Chapter1. Introduction
Order Number: EK–SM1TB–UG. E01
1–3
Figure 1–2 CompacTape III Cartridge
1.3.2 Cartridge Packaging
Your CompacTape III cartridge comes supplied with:
1. A set of slide-in labels
2. A cartridge-handling information sheet
1.4
Reading and Writing Data
The 10/20-GB DLT Cartridge Tape Drive writes 64 pairs of tracks — 128 tracks total — on
the CompacTape III tape. The drive reads and writes data in a two-track parallel, serpentine
fashion, traveling the entire length of tape on two tracks (at about 110 inches per second).
The drive then steps the head, reverses tape direction, and continues to read/write on the next
two tracks, repeating this same process for a total of 64 times per tape.
1.4.1 Write-Protecting Data
The CompacTape III cartridge has a write-protect slide-bar switch on its front surface that
lets you prevent accidental erasure of data. When you move that switch to the left, so that a
small orange rectangle is visible in the aperture over the left arrow symbol on the switch (see
Figure 1–2), the tape is write-protected and data cannot be written to the tape. When you
move the switch to the right, so that no orange color shows in the rectangular aperture, the
tape is write-enabled, and the tape drive can write to the tape. The symbols on the slide-bar
switch indicate this function by depicting data flow as a downward-pointing arrow and the
tape medium as a horizontal line below the arrow’s point. The arrow on the left side of the
slide-bar switch depicts a barrier line between the data-flow arrow and the tape; this symbol-
izes that the data cannot reach the tape when the switch is moved to the left. No such barrier
line appears below the arrow on the right side of the switch, indicating that data can flow to
the tape when the switch is moved to the right.
