M. LUTFAR RAHMAN
CD-ROM stands for compact disc read-only memory. It is a secondary storage that uses laser technology to read data from and to write data on it. Presently available CD-ROM has reasonably fast access time (about 300 milliseconds) and vast storage capacity (500 to 700 megabytes). CD-ROM based database consist sting of scientific articles, research reports, books, journals, conference papers etc. are commercially available now.
A CD-ROM database, called International Nuclear Information System - INIS, has recently been installed in the Institute of Computer Science of the Atomic Energy Research Establishment, at Savar, in Dhaka. This database is maintained in a single CD-ROM disc, whose capacity is 600 MB (equivalent to 330,000 pages of typical prated pages). Necessary information from the CD-ROM can be retrieved and displayed on the monitor of a PC, or can be printed by a printer through a CD-ROM drive interfaced to the PC. Information can also be downloaded on a floppy disc for later use by a PC. The INIS database contains more than 1,000,000 records obtained from most of the scientific and technical literature of the world. It is a PC based system that allows the users menu-driven searching facilities.
Information stored on a CD-ROM can be regard as an “electronic book”, a CD-ROM player is required to retrieve information from such an electronic book. Microelectronics has made it possible to store the contents of books on the CD-ROM which can be read with the help of even a portable CD-ROM player. The commercially available Sony Data Discman is an example of such a CD-ROM player. This unit is slightly smaller in width and depth than a normal compact disc player, but is slightly thicker. The machine has recently been launched in the United Kingdom by the name DD- 1EX with a recommended price of 350 UK Pounds. The unit weighs just 700 grams. After opening up the lid of the machine one can see the QWERTY keypad and a 3.5-inch diagonal back-lit liquid crystal screen. The screen, having a resolution of256x200pixcls, displays texts in 30 columns and 10 lines.
Under the keypad is the electronic book” bay which can be accessed by flipping the keypad. These Data Discman electronic books are actually 3.2 – inch CD-ROM discs enclosed in protective cases like 3.5 inch floppy discs. The capacity of the disc is 200 megabytes. A disk can store 100,000 pages of text. The storage facility is not only restricted to written words only, up to 32,000 illustrations can be held in a disc. This is just not enough! If one gets bored with electronic book, it is possible to swap it for a standard 3-inch audio CD-ROM and listen via a 3.5 mm stereo headphone. The unit can be powered by batteries or main electricity supply.
Several English language electronic books are already available with the machine and many more titles will be made available in the near future, the titles include dictionaries, travel guides, sports information etc. The graphics capabilities of the electronic book have been exploited by the London Guide published by Nicholson by featuring a series of maps accompanying texts on theatres, shopping information and so on. Prices of the so called electronic books range from UK Pounds 40 to 60 per title. The DD-1EX is provided with TV/Video display adapter and three main TV standards, such as, Pal, Seam, and NTSC. Presently facilities are available to support twelve languages.
Numerous search options are available to help reader to find required information. Searches by words, parts of words, thesaurus like search. Menu search, combination search and graphics search facilities are available.
The portable Data Discman is probably the practical, and useful alternative to the printed books for the years to come.
Source: Computer Jagat magazine 1992