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TAPE FORMATS
6.7 Individual Track Layout
The layout of an individual track is made up of a main area and two subareas, as shown in Figure 6-4.
INDIVIDUAL TRACK FORMAT
l l . . .
4----------
.925" TRACK LENGTH
13.6J1m
T
6.7.1 Main Area
w
0
LL
DATA AREA
0
0
~
4096
BYTES
[Q
::l
(J)
J~
t
HEAD TRANSPORT
-.
DIRECTION
ATF AREA
(Automatic Tracking Finding)
SUBCODE AREA
DATA AREA
2912 USER BYTES
1184 ECC BYTES
Figure 6-4
Individual Track Layout
w
0
LL
0
~
~
r
t
J~
ATFAREA
SUBCODE AREA
Within the individual track, the main area is made up of the 128 main data blocks. Each main data block is
made up of the following:
o
Synchronization (8 bits)
o
Main ID (16 bits -- WI and W2)
o
Main ID parity (8 bits)
o
Main data (256 bits)
Synchronization Pattern: The 10-channel bit synchronization pattern corresponds to 8 bits, which are
contained in the synchronization portion of the main data block.
Main ID: The Main ID is made up of WI (8 bits) and W2 (8 bits). These bits identify various characteristics
about the main data area.
The Block Address is determined by W2, bit 7, which identifies the type of block. The remaining seven bits
of W2 -- B6 (msb) through BO (lsb) -- are the identify bits for the main data block address (0 to 127) in one
track.
The Frame Address is a 4-bit code of WI -- B3 (msb) through BO (lsb) -- in even address blocks. The frame
address repeats from 0000 to 1111.
6-9
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