Disk and Memory Characteristics

Physical organization

• A disk is a set of platters.
• Each platter has a sequence of tracks.
• Each track has a sequence of sectors.
• Sector size is typically 4k or 8k bytes.

To access data at (p, t, s)

1. Move arm to track t.
2. Wait for sector s to rotate under head.
3. Read or write sector on the platter p.
4. Multiple adjacent sectors can be read or written without repeating steps 1-2 for each.