Storage Device Summary

CD and DVD are much slower than a hard disk for data transfer.

Device

Physical Method of Storage (Check)

Type Memory
Retention (Check)

Access Method (Check)

Type Access
Permitted
(Check)

Speed (Bytes/sec)

Density
(Bits
/length,
area,
 volume)

Capacity
(Bytes)

Power
Consumption  to Keep Data (Check)

Electronic

Magnetic

Chemical

Topological

Acoustic

Volatile

Non-
Volatile

Sequential

Direct

Read

Write

Read

Write

 

 

High

Low

Semiconductor
Memory

X

 

 

 

 

X

 

 

  x

  x

  x

  1.25 - 15 ns

 

 

  256 MB common on PCs

 

 

Magneto-electronic

 

X

 

 

 

 

X

 

  x

  x

  x

 

 

 

 

 

 

Deltic

 

 

 

 

X

X

 

  x

 

  x

  x

  0.707 ms

 

 

 

 

 

ROM

 

X

 

 

 

 

 

X

 

  x

  x

 

  25 - 250 ns

 

 

 

 

 

CMOS

 

X

 

 

 

 

X

 

 

  x

  x

  x

 

 

 

 

 

 

Floppy disk

 

 

X

 

 

 

 

 

 

  x

  x

  x

  84 ms

 

  21 kB/cm2

  1.44 MB common

 

 

Zip disk 100 MB

 

 

X

 

 

 

 

 

 

  x

  x

  x

 

 

  1.44 MB/cm2

  96 MB

 

 

Zip disk 250 MB   x             x x x     3.6 MB/cm2 250 MB    

JAZ disk

 

 

X

 

 

 

 

X

 

  x

  x

  x

 

 

 

 

 

 

Hard disk

 

 

X

 

 

 

 

X

 

  x

  x

  x

 

 

  930 MB/cm2

  100 GB retail for PCs 2002

 

 

Cassette Tape

 

 

X

 

 

 

 

X

  x

 

  x

  x

 

 

 

 

 

 

Quarter Inch Tape

 

X

 

 

 

 

X

  x

 

  x

  x

  @ 40 s

 

 

 

 

 

DAT Tape

   x         x x   x x @ 20 s          

Digital Linear Tape

   x         x x   x x       70 GB    

CD-ROM

 

 

 

 

X

 

 

X

 

  x

  x

 

  80 - 800 ms

 

  7 MB/cm2

  650 MB

 

 

CD-R

 

 

 

X

 

 

 

X

 

  x

  x

  Once

 

 

 

 

 

 

CD-RW

 

 

 

X

 

 

 

X

 

  x

  x

  x

 

 

 

 

 

 

DVD-ROM

 

 

 

 

 

 

 

X

 

  x

  x

 

 

 

 

  4.7 GB

 

 

Optical Cube

 

 

 

 

 

 

  x

  x

  x

 

 

 

 

 

 

Punched Card

 

 

 

 

X

 

 

X

  x

 

  x

  Once

 

 

 

 

 

 

Paper Tape

 

 

 

 

X

 

 

X

  x

 

  x

  Once

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

The CD-ROM is recorded by using a laser to burn microscopic pits into the recording surface.
When recording, CD-R, CD-RW use a laser as a heat source to cause a chemical reaction.  Learn more in the lesson plan on storage devices.