Download - CP1610: Introduction to Computer Components
CP1610:Introduction to Computer Components
Archival Storage Devices
What is Archival Storage?
Similar to secondary storage. Typically more durable. Used for long-term or permanent storage:
Data backups from hard disks;Permanent storage of data that will not be
changed (ex: music or movies);
Common Archival Storage Media
Optical Storage Flash Memory Magnetic Storage
Optical Storage
Use light (lasers) to read and write data. Not subject to data loss or corruption. Compact Discs (CD’s) Digital Video Disks (DVD’s)
How Optical Storage Works
Light is used to burn a series of ‘pits’ (dark spots) on a disk.
Dark spots and light spots are read as 0’s and 1’s (binary).
Re-writable discs use ‘Phase’ technology:Special dyes are used that react to the laser;The ‘Phase’ of the dyes can be changed to
change the data.
Data Storage on Optical Media
CD-ROM drives Use CDFS (Compact Disc File System) or UDF (Universal Disk
Format);
Hold about 780 MB of data.
DVD drives Use only UDF;
Uses the MPEG-2 encoding standard;
Standard hold about 4.5 GB of data.
Dual-layered DVD’s can hold up to 8.5 GB of data.
Optical discs have tracks and sectors, just like magnetic disks.
Tracks and sectors are arranged in a spiral, instead of concentric circles.
Floppy Disk
Flash Memory
Also called solid-state storage. No moving parts (Data on the media is altered
using electrical signals). Relatively high memory capacity. Commonly used for:
USB drives; MP3 players; Digital camera memory; Mobile phone and PDA memory;
Multimedia Compression Standards
MPEG-1 standard Image compression for business/home applications
MPEG-2 standard Video film compression on DVD-ROM
MPEG-3 standard Audio compression
MPEG-4 standard Video transmissions over the Internet
Magnetic Storage
Like a cross between a floppy or hard disk, and an audio cassette.
Stores data by aligning magnetic particles on a ‘tape.’
Magnetic particles are read as 0’s or 1’s (binary).
Advantages of Magnetic Storage Advantages
Inexpensive and convenient
Large capacity
Several types and formats
Disadvantage
Sequential access
Other Archival Storage Media ZIP Disks (By Iomega)
and SuperDisks (by Imation). Similar to 3.5 inch floppy
disks, but bigger, with more capacity.
Never became popular because of CD’s and DVD’s