Page 30 - Cataloging and Classification for Library Technicians, 2nd Edition

Library Catalogs 13

COM (Computer Output Microform) Catalog

In this for mat, bib liographic re cords are pho tographed and pro duced
on mi crofilm or microfiche, which is relatively inexpensive. Space is
saved com pared to the card cat alog and the book catalog for mats.
The dis advantages are some what sim ilar to those of the book cat alog,
in the sense that it is dif ficult and ex pensive to up date. It is in convenient
for us ers to em ploy the many sup plements and trou blesome, ini tially, to
learn to use the nec essary equipment, the mi crofilm/fiche reader/printer.
It also means extra ex penses because the li brary has to ac quire sev eral of
these ma chines. This form of catalog was adopted by some libraries for a
short while in the 1970s but never be came very pop ular.

OPAC (Online Public Access Catalog)

OPACs be gan to ap pear in li braries in the late 1970s and the early
1980s. They quickly gained wide ac ceptance and be came the most
popular cat alog form. With ei ther the touch screen or the key board, us -
ers can ac cess the most up-to-date in formation on the library’s col lec-
tion and can get a print out of that information. OPAC of fers fast
retrieval and an im mediate dis play. In a shared on line catalog, us ers
can re trieve in for ma tion from other par tic i pat ing li brar ies. These sys-
tems not only in dicate the holdings of dif ferent li braries but also tell the
circulation sta tus of an item, whether it is on the shelf and, if not, when
the item is due back. Some sys tems al low us ers to place a hold on the
desired item or to di rectly re quest an item from other li braries through
interlibrary loan agreements among the li braries in the system.
Due to ad vances in com puter tech nology and the im plementation
of stan dards in the technology world, li brary us ers now can search
hundreds of on line catalogs through re mote log-in fa cilities on the
Internet. The new gen eration of OPACs is eas ier to use and offers
more op tions.
The on line cat a log has changed tra di tional cat a log ing in sev eral
ways:
1. The dependence on shared bibliographic databases for cataloging
has increased copy cataloging and decreased original cataloging
activities.