Specifications
Status
Bits Status
Description
10=1
Seek Error
(Contd)
The controller has been unable to
obtain the sector record address
selected during a write, read,
compare, and checkword check
operation.
The
bit
is
cleared
by
any function that sets the
busy
status bit.
11=1
12=1
13=1
14=1
15=1
Address error The controller has detected an
illegal file address received from
the computer or the controller
has advanced the sector record
address beyond the limits of file
storage.
The
bit is cleared
by
any output function.
Defective
track
Storage
parity error
Protect
fault
Reserve
The controller has attempted to
access a file storage address that
had previously been labeled as
being
in
a defective track.
Bit
12
is
cleared
by
any output
function.
The controller has received a
parity error signal from the
direct storage
bus
while receiv-
ing data or control information.
If
the error is detected during
control information transfer, the
operation ends immediately.
If
the error is detected during data
transfer, the operation ends
at
the end of the current sector.
Bit
13
is cleared
by
any output
function.
An
unprotected controller opera-
tion attempts
to
write into a
protected computer storage
area.
When
the error is detected
while transferring data to
storage, the operation ends
at
the end of the current sector.
The bit is cleared
by
any output
function.
This computer has the controller
reserved.
1733-2/856-2/856-.4
Cartridge
Disk
Controller
Status'
Bits
0=1
Status
Ready
96769450 A
Description
The ready status bit indicates
that the drive
is available and
ready to operate. The drive
becomes not ready for the
following reasons:
• The disk pack is not in the
drive unit.
Status
Bits
0=1
1=1
2=1
3=1
4=1
Ready
(Contd)
Busy
Status
Interrupt
On
cylinder
End-of-
operation
Description
• The disk drive motor
is
not
up
to operating speed.
•
The
read/write heads are
not
in
the operating posi-
tion.
• A fault condition develops
in
the drive.
The
status condition is affected
by
the operating program only if
it
selects a nonexisting device or
a device
that
is not ready
Normally, the ready status bit
indicates
that
manual interven-
tion is required
at
the selected
drive unit.
The
busy
status bit indicates
that
the controller and/or the drive
unit is presently involved
in the
performance of an operation.
The bit is
set
by
the acceptance
of a load address, write, read,
compare, checkword check, or
write address function.
The
busy
status bit
is
cleared
when
the controller and/or drive
unit has completed its operation
or
an
abnormal condition
is
detected
that
aborts the opera-
tion. Once initiated, the com-
puter 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-cyclinder 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
fun~tion.
6-15