Figure 2-4.—Checking for BOT and EOT with read/write head.
is referred to as an external label. External labels are
the labels we are interested in. The second type is
written directly onto the media and is referred to as
an internal label. Internal labels contain information
that is needed by the executive control programs
(systems software) of the computer to allow for the
proper functioning of applications programs.
External Labels
External labels are considered permanent or
nonpermanent, depending on their purpose (see
figure 2-5). The two types of permanent tape and
disk labels are the identification label, which
indicates the number that has been assigned to the
media; and the certification label, which indicates
the last time the media was certified (tested for its
reading and writing capability). Nonpermanent
labels include usage labels to tell you how often the
media has been used on the computer, cleaning
labels to indicate when and how often the media has
been cleaned, and save labels to indicate the file or
files that are contained on the media. As the magnetic
media librarian, you are responsible for initiating and
maintaining the first four types of external labels:
identification, certification, usage, and cleaning
Figure
2-5.—Examples
of
media
labels.
2-11
