Specifications
Status
Bits
7=1
8=1
9=1
10=1
11=1
12=1
13=1
6-18
Status
Protected
Check word
error
Lost
data
Seek error
Address
error
Defective
track
Storage
parity error
Description
A selected drive unit is pro-
tected
and may only be accessed
by
protected computer instruc-
tions.
When
bit 7 is
set,
it can
be cleared
by
a protected direc-
tor
function
that
has the release
bit
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. This bit is
cleared
by
any output function.
The direct access bus of the
20mputer has not been able
to
keep
up
with the file data trans-
fer
rate
during a write, read, or
compare operation. The bit is
cleared
by
any output function.
The drive unit has detected a
head positioner that has moved
beyond the legal limits of the
device during a load
address,
write,
read, compare, checkword
check, or write address function.
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.
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.
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
Status
Bits
13=1
14=1
Status
Storage
parity error
(Contd)
Protect
fault
Description
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
stor-
age, the operation ends
at
the
end of the current sector. This
bi
t is cleared
by
any output
function.
1739-1
Cartridge
Disk
Drive
Status
Bits
0=1
1=1
Status
Ready
Busy
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.
• 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,
check word check, or
write address function.
96769450 A