IBM System/360

2803 TAPE CONTROL (Continued)
Bit Name
Description
O Attention
Not used.
1 Status Modifier Present with busy to indicate TCU busy.
4
Control Unit
End
Busy
Channel End
Device End
Unit Check
SigMled by the TCU:
(a) At completion of operations during which
a TC U busy was indicated.
(h) At the completion of a control immediate
operation during which a unit check O.l"
unit exception is detected.
When presented without bit 1 (status modifier
bit), indicates that the tape unit is busy.
Indicates that a read, read backward, write,
mode set ·Or 'sense has been completed, or
that a control command has been accepted.
Indicates that the tape unit has completed
operation at TU level of command. Device
end indicated with channel end at the comple-
tion of <Jomrnand.
Set whenever:
(a) Any bit is on in.sense byte O.
(b) Tape unit performing read backward,
backspace record or backspace file into
or at load point.
(c) A rewind and unload is completed at the
TCU level.
7 Unit Ei<ception Set when:
82 S/360
(a) A write, WTM or ERG operation is per-
formed in the end of tape area.
(b) A tape mark ls sensed during a read, read
backward_, _forward space record} or back ...
space record.
IBM <JQNFIDEN'l'l'.AL