How to create extended partition???

[Barriehie]

I would like to install Xubuntu on sda4 and when the install CD got to the partitioner it was asking me for the mount point. Would this be /??? I want to be able to dual boot xubuntu and ubuntu. Will it update GRUB???




Disk /dev/sda: 200.0 GB, 200049647616 bytes
255 heads, 63 sectors/track, 24321 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0xd5ddd5dd

Device Boot Start End Blocks Id System
/dev/sda1 1 4207 33792000+ 83 Linux
/dev/sda2 * 12749 23569 86919682+ 7 HPFS/NTFS
/dev/sda3 23570 24321 6040440 5 Extended
/dev/sda4 4208 12748 68605582+ 83 Linux
/dev/sda5 23570 24321 6040408+ 82 Linux swap / Solaris

Partition table entries are not in disk order

Disk /dev/sdb: 82.3 GB, 82348277760 bytes
255 heads, 63 sectors/track, 10011 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x4b36bdea

Device Boot Start End Blocks Id System
/dev/sdb1 1 6187 49697046 83 Linux
/dev/sdb2 6188 10011 30716280 83 Linux

Disk /dev/sdc: 4076 MB, 4076863488 bytes
156 heads, 48 sectors/track, 1063 cylinders
Units = cylinders of 7488 * 512 = 3833856 bytes
Disk identifier: 0xc3072e18

Device Boot Start End Blocks Id System
/dev/sdc1 1 1064 3981288 83 Linux



TIA!