NOT tested on IDE Jaz drive
Jaz drives are SCSI, even when connected to the parallel port. Therefore, your kernel must have support for the correct SCSI card either compiled into the kernel, or compiled as a module.
There is a truly excellent GUI for handling Jaz/Zip drives. You can download it at www.scripps.edu/~jsmith/jazip/*. Note that it needs XForms (available from world.std.com/~xforms/*) installed.
tar zxvf jaZip-x.x.src.tar.gz
mkdir -p /mnt/jaz
/dev/sda4 /mnt/jaz auto auto 0 0