Hard drives
Geometry: heads, tracks (sectors) and cylinder
Disk capacity:
- INT13: ROM BIOS uses INT13 to boot from drive
- originally 1024 cylinders, 16 heads, 63 sectors, 512 bytes => 528 MB barrier
- Large or ECHS: heads x 2 and cylinders / 2
- LBA: assume that the BIOS will do it today
- increased to 256 heads (1024x256x63x512) => 8.4 GB barrier
- Extended INT13 and 64-bit LBA
- present limit 144 Pentabytes (million gigabytes)
Speed: tens of milliseconds
- with Ultra DMA up to 133 MBs
