Tracks; Files - IBM 5100 Maintenance Information Manual

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Tracks
The tape unit records on two tracks. The upper track
(channel 0) contains the format records. and the lower
track (channel 1) contains the data records. Each track
occupies approximately 1/2 the width of the tape. The
following illustration shows the relationship between
tracks.
~
Forward Tape Motion
~
0
load
Po;nt
Hoi.
Format Track
I
I
Data Track
.... --2.5 inch
(63.5 mm)
.1-
- -..... - - - - 2.9 inch
.--~----­ 5.2 inch
(73.6 mm)
Files
Tape records are grouped into files. A file is made up of
a single header record and an even number of data
records. The header record and each data record are
preceded by a format record that is recorded on the
format track of the tape. The following figure shows the
arrangement of records on the tape.
~
Forward Tape Motion
Format
f
Last Data
Record in
Previous
File
Record
I
r
Header Record
Format
Record
(132.1 mm)
Minimum File Size
f
Data Record
Number 1
Format
Record
r
I
.1
t
Data Record
Number 2
)
~
Tape 4-33