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'rABLE 3-3.
COMMANDS (CONT' D)
Command
DefinitionlFunction
(BOL)
(Cont'd)
Taqs
OA-oS
Write
(WRr)
Taq OP
Recalibrate
(RCB)
'rag
12
Set Standby
State (SSS)
'raq 13
Set Local
State (SLS)
'rag 14
Seize Device
(SZE) '1'ag 10
Release Device
(RLS) '1'ag 11
3-28
3. The bidirectional data lines decode as follows:
ill.
Decode
2°
BAR.
1
21
BAR 2
22
BAR 3
2 3
BAR 8
24
BAR 16
2 5 _2'
Not Used
Zavalid commands
1.
An
output infoxmation
COlIID4nd.
2.
This cOllllllaJ1d causes the drive to Write data on the disk pac:lc.
See the discussion on Write operations for. more information.
1.
A
control command.
2. Causes the Head register and Cylinder Address register to be
set to zero and the heads to return to track 000
(R~Z).
1. A
control command.
2.
Causes the drive to turn off the pack motor, unload the heads
and extinquish the
ST~
indicator.
3. '1'0 return to the ready state the operator must push the S'1'AR'.r
button.
1. A control command.
2. Removes drive from on line status.
It breaks I/O communication
between drive and controller and lights the LOCAL indicator.
3. Drive is returned to On Line status by moving the ON LINE/OFF
LINE switch from ON LINE to OFF LINE and then back to ON LINE.
1. A control command.
2. When 2 controllers are connected to a drive (dual channel) this
signal is used to seize (select) the drive.
For dual channel
operation the drive must be seized before it will respond to
o~~er
instructions (other than Summary Status Byte Request).
However the seize is not required for single channel operation.
3. '1'he drive responds to the command only if it has not been pre-
viously seized by the other controller.
1. A control command.
2. Issued by the controller having the drive seized, it releases
the drive from the seized condition thus making it available to
both controllers.
3. The drive sends a Device Event Notification (DEN) to
~~e
other
controller telling it the drive is now available.
83318200
A
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