Page 159 - DLIS006_INFORMATION SOURCES AND SERVICES

Information Sources and Services

Notes Transparent Jacket: This is a holder for individual images or strips of film, ranging in size
from 3 × 5 inches to 5 × 8 inches (standard file-card size). A 4 × 6 inch jacket can hold
70 images of letter-size documents, with 100 jackets being approximately 1-inch thick.
Individual jackets can hold medical case histories, stock portfolios, or any other information
that needs to be updated continually.
Microfiche (pronounced “microfeesh”): This is about the same size as the microfilm jacket
but is a whole sheet of microfilm with rows of images. A 4 × 6 inch sheet of microfiche can
hold 98 images of 81/2 * 11 inch documents, with up to 500 images of smaller documents.
Ultrafiche is microfiche with a much greater image reduction. Microfiche can be
economically mass-produced to distribute such information as research data, service, and
parts data. Whole medical or client files can also be stored on “fiche,” as it is abbreviated.

Aperture Card: This is 3'/4 x 7% inches (the size of a standard keypunch card) and contains
space for printed filing and retrieval information as well as openings in which the microfilm
is mounted. Cards that have filing information keypunched into them can be quickly
sorted with the use of data processing equipment. Useful applications of aperture cards
include the filing of engineering blueprints and patent information.
Figure 7.11: A Computer Output Microfilm Processor.
(Courtesy of Eastman Kodak Company)

Computer Output Microfilm

Computer output microfilm, abbreviated COM, is film produced by converting computer-
generated signals into readable characters at high speeds. Using magnetic tape as input, a computer
output microfilmer can translate data into microforms at speeds of up to 120,000 characters a
second, or 342 standard-size computer pages a minute. Because no hard copy is produced unless
needed, COM eliminates the space required to store massive amounts of computer-printout
information. Each computer-generated microfiche contains from 72 to 288 times more information
than a standard-size-computer printed page.

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