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.