Using the NCR53c810 SCSI adapter with OS/2 Warp (and Linux)

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Last update: 6th November, 1995



NCRADD: One or more of your SCSI devices is malfunctioning.


NCR 53c810 SCSI Adapter


The adapter has not been configured to use level triggering.


Change the adapter so that it uses LEVEL triggering as per the


I have had problems with my NCR 53c810 since februar 1995 with OS/2 Warp ver. 3.0. I got the very same error message as you:

NCRADD: One or more of your SCSI devices is malfunctioning.

I have found that it is not the NCR 53c810 nor the OS2CAM.ADD which has guilt in making this trouble. The problem is the MANUAL for the NCR 53c810 which recommends to use EDGE triggering.

I trusted the manual to be correct in this statement. But after sending and receiving some email to NCR.

I found that it is the LEVEL triggering which works with OS2CAM.ADD.

After I changed to LEVEL triggering on the NCR 53c810 (with jumper settings) all my SCSI devices works in OS2CAM.ADD. I have a Pioneer DRM 604x SCSI CD-ROM player, and now it works very well.

I am also able to install LINUX on my computer when using LEVEL triggering. I have tried to install LINUX on my computer since Autumn 1994 with no success. I could not access any SCSI devices earlier. But suddenly everything worked with LEVEL triggering.

But LINUX is even more specific to configure than OS/2 WARP. I had to put my motherboard to INT C (with jumpers) for the PCI slot 1, and my NCR 53c810 to INTR C# LEVEL triggering (with jumpers). In the CMOS BIOS Setup I had to put my NCR 53c810 to irq=11, and PCI slot 1 to irq=11. It was important to put the irq=11 two places in the CMOS BIOS Setup for LINUX installation. The MANUAL for my motherboard GA 586 IS told me that INT C requires irq=11. The motherboard MANUAL said:

    INT A  means irq=9
    INT B  means irq=10
    INT C  means irq=11
    INT D  means irq=14

I hope this makes it clearer to other users of the NCR 53c810.

Gaute Tjelflaat