This picture shows a system with three hard drives and two DVD-ROM drives.
The first drive (Disk 0) has been partitioned with one primary partition using the full 28.63 GB (the drive is classed as a '30 gig' hard drive). It is assigned the letter C.
The second drive (Disk 1) has two primary partitions and the partitions are assigned the letters F and G, as D and E are automatically assigned to the two DVD drives because these were installed before the second hard drive.
The third drive (Disk 2) has three partitions and an unallocated section. The first two partitions are primary (assigned H and I) and the third is extended with one logical drive J and free space that can be assigned one or more logical drives.
CD-ROM 0 and 1 are DVD drives with a CD in 0 using the CDFS file system.