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The seven bits of the frame number (command word 3) designate the head which is to perform
the read or write operation as well as the number of the frame. All the
96
frames capable of
being read when the positioning arm is in a given position can be addressed by the seven frame
number bits whose binary value varies from 0000000 for frame 0 to 1011111 for frame 95,
as follows:
Command Word
3
Bits
8 7 6 5 4 3 2
0 0 0 0 0 0 0
to
0 0 0 0 1 1 1
0 0 0 1 0 0 0
to
0 0 0 1 1 1 1
0 0 1 0 0 0 0
to
0 0 1 0 1 1 1
0 0 1 1 0 0 0
to
0 0 1 1 1 1 1
0 1 0 0 0 0 0
to
0 1 0 1 1 1 1
Bits 8 7 6 5 4 3 2
0 1 1 0 0 0 0
to
0 1 1 1 1 1 1
1 0 0 0 0 0 0
to
1 0 0 1 1 1 1
1 0 1 0 0 0 0
to
1 0 1 1 1 1 1
1 1 0 0 0 0 0
to
1 1 1 1 1 1 1
Inner Tracks 0 - 63
Frames
0
through
7
Inner Tracks
0 -
63
Frames 8 through 15
Inner Tracks
0 -
63
Frames 16 through 23
Inner Tracks
0 -
63
Frames 24 through 31
Outer Tracks
0 -
·63
Frames 32 through 47
Outer Tracks
0 -
63
Frames 48 through 63
Outer Tracks
0 -
63
Frames 64 through 79
Outer Tracks
0 -
63
Frames 80 through 95
96
through
12 7
Invalid Address
Top Side
Top Side
Bottom Side
Bottom Side
Top Side
Top Side
Bottom Side
Bottom Side
The maximum number of frames which can be transferred by one instruction is 16. It is not
necessary that these 16 frames (or any part of 16 frames) all be in the outer tracks or all be
in the inner tracks.
The transfer of information during the execution of an instruction can start
[ID/A\1J&~~1J~~@------------
V-39
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