/dev/hda is the Primary Master ide device (your first hard drive)
/dev/hdb is Primary Slave
/dev/hdc is Secondary Master
/dev/hdd is Secondary Salve
They should stay the same unless you manually move the drives around. /dev/hda1 is the first primary partition on the first hard drive. /dev/hda2-4 are either primary or extended partitons. /dev/hda5 or greater are logical partitions contained in an extended one.
You don't need to switch drives around. Simply partition and install Linux to your second hard drive, and skip lilo configuration. Then use your cd to boot temporarily.
boot: bare.i root=hda2 noinitrd ro
root=hda2 should no longer work if you are planning to use your second hard drive. If your second hard drive is /dev/hdb, it should be /dev/hdbx, with 'x' being the partition Slack was installed to.
mkfs -t msdos /dev/fd0
dd if = /dev/hda2 of = /bootsect.lnx bs = 512 count = 1
mcopy /bootsect.lnx a:
These were the commands for copying LILO to a file, so WinXP could use it as an option in it's boot menu. First, you must install LILO. Make it's configuration file, /etc/lilo.conf, with the help of the 'lilo.conf' man page. There are some tools for making it automatically. Before using an automatically-generated config, check if it was made properly. For example, if you want to use XP's bootloader, you don't want to have a 'boot=/dev/hda' or 'boot=/dev/hda1' in your lilo.conf. This would overwrite the XP bootloader and put lilo there instead. You might want something like 'boot=/dev/hdb' there. This will install LILO to your second hard disk. After LILO is installed, you copy it to a file using the 'dd' command. Change the 'if=/dev/hda2' part to 'if=/dev/hdb'. This copies lilo from the boot sector of your second hard disk to a file, which, after being put on the Windows drive 'C:', you can use it to dual-boot with XP's bootloader.