Summary

Table G.1 summarises the characteristics of storage devices. It reflects the state of technology in mid '95.

 

Memory Disk Tape

RAM Floppy Hard Magneto CD CD-R QIC Exa- DAT

Optical byte

volatility volatile non-volatile

- 2y 5y 10y 40y 2y 2y

technology CMOS magnetic mag/opt optical magnetic

access random sequential

mode read/write many read read many/ read/write many

only write once

access time s s s s s

data rate b b b b

$500 $200 >$1000 $600

medium $50/M $1/M $.5/M $1/M $.01/M $.03/M $1/M $0.02/M workstation

16M 1.4M 500M 500M 600M 250M 2000M

# 2 1 external 1 external external future (97)

config 64M 1.4M 4000M 1200M

# 2 1 external 1 external external

In the near future, workstations are expected to be equipped with the same number of devices as today (i.e. still one hard disk, one CD drive), but of larger size or higher speed. In general, an improvement of 2 to 8-fold can be expected. Optical media, including CD, will profit from shorter wavelength lasers currently being developed in research labs, but it will take until '97 for higher capacity devices to reach the market.

Tapes will continue to be used for archival and backup storage mainly due to the slow sequential access. Their capacity will increase - 5 to 12 gigabyte ExaByte tapes have been presented. Some of the gain in capacity is the result of on-line compression.