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7340 HYPERTAPE DRIVE (Continued)
Byte 0, Bit 6 - Word Count Zero is set during a Write Operation
when the operation has been terminated without any byte of
data transferred between the 2802 and the channel.
Byte 0, Bit 7 - Spare
Byte 1, Bit 0 - Selected Dri're at EOT is set whenever the
Selected drive indicates End of Tape.
Byte 1, Bit 1 - Selected TD Status A and B will be set to the condi-
tion of tape drive status lines that are used to decide
the responses to Initial S13lection. The bits reflect the status
of the drive at the moment Sense Byte 2 is assembled. The
meanings and the responses during Initial Selection are listed
below:
TD Status A
(Sel and Rdy)
0
0
TD Status B
(Not Rdy or Busy
or Switched*)
0
Response to
TD Status
Initial Selection
Non existent TD Unit Check
Not Ready
Unit Check-Arm
for Device End
Ready, Not Busy, Clean Status
Not Switched
Ready and (Busy Busy-Arm for
or Switched)
Device End
*
Switched indicates the TD is selected by some other Control Unit
under control of a Tape Unit Switch.
Note:
The following bits refer only to the Selected drive which
may or may not be the drivE: referred to by the remaining status.
Byte 1, Bit 3 - Spare
Byte 1, Bit 4 - Selected Drive at BOT is set whenever the Selected
drive indicates Beginning of Tape.
Byte 1, Bit 5 - Selected Drive in Write Status is set whenever the
Selected drive indicates ·write Status.
Byte 1, Bit 6 - Selected Drive File Protected is set whenever the
Selected drive indicates that the currently loaded cartridge
is _File Protected.
Byte 1, Bit 7 - Selected Drive in
EWA
is set whenever the Selected
drive indicates End of Warning Area.
Byte 2, Bits
O,
1, and 7 - Spares
Byte 2, Bits 2-6 - These Data Check Detail bits are set
whenever:
The last drive operation was Write, Read, or Read Backward.
An error (s) has occurred as defined in the section of the
2802 specifications describing these commands.
IBM CONFIDENTIAL
S/360
107
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