<s>
The	O
IBM	B-Device
1401	I-Device
is	O
a	O
variable-wordlength	O
decimal	B-Device
computer	I-Device
that	O
was	O
announced	O
by	O
IBM	O
on	O
October	O
5	O
,	O
1959	O
.	O
</s>
<s>
The	O
first	O
member	O
of	O
the	O
highly	O
successful	O
IBM	B-Device
1400	I-Device
series	I-Device
,	O
it	O
was	O
aimed	O
at	O
replacing	O
unit	O
record	O
equipment	O
for	O
processing	O
data	O
stored	O
on	O
punched	B-Architecture
cards	I-Architecture
and	O
at	O
providing	O
peripheral	O
services	O
for	O
larger	O
computers	O
.	O
</s>
<s>
The	O
1401	O
was	O
operated	O
as	O
an	O
independent	O
system	O
,	O
in	O
conjunction	O
with	O
IBM	O
punched	B-Architecture
card	I-Architecture
equipment	O
,	O
or	O
as	O
auxiliary	O
equipment	O
to	O
IBM	B-Device
700	I-Device
or	I-Device
7000	I-Device
series	I-Device
systems	O
.	O
</s>
<s>
Commonly	O
used	O
by	O
small	O
businesses	O
as	O
their	O
primary	O
data	O
processing	O
machines	O
,	O
the	O
1401	O
was	O
also	O
frequently	O
used	O
as	O
an	O
off-line	O
peripheral	O
controller	O
for	O
mainframe	B-Architecture
computers	I-Architecture
.	O
</s>
<s>
In	O
such	O
installations	O
,	O
with	O
an	O
IBM	B-Device
7090	I-Device
for	O
example	O
,	O
the	O
mainframe	B-Architecture
computers	I-Architecture
used	O
only	O
magnetic	O
tape	O
for	O
input-output	O
.	O
</s>
<s>
It	O
was	O
the	O
1401	O
that	O
transferred	O
input	O
data	O
from	O
slow	O
peripherals	O
(	O
such	O
as	O
the	O
IBM	B-Device
1402	I-Device
Card	O
Read-Punch	O
)	O
to	O
tape	O
,	O
and	O
transferred	O
output	O
data	O
from	O
tape	O
to	O
the	O
card	O
punch	O
,	O
the	O
IBM	B-Device
1403	I-Device
Printer	O
,	O
or	O
other	O
peripherals	O
.	O
</s>
<s>
This	O
allowed	O
the	O
mainframe	B-Architecture
's	O
throughput	O
to	O
not	O
be	O
limited	O
by	O
the	O
speed	O
of	O
a	O
card	O
reader	O
or	O
printer	O
.	O
</s>
<s>
(	O
For	O
more	O
information	O
,	O
see	O
Spooling	B-Device
.	O
)	O
</s>
<s>
Elements	O
within	O
IBM	O
,	O
notably	O
John	O
Haanstra	O
,	O
an	O
executive	O
in	O
charge	O
of	O
1401	O
deployment	O
,	O
supported	O
its	O
continuation	O
in	O
larger	O
models	O
for	O
evolving	O
needs	O
(	O
e.g.	O
,	O
the	O
IBM	B-Device
1410	I-Device
)	O
but	O
the	O
1964	O
decision	O
at	O
the	O
top	O
to	O
focus	O
resources	O
on	O
the	O
System/360	B-Application
ended	O
these	O
efforts	O
rather	O
suddenly	O
.	O
</s>
<s>
IBM	O
was	O
facing	O
a	O
competitive	O
threat	O
from	O
the	O
Honeywell	B-Device
200	I-Device
and	O
the	O
360	O
's	O
incompatibility	O
with	O
the	O
1401	O
design	O
.	O
</s>
<s>
IBM	O
pioneered	O
the	O
use	O
of	O
microcode	B-Device
emulation	B-Application
,	O
in	O
the	O
form	O
of	O
ROM	O
,	O
so	O
that	O
some	O
System/360	B-Application
models	O
could	O
run	O
1401	O
programs	O
.	O
</s>
<s>
The	O
B	O
,	O
A	O
bits	O
are	O
called	O
zone	O
bits	O
and	O
the	O
8	O
,	O
4	O
,	O
2	O
,	O
1	O
bits	O
are	O
called	O
numeric	O
bits	O
,	O
terms	O
taken	O
from	O
the	O
IBM	O
80	B-Architecture
column	I-Architecture
punched	B-Architecture
card	I-Architecture
.	O
</s>
<s>
For	O
alphabetic	O
characters	O
the	O
setting	O
of	O
bits	O
is	O
derived	O
from	O
the	O
zone	O
and	O
digit	O
punches	O
of	O
the	O
IBM	O
80	B-Architecture
column	I-Architecture
punched	B-Architecture
card	I-Architecture
character	O
code	O
:	O
B	O
,	O
A	O
from	O
12	O
,	O
B	O
from	O
11	O
,	O
and	O
A	O
from	O
0	O
;	O
the	O
setting	O
of	O
bits	O
8	O
,	O
4	O
,	O
2	O
,	O
1	O
from	O
BCD	O
encoding	O
of	O
the	O
1	O
through	O
9	O
punches	O
.	O
</s>
<s>
Thus	O
the	O
letter	O
A	O
,	O
12	O
,	O
1	O
in	O
the	O
punched	B-Architecture
card	I-Architecture
character	O
code	O
,	O
is	O
encoded	O
B	O
,	O
A	O
,	O
1	O
.	O
</s>
<s>
Encodings	O
of	O
punched	B-Architecture
card	I-Architecture
characters	O
with	O
two	O
or	O
more	O
digit	O
punches	O
can	O
be	O
found	O
in	O
the	O
Character	O
and	O
op	B-Language
codes	I-Language
table	O
.	O
</s>
<s>
The	O
1401	O
's	O
alphanumeric	O
collating	O
sequence	O
is	O
compatible	O
with	O
the	O
punched	B-Architecture
card	I-Architecture
collating	O
sequence	O
.	O
</s>
<s>
Associated	O
with	O
each	O
memory	B-General_Concept
location	O
are	O
two	O
other	O
bits	O
,	O
called	O
C	O
for	O
odd	B-Error_Name
parity	I-Error_Name
check	O
and	O
M	O
for	O
word	B-Device
mark	I-Device
.	O
</s>
<s>
M	O
is	O
present	O
in	O
memory	B-General_Concept
but	O
not	O
on	O
punched	B-Architecture
cards	I-Architecture
,	O
and	O
has	O
to	O
be	O
set	O
using	O
special	O
machine	O
instructions	O
;	O
when	O
printing	O
memory	B-General_Concept
it	O
is	O
typically	O
displayed	O
by	O
underlining	O
the	O
character	O
.	O
</s>
<s>
C	O
is	O
calculated	O
automatically	O
and	O
is	O
also	O
not	O
present	O
on	O
punched	B-Architecture
cards	I-Architecture
.	O
</s>
<s>
Each	O
memory	B-General_Concept
location	O
then	O
,	O
has	O
the	O
following	O
bits	O
:	O
</s>
<s>
The	O
1401	O
was	O
available	O
in	O
six	O
memory	B-General_Concept
configurations	O
:	O
1	O
,	O
400	O
,	O
2	O
,	O
000	O
,	O
4	O
,	O
000	O
,	O
8	O
,	O
000	O
,	O
12	O
,	O
000	O
,	O
or	O
16,000	O
characters	O
.	O
</s>
<s>
Some	O
operations	O
use	O
specific	O
memory	B-General_Concept
locations	O
(	O
those	O
locations	O
are	O
not	O
reserved	O
and	O
can	O
be	O
used	O
for	O
other	O
purposes	O
)	O
.	O
</s>
<s>
Read	O
a	O
card	O
stores	O
the	O
80	B-Architecture
columns	I-Architecture
of	O
data	O
from	O
a	O
card	O
into	O
memory	B-General_Concept
locations	O
001	O
–	O
080	O
.	O
</s>
<s>
Index	B-General_Concept
registers	I-General_Concept
1	O
,	O
2	O
and	O
3	O
are	O
in	O
memory	B-General_Concept
locations	O
087	O
–	O
089	O
,	O
092-094	O
and	O
097-099	O
respectively	O
.	O
</s>
<s>
Punch	O
a	O
card	O
punches	O
the	O
contents	O
of	O
memory	B-General_Concept
locations	O
101-180	O
into	O
a	O
card	O
.	O
</s>
<s>
Write	O
a	O
line	O
prints	O
the	O
contents	O
of	O
memory	B-General_Concept
locations	O
201	O
–	O
332	O
.	O
</s>
<s>
Opcodes	B-Language
are	O
one	O
character	O
.	O
</s>
<s>
Memory	B-General_Concept
addresses	O
(	O
"	O
I	O
"	O
a	O
branch	O
target	O
,	O
"	O
A	O
"	O
and	O
"	O
B	O
"	O
data	O
)	O
and	O
unit	O
address	O
are	O
three	O
characters	O
.	O
</s>
<s>
The	O
opcode	B-Language
modifier	O
is	O
one	O
character	O
.	O
</s>
<s>
Instruction	B-General_Concept
length	O
is	O
then	O
1	O
,	O
2	O
,	O
4	O
,	O
5	O
,	O
7	O
,	O
or	O
8	O
characters	O
.	O
</s>
<s>
Most	O
instructions	O
have	O
to	O
be	O
followed	O
by	O
a	O
word	B-Device
mark	I-Device
(	O
a	O
requirement	O
commonly	O
met	O
by	O
the	O
word	B-Device
mark	I-Device
with	O
the	O
opcode	B-Language
of	O
the	O
next	O
instruction	B-General_Concept
)	O
.	O
</s>
<s>
See	O
Character	O
and	O
op	B-Language
codes	I-Language
for	O
a	O
list	O
of	O
operations	O
.	O
</s>
<s>
A	O
three-character	O
memory	B-General_Concept
address	O
in	O
an	O
instruction	B-General_Concept
is	O
an	O
encoding	O
of	O
a	O
five-digit	O
memory	B-General_Concept
address	O
.	O
</s>
<s>
The	O
zone	O
bits	O
of	O
the	O
high-order	O
character	O
specify	O
an	O
increment	O
as	O
follows	O
:	O
A	O
1000	O
,	O
B	O
2000	O
,	O
B	O
and	O
A	O
together	O
3000	O
,	O
giving	O
an	O
addressability	O
of	O
4,000	O
memory	B-General_Concept
locations	O
.	O
</s>
<s>
The	O
zone	O
bits	O
of	O
the	O
low-order	O
character	O
specify	O
increments	O
of	O
4000	O
,	O
8000	O
,	O
or	O
12000	O
,	O
to	O
address	O
16,000	O
memory	B-General_Concept
locations	O
(	O
with	O
an	O
IBM	O
1406	O
Storage	O
Unit	O
)	O
.	O
</s>
<s>
For	O
example	O
,	O
the	O
three-character	O
address	O
"	O
I99	O
"	O
is	O
a	O
reference	O
to	O
memory	B-General_Concept
location	O
3000	O
+	O
999	O
,	O
or	O
3999	O
.	O
</s>
<s>
The	O
zone	O
bits	O
of	O
the	O
middle	O
character	O
of	O
a	O
three-character	O
memory	B-General_Concept
address	O
can	O
specify	O
one	O
of	O
three	O
index	B-General_Concept
registers	I-General_Concept
,	O
one	O
of	O
many	O
optional	O
features	O
.	O
</s>
<s>
Operands	O
referenced	O
by	O
the	O
A-address	O
and	O
B-address	O
can	O
be	O
:	O
a	O
single	O
memory	B-General_Concept
location	O
,	O
a	O
variable-length	O
field	O
,	O
or	O
a	O
variable-length	O
record	O
.	O
</s>
<s>
Variable-length	O
fields	O
are	O
addressed	O
at	O
their	O
low-order	O
(	O
highest-addressed	O
)	O
position	O
,	O
their	O
length	O
defined	O
by	O
a	O
word	B-Device
mark	I-Device
set	O
at	O
their	O
high-order	O
(	O
lowest-addressed	O
)	O
position	O
.	O
</s>
<s>
The	O
only	O
limit	O
on	O
the	O
length	O
of	O
such	O
fields	O
is	O
the	O
available	O
memory	B-General_Concept
.	O
</s>
<s>
Instructions	O
applicable	O
to	O
variable-length	O
fields	O
include	O
:	O
Add	O
,	O
Subtract	O
,	O
Multiply	O
,	O
Divide	O
,	O
Compare	O
,	O
Move	O
Characters	O
to	O
A	O
or	O
B	O
Word	B-Device
Mark	I-Device
,	O
Move	O
Characters	O
and	O
Edit	O
.	O
</s>
<s>
A	O
variable-length	O
record	O
is	O
addressed	O
at	O
its	O
high-order	O
position	O
,	O
its	O
length	O
defined	O
by	O
a	O
group-mark	O
character	O
with	O
a	O
word	B-Device
mark	I-Device
or	O
a	O
record-mark	O
character	O
in	O
its	O
low-order	O
position	O
.	O
</s>
<s>
The	O
instruction	B-General_Concept
Move	O
Characters	O
Record	O
or	O
Group	O
Mark	O
can	O
be	O
used	O
to	O
assemble	O
a	O
block	O
of	O
records	O
.	O
</s>
<s>
A	O
variable-length	O
record	O
,	O
or	O
block	O
of	O
records	O
,	O
to	O
be	O
written	O
to	O
magnetic	O
tape	O
is	O
addressed	O
at	O
its	O
high-order	O
position	O
,	O
its	O
length	O
defined	O
by	O
a	O
group-mark	O
character	O
with	O
a	O
word	B-Device
mark	I-Device
immediately	O
following	O
its	O
low-order	O
position	O
.	O
</s>
<s>
When	O
the	O
LOAD	O
button	O
on	O
the	O
1402	B-Device
Card	O
Read-Punch	O
is	O
pressed	O
,	O
a	O
card	O
is	O
read	O
into	O
memory	B-General_Concept
locations	O
001	O
–	O
080	O
,	O
a	O
word	B-Device
mark	I-Device
is	O
set	O
in	O
location	O
001	O
to	O
indicate	O
that	O
it	O
is	O
an	O
executable	O
instruction	B-General_Concept
,	O
the	O
word	B-Device
marks	I-Device
in	O
locations	O
002-080	O
(	O
if	O
any	O
)	O
are	O
cleared	O
,	O
and	O
execution	O
starts	O
with	O
the	O
instruction	B-General_Concept
at	O
location	O
001	O
.	O
</s>
<s>
That	O
is	O
always	O
the	O
Set	O
Word	B-Device
Mark	I-Device
,	O
to	O
set	O
word	B-Device
marks	I-Device
on	O
the	O
two	O
following	O
words	O
(	O
instructions	O
)	O
.	O
</s>
<s>
A	O
single	O
Set	O
Word	B-Device
Mark	I-Device
instruction	B-General_Concept
can	O
set	O
two	O
word	B-Device
marks	I-Device
but	O
requires	O
one	O
word	B-Device
mark	I-Device
to	O
have	O
been	O
on	O
itself	O
,	O
so	O
a	O
sequence	O
of	O
these	O
instructions	O
are	O
needed	O
,	O
which	O
incrementally	O
set	O
word	B-Device
marks	I-Device
in	O
the	O
program	O
's	O
code	O
or	O
data	O
,	O
and	O
set	O
word	B-Device
marks	I-Device
for	O
subsequent	O
Set	O
Word	B-Device
Mark	I-Device
instructions	O
.	O
</s>
<s>
Execution	O
of	O
instructions	O
in	O
the	O
card	O
continues	O
,	O
setting	O
word	B-Device
marks	I-Device
,	O
loading	O
the	O
program	O
into	O
memory	B-General_Concept
,	O
and	O
then	O
branching	O
to	O
the	O
program	O
's	O
start	O
address	O
.	O
</s>
<s>
To	O
read	O
subsequent	O
cards	O
,	O
an	O
explicit	O
Read	O
command	O
(	O
opcode	B-Language
1	O
)	O
must	O
be	O
executed	O
as	O
the	O
last	O
instruction	B-General_Concept
on	O
every	O
card	O
to	O
get	O
the	O
new	O
card	O
's	O
contents	O
into	O
locations	O
001	O
–	O
080	O
.	O
</s>
<s>
Note	O
that	O
the	O
word	B-Device
marks	I-Device
are	O
not	O
erased	O
when	O
the	O
Read	O
command	O
is	O
executed	O
,	O
but	O
are	O
kept	O
as-is	O
for	O
the	O
next	O
card	O
read	O
in	O
.	O
</s>
<s>
This	O
is	O
convenient	O
,	O
because	O
much	O
of	O
what	O
the	O
first	O
few	O
cards	O
do	O
is	O
set	O
word	B-Device
marks	I-Device
in	O
the	O
proper	O
locations	O
;	O
having	O
the	O
first	O
half	O
dozen	O
or	O
so	O
word	B-Device
marks	I-Device
set	O
means	O
the	O
programmer	O
does	O
not	O
need	O
to	O
set	O
those	O
word	B-Device
marks	I-Device
again	O
.	O
</s>
<s>
The	O
program	O
will	O
automatically	O
set	O
its	O
own	O
wordmarks	B-Device
,	O
assuming	O
that	O
the	O
first	O
,	O
has	O
a	O
wordmark	B-Device
already	O
.	O
</s>
<s>
Following	O
conventional	O
IBM	O
notation	O
,	O
the	O
underscores	O
show	O
where	O
word	B-Device
marks	I-Device
are	O
set	O
in	O
memory	B-General_Concept
once	O
the	O
program	O
has	O
run	O
;	O
on	O
punched	B-Architecture
cards	I-Architecture
they	O
would	O
not	O
be	O
indicated	O
visually	O
or	O
present	O
in	O
the	O
punched	O
data	O
.	O
</s>
<s>
Set	O
Word	B-Device
Mark	I-Device
(	O
opcode	B-Language
,	O
operands	O
036	O
008	O
)	O
.	O
</s>
<s>
This	O
must	O
always	O
be	O
the	O
first	O
instruction	B-General_Concept
,	O
and	O
one	O
of	O
its	O
operands	O
must	O
always	O
be	O
008	O
or	O
else	O
the	O
next	O
instruction	B-General_Concept
would	O
not	O
have	O
a	O
word	B-Device
mark	I-Device
to	O
indicate	O
that	O
it	O
is	O
an	O
executable	O
instruction	B-General_Concept
.	O
</s>
<s>
Additional	O
Set	O
Word	B-Device
Marks	I-Device
.	O
</s>
<s>
The	O
underscores	O
show	O
where	O
the	O
word	B-Device
marks	I-Device
are	O
after	O
completing	O
all	O
,	O
opcodes	B-Language
.	O
</s>
<s>
Only	O
word	B-Device
marks	I-Device
from	O
036	O
and	O
further	O
are	O
needed	O
for	O
the	O
"	O
guts	O
"	O
of	O
the	O
program	O
;	O
word	B-Device
marks	I-Device
up	O
through	O
029	O
are	O
only	O
needed	O
for	O
Set	O
Word	B-Device
Mark	I-Device
instructions	O
.	O
</s>
<s>
Since	O
the	O
core	O
of	O
the	O
program	O
needs	O
six	O
word	B-Device
marks	I-Device
,	O
five	O
Set	O
Word	B-Device
Mark	I-Device
instructions	O
are	O
needed	O
in	O
total	O
.	O
</s>
<s>
to	O
the	O
print	O
area	O
(	O
opcode	B-Language
L	O
,	O
operands	O
065	O
and	O
213	O
.	O
</s>
<s>
Write	O
a	O
Line	O
on	O
the	O
printer	O
(	O
opcode	B-Language
2	O
;	O
"	O
HELLO	O
,	O
WORLD	O
!	O
"	O
</s>
<s>
Halt	O
(	O
opcode	B-Language
.	O
)	O
</s>
<s>
Most	O
of	O
the	O
logic	O
circuitry	O
of	O
the	O
1401	O
is	O
a	O
type	O
of	O
diode	B-General_Concept
–	I-General_Concept
transistor	I-General_Concept
logic	I-General_Concept
(	O
DTL	B-General_Concept
)	O
,	O
that	O
IBM	O
referred	O
to	O
as	O
CTDL	O
(	O
Complemented	O
Transistor	O
Diode	O
Logic	O
)	O
.	O
</s>
<s>
Later	O
upgrades	O
(	O
e.g.	O
,	O
the	O
TAU-9	O
tape	O
interface	O
)	O
use	O
a	O
faster	O
type	O
of	O
DTL	B-General_Concept
using	O
"	O
drift	O
"	O
transistors	O
(	O
a	O
type	O
of	O
transistor	O
invented	O
by	O
Herbert	O
Kroemer	O
in	O
1953	O
)	O
for	O
their	O
speed	O
,	O
that	O
IBM	O
referred	O
to	O
as	O
SDTDL	O
(	O
Saturated	O
Drift	O
Transistor	O
Diode	O
Logic	O
)	O
.	O
</s>
<s>
These	O
circuits	O
are	O
constructed	O
of	O
discrete	O
components	O
(	O
resistors	O
,	O
capacitors	O
,	O
transistors	O
)	O
mounted	O
on	O
single-sided	O
paper-epoxy	O
printed	O
circuit	O
boards	O
either	O
with	O
a	O
16-pin	O
gold-plated	O
edge	O
connector	O
(	O
single	O
wide	O
)	O
or	O
with	O
two	O
16-pin	O
gold-plated	O
edge	O
connectors	O
(	O
double	O
wide	O
)	O
,	O
that	O
IBM	O
referred	O
to	O
as	O
SMS	O
cards	O
(	O
Standard	B-Device
Modular	I-Device
System	I-Device
)	O
.	O
</s>
<s>
The	O
amount	O
of	O
logic	O
on	O
one	O
card	O
is	O
similar	O
to	O
that	O
in	O
one	O
7400	O
series	O
SSI	O
or	O
simpler	O
MSI	O
package	O
(	O
e.g.	O
,	O
three	O
to	O
five	O
logic	O
gates	O
or	O
a	O
couple	O
of	O
flip-flops	B-General_Concept
on	O
a	O
single-wide	O
card	O
up	O
to	O
about	O
twenty	O
logic	O
gates	O
or	O
four	O
flip-flops	B-General_Concept
on	O
a	O
double-wide	O
card	O
)	O
.	O
</s>
<s>
A	O
stack	O
of	O
eight	O
such	O
planes	O
store	O
the	O
six	O
data	O
bits	O
,	O
word	B-Device
mark	I-Device
bit	O
,	O
and	O
parity	B-Error_Name
bit	I-Error_Name
for	O
4000	O
memory	B-General_Concept
locations	O
.	O
</s>
<s>
Together	O
with	O
eight	O
additional	O
planes	O
with	O
fewer	O
cores	O
on	O
them	O
for	O
additional	O
storage	O
functions	O
,	O
this	O
made	O
up	O
a	O
4000-character	O
memory	B-General_Concept
module	O
.	O
</s>
<s>
The	O
additional	O
modules	O
are	O
contained	O
in	O
an	O
add-on	O
box	O
,	O
the	O
1406	O
Core	B-General_Concept
Memory	I-General_Concept
Unit	O
,	O
which	O
is	O
about	O
two	O
feet	O
square	O
and	O
three	O
feet	O
high	O
.	O
</s>
<s>
Operands	O
in	O
memory	B-General_Concept
are	O
accessed	O
serially	O
,	O
one	O
memory	B-General_Concept
location	O
at	O
a	O
time	O
,	O
and	O
the	O
1401	O
can	O
read	O
or	O
write	O
one	O
memory	B-General_Concept
location	O
within	O
its	O
basic	O
cycle	O
time	O
of	O
11.5	O
microseconds	O
.	O
</s>
<s>
All	O
instruction	B-General_Concept
timings	O
are	O
cited	O
in	O
multiples	O
of	O
this	O
cycle	O
time	O
.	O
</s>
<s>
The	O
IBM	B-Device
1403	I-Device
printer	O
was	O
introduced	O
in	O
October	O
1959	O
with	O
the	O
1401	B-Device
Data	I-Device
Processing	I-Device
System	I-Device
.	O
</s>
<s>
1401	B-Language
Symbolic	I-Language
Programming	I-Language
System	I-Language
assembler	O
.	O
</s>
<s>
Autocoder	B-Device
on	O
Tape	O
,	O
a	O
more	O
advanced	O
assembler	O
,	O
required	O
at	O
least	O
4000-character	O
memory	B-General_Concept
and	O
four	O
tape	O
drives	O
.	O
</s>
<s>
Autocoder	B-Device
on	O
Disk	O
,	O
similar	O
to	O
,	O
but	O
not	O
compatible	O
with	O
,	O
Autocoder	B-Device
on	O
Tape	O
,	O
required	O
at	O
least	O
one	O
1311	O
disk	O
drive	O
.	O
</s>
<s>
COBOL	B-Application
required	O
at	O
least	O
4000-character	O
memory	B-General_Concept
and	O
four	O
tape	O
drives	O
.	O
</s>
<s>
FARGO	B-Language
(	O
Fourteen-o-one	O
Automatic	O
Report	O
Generation	O
Operation	O
)	O
,	O
a	O
predecessor	O
of	O
RPG	B-Language
,	O
required	O
at	O
least	O
4000-character	O
memory	B-General_Concept
.	O
</s>
<s>
FORTRAN	O
II	O
required	O
at	O
least	O
8000-character	O
memory	B-General_Concept
;	O
the	O
1401	O
Fortran	O
compiler	O
is	O
described	O
in	O
Haines	O
,	O
L.H.	O
</s>
<s>
The	O
Fortran	O
compiler	O
,	O
to	O
generate	O
code	O
for	O
small	O
memories	O
,	O
used	O
a	O
pioneering	O
form	O
of	O
interpreted	O
"	O
p-code	B-Language
"	O
although	O
its	O
programmers	O
had	O
no	O
name	O
for	O
what	O
it	O
was	O
that	O
they	O
did	O
.	O
</s>
<s>
FORTRAN	O
IV	O
required	O
at	O
least	O
12000-character	O
memory	B-General_Concept
and	O
either	O
four	O
tape	O
drives	O
or	O
at	O
least	O
one	O
IBM	B-Device
1311	I-Device
disk	O
drive	O
.	O
</s>
<s>
RPG	B-Language
(	O
Report	B-Language
Program	I-Language
Generator	I-Language
)	O
;	O
Basic	O
RPG	B-Language
required	O
at	O
least	O
4000-character	O
memory	B-General_Concept
.	O
</s>
<s>
For	O
the	O
IBM	O
Catalog	O
of	O
1401	O
software	O
,	O
see	O
IBM	B-Device
1400	I-Device
series	I-Device
.	O
</s>
<s>
The	O
1401	O
's	O
operation	B-Language
codes	I-Language
are	O
single	O
characters	O
.	O
</s>
<s>
Note	O
:	O
If	O
Word	B-Device
mark	I-Device
bit	O
is	O
set	O
,	O
then	O
the	O
C	O
bit	O
will	O
be	O
opposite	O
of	O
shown	O
.	O
</s>
<s>
12-3-8	O
BA8	O
21	O
Halt	O
⌑	O
⌑	O
)	O
12-4-8	O
CBA84	O
Clear	O
Word	B-Device
Mark	I-Device
Lozenge	O
[	O
12-5-8	O
BA84	O
1	O
<	O
12-6-8	O
BA842	O
Less	O
Than	O
File:IBM	O
1401	O
Group	O
Mark.GIF	O
12-7-8	O
CBA8421	O
Group	O
Mark	O
&	O
&	O
+	O
12	O
CBA	O
$	O
$	O
$	O
11-3-8	O
CB	O
8	O
21	O
*	O
*	O
*	O
11-4-8	O
B	O
84	O
]	O
11-5-8	O
CB	O
84	O
1	O
;	O
11-6-8	O
CB	O
842	O
Δ	O
11-7-8	O
B	O
8421	O
Delta	O
(	O
Mode	O
Change	O
)	O
-	O
-	O
-	O
11	O
B	O
/	O
/	O
/	O
0-1	O
C	O
A	O
1	O
Clear	O
Storage	O
,,,	O
0-3-8	O
C	O
A8	O
21	O
Set	O
Word	B-Device
Mark	I-Device
%	O
%	O
(	O
0-4-8	O
A84	O
Divide	O
Optional	O
special	O
feature	O
.	O
</s>
<s>
Blank	O
with	O
"	O
even-parity	O
"	O
on	O
tape	O
.	O
</s>
<s>
4000	O
characters	O
of	O
memory	B-General_Concept
)	O
@	O
@	O
'	O
4-8	O
C	O
84	O
Multiply	O
Optional	O
special	O
feature	O
.	O
</s>
<s>
&	O
&	O
12-0	O
CBA8	O
2	O
Zero	O
and	O
Add	O
Plus	O
Zero	O
A	O
A	O
A	O
12-1	O
BA	O
1	O
Add	O
B	O
B	O
B	O
12-2	O
BA	O
2	O
Branch	O
or	O
Branch	O
on	O
Indicator	O
See	O
"	O
Modifiers	O
for	O
five-character	O
Branch	O
on	O
Indicator	O
(	O
B	O
)	O
instruction	B-General_Concept
"	O
section	O
C	O
C	O
C	O
12-3	O
CBA	O
21	O
Compare	O
D	O
D	O
D	O
12-4	O
BA	O
4	O
Move	O
Numerical	O
(	O
Bits	O
)	O
E	O
E	O
E	O
12-5	O
CBA	O
4	O
1	O
Move	O
Characters	O
and	O
Edit	O
F	O
F	O
F	O
12-6	O
CBA	O
42	O
Control	O
Carriage	O
(	O
Printer	O
)	O
G	O
G	O
G	O
12-7	O
BA	O
421	O
H	O
H	O
H	O
12-8	O
BA8	O
Store	O
B-Address	O
Register	O
Optional	O
special	O
feature	O
.	O
</s>
<s>
The	O
B	O
opcode	B-Language
,	O
if	O
followed	O
by	O
a	O
three-character	O
operand	O
,	O
was	O
a	O
simple	O
unconditional	O
branch	O
to	O
the	O
indicated	O
address	O
.	O
</s>
<s>
If	O
a	O
fourth	O
operand	O
character	O
was	O
present	O
(	O
making	O
five	O
characters	O
total	O
including	O
the	O
opcode	B-Language
)	O
,	O
this	O
made	O
it	O
a	O
conditional	O
branch	O
.	O
</s>
<s>
BCD	O
Character	O
Unit	O
Meaning	O
Blank	O
1401	O
Unconditional	O
—	O
no	O
word	B-Device
mark	I-Device
needed	O
in	O
next	O
character	O
1	O
1009	O
in	O
run	O
condition	O
1011	O
punch	O
in	O
backspace	O
operation	O
1011	O
reader	O
parity	B-Error_Name
indicator	O
on	O
1231	O
auto	O
select	O
1285	O
error	O
1412	O
control-check	O
indicator	O
on	O
1418	O
late	O
read	O
1419	O
document	O
to	O
be	O
read	O
1428	O
late	O
read	O
or	O
late	O
reading	O
mode	O
change	O
1445	O
printer	O
error	O
7340	O
hypertape	O
unusual	O
end	O
7740	O
transmission	O
complete	O
with	O
abnormal	O
status	O
DDC	O
transmission	O
error	O
2	O
1009	O
buffer	O
available	O
1011	O
punch	O
ready	O
1011	O
reader	O
ready	O
1231	O
full	O
buffer	O
1285	O
end	O
of	O
line	O
1412	O
reader-not-ready	O
signal	O
on	O
1418	O
ready	O
to	O
engage	O
1419	O
document	O
under	O
read	O
head	O
(	O
PDS	O
4	O
)	O
1428	O
ready	O
to	O
engage	O
7340	O
hypertape	O
normal	O
end	O
7740	O
transmission	O
complete	O
successfully	O
DDC	O
transmission	O
ended	O
by	O
GMWM	O
3	O
1009	O
good	O
transmission	O
occurred	O
1011	O
punch	O
not	O
ready	O
to	O
receive	O
data	O
1231	O
ready	O
to	O
read	O
1285	O
reader	O
transporting	O
1412	O
read-check	O
indicator	O
on	O
1418	O
document	O
under	O
selected	O
read	O
station	O
1419	O
valid	O
amount	O
field	O
1428	O
document	O
under	O
selected	O
read	O
station	O
7340	O
hypertape	O
control	O
unit	O
7641	O
busy	O
7740	O
receive	O
request	O
DDC	O
read	O
request	O
4	O
1009	O
reply-bad	O
indicator	O
on	O
1011	O
punch	O
not	O
ready	O
to	O
read	O
1231	O
empty	O
hopper	O
1285	O
marked	O
line	O
1412	O
amount-field	O
indicator	O
on	O
1419	O
valid	O
process-control	O
field	O
7340	O
hypertape	O
attention	O
7740	O
7740	O
attention	O
DDC	O
write	O
request	O
5	O
1009	O
error	O
reply	O
acknowledgement	O
1011	O
punch	O
overextended	O
1231	O
read	O
error	O
or	O
overrun	O
1285	O
header	O
information	O
1412	O
process-control	O
indicator	O
on	O
1418	O
document	O
end	O
1419	O
valid	O
account-number	O
field	O
1428	O
document	O
end	O
1445	O
printer	O
busy	O
6	O
1009	O
program	O
attention	O
required	O
1011	O
punch	O
supply	O
reel	O
low	O
or	O
chad	O
box	O
full	O
1231	O
timing	O
mark	O
check	O
1285	O
ready	O
to	O
read	O
a	O
line	O
1412	O
account-number	O
indicator	O
on	O
1418	O
character	O
on	O
line	O
1419	O
valid	O
transit-number	O
field	O
1428	O
character	O
on	O
line	O
1445	O
carriage	O
busy	O
DDC	O
write	O
in	O
progress	O
7	O
1009	O
end	O
of	O
message	O
1285	O
reader	O
ready	O
1412	O
transit-number	O
indicator	O
on	O
1418	O
empty	O
hopper	O
and	O
transport	O
(	O
end	O
of	O
file	O
)	O
1419	O
valid	O
serial-number	O
field	O
1428	O
empty	O
hopper	O
and	O
transport	O
(	O
end	O
of	O
file	O
)	O
1445	O
carriage	O
channel	O
9	O
DDC	O
read	O
in	O
progress	O
8	O
1009	O
end	O
of	O
file	O
1285	O
end	O
of	O
file	O
1412	O
document-spacing-check	O
indicator	O
on	O
1418	O
ready	O
to	O
read	O
1419	O
auto-select	O
1428	O
ready	O
to	O
read	O
1448	O
carriage	O
channel	O
12	O
DDC	O
system	O
A	O
stopped	O
9	O
1403	B-Device
carriage	O
tape	O
channel	O
9	O
0	O
1404	O
validity	O
error	O
'	O
or	O
@	O
1403	B-Device
carriage	O
tape	O
channel	O
12	O
>	O
1448	O
end	O
of	O
block	O
/	O
1401	O
unequal	O
compare	O
S	O
1401	O
equal	O
compare	O
T	O
1401	O
low	O
compare	O
U	O
1401	O
high	O
compare	O
V	O
1301	O
disk	O
error	O
1311	O
disk	O
error	O
1405	O
read	O
or	O
write	O
parity	B-Error_Name
check	I-Error_Name
or	O
read	O
back	O
check	O
error	O
W	O
1301	O
wrong-length	O
record	O
1311	O
wrong-length	O
record	O
1405	O
wrong-length	O
record	O
X	O
1301	O
unequal	O
address	O
compare	O
1311	O
unequal	O
address	O
compare	O
1405	O
unequal	O
address	O
compare	O
Y	O
1301	O
any	O
disk-unit	O
error	O
condition	O
1311	O
any	O
disk-unit	O
error	O
condition	O
1405	O
any	O
disk-unit	O
error	O
condition	O
Z	O
1401	O
arithmetic	O
overflow	O
‡	O
1403	B-Device
printer	O
error	O
(	O
record	O
mark	O
)	O
(	O
or	O
%	O
1401	O
process	O
check	O
with	O
process	O
check	O
switch	O
off	O
1440	O
I/O	O
check	O
stop	O
switch	O
off	O
\	O
1301	O
access	O
busy	O
1311	O
access	O
busy	O
J	O
1419	O
I/O	O
channel-busy	O
indicator	O
TAU	O
tape	O
busy	O
SIO	O
serial	O
input-output	O
busy	O
K	O
TAU	O
end	O
of	O
reel	O
(	O
writing	O
)	O
or	O
tape	O
mark	O
(	O
reading	O
)	O
L	O
TAU	O
tape	O
error	O
N	O
1301	O
access	O
inoperable	O
1311	O
access	O
inoperable	O
1405	O
access	O
inoperable	O
P	O
1403	B-Device
printer	O
busy	O
Q	O
1407	O
inquiry	O
request	O
R	O
1403	B-Device
carriage	O
busy	O
!	O
</s>
<s>
1402	B-Device
punch	O
error	O
*	O
1407	O
inquiry	O
clear	O
+	O
or	O
&	O
1442	O
last	O
card	O
(	O
Reader	O
unit	O
2	O
)	O
A	O
1402	B-Device
last	O
card	O
if	O
SS	O
A	O
is	O
on	O
B	O
1401	O
SS	O
B	O
7340	O
hypertape	O
attention	O
response	O
C	O
1401	O
SS	O
C	O
D	O
1401	O
SS	O
D	O
E	O
1401	O
SS	O
E	O
7340	O
hypertape	O
end	O
response	O
F	O
1401	O
SS	O
F	O
G	O
1401	O
SS	O
G	O
H	O
1402	B-Device
reader	O
busy	O
I	O
1402	B-Device
punch	O
busy	O
?	O
</s>
<s>
The	O
Select	O
Stacker	O
(	O
K	O
)	O
instruction	B-General_Concept
sent	O
commands	O
to	O
various	O
devices	O
.	O
</s>
<s>
It	O
was	O
named	O
for	O
its	O
relevance	O
to	O
the	O
1402	B-Device
reader/punch	O
.	O
</s>
<s>
BCD	O
Character	O
Unit	O
Meaning	O
Blank	O
1401	O
set	O
program	O
activity	O
recording	O
at	O
BBB	O
only	O
if	O
A	O
is	O
,	O
dd	O
1	O
1402	B-Device
select	O
last	O
card	O
read	O
to	O
stacker	O
1	O
if	O
within	O
10	O
ms	O
2	O
1402	B-Device
select	O
last	O
card	O
read	O
to	O
stacker	O
8/2	O
if	O
within	O
10	O
ms	O
4	O
1402	B-Device
select	O
previous	O
card	O
punched	O
to	O
stacker	O
4	O
8	O
1402	B-Device
select	O
previous	O
card	O
punched	O
to	O
stacker	O
8/2	O
=	O
or	O
#	O
1444	O
select	O
previous	O
card	O
punched	O
to	O
stacker	O
2	O
L	O
1009	O
operate	O
in	O
load	O
mode	O
$	O
1402	B-Device
overlap	O
on	O
A	O
1009	O
suppress	O
3-second	O
alarm	O
C	O
DDC	O
read	O
request	O
D	O
1009	O
set	O
direction	O
to	O
receive	O
DDC	O
write	O
request	O
E	O
1009	O
set	O
direction	O
to	O
transmit	O
DDC	O
reset	O
F	O
1009	O
send	O
EOF	O
.	O
</s>
<s>
In	O
October	O
2006	O
,	O
Icelandic	O
avant-garde	O
musician	O
Jóhann	O
Jóhannsson	O
released	O
the	O
album	O
IBM	B-Device
1401	I-Device
,	O
A	O
User	O
's	O
Manual	O
through	O
music	O
publisher	O
4AD	O
.	O
</s>
<s>
IBM	B-Device
1401	I-Device
was	O
the	O
first	O
computer	O
introduced	O
in	O
Nepal	O
for	O
the	O
census	O
purpose	O
in	O
1971	O
.	O
</s>
<s>
A	O
truck-based	O
IBM	B-Device
1401	I-Device
configured	O
in	O
1960	O
for	O
military	O
use	O
was	O
designated	O
a	O
portable	O
computer	O
,	O
and	O
nicknamed	O
a	O
DataMobile	O
.	O
</s>
