Key Concepts Secondary storage is non volatile Access method Sequential Direct Relative access time Data retention technology Magnetic Optical Film Chip Capacity Life span range Storage Holds data, instructions, and information for future use Store medium is the physical material on which a computer keeps data, instructions, and information Capacity is the number of bytes a storage medium can hold Kilobyte (1 thousand bytes or 1,024) Megabyte (1 million bytes) Gigabyte (1 billion)
Terabyte (1 trillion) Storage device is the computer hardware that records and retrieves items to and from storage media. Reading is the process of transferring items from storage medium to memory Writing is process of transferring items from memory to storage medium Access time measures: Amount of time for storage device to locate an item on storage medium Time required to deliver an item from memory to processor Memory (most RAM) Stores items waiting to be interpreted and executed by processer Fastest transfer rates Hard Disk Operating system; application software; user data and info, (photos, music, videos, backups) Contains 1 or more inflexible, circular platters that use magnetic particles to store data, instructions, and information Formatting is the process of dividing the disk into tracks and sectors so that the op system can store and locate data and information on the disk Sample hard disk: Advertised capacity: 1 TB Platters: 4 Read/write heads: 8 Cylinders: 16,383 Bytes per sector: 512 Sectors per track: 63
Sectors per drive: 1,953,525,168 Revs per minute: 7,200 Transfer rate: 300 mbps Access time: 8.5 ms 1 TB disk can store any of the following: 500,000 pages of text 285,000 photos 250,000 songs 120 hours od video sample equation: (2 sides
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- Flash memory, Optical disk, Memory card