I have installed kernel 2.6.4 recently on my computer, running slackware 9.1
All works fine, except for some small annoying things:

I have a SCSI removable optical drive(something like a zip drive). At boot up, when the system detects the SCSI-devices, it finds the optical drive, and then says
"spinning up disk..", thereby trying to read the disk. Ofcourse this fails, since there is no disk in the drive. The bad thing is, the system wont go on after this until it can read from the disk(or so it seems. I have let it running for a few minutes or so, didn't continue)

It looks the kernel thinks this is a hard-disk, and tries to read the partition-table. kernel 2.4 did this to, but thatone tried to read it once, than continue.
Is there some option to get the behavior from kernel 2.4 back here?(or did i forget to set some option in the kernel?)

Try upgrading your hotplug scripts with the latest ones available on kernel.org. The hotplug scripts associated with Slack 9.1 are ill-suited to 2.6.4.

Additionally you probably want to set up sysfs. (There's a thread on that first page.)