Specifications
Status
Bits
4=1
3=1
4=1
5=1
6=1"
Status
Interrupt
On
cylinder
End-of-
operation
Alarm
No
compare
96769450 A
Description
The busy
status
bit is cleared
when the controller and/or drive
unit has completed
its
operation
or an abnormal condition is de-
tected
that
aborts the operation.
Once initiated, the computer
cannot clear the busy condition.
The interrupt
status
bit indicates
that
a selected interrupt condi-
tion has occurred.
The bit is cleared
by
the accep-
tance of any output function.
The on-cylinder
status
bit is
set
when the drive positioner is
on
cylinder.
The bit is cleared if the drive
unit is presently positioning or if
a seek error is detected.
The end-of-operation status bit
is
set
whenever the controller
portion of an operation is com-
plete. The busy
status
bit may
remain
set
if
the selected unit is
positioning.
The bit is cleared
by
any output
function.
The alarm
status
bit indicates
that
one of the following abnor:'
mal conditions occurred:
Not ready
Checkword error
Lost
data
Seek error
Address error
Storage parity error
Protect fault
Any
output function clears the
bit. The not ready condition can
be changed
by
manual interven-
tion.
The data received from com-
puter core storage does not com-
pare with
data
read from file
storage during the compare
operation.
Status
Bits
6=1
7=1
8=1
9=1
10=1
11=1
Status
No
compare
(Contd)
Protected
Checkword
error
Lost
data
Description
The bit
is
cleared
by
any output
function.
The controller is presently
reserved for
or
being operated
on
by protected computer instruc-
tions, or the drive unit is pro-
tected
and may only be accessed
by
protected computer instruc-
tions.
The controller is reserved for or
being operated
on
by
a protected
instruction;
it
can be cleared by
a protected director function
that
has the release bit
set
in
A.
The drive unit is
protected
by
the
protect
switch
on
the
operator's panel,
it
can then be
cleared by changing
the
protect
switch to
its
off position (down)
or
by
deselecting the unit with a
director function
that
has the
proper
protect
code
set
in
A.
The controller logic has
detected
an incorrect checkword in
data
read from file storage during a
read, compare, or checkword
check operation.
The bit is cleared
by
any output
function.
The direct access bus of the
computer has not been able
to
keep
up
to the file
data
transfer
rate
during a write, read, or
compare operation.
The bit is cleared
by
any output
function.
Address error The controller has
detected
an
illegal file address received from
the computer, or the controller
has advanced
the
file address
beyond the limits of file storage.
Controller
seek error
The bit is cleared
by
any output
function.
The controller has been unable
to
obtain the file address selected
during a write, read, compare, or
checkword check operation. This
error usually indicates a posi-
tioning error. The error can be
6-19