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Unformatted text preview: ge on to a CRT screen. A high-speed camera, in-built into the system, then takes a
picture of the displayed information. In some systems, the recorder processes the film
from the camera, and in other systems, a separate automated film developer is used to
produce the filmed images of the output information.
A microfilm reader that is used to view the output information recorded on a microfiche
is shown in Figure 9.36. It operates on a "back projection" principle and displays a frame
(a single page of information) at a time on a translucent screen whose typical size is about
8"xll". A user can read the displayed information on the screen. Most microfilm readers also have a printer in-built into it or attached to it to allow a user to selectively print and
take a hard copy of the desired pages.
Most COM systems come with computer-assisted-retrieval software that allows a user to
quickly search < particular document, from the thousands of pages of recorded
information on the film, simply by specifying the pre-assigned index that corresponds to
the desired document. Without this, users would be required to spend lots of time in
manually searching through the film cartridge or card to find the desired document.
As compared to a printer, a COM system has the following advantages and limitations:
1. Information recording speed is many times faster for a COM system as compared to
a printer. A COM system is 20 to 25 times faster than an average line printer in this
2. Microfilm output is many times more compact than a printed page output. A single
microfiche can hold about 300 times as much information as a standard computer printed
page. Thus the mailing and storage costs of filmed documents are much less than paper
Microfilm output is less costly than printed output. The cost of paper needed for
printing a 1000 page document is about 20 to 30 times more than the cost of the film
needed to record the same information.
4. The initial investment required for installing a COM system is much more than that
required for buying an ordinary printer. Hence use of a COM system is justified only in
case of high volume workload.
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This document was uploaded on 04/07/2014.
- Spring '14