i justed add a second hardrive hdc when i go to partition it in to 2 more partition's it askes me if i want to write them out will this overwrite the other hardrives partition's hda i have is there a way to add this to the existing hardrive and partition's i have i am using slackware 9.1 with a 30 gig old and a new 80 gig i just added ext3 is the fs

If you are using a partition editor like fdisk on hdc it will not alter hda at all. It only operates on one disk at a time. Just make sure you are working on the right disk!

To make your system recognise the new disk you need to make an entry in /etc/fstab specifying where you want to mount the new partitions. You can model the new entry on the existing (non-root) entries in /etc/fstab.

thanks here is my sftab will i just add 2 lines for my other 2 partition's
/dev/hda5 swap swap defaults 0 0
/dev/hda1 / ext3 defaults 1 1
/dev/hda6 /home ext3 rw,nosuid,nodev,noatime,usrquota $/dev/hda7 /tmp ext3 rw,nosuid,nodev,noatime,usrquota $/dev/hda8 /var ext3 rw,nosuid,nodev,noatime,noexec $/dev/hda10 /usr ext3 rw,nodev,noatime 1 2
/dev/hda9 /boot ext3 rw,nodev,nosuid,noexec,noatime $/dev/cdrom /mnt/cdrom iso9660 noauto,owner,ro 0 0
/dev/fd0 /mnt/floppy auto noauto,owner 0 0
devpts /dev/pts devpts gid=5,mode=620 0 0
proc /proc proc defaults 0 0

Your editor seems to have joined some lines in a funny way with those $ signs. Minimum entry is something like...

/dev/hdc1 /<path to dir1> ext3 defaults 0 2
/dev/hdc2 /<path to dir2> ext3 defaults 0 2

but you can also put in extra options as in your existing fstab (for extra security I think). Do 'man fstab' to see the meaning of all the fields. Also you have to decide where to mount the partitions and set 'path to dir1/2' accordingly (and make the directories if necessary). Then 'mount /dev/hdc1' etc will mount the partitions, and they will mount automatically next time you boot.