sda is not a valid block device
 

i am trying to install a usb mass storage device
i correctly installed it and had it working, but changed
computers. i used the same harddrive, but
completely reinstalled linux.

i reinstalled redhat 7.3 on a duran 950 / aopen ak73 machine
i installed everything
everything works. i can mount the floopy and cdrom

i mounted the usbhd using the same method that worked
previously. i get the message 'sda is not a valid block device'

i installed using the
usb howto
i checked to see that the kernal had
usb-uhci and usbcore
i added the sub dir
/mnt/sda
i added to /etc/fstab
/dev/sda /mnt/usbhd auto defaults 1 2
i used the mount command
mount /mnt/usbhd
i also tried the command
mount /dev/sda
i also tried the kde mount
command. all three gave the same error code.
i checked /dev/ and saw a file
sda that is a block device file

i would appreciate any help. thank you.:newbie:

As the harddrive is loaded as a scsi drive dont you need too load scsi support also?

thank you for you comments

i check to see that scsi support was in the
kernal, but since i dont really know enough,
i would like to know how to check to make
sure that scsi support is turned on.

I don't know how helpful this will be, But try
ksyms | grep scsi

If you can see the symbols containing "scsi" in their name, mostly it is supported.
If not try
modprobe scsi_mod
But you might still need to load some specific modules ( I am not too sure about it).
--Sarin

I believe that you'd need to do the following:
modprobe usb-ohci (or usb-uhci)
modprobe usb-storage
ls /dev/sd* -l
and there should be a listing of /dev/sda1.

The usb harddisk is likely to have at least 1 partition on it, so would you not need to mount that rather than the disk itself (mount /dev/sda1 rather than /dev/sda)?

Just a thought...

thank you for your comments
i have tried all of the above and
more
no change

Maybe this can help you http://www.linux-usb.org/USB-guide/x498.html

thank you for that last idea. i didnt get a
chance to try it, because it now works.

i reinstalled rehat 7.3 and installed everything.
i mean everything.

not a really good method, but it worked.
i made no other corrections.

thanks again to everyone who helped.:p