I know that for some reason, the Debian 2.1 Linux boot disk hoses up on systems with aic7xxx cards because of some conflict with the WD7000 driver; when you remove this driver from their default kernel setup, it boots ok.
I don't suppose that the WD7000 driver is compiled into gnumach, and if so, whether someone could compile it without this? Mach is hosing up in a different place, though. The last information the Linux boot displayed was about downloading instructions from the Adaptec card. Mach gets past this point; it crashes after displaying the devices on my SCSI bus. So the WD7000 thing could be a red herring. Anyone got a Mylex BT-958 for sale? I'll trade you for the smashed and burnt remains of a 2940UW...

