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VCF XT-IDE  -  Problems


The scope of this web page is the XT-IDE series of cards produced by the Vintage Computer Forums (VCF)
To date, there have been four releases: revision 1 (rev 1), revision 2 (rev 2), revision 3 (rev 3), and revision 4 (rev 4).

Some companies and individuals have designed products containing similar functionality.  Some of the information on this web page may not apply to those products.

Note that for the symptoms listed below, there can be causes other than the ones that I have described.


Symptom Although the normal FDISK and FORMAT/S commands had been performed against the CF card to make it bootable, the computer will not boot from the CF card.  The XTIDE Universal BIOS 'recognises' the CF card.  You discover that if the computer is booted from floppy, the CF card is accessible (you can read/write/copy files on it) as C: drive.
Frequency Very common
Cause Non-standard 'master boot code' within the master boot record (MBR) of the CF card.
Fix # 1 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
Fix # 2 Or wipe (blank) the CF card, then redo partitioning and formatting.
Notes • The /MBR option of FDISK.EXE does not exist in early versions of DOS.
• The /MBR option of FDISK.EXE targets the first hard drive (relevant if you have multiple hard drives in your computer).
• The /MBR option of FDISK.EXE is further described at here.
• Using FDISK.EXE to delete then recreate partitions does not 'touch' any existing master boot code in the MBR.  That is why such use of FDISK.EXE does not fix the subject problem.
• Using SYS.COM will not work, because, against a hard drive, SYS targets a DOS partition, not the MBR.


Symptom The computer will not boot from the CF card.  However, it is discovered that if the computer is booted from floppy (same DOS version as what is on the CF card), the CF card is accessible (you can read/write/copy files on it) as D: or E: drive.
Cause In an IBM 5150, 5155, or 5160, the floppy-count switches on the motherboard are set for 3 or 4 floppy drives.
Note May only be applicable to early versions of DOS.  Yet to verify.


Symptom The XT-IDE card recognises/sees some CF cards but not others.
Cause • Be aware that some CF cards are not compatible with the XT-IDE card.
• There are reports of some CF cards not being compatible with some CF-to-IDE adapters.


Symptom The XT-IDE card does not recognise/see any CF card.
Cause A CF-to-IDE adapter is being used, but the user is not supplying power to the adapter.
Fix • At here is an example of an CF-to-IDE adapter being powered via a power cable.
• At here is an example of an CF-to-IDE adapter being powered via pin 20 on the IDE connector.   (Not all CF-to-IDE adapters can be powered this way.)


Symptom The XT-IDE card does not recognise/see any CF card.
Cause A faulty CF-to-IDE adapter is a possibility.
• Do not assume that it was fully tested before it left the Chinese factory.
• Of course, a CF-to-IDE adapter can always fail whilst in use.


Symptom Does not work in an early IBM 5150 (IBM PC).
Background The XT-IDE card uses a 'BIOS expansion ROM' (the EEPROM on the card) (a.k.a. boot ROM).
Cause The motherboard BIOS supplied in an early IBM 5150 does not support BIOS expansion ROMs.
Fix Upgrade the motherboard BIOS to the final one (revision 10/27/82).  That BIOS supports BIOS expansion ROMs.


Symptom Does not work in a Compaq Portable.
Background The XT-IDE card uses a 'BIOS expansion ROM' (the EEPROM on the card) (a.k.a. boot ROM).
Cause The motherboard BIOS supplied (revision B) in a Compaq Portable does not support BIOS expansion ROMs.
Fix Upgrade the motherboard BIOS to the one that is found in a Compaq Portable Plus; the BIOS of revision C.  Revision C supports BIOS expansion ROMs.
Note Images of the C revision BIOS ROMs are at here.  You (or others) will need to burn the images to 2764 type EPROMs.
Note Revision A of the BIOS was never released.  (Source)


Symptom An XT-IDE card, of Rev 2 or later, does not work in an Olivetti M24 or AT&T PC6300.  It is observed that an XT-IDE card of Rev 1, works.
Background The Rev 2 revision of the XT-IDE card introduced a new mode of operation called 'hi-speed' mode (A.K.A. Chuck mod).
Cause The M24 and PC6300 have different byte ordering compared to IBM PC family computers.
Because of that, the 'hi-speed' mode of the XT-IDE does not work.
Fix Step 1: Jumper the XT-IDE card to 'compatibilty' mode.  ( 'compatibilty' = compatible with Rev 1.)
Step 2: Reconfigure versions 2.x.x of the XTIDE Universal BIOS to the device type of 'XTIDE rev 1'.  Or instead, use a version 1.x.x of the XTIDE Universal BIOS.


Symptom Nil or unstable operation in an IBM 5170 (IBM AT).
Cause An incompatibility is known to exist between the XTIDE Universal BIOS and the 5170 motherboard's IBM BIOS ROMs.
• The result is corrupted reads of files (as evidenced by CRC comparisons to what was written).
• The degree/frequency of corruption is related the revision of the motherboard BIOS.  There were three revisions.  The more modern the revision, the less corruption.
• The symptom disappears entirely if the IBM BIOS is swapped out for a non-IBM one.
Fix Swap out the IBM motherboard BIOS for a non-IBM one (a BIOS compatible with the IBM 5170).  Some can be found at here.


Symptom Nil or unstable operation in an IBM 5162 (IBM XT Model 286).
Cause An incompatibility is known to exist between the XTIDE Universal BIOS and the 5162 motherboard's IBM BIOS ROMs.
• The result is corrupted reads of files (as evidenced by CRC comparisons to what was written).
• The symptom disappears entirely if the IBM BIOS is swapped out for a non-IBM one.
Fix Swap out the IBM motherboard BIOS for a non-IBM one (a BIOS compatible with the IBM 5162).


Symptom A just-made XT-IDE card stops computer from booting.  Removing XT-IDE card allows computer to boot.
Cause Some possibilities:
• Bad soldering
• One or more faulty components
• One or more wrong components
• Components inserted in wrong orientation
• EEPROM has bad content  [as an experiment, disable EEPROM and see if computer then boots]
• Resource conflict  [see here]


Symptom I have a 2.x.x version of the XTIDE Universal BIOS in my XT-IDE card.  The XT-IDE works, but there is no boot menu.
Background The 2.x.x versions of the XTIDE Universal BIOS can be built (compiled), if desired, without certain optional modules/features.  For example, if your XT-IDE has no serial port, then the optional module of the XTIDE Universal BIOS that supports the serial port ("MODULE_SERIAL_FLOPPY") can be omitted.
Cause The XTIDE Universal BIOS, of version 2.x.x, flashed into your XT-IDE card, was built without the 'boot menu' module ("MODULE_BOOT_MENU").
Note Additional information is in the 'Boot menu' section at here.


Symptom A DIR command takes a very long time to display the directory.
Cause This is not caused by the XT-IDE card nor the XTIDE Universal BIOS.
Read the 'MS-DOS DIR command takes a very long time' section at here.


Problem "If you move a drive handled by a v1.x.x or v2.0.0 beta 1 BIOS to another system or upgrade to v2.x.x you risk data corruption"
Cause Read the 'Important if you are upgrading from any previous XTIDE Universal BIOS version' section at here.