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NT4: Drivers needed for IDE operation?

Brian_RBrian_R Member Posts: 3

Hello. I’ve been gone from OSR since the early mail and email days of NT Insider. It is my hope that this post is “in keeping with the overall spirit and purpose of the Community” albiet not driver authoring related.

My quest: To restore the NT4 (SP6) box that I used to develop an NT driver in the late 90s. It’s been a real stickler but I think I’m getting there.

I'm hoping someone can help me determine which drivers to enable for IDE HD support in NT4 (SP6). I have a SuperMicro P5STE motherboard with an early Pentium CPU. The chipset is an Intel SB82371SB which includes the IDE interface. The system has the original SCSI HBA and HD which are working but the HD is on it's very last legs, so I am trying to clone it to an IDE HD. Since I never used the IDE ports on this system the drivers for IDE are not enabled, so a clone to IDE starts to boot then fails halfway through with "INACCESSIBLE_BOOT_DEVICE". I'm guessing this is when Windows wants to start using its driver vs the BIOS that started the boot.

I see that ATDISK.SYS is described online as "ISA/EISA non-SCSI (WD1003 compatible controller)". I am not sure my chipset is compatible and looking at its datasheet isn't helping me determine that. Since hardware of the day at this level usually had a popular standard, I'm guessing it's compatible. OOPS: I just discovered the WD1003 adapters were for MFM / RLL. On the other hand I have found "The ATA IDE interface was modeled after the WD1003 controller IBM used in the original AT system" so perhaps this is still the driver to use for IDE.

I also see ATAPI.SYS is described as "CD-ROM driver with non-SCSI interface". I'll guess that I need this if I want to put a CD drive on the IDE cable.

Do those descriptions sound accurate? Are there any other necessary drivers I might be forgetting? SCSIPORT.SYS is already enabled.

I definitely do not want to "brick" my SCSI HD boot by making a bad change in driver management. Is there a way to protect myself? There's no "Last known good boot" option for NT4. I can boot from floppy and access the FAT C: drive, but I’ve forgotten which registry file I need to back up. Hopefully it fits on a floppy.

All feedback appreciated!


  • Phil_BarilaPhil_Barila Member - All Emails Posts: 154
    via Email
    You'd be better off just getting a healthy SCSI disk and clone the boot HD to that.

    Phil B

    On 10/23/20, 9:35 PM, "Brian_R" wrote:


    My quest: To restore the NT4 (SP6) box that I used to develop an NT driver in the late 90s. It’s been a real stickler but I think I’m getting there.


    The system has the original SCSI HBA and HD which are working but the HD is on it's very last legs, so I am trying to clone it to an IDE HD.

  • Peter_Viscarola_(OSR)Peter_Viscarola_(OSR) Administrator Posts: 8,499

    P2V the system and be done with it.


    Peter Viscarola

  • Brian_RBrian_R Member Posts: 3

    Thanks for the replies so far…
    Phil: To replace with an identical ST15150N (4.3G, circa 1995) from ebay, the prices start at $250+ and since the 2 2G FAT partitions are full I want some extra space, so would need a second drive. I see a different 4.5G drive but even that is $50+. I already picked up an IDE for $19 (6G, circa 2000).

    Peter : But then I wouldn’t be able to play with the (ISA) adapter I wrote the driver for, and secondarily I have some floppies I want to go through – this is my only box with a floppy interface. P.S. I've loved the "Peter Pontificates" column since day 1! In a way it reminds me of Hal Hardenberg's newsletter DTACK Grounded about the 68000 chip in the 80's.

    SO, I’ve been digging in and re-learning the registry details. It looks like the registry file I need to be sure to backup is C:\WINNT\system32\config\system

    I think I’m correct but would appreciate a confirmation here.

    I’ve found this info:
    “In Microsoft Windows NT 4.0, the port/miniport driver pair associated with the IDE bus is a SCSI miniport driver, atapi.sys, that linked to the SCSI port driver, scsiport.sys.” However, another source says Atdisk.sys is the WD1003 compatible controller while atapi.sys is for CD-ROMs.
    Also found: “NT4 and less don’t use ATAPI.sys/SCSIPORT.sys for IDE HDDs, but the unoptimized slow and CPU/interrupt intensive dog ATDISK.sys, a very basic ST506/WD100x driver which doesn’t even know how to do proper MWDMA/UDMA transfers” which seems to be a contradiction of what MS’s page says. I tend to believe the MS page but would like to confirm with info from elsewhere.
    I see that my aic78xx driver that’s running the SCSI adapter card (HBA) for scsiport.sys is set as “BOOT” Startup, and I have questions about that. If I were to set both atapi.sys and atdisk.sys to “BOOT” (vs Automatic) but only one is needed, would that prevent booting? And perhaps they’d conflict :(

  • Brian_RBrian_R Member Posts: 3
    edited October 2020


    Booting from the SCSI drive I set ATAPI.SYS to Startup=Boot, cloned that to the IDE, and I'm now booting from the IDE!

    For NT4 it seems ATAPI.SYS is the better mini-port driver to SCSIPORT.SYS for IDE. From what I've read ATDISK.SYS was perhaps before NT4 (NT3.51?) and optical drive support, and MS made a new stack for IDE/ATAPI w/o SCSIPORT.SYS soon after NT4.

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