Media

Review:
How many bits/byte?
How many bytes to store 1 character?
What is a GB?

ASCII-American Standard Code for Information Interchange
A 0100 0001

magnetic media vs. optical media
random (direct) access vs sequential access

floppy disks (HD 1.44 MB)
high capacity floppy disks (Iomega ZIP, +100MB)
hard disks (Capacity varies, usually GB)

floppy drive (A:), hard drive (C:)

FAT-file allocation table

fragmentation

formatting (initialization)

tracks (concentric rings) and sectors (pie shapes)

(HD floppy: 18 sectors per side, 80 tracks per side)

access time (seek + read time) milliseconds (thousandth of a second)
transfer time MBps

cartridge drives (e.g. Iomega Jaz) 
	12 ms seek time, 3.3 MBps transfer time

compression

optical media


CDROMs  read-only media.  Useful for storing large quantities of
information (up to 740 MB) that will not be changed.  They are made
of plastic and aluminum (reflective).  Information stored is as reflective
and non-reflective areas (pits) on the surface. A beam of light
bounces light off the surface and a photodetectors reads light if it is
reflected.  This media uses a single track.


CD ROM (Compact Disk Read Only Memory)
CD ROM drive (often D: or E: drive)

WORM disks (write-once-read-many)

DVD-ROM (digital video disks)  For more information  Click here.  
DVDs are new, high capacity optical disks, much faster
than conventional CD ROMs.  The capacity ranges from 4.7-17GB depending
on whether the disk is single layer or double layer and whether it is
single sided or double sided.

magneto-optical: combination technology used to create a writeable optical
disk.  When the disk is heated with a laser beam, the magnetic fields can
be changed (written).  The disk is read by using a laser and determining
how the light is polarized.

PCMCIA (PCI) cards (used in laptops/notebook computers) "personal computer
memory card international association").  Types I (thinnest), II, and III
(thickest).  Used to add a modem or hard drive to a notebook/laptop
computer.

Multimedia--combining sound/graphics/video/animation etc.  Often used
to create "virtual reality" environments.  Multimedia is media intensive
and greatly increases the requirements for storage and speed.