in a terminal window run
sudo sfdisk -l
output should look something like (this is the from an eeepc 901)
Disk /dev/sda: 490 cylinders, 255 heads, 63 sectors/track Units = cylinders of 8225280 bytes, blocks of 1024 bytes, counting from 0 Device Boot Start End #cyls #blocks Id System /dev/sda1 0+ 399 400- 3212968+ 83 Linux /dev/sda2 400 487 88 706860 83 Linux /dev/sda3 488 488 1 8032+ c W95 FAT32 (LBA) /dev/sda4 489 489 1 8032+ ef EFI (FAT-12/16/32) Disk /dev/sdb: 1962 cylinders, 255 heads, 63 sectors/track Units = cylinders of 8225280 bytes, blocks of 1024 bytes, counting from 0 Device Boot Start End #cyls #blocks Id System /dev/sdb1 0+ 1961 1962- 15759733+ 83 Linux /dev/sdb2 0 - 0 0 0 Empty /dev/sdb3 0 - 0 0 0 Empty /dev/sdb4 0 - 0 0 0 Empty