I have a zip drive that alternately mounts on /dev/sda and /dev/sdb each time I reboot. I'm not positive that it switches EVERY time, but it's pretty close to it. My system is the same each time I boot, so am confused as to why the alternation. It is somewhat of a pain because I'm trying to wean my wife from windoze and have a desktop icon set up for mounting and I really want some consistency.

my zip (para port, 250 mb) always stays mounted to /dev/sda4
is yours external or internal?? is it para port or USB??
what do you have listed in /etc/fstab

???

That's pretty strange. I thought the system allocated the devices sequentially, so if you had a /dev/sdb then /dev/sda must be in use for something else. Try also command

dmesg | grep /dev/sd

to see what else might be around when zip is at /dev/sdb.

Sorry to have taken so long to get back. Here is my output for "dmesg | grep sd"

UMSDOS: msdos_read_super failed, mount aborted.
Attached scsi removable disk sda at scsi1, channel 0, id 0, lun 0
sda: Unit Not Ready, sense:
sda : READ CAPACITY failed.
sda : status = 1, message = 00, host = 0, driver = 08
Current sd00:00: sns = 70 2
sda : block size assumed to be 512 bytes, disk size 1GB.
sda: I/O error: dev 08:00, sector 0
Attached scsi removable disk sdb at scsi2, channel 0, id 6, lun 0
SCSI device sdb: 489532 512-byte hdwr sectors (251 MB)
sdb: Write Protect is off
sdb: sdb4
sda: Unit Not Ready, sense:
sda : READ CAPACITY failed.
sda : status = 1, message = 00, host = 0, driver = 08
Info fld=0xa00 (nonstd), Current sd00:00: sns = 70 2
sda : block size assumed to be 512 bytes, disk size 1GB.
sda: test WP failed, assume Write Enabled
sda: I/O error: dev 08:00, sector 0
sda: Unit Not Ready, sense:
sda : READ CAPACITY failed.
sda : status = 1, message = 00, host = 0, driver = 08
Info fld=0xa00 (nonstd), Current sd00:00: sns = 70 2
sda : block size assumed to be 512 bytes, disk size 1GB.
sda: test WP failed, assume Write Enabled
sda: I/O error: dev 08:00, sector 0

Since "scsi" came up in the above, here's the result of "dmesg | grep scsi"

tim@sbc:~$ dmesg | grep scsi
Kernel command line: auto BOOT_IMAGE=SLACK ro root=2141 hdb=ide-scsi
ide_setup: hdb=ide-scsi
kmod: failed to exec /sbin/modprobe -s -k scsi_hostadapter, errno = 2
kmod: failed to exec /sbin/modprobe -s -k scsi_hostadapter, errno = 2
kmod: failed to exec /sbin/modprobe -s -k scsi_hostadapter, errno = 2
hdb: attached ide-scsi driver.
scsi0 : SCSI host adapter emulation for IDE ATAPI devices
Attached scsi CD-ROM sr0 at scsi0, channel 0, id 0, lun 0
sr0: scsi3-mmc drive: 40x/40x writer cd/rw xa/form2 cdda tray
scsi1 : SCSI emulation for USB Mass Storage devices
Attached scsi removable disk sda at scsi1, channel 0, id 0, lun 0
scsi2 : Iomega VPI2 (imm) interface
Attached scsi removable disk sdb at scsi2, channel 0, id 6, lun 0


It is an external parallel port zip drive

here's fstab:

/dev/hdf1 / reiserfs defaults 1 1
/dev/hdf2 /home reiserfs defaults 1 2
/dev/hde1 /windows vfat gid=100,umask=002,noexec,nosuid 0 0
/dev/hde2 /w2 vfat defaults 1 0
/dev/hde3 /w3 vfat defaults 1 0
/dev/hde5 /w4 vfat defaults 1 0
/dev/hde6 /w5 vfat defaults 1 0
/dev/sdb1 /mnt/camera vfat noauto,users 0 0
/dev/cdrom /mnt/cdrom iso9660 noauto,users,ro 0 0
/dev/fd0 /mnt/floppy auto noauto,owner 0 0
devpts /dev/pts devpts gid=5,mode=620 0 0
/dev/sda4 /mnt/zip vfat noauto,user 0 0
#/dev/sdb4 /mnt/zip vfat noauto,user 0 0
proc /proc proc defaults 0 0
/dev/hdf6 /suse reiserfs defaults 0 0

I alternately comment/uncomment depending on the mood of my system. Today it likes sdb4, but when I tried sda4 as above, I get:

mount: /dev/sda4 is not a valid block device

The ref to /mnt/camera suggests you may sometimes have a USB device (like a camera) attached. That could certainly have an effect on device allocation.

I don't know how to interpret the error messages. There is file called parport.txt in the kernel source (in Documentation subdir) which has some relevant looking info.

What kernel version is this?

The camera usb cable is always plugged into the computer at boot, but the camera is never hooked up on boot, and it is rarely used anyway, so that is constant. I am using the current slack10 kernel, 2.4.26 I believe. I didn't see anything in parport.txt that looked useful to my situation.

The kernel messages seem to indicate a faulty USB mass storage device is detected, and this is occupying /dev/sda. It seems unlikely, but maybe the camera cable itself is generating some spurious feedback when the port is probed. Anyway, that is all I can think of.