QNX 2.21 won't boot (corrupt bootloader?)


I have an QNX 2 machine that doesn’t want to boot.


One of our QNX 2 machines doesnt want to boot after making a raw ghost image of it. When booting it states:

QNX loader
Boot partition 1
Missing Operating System

What have i done so far:

I recreated the Bootdisk, and booted te machine that is having problems. The data still exists on the disk (pfew), i tried to tell the machine to boot with an OS file (NON-RT), the commando i used is:

boot 3:/netboot/os.2.21atb d=/drivers/disk.at +qnxloader

That didn’t work, after that i fdisked the drive non bootable (rebooted) reissuid the boot command and made the partition bootable again. Without succes.

Ideas anyone?


Usually when we have a boot problem on Qnx2 it’s because someone changed the drive settings in CMOS, but if you can access them with the floppy boot disk, they must be ok.

Don’t know if this was a typo or not, but for the boot file in your boot command, shouldn’t it be a ‘p’ at the end and not a ‘b’? “os.2.21atp” and not “os.2.21atb”.
All I see under 3:/netboot for boot files for os.2.21 are “atp”, “atpb” and “pcat”.

Also, we always specify the complete path, so for the driver we use “d=3:/drivers/disk.atc”.

We use disk.atc instead of disk.at, but I’m not sure what are the differences.


disk.at is an older driver that reads one sector at a time from the disk. disk.atc (c for caching) is a newer driver that reads multiple sectors at a time from the disk. It reads ahead, and delays writes in the hope of decreasing physical I/O’s with the disk. There is also an even newer disk.ata driver around, based on the atc driver, which understands LBA disks.