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


  • Filter
  • Time
  • Show
Clear All
new posts

    XTIDE Rev2

    This is the main page for the XTIDE project, revision 2 cards. This card features the same basic design as the original XTIDE, using 74xxx logic parts, but adds support for a high speed UART, a larger boot ROM, and built in "chuck mod" to improve drive performance.

    Feature list

    * Works "as you'd expect" as a functioning IDE controller for 8-bit ISA slots. Just attach up to 2 PATA hard drives to a cable and start using it.
    * No drivers to load. All HDD support is added through the onboard boot ROM (technically, a 'BIOS expansion ROM').
    * Onboard boot ROM (EEPROM type of ROM) can be flash upgraded. No ROM programmer required.
    * Supports drives of any size. There are restrictions in the operating system though (DOS 6.22 limits drive size to 8.4Gb)
    * The UART (optional) allows the card to boot over a serial link from a high speed modern computer, reading and writing to an .IMG file that represents a bootable hard disk image.
    * Supports most Compact Flash devices attached to CF->IDE converters.
    * Supports most DOM devices. (see test results page below)
    * Adds a boot menu (optional) to your machine- Boot to any drive attached to your computer, including the B: drive!
    * Onboard power connector for powering either CF devices (5 volts) or standard HDDs (12 volts) for machines without spare wiring from the power supply (such as the IBM model 25).

    High resolution photos

    Photo #1 ( Note: 28C64 ROM in use - jumpers K2 and K1 are incorrectly set for that. )
    Photo #2 ( Note: Optional UART circuitry not fitted. )

    Modes of operation

    There are two possible hardware 'modes' of operation. The mode that is used is selected by jumpers on the card.

    Compatibility Mode

    'Compatibility' means IDE hardware compatibility with an (unmodified) XT-IDE revision 1 card. If your revision 2 card is jumpered for Compatibility mode, the 'device type' option within version v2.0.0 beta 3 of the 'XTIDE Universal BIOS' needs to be set to 'XTIDE rev 1'.

    Hi-Speed Mode

    During production of the XT-IDE revision 1 card, some people made a modification to both the card and the BIOS software, in order to make the card run faster. That modification to revision 1 cards became known as the 'Chuck mod'. The hardware component of that modification (there is both a hardware and software component) has been incorporated into the XT-IDE revision 2 as 'Hi-Speed Mode'.

    As for the software component of the modification, that is in the BIOS: If your revision 2 card is jumpered for Hi-Speed mode, the 'device type' option within version v2.0.0 beta 3 of the 'XTIDE Universal BIOS' needs to be set to 'XTIDE rev 2 or modded rev 1'.


    The XT Universal BIOS can be downloaded from

    Versions earlier than 2.0.0 are intended for XT-IDE revision 1, not XT-IDE revision 2. If you want to try a BIOS version earlier than 2.0.0, then note that:
    * your XT-IDE revision 2 card will need to be jumpered for Compatibility mode, and
    * there is no UART support.

    Presently (NOV13), 'v2.0.0 beta 3' is the latest version. When configuring that BIOS, the 'device type' option needs to be set according to the mode that the XT-IDE revision 2 card is jumpered for:
    * XT-IDE rev 2 jumpered for Compatibility mode: Set the 'device type' option to 'XTIDE rev 1'
    * XT-IDE rev 2 jumpered for Hi-Speed mode : Set the 'device type' option to 'XTIDE rev 2 or modded rev 1'

    Schematic diagram

    Jumper settings

    There are two options for jumper diagrams:

    Option #1

    XT-IDE REV.2 jumper settings

    Option #2

    1. Basic IDE functionality
    2. Boot ROM
    3. Optional UART

    Other information

    Note that changing the I/O address requires a BIOS re-flash so that the BIOS knows where you moved the I/O space to.

    P9 near the IDE connector is a power enable/disable jumper to pin 20 (Vcc) If you are using a DOM or other low power device that can accept 5 volts on pin 20 to power the device itself, put a jumper on P9. Then you won't need an external power cable.

    Resistor R6

    A design error in the XT-IDE revision 1 card, which carried through to the revision 2 card, concerns the 'cable select' functionality (CS) of the IDE specification.
    Discussion of this design error in the XT-IDE appears in the XT-IDE thread starting [here].

    For a lot of XT-IDE users, that won't be a problem, because the IDE device in use will probably be set to 'master', not CS.

    If the IDE device that you attach to the XT-IDE does not have master/slave/CS jumpers, then it is possibly using CS.
    Note that a lot of IDE-to-CF adapters have master/slave jumpers.

    Should you wish to correct the design error, replace R6 with a wire link (photo), or bridge the ends of R6 using a piece of wire.

    Known problems

    SYMPTOM: The XT-IDE card 'sees' the CF card, but will not boot from it.
    CAUSE: Non-standard boot sector on CF card.
    FIX: Use the /MBR option of FDISK.EXE (from DOS version 5 or later) against the CF card. So, after booting from a DOS 5 (or 6) boot floppy, enter: FDISK /MBR

    SYMPTOM: On an IBM 5150 or 5160, the XT-IDE card 'sees' the CF card, but will not boot from it.
    CAUSE: Motherboard configuration switches set for 3 or 4 floppy drives.
    NOTE: Seen with XT Universal BIOS verion 'v2.0.0 beta 3'. Other versions may be affected.
    NOTE: Two CF cards were used - one containing DOS 3.3 and the other containing DOS 6.22

    Test results

    Bill of Materials

    Part #           Description                  Qty   Notes
    25523 	       @ CAP,MONO,.1uF,50V,20%        14 - decoupling caps
    1945428        @ CAP,RADIAL,47uF,35V,         1	
    45129 	       IC,74HCT688                    3
    46316 	       IC,74LS04                      1
    46375 	       IC,74LS08                      1
    46607 	       IC,74LS138                     1
    47466 	       IC,74LS32                      1
    64418 	       IC,SN74F573N,DIP-20,           3
    287144 	       IC,74F245,DIP-20,              1
    698576 	       DUAL EIA-232 DRIVERS           1
    53605 	       HEADER,RT MALE,2RW,40 CONT,    1	 - right angle IDE connector
    109576 	       HEADER,.1"ST MALE,1RW,3PIN,    6	 
    117197 	       HEADER,ST MALE,2RW,80 PIN,     1	 - break apart for the 2x5's and single jumpers
    41111 	       @ SOCKET,IC,40 PIN,.600",TIN,  1	
    112214 	       @ SOCKET,IC,14PIN,DUAL WIPE,   3
    112248 	       @ SOCKET,IC,DUAL WIPE,20PIN    7
    112432 	       @ SOCKET,SHORTNG BLKS,RED,CLSE 16
    112272 	       @ SOCKET,IC,DUAL WIPE,28PIN    1
    526205 	       @ SOCKET,IC,16 PIN,390261-4,   2
    333949 	       @LED,GREEN,572NM,T-1 3/4       1
    691104 	       @ RES,CF,10K OHM,1/4 WATT,5%,  6
    690785 	       RES,CF,470 OHM,1/4 WATT,5%     2
    857160 	       MOLDED SIP,10PIN,BUSSED,10K,   3
    2094389        SCREW,PAN HEAD,PPN4-40X1/4     2
    Optional UART components: (You'll save a bit of money not buying these if you don't plan on using UART)
    33664 	       CAP,TANT,1uF,35V,10%           5	- for the 232 driver for uart
    288809 	       IC,UART,TL16C550CN,5V,DIP-40   1	
    133006 	       SOCKET,OSC.CRYSTAL,14POS,4-PIN 1	- special oscillator socket
    117568 	       CONNECTOR,DISK DRIVE,MALE PCB  1	- molex power plug
    325358 	       OSCILLATOR,7.3728MHZ,FULL CAN, 1	- high speed clock
    + from
    556-AT28C64B   Atmel EEPROM                   1	
    534-9202       Keystone bracket, ISA          1
    + from Andrew Lynch:
    XTIDE rev2 PCB                                1
    Assembly notes

    Some notes for building the card:
    * SIP resistors are mounted with the printing facing down, toward the ISA connector.
    * The 14 decoupling caps are not polarity sensitive.
    * The 5 caps around the 232 driver IC are polarized. Note the + mark on the PCB must match the + on the cap.
    * The single large cap is also polarized.
    * The LED is polarized. It has one side flattened to indicate polarity. Match the flattened side of the LED with the PCB silkscreen.
    * Pin 1 for the IDE connector is down, closest to the ISA connector.
    * Pin 1 for the 9 pin serial header is on the left side (look for the square hole on the back of the PCB).
    * The card can self-program the EEPROM, so don't worry about needing an EEPROM burner to get a complete card. In fact the card can actually function AS an EEPROM programmer; the XTIDECFG flash program available with the BIOS allows for ROMs between 8 and 64k to be written.

    Booting via UART

    Supporting software, serdrive.exe and FreeDOS.img, is here.

    Click here for instructions.
    Where in those instructions it specifies "SerDrive ImageFile.img", you will use "SerDrive FreeDOS.img".

    Note that IMG drives show up as normal drive letters in DOS. So you have the option of booting to a local drive and then accessing the serial drive as D: or E:.
    Attached Files

    Parts for rev 2 boards

    Anyone want to go in on a group buy for parts for this board? I have a rev 2 board but some of the parts can't be bought in qtys. less than 10 ea. Anyone interested please PM me or email me


      Is there still someone that hasa few PCB's or a kit for the rev2 boards for sale?


        Originally posted by w1ll14m View Post
        Is there still someone that hasa few PCB's or a kit for the rev2 boards for sale?
        hey man, i have the dangerous prototype v2 board available.


          Does someone have a working link to the schematic files ? The link is broken.
          Are PCBs available from someone ? If not, and someone send me a link to the PCB files, I can order a new batch from oshpark and share with the community.



            Originally posted by BzzBR View Post
            Does someone have a working link to the schematic files ? The link is broken.
            Try this.
            Looking for a cache card for the "ICL ErgoPRO C4/66d V"


              Originally posted by Krille View Post
              Try this.
              Krille, Thank you for the link. I will check the files.


                Additional info at


                  Originally posted by Krille View Post
                  Try this.
                  Page on the new wiki is here -


                    Has anyone made a bill of materials for Mouser? I am pretty much forced to use Mouser because of the shipping costs - when I purchase more than EUR 50, shipping is free to Finland. Also, with Mouse I end up not paying any customs, for whatever logistical magic reason.


                      I am not sure why the URL shortening in this forum mangles links to the RBC wiki.

                      Here is a Preview TinyURL link (allows you to see where it is sending you before you go there) -

                      I am working on moving over the XT-IDE content from the VCF Wiki (which seems to be defunt as far as being a wiki, it's just posts now) and the former Google Code Wiki (which is definitely defunct with Google Code shut down) to the RBC wiki.


                        Originally posted by MarsMan2020 View Post
                        I am not sure why the URL shortening in this forum mangles links to the RBC wiki.
                        I think it will work if you check the "Disable smilies in text"-box.

                        If I'm right this should work:

                        Another way is to do a proper link like this.

                        EDIT: Yep, both links confirmed working.
                        Looking for a cache card for the "ICL ErgoPRO C4/66d V"


                          Originally posted by Sir_Fartalot View Post
                          Has anyone made a bill of materials for Mouser? I am pretty much forced to use Mouser because of the shipping costs - when I purchase more than EUR 50, shipping is free to Finland. Also, with Mouse I end up not paying any customs, for whatever logistical magic reason.
                          Did you come up with a BOM from Mouser? I can't seem to find everything at Jamco, so I will probably go the route of Mouser too. I have three board to build (I probably have the last three boards in existence).


                            holy shit my mobo is and the bios dose NOT load at all which concerns me! wwww the card works fine on other mother boards and if i load the bios on a separate card, everything works fine~


                              lost image republished!

                              XTIDE REV2 settings.jpg