A CD-ROM (compact disc read-only memory) can hold the same amount of data as about 550 floppy disks or 300,000 pages of paper. CD-ROMs are therefore very popular for storing databases and full-text materials. Many databases containing details of medical, health or development materials are available on CD-ROM – for example, African HealthLine, AIDSLine, Medline, and POPLINE (see section 6.9.5 for other useful examples). Most CD-ROM databases are updated regularly. The only cost is an annual subscription. An increasing number of free CD-ROMs contain collections of full-text documents such as e-Talc, and the Humanity Development Library (see section 6.9.5 for other examples). No special software is needed to use CD-ROMs. Using CD-ROMs to distribute and access information is useful in situations where using the Internet is costly, unreliable or unavailable.
Advantages of CD-ROMs:
- can provide access to large databases
- easy to search
- fast to use
- easy to transport
- durable; not easily damaged
- can be used on any computer with a CD drive
- available in multimedia (containing sound and movement) on a computer with multimedia facilities
- no telephone/internet service costs
- no reliance on telephone/internet access/availability
- fixed subscription cost.
Disadvantages of CD-ROMs:
- data may not be completely up-to-date
- subscription costs can be high.