not work with Commodore?

          http://www.vintage-computer.com/vcfo...odore-PC10-III
          Last edited by archeocomp; March 6, 2015, 12:55 PM.

          Comment


            #6
            The problem is that XTA protocol is very different from ATA. So you need other software to address the CF card, which is an ATA device.
            Reach me: vcfblackhole _at_ protonmail dot com.

            Comment


              #7
              Originally posted by Chuck(G) View Post
              Another place for your modification might be the IBM PS/2 Model 25 and 30, which uses a very similar interface:

              http://ps-2.kev009.com/ohlandl/misc/IBM_IDE.html
              That proprietary 8-bit IDE interface is also used by the original 286-based IBM PS/1 (Model 2011), as well as the PS/2 Model 30-286.

              Why they thought it was a good idea to put a slow 8-bit hard drive interface with a 3:1 interleave into 286 systems that were fully capable of supporting a 16-bit interface with 1:1 interleave, I'll never know...

              Edit: And also the Sega TeraDrive, a 286 PC combined with Sega MegaDrive/Genesis game console hardware, developed by IBM:

              Comment


                #8
                Originally posted by vwestlife View Post
                Why they thought it was a good idea to put a slow 8-bit hard drive interface with a 3:1 interleave into 286 systems that were fully capable of supporting a 16-bit interface with 1:1 interleave, I'll never know...
                Like with CPU and RAM Silicon, not all manufactured media lives up to expectations. Intel will cripple half a quad and sell it as a duo, or disable half a 486DX because one side is bad and sell it as a 486SX or 487, or how they will manufacture a slew of chips, test them until they break, and rate their speed based on when they break.

                Hell, just look at what Woz did with "incomplete" shugart floppy drives.

                I'm willing to bet IBM and/or their OEM's had a bunch of parts lying around that couldn't keep up with the higher interleave, data-rate, or some other bit of tech in the product.

                So... destroy it, leave it gathering dust, or put it into a low-end system? Which of those at least has a CHANCE of making money? Or at least, if not making money then not losing as much money.

                ... at least if I were to take a guess, I'd say that's what was going on there.
                From time to time the accessibility of a website must be refreshed with the blood of owners and designers. It is its natural manure.
                CUTCODEDOWN.COM

                Comment


                  #9
                  Originally posted by vwestlife View Post
                  That proprietary 8-bit IDE interface is also used by the original 286-based IBM PS/1 (Model 2011), as well as the PS/2 Model 30-286.

                  Why they thought it was a good idea to put a slow 8-bit hard drive interface with a 3:1 interleave into 286 systems that were fully capable of supporting a 16-bit interface with 1:1 interleave, I'll never know...

                  Edit: And also the Sega TeraDrive, a 286 PC combined with Sega MegaDrive/Genesis game console hardware, developed by IBM
                  I tried some years ago the same approach explained by Simone2013 in the PS/1 2011, but it didn't work. It seems that there are some kind of control port that blocks standard I/O operations in the hard disk interface. The hard disk port is located at 0x320, but sending INs and OUTs from debug don't make the /CS signal active.
                  My videos:
                  IBM PS/1 model 2011 restored and enhanced
                  IBM PC Advanced Diagnostics Cassette load

                  Comment


                    #10
                    Originally posted by deathshadow View Post
                    Like with CPU and RAM Silicon, not all manufactured media lives up to expectations. Intel will cripple half a quad and sell it as a duo, or disable half a 486DX because one side is bad and sell it as a 486SX or 487, or how they will manufacture a slew of chips, test them until they break, and rate their speed based on when they break.
                    A 467 was complete 486DX with an extra pin which disabled the 486SX IIRC. https://books.google.co.nz/books?id=...%20cpu&f=false
                    Thomas Byers (DRI)- "You'll have a million people using the A> [MS-DOS prompt] forever. You'll have five million using [nongraphic] menu systems such as Topview, Concurrent PC-DOS, Desq, and those types. But there'll be 50 to 100 million using the iconic-based interfaces."

                    Comment


                      #11
                      Originally posted by Simone2013 View Post
                      ...The trick is forcing the CF in 8bit mode and using the existing (but sligtly modified) XTA 40 pin connector...
                      Ok, I have a question. How does one force a CF into 8 bit mode? And is this something a machine expecting a WD1000-style register set such as the TRS-80's could use to good effect?
                      --
                      Thus spake Tandy Xenix System III version 3.2: "Bughlt: Sckmud Shut her down Scotty, she's sucking mud again!"

                      Comment


                        #12
                        Hi to all!

                        @ Chuck(G): This is True with IBM P/S model that have an IDE 40 Pin attachment, and also simpler because we have the Address Bit 2 (mine don't!) You're right, the XTA protocol is very different from ATA so I had to integrate the XT-IDE BIOS

                        @archeocomp: I didn't replace original BIOS, but i added “XT-IDE Universal BIOS” in a free rom space (then ok, i forced original bios to scan the ROM for it). In my case I had 32k free bios space (@F000) and the commodore have 32k BIOS so it's possible to add then 16k “XT-IDE Universal BIOS” to that space

                        @ vwestlife: is less useful if you have an "edge" connector (i.e. ISA like) because you must create an adapter (not simple, i think)

                        @ nestor: in my research i find a similar problem to yours, nothing appear to react to I/O. CF register show Always the same value and i was thinking like you had. In the End I find that the RESET line was inverted. Cutting it (pin 1) I "activated" the I/O!

                        @lowen: The CF is forced in 8 bit by the famous “XT-IDE Universal BIOS” that I mentioned. I have also managed it to 8 bit in the past by the right sequence of command to IDE (it's called -set feature-)

                        Happy modding to ALL!
                        Last edited by Simone2013; March 9, 2015, 10:24 AM.

                        Comment


                          #13
                          Hey, can you explain a couple of things about the wires cut/spliced in the IDE cable? Which signal is pin 27 on the PC1? I was looking at info on the IDE-XT interface and what I've found says it's DACK3 on IBM controllers, but you have it routed to CS1 on the Compact Flash side, so I'm trying to understand what's going on there. Additionally, what is the purpose of bending out the pin on the '2P20' chip? Is there a buffered A2 line coming from the CPU under there? And why does the 2P20 pin need to be tied 'LOW'?

                          Also, did you modify the XT-IDE BIOS, or did you use the stock bios? If you modified it, what changes did you make?

                          I'm just trying to understand this fully because I think it might be a useful mod on the CompuAdd machine I recently got, but since the circuits aren't exactly the same I need to understand why you're making the changes you made so I can apply it to the circuits I do have.
                          Last edited by jmetal88; March 20, 2015, 07:25 PM.

                          Comment


                            #14
                            Okay, on my own machine I found where chip select for the IDE drive comes out of a PAL and gets ORed with A2 (or -A2, depending on whether you have the jumper set for the first or second drive). Now I guess I need to figure out during which addresses that PAL output is actually active (and should be active LOW if I traced everything out correctly) to see which addresses I'd need to set the XT-IDE BIOS to check and if I need to add/change any address decode logic other than routing an A2 signal to the connector.

                            EDIT: Progress on mine. I figured out where most of the PAL's inputs were coming from and popped it into a breadboard for some testing. The output I mentioned gets set LOW at 0x320-0x327 if the controller is set for the primary address (actually responding to both primary and secondary address locations). The output goes LOW from ONLY 0x324-0x327 if the controller is set for the secondary address. In primary mode, I could use this outright for the CS1FX line, but I'd need to add my own circuit to decode CS3FX.

                            EDIT 2: Eh, I've decided I don't want to mod this motherboard quite that extensively when I still have the option of buying/building an XT-IDE card which would be a plug-in solution. If that PAL had ended up decoding to 0x320-0x32F instead of what it did, I might feel more encouraged to complete the mod since I could take the signal from there and OR it with A3 and -A3 to get CS1FX and CS3FX. As it stands now, it decodes to CS1FX all on its own, but I'd have to add in my own 0x3F8-0x3FF decoding for CS3FX. And all that modding would NOT be easily undone.

                            EDIT 3: And now I'm considering ordering an XT bus prototype board to put the address decode logic on and sort of make a hybrid XT-CF. That might be more doable for me than either other solution. Just get the signals I need for the chip selects off the XT bus along with A2 and splice them into the IDE cable. That would be completely removable (only permanently attached at the cable), and would probably cost slightly less than putting together one of the standalone boards. I can either duplicate the address decode logic on Lo-Tech's ISA-CF card or possibly re-work it to work with chips I already have. But I guess I need to take a look at how the data lines on my board are buffered first, now that I think about it. If the buffer is shut off during transfers to other addresses, it might not be such a good idea to try to keep using the on-board connector.
                            Last edited by jmetal88; March 21, 2015, 10:34 PM.

                            Comment


                              #15
                              I stumbled across this Tandy 1000TL/2 on eBay and was intrigued that someone had attached a modern Fujitsu ATA drive to its onboard IDE-XT interface. Did they actually get it to work? There's no way to tell, because the seller doesn't have a compatible monitor to test it with:

                              http://www.ebay.com/itm/221437381160

                              Comment

                              Working...
                              X