Secondary Storage

1975 – 1980’s 5 ¼” Floppy Drive – very low storage capacity maxing out at 1.2 Mb Mid-1980’s – 1990’s 3 ½” Floppy Drive – low storage capacity maxing out at 1.44 Mb 1970’s 8” Floppy Drive – very low storage capacity maxing out at 1.2 Mb. Some were double sided

Secondary Storage cont’d CD SD CARD FLASH DRIVE BLU-RAY DVD

Optical Media Storage Devices CD-R CD-RW DVD-R DVD-RW Storage capacities ranging from 700 Mb to 9.4 Gb Data is stored as tiny pits that are burned into a disk by a high speed laser Data is read off the CD by a laser beam – the pits and non pits translate into 1’s and 0’s.

CD-ROM: Read-only optical disks (you can’t save any data to it) CD-RW: Compact Disc-Read/Writable CD-R: Compact Disc-Recordable (you can write to it once) DVD: Digital Video Disc less space between tracks and smaller pits enable it to store more. Audio and video quality is superior to CD’s Some DVD’s can store data on both sides giving them a maximum capacity of 17 GB. DVD-R : DVD Recordable – cannot be changed

DVD-RW: DVD Re-writable – can be re-written BLU-RAY DISK Single Sided can store as much as 25 GB Double Sided can store as much as 50 GB “blue” refers to the fact that a blue laser is used to write and read these discs

Record speed x Re-write speed x Playback speed Ex: 52X 32X 52X Record Data at 52X Re-write data at 32X Play-back data at 52X For CD’s : the X after each number represents the transfer of 150 KB of data per second. For DVD’s: the X after each number represents the transfer of 1.3 MB of data per second. For Blu-Ray: The X after each number represents the transfer of 36 MB of data per second.

Flash Drives and Cards Flash memory card o A chip that is nonvolatile o Small and can be easily modified and reprogrammed o Sometimes referred to as media cards o USB flash drive  Small, flash memory modules

Connecting an external device Expansion Port o Any connector that passes data in and out of a computer or a peripheral device Cables

Expansion USB o Provides connection to computer for data transfer o Provides power line o Goal was to replace all other ports. o USB 1 – 12 Mbps; USB Mbps, USB 3 – ~5Gbps? Firewire o Competes with USB as standard for connecting devices to PCs o IEEE-1394 currently handles up to 400 Mbps o Firewire 800 ~800Mbps o 63 devices can be connected to the host

USB 2.0 Firewire Ethernet

USB Mbps

Firewire 400/800 Mbps

Ethernet Up to 1000 Mbps

Serial Parallel USB 1.1

Serial Port 56 Kbps

Parallel Port 12 Mbps

USB Mbps