<s>
The	O
IBM	B-Device
1130	I-Device
Computing	O
System	O
,	O
introduced	O
in	O
1965	O
,	O
was	O
IBM	O
's	O
least	O
expensive	O
computer	O
at	O
that	O
time	O
.	O
</s>
<s>
A	O
binary	O
16-bit	B-Device
machine	O
,	O
it	O
was	O
marketed	O
to	O
price-sensitive	O
,	O
computing-intensive	O
technical	O
markets	O
,	O
like	O
education	O
and	O
engineering	O
,	O
succeeding	O
the	O
decimal	B-Device
IBM	B-Device
1620	I-Device
in	O
that	O
market	O
segment	O
.	O
</s>
<s>
Typical	O
installations	O
included	O
a	O
1	O
megabyte	O
disk	B-Device
drive	I-Device
that	O
stored	O
the	O
operating	B-General_Concept
system	I-General_Concept
,	O
compilers	B-Language
and	O
object	O
programs	O
,	O
with	O
program	O
source	O
generated	O
and	O
maintained	O
on	O
punched	B-Architecture
cards	I-Architecture
.	O
</s>
<s>
Fortran	B-Application
was	O
the	O
most	O
common	O
programming	O
language	O
used	O
,	O
but	O
several	O
others	O
,	O
including	O
APL	B-Language
,	O
were	O
available	O
.	O
</s>
<s>
The	O
1130	O
was	O
also	O
used	O
as	O
an	O
intelligent	O
front-end	O
for	O
attaching	O
an	O
IBM	B-Device
2250	I-Device
Graphics	I-Device
Display	I-Device
Unit	I-Device
,	O
or	O
as	O
remote	B-Protocol
job	I-Protocol
entry	I-Protocol
(	O
RJE	B-Protocol
)	O
workstation	O
,	O
connected	O
to	O
a	O
System/360	B-Application
mainframe	O
.	O
</s>
<s>
Its	O
price-performance	O
ratio	O
was	O
good	O
and	O
it	O
notably	O
included	O
inexpensive	O
,	O
removable	O
disk	B-Device
storage	I-Device
,	O
with	O
reliable	O
,	O
easy-to-use	O
software	O
that	O
could	O
be	O
in	O
several	O
high-level	O
languages	O
.	O
</s>
<s>
The	O
low	O
price	O
(	O
from	O
around	O
$	O
32,000	O
or	O
$	O
41,000	O
with	O
disk	B-Device
drive	I-Device
)	O
and	O
well-balanced	O
feature	O
set	O
enabled	O
interactive	O
"	O
open	O
shop	O
"	O
program	O
development	O
.	O
</s>
<s>
The	O
IBM	B-Device
1130	I-Device
uses	O
the	O
same	O
electronics	O
packaging	O
,	O
called	O
Solid	B-Algorithm
Logic	I-Algorithm
Technology	I-Algorithm
(	O
SLT	O
)	O
,	O
used	O
in	O
System/360	B-Application
.	O
</s>
<s>
It	O
has	O
a	O
16-bit	B-Device
binary	O
architecture	O
,	O
as	O
do	O
later	O
minicomputers	B-Architecture
like	O
the	O
PDP-11	B-Device
and	O
Data	B-Device
General	I-Device
Nova	I-Device
.	O
</s>
<s>
The	O
address	B-General_Concept
space	I-General_Concept
is	O
15	O
bits	O
,	O
limiting	O
the	O
1130	O
to	O
words	O
(	O
)	O
of	O
memory	O
.	O
</s>
<s>
IBM	O
implemented	O
five	O
models	O
of	O
the	O
1131	O
Central	O
Processing	O
Unit	O
,	O
the	O
primary	O
processing	O
component	O
of	O
the	O
IBM	B-Device
1130	I-Device
.	O
</s>
<s>
The	O
Model	O
1	O
through	O
Model	O
5	O
describe	O
the	O
core	O
memory	O
cycle	O
time	O
,	O
as	O
well	O
as	O
the	O
model	O
's	O
ability	O
to	O
have	O
disk	B-Device
storage	I-Device
.	O
</s>
<s>
The	O
IBM	B-Device
1132	I-Device
printer	O
relies	O
on	O
the	O
1130	O
processor	O
rather	O
than	O
internal	O
logic	O
to	O
determine	O
when	O
to	O
fire	O
the	O
print	O
wheels	O
as	O
they	O
rotated	O
.	O
</s>
<s>
The	O
hardware	O
manual	O
discloses	O
that	O
when	O
the	O
Model	O
4	O
was	O
servicing	O
the	O
two	O
highest-level	O
interrupts	B-Application
(	O
the	O
level	O
0	O
card-reader	O
column	O
interrupt	B-Application
or	O
the	O
level	O
1	O
printer	O
interrupt	B-Application
)	O
,	O
it	O
ran	O
at	O
the	O
faster	O
3.6μs	O
cycle	O
time	O
.	O
</s>
<s>
Some	O
users	O
of	O
the	O
Model	O
4	O
would	O
write	O
a	O
phony	O
printer	B-Application
driver	I-Application
that	O
did	O
not	O
dismiss	O
the	O
printer	O
interrupt	B-Application
,	O
in	O
order	O
to	O
benefit	O
from	O
the	O
higher	O
processor	O
speed	O
.	O
</s>
<s>
However	O
,	O
lower-level	O
interrupts	B-Application
are	O
disabled	O
during	O
this	O
interval	O
,	O
even	O
the	O
end-of-card	O
interrupt	B-Application
(	O
level	O
4	O
)	O
from	O
the	O
1442	O
card	B-Architecture
reader	O
.	O
</s>
<s>
The	O
IBM	B-Device
1800	I-Device
,	O
announced	O
November	O
,	O
1964	O
,	O
is	O
a	O
predecessor	O
of	O
the	O
IBM	B-Device
1130	I-Device
for	O
process	O
control	O
applications	O
.	O
</s>
<s>
It	O
uses	O
hardware	O
rather	O
than	O
core	O
memory	O
for	O
the	O
three	O
index	O
registers	O
and	O
features	O
two	O
extra	O
instructions	B-General_Concept
(	O
CMP	O
and	O
DCM	O
)	O
plus	O
extra	O
interrupt	B-Application
and	O
I/O	B-General_Concept
capabilities	O
.	O
</s>
<s>
It	O
is	O
a	O
successor	O
to	O
the	O
IBM	B-Device
1710	I-Device
,	O
as	O
the	O
IBM	B-Device
1130	I-Device
is	O
a	O
successor	O
to	O
the	O
IBM	B-Device
1620	I-Device
.	O
</s>
<s>
The	O
IBM	B-Device
1500	I-Device
is	O
a	O
multi-user	O
educational	O
system	O
based	O
around	O
either	O
an	O
IBM	B-Device
1130	I-Device
or	O
an	O
IBM	B-Device
1800	I-Device
.	O
</s>
<s>
The	O
IBM	B-Device
System/7	I-Device
is	O
a	O
process	O
control	O
and	O
real-time	O
system	O
,	O
and	O
the	O
IBM	B-Device
Series/1	I-Device
is	O
a	O
general-purpose	O
16-bit	B-Device
minicomputer	B-Architecture
,	O
both	O
having	O
different	O
architectures	B-General_Concept
from	O
the	O
1130	O
,	O
and	O
from	O
each	O
other	O
.	O
</s>
<s>
Also	O
announced	O
is	O
the	O
IBM	B-Device
1132	I-Device
printer	O
,	O
the	O
lowest	O
cost	O
online	O
computer	O
printer	O
ever	O
announced	O
by	O
IBM	O
at	O
that	O
time	O
.	O
</s>
<s>
March	O
31	O
,	O
1966	O
–	O
IBM	O
introduces	O
the	O
IBM	B-Device
1500	I-Device
educational	O
system	O
.	O
</s>
<s>
April	O
1966	O
–	O
IBM	B-Device
1800	I-Device
ships	O
.	O
</s>
<s>
August	O
9	O
,	O
1966	O
–	O
IBM	O
rolls	O
out	O
the	O
1130	O
synchronous	O
communications	O
adapter	O
,	O
which	O
permits	O
the	O
small	O
1130	O
system	O
to	O
be	O
connected	O
by	O
regular	O
leased	O
telephone	O
lines	O
to	O
,	O
and	O
function	O
as	O
a	O
communications	O
terminal	O
for	O
,	O
any	O
model	O
of	O
the	O
IBM	B-Application
System/360	I-Application
.	O
</s>
<s>
Five	O
times	O
the	O
disk	B-Device
storage	I-Device
and	O
four	O
times	O
the	O
core	O
memory	O
;	O
</s>
<s>
1973	O
-	O
The	O
Xerox	O
530	O
was	O
marketed	O
as	O
a	O
possible	O
successor	O
to	O
IBM	B-Device
1130	I-Device
customers	O
.	O
</s>
<s>
To	O
maximize	O
speed	O
and	O
conserve	O
space	O
,	O
the	O
operating	B-General_Concept
system	I-General_Concept
and	O
compilers	B-Language
are	O
written	O
entirely	O
in	O
assembly	B-Language
language	I-Language
and	O
employ	O
techniques	O
that	O
are	O
rare	O
today	O
,	O
including	O
intermixing	O
code	O
and	O
data	O
as	O
well	O
as	O
self-modifying	B-Application
code	I-Application
.	O
</s>
<s>
Much	O
user	O
programming	O
is	O
done	O
in	O
Fortran	B-Application
.	O
</s>
<s>
The	O
1130	O
Fortran	B-Application
compiler	B-Language
can	O
run	O
on	O
a	O
machine	O
with	O
only	O
4,096	O
words	O
of	O
core	O
—	O
though	O
the	O
compiled	B-Language
program	O
might	O
not	O
fit	O
on	O
such	O
a	O
machine	O
.	O
</s>
<s>
In	O
this	O
multi-pass	B-Application
compiler	I-Application
,	O
each	O
"	O
phase	O
"	O
processes	O
the	O
entire	O
source	O
program	O
and	O
takes	O
it	O
another	O
step	O
toward	O
machine	O
code	O
.	O
</s>
<s>
The	O
compiler	B-Language
is	O
available	O
in	O
a	O
disk-resident	O
version	O
as	O
well	O
as	O
on	O
8-channel	O
punched	O
paper	O
tape	O
or	O
punched	B-Architecture
cards	I-Architecture
.	O
</s>
<s>
The	O
most	O
widely	O
used	O
operating	B-General_Concept
system	I-General_Concept
for	O
the	O
1130	O
is	O
the	O
Disk	B-Device
Monitor	O
System	O
Version	O
2	O
(	O
DM2	O
)	O
introduced	O
in	O
1967	O
.	O
</s>
<s>
DM2	O
is	O
a	O
single-task	O
batch-oriented	B-General_Concept
system	O
.	O
</s>
<s>
It	O
requires	O
a	O
system	O
with	O
at	O
least	O
4KB	O
of	O
core	O
memory	O
and	O
one	O
integrated	O
2310	O
disk	B-Device
drive	I-Device
for	O
system	O
residence	O
.	O
</s>
<s>
The	O
Supervisor	O
is	O
tiny	O
by	O
modern	O
standards	O
,	O
containing	O
assorted	O
system	O
details	O
such	O
as	O
first-level	O
interrupt	B-Application
routines	O
,	O
called	O
Interrupt	B-Application
Level	O
Subroutines	O
,	O
plus	O
the	O
disk	B-Device
driver	O
and	O
routines	O
to	O
load	O
the	O
interpreter	O
of	O
job	B-Application
control	I-Application
commands	O
and	O
the	O
card	B-Architecture
reader	O
driver	O
.	O
</s>
<s>
Device	B-Application
drivers	I-Application
for	O
other	O
I/O	B-General_Concept
devices	I-General_Concept
required	O
by	O
a	O
job	O
are	O
incorporated	O
as	O
part	O
of	O
the	O
loading	O
of	O
that	O
job	O
,	O
which	O
might	O
also	O
include	O
the	O
replacement	O
of	O
the	O
basic	O
disk	B-Device
driver	O
by	O
a	O
more	O
advanced	O
driver	O
.	O
</s>
<s>
During	O
the	O
execution	O
of	O
a	O
job	O
,	O
only	O
a	O
resident	B-Application
monitor	I-Application
,	O
called	O
the	O
Skeleton	O
Supervisor	O
,	O
resides	O
in	O
memory	O
.	O
</s>
<s>
When	O
the	O
job	O
ends	O
or	O
is	O
aborted	O
,	O
the	O
supervisor	O
loads	O
the	O
Monitor	O
Control	O
Record	O
Analyzer	O
(	O
MCRA	O
)	O
to	O
read	O
the	O
job	B-Application
control	I-Application
for	O
the	O
next	O
.	O
</s>
<s>
Aside	O
from	O
device	B-Application
drivers	I-Application
and	O
interrupt	B-Application
processing	O
all	O
CPU	O
time	O
is	O
entirely	O
devoted	O
to	O
the	O
job	O
's	O
activities	O
.	O
</s>
<s>
Other	O
programs	O
distributed	O
as	O
part	O
of	O
the	O
operating	B-General_Concept
system	I-General_Concept
are	O
a	O
core	B-Error_Name
dump	I-Error_Name
utility	O
,	O
DUMP	O
,	O
and	O
the	O
Disk	B-Application
Utility	I-Application
Program	I-Application
,	O
DUP	O
.	O
</s>
<s>
A	O
Card/Paper	O
Tape	O
Programming	O
System	O
was	O
available	O
to	O
support	O
systems	O
without	O
disk	B-Device
.	O
</s>
<s>
There	O
is	O
a	O
hierarchy	O
of	O
device	B-Application
drivers	I-Application
:	O
those	O
with	O
names	O
ending	O
in	O
Z	O
are	O
for	O
Fortran	B-Application
,	O
such	O
as	O
DISKZ	O
,	O
while	O
assembler	B-Language
programmers	O
might	O
use	O
DISK0	O
,	O
and	O
DISK1	O
was	O
even	O
faster	O
at	O
reading	O
multiple	O
disk	B-Application
sectors	I-Application
.	O
</s>
<s>
But	O
DISKZ	O
starts	O
its	O
sector	O
addressing	O
with	O
the	O
first	O
available	O
unused	O
sector	O
,	O
while	O
the	O
others	O
start	O
with	O
sector	O
zero	O
of	O
the	O
disk	B-Device
,	O
making	O
it	O
possible	O
for	O
a	O
programmer	O
unfamiliar	O
with	O
disk	B-Device
organization	O
to	O
inadvertently	O
overwrite	O
the	O
bootstrap	B-Operating_System
loader	I-Operating_System
.	O
</s>
<s>
APL	B-Language
,	O
</s>
<s>
COBOL	B-Application
,	O
</s>
<s>
FORTH	B-Application
,	O
</s>
<s>
RPG	B-Language
.	O
</s>
<s>
There	O
is	O
even	O
a	O
French	O
language	O
ALGOL	B-Language
compiler	B-Language
,	O
in	O
which	O
for	O
example	O
"	O
Debut	O
Fin	O
...	O
;	O
"	O
take	O
the	O
place	O
of	O
"	O
Begin	O
...	O
End	O
;	O
"	O
.	O
</s>
<s>
All	O
its	O
messages	O
are	O
in	O
French	O
,	O
so	O
"	O
Bonne	O
compilation	B-Language
"	O
is	O
the	O
goal	O
.	O
</s>
<s>
Eastern	O
Michigan	O
University	O
developed	O
a	O
Fortran	B-Application
IV	O
compiler	B-Language
for	O
the	O
1130	O
,	O
known	O
as	O
Fortran-EMU	O
,	O
as	O
an	O
alternative	O
to	O
the	O
Fortran	B-Application
IV	O
(	O
subset	O
)	O
compiler	B-Language
provided	O
by	O
IBM	O
.	O
</s>
<s>
It	O
adds	O
many	O
Fortran	B-Application
Iv	O
features	O
not	O
supported	O
by	O
the	O
IBM	O
compiler	B-Language
,	O
including	O
the	O
LOGICAL	O
data	O
type	O
,	O
six-letter	O
variable	O
names	O
,	O
and	O
enhanced	O
diagnostics	O
.	O
</s>
<s>
The	O
Fortran-EMU	O
compiler	B-Language
was	O
distributed	O
as	O
a	O
deck	O
of	O
punched	B-Architecture
cards	I-Architecture
in	O
a	O
disk	B-Device
image	O
file	O
format	O
with	O
all	O
the	O
remaining	O
system	O
area	O
deleted	O
,	O
to	O
prevent	O
copying	O
other	O
modules	O
that	O
would	O
normally	O
reside	O
on	O
the	O
same	O
disk	B-Device
,	O
such	O
as	O
the	O
assembler	B-Language
or	O
compilers	B-Language
.	O
</s>
<s>
Oklahoma	O
State	O
University	O
developed	O
an	O
ALGOL	B-Language
68	I-Language
compiler	B-Language
,	O
written	O
in	O
ANSI	O
Fortran	B-Application
1966	O
.	O
</s>
<s>
A	O
FOCAL	B-Language
interpreter	O
was	O
developed	O
at	O
the	O
University	O
of	O
Michigan	O
.	O
</s>
<s>
The	O
1130	O
also	O
occupied	O
a	O
niche	O
as	O
a	O
data	B-General_Concept
processing	I-General_Concept
machine	O
for	O
smaller	O
organizations	O
:	O
</s>
<s>
Batch	O
operation	O
of	O
the	O
1130	O
is	O
directed	O
by	O
control	O
records	O
in	O
the	O
primary	O
input	O
stream	O
(	O
card	B-Architecture
or	O
paper	O
tape	O
reader	O
)	O
.	O
</s>
<s>
If	O
column	O
14	O
contains	O
"	O
L	O
"	O
,	O
and	O
the	O
program	O
is	O
in	O
Disk	B-Device
System	O
Format	O
(	O
not	O
core-image	O
)	O
a	O
core	O
map	O
will	O
be	O
printed	O
by	O
the	O
Core	O
Load	O
Builder	O
.	O
</s>
<s>
Column	O
19	O
optionally	O
indicated	O
which	O
disk	B-Device
driver	O
routine	O
is	O
to	O
be	O
linked	O
.	O
</s>
<s>
"	O
0	O
"	O
,	O
"	O
1	O
"	O
,	O
or	O
"	O
N	O
"	O
,	O
request	O
DISK1	O
,	O
DISK2	O
,	O
or	O
DISKN	O
,	O
any	O
other	O
character	O
,	O
including	O
blank	O
,	O
requests	O
DISKZ	O
,	O
the	O
FORTRAN	B-Application
disk	B-Device
routine	O
.	O
</s>
<s>
+	O
Supervisor	O
Control	O
Records	O
Control	O
record	O
Description	O
*	O
LOCAL	O
Supplies	O
a	O
list	O
of	O
subprograms	O
which	O
will	O
be	O
loaded	O
as	O
overlays	B-General_Concept
at	O
run	O
time	O
,	O
rather	O
than	O
included	O
with	O
the	O
main	O
program	O
*	O
NOCAL	O
Supplies	O
a	O
list	O
of	O
subprograms	O
to	O
be	O
linked	O
with	O
the	O
main	O
program	O
,	O
even	O
though	O
they	O
are	O
never	O
called	O
.	O
</s>
<s>
These	O
are	O
usually	O
either	O
debug	O
routines	O
which	O
the	O
operator	O
can	O
manually	O
branch	O
to	O
from	O
the	O
console	O
,	O
or	O
interrupt	B-Application
service	O
routines	O
*	O
FILES	O
Equates	O
File	O
Identification	O
Numbers	O
from	O
the	O
FORTRAN	B-Application
DEFINE	O
FILE	O
statement	O
or	O
the	O
Assembler	B-Language
FILE	O
statement	O
to	O
named	O
files	O
on	O
disk	B-Device
.	O
</s>
<s>
The	O
enduring	O
memories	O
of	O
the	O
IBM	B-Device
1130	I-Device
may	O
have	O
resulted	O
from	O
its	O
need	O
for	O
continual	O
human	O
intervention	O
.	O
</s>
<s>
It	O
was	O
usually	O
occupied	O
running	O
"	O
jobs	O
"	O
specified	O
by	O
a	O
deck	O
of	O
punched	B-Architecture
cards	I-Architecture
.	O
</s>
<s>
The	O
human	O
operator	O
would	O
load	O
jobs	O
into	O
the	O
card	B-Architecture
reader	O
and	O
separate	O
them	O
back	O
into	O
jobs	O
for	O
return	O
,	O
perhaps	O
along	O
with	O
printed	O
output	O
,	O
to	O
the	O
submitter	O
.	O
</s>
<s>
Marking	O
the	O
start	O
of	O
a	O
job	O
was	O
a	O
punched	B-Architecture
card	I-Architecture
that	O
started	O
with	O
//	O
JOB	O
.	O
</s>
<s>
Any	O
card	B-Architecture
that	O
started	O
with	O
//	O
was	O
a	O
command	O
to	O
the	O
Supervisor	O
and	O
could	O
not	O
be	O
used	O
as	O
user	O
program	O
or	O
data	O
.	O
</s>
<s>
Other	O
commands	O
included	O
//	O
DUP	O
to	O
execute	O
the	O
Disk	B-Application
Utility	I-Application
Program	I-Application
(	O
to	O
delete	O
files	O
or	O
add	O
the	O
file	O
in	O
the	O
temporary	O
area	O
to	O
the	O
file	O
collection	O
)	O
and	O
//	O
XEQ	O
to	O
execute	O
a	O
named	O
program	O
from	O
disk	B-Device
.	O
</s>
<s>
If	O
a	O
user	O
program	O
tried	O
to	O
read	O
a	O
command	O
card	B-Architecture
,	O
the	O
standard	O
card	B-Architecture
reader	O
routine	O
would	O
signal	O
end-of-input	O
to	O
the	O
program	O
and	O
save	O
that	O
card	B-Architecture
's	O
content	O
for	O
the	O
Supervisor	O
.	O
</s>
<s>
Unlike	O
the	O
IBM	B-Application
360	I-Application
,	O
where	O
a	O
booting	B-Operating_System
device	O
can	O
be	O
selected	O
from	O
the	O
system	O
console	O
,	O
an	O
IBM	B-Device
1130	I-Device
can	O
only	O
be	O
"	O
booted	O
"	O
(	O
IPL	O
'd	O
:	O
Initial	O
Program	O
Load	O
)	O
from	O
an	O
external	O
device	O
:	O
a	O
card	B-Architecture
reader	O
or	O
a	O
paper	O
tape	O
reader	O
.	O
</s>
<s>
The	O
bootstrap	O
procedure	O
reads	O
one	O
card	B-Architecture
from	O
the	O
card	B-Architecture
reader	O
.	O
</s>
<s>
The	O
boot	B-Operating_System
card	B-Architecture
contains	O
binary	O
code	O
to	O
read	O
the	O
contents	O
of	O
sector	O
zero	O
of	O
the	O
disk	B-Device
drive	I-Device
,	O
which	O
in	O
turn	O
handles	O
the	O
"	O
operation	O
complete	O
"	O
interrupt	B-Application
from	O
the	O
disk	B-Device
drive	I-Device
and	O
performs	O
additional	O
disk	B-Device
reads	O
to	O
prepare	O
the	O
1130	O
for	O
the	O
first	O
punched-card	B-Architecture
job	O
.	O
</s>
<s>
When	O
the	O
IBM	B-Device
1130	I-Device
is	O
started	O
,	O
the	O
Supervisor	O
is	O
still	O
in	O
memory	O
and	O
probably	O
intact	O
,	O
as	O
core	O
memory	O
retains	O
its	O
state	O
without	O
power	O
.	O
</s>
<s>
If	O
the	O
operator	O
concludes	O
that	O
a	O
user	O
program	O
has	O
stalled	O
,	O
the	O
Supervisor	O
can	O
sense	O
a	O
key	O
press	O
to	O
abort	O
the	O
program	O
and	O
skip	O
ahead	O
to	O
the	O
next	O
//	O
card	B-Architecture
.	O
</s>
<s>
Nor	O
was	O
there	O
protection	O
against	O
writing	O
to	O
disk	B-Device
.	O
</s>
<s>
If	O
the	O
copy	O
of	O
the	O
system	O
software	O
on	O
disk	B-Device
is	O
modified	O
,	O
it	O
can	O
be	O
restored	O
by	O
reloading	O
it	O
from	O
about	O
4000	O
binary-coded	O
punched	B-Architecture
cards	I-Architecture
(	O
approximately	O
two	O
boxes	O
)	O
.	O
</s>
<s>
The	O
IBM	B-Device
2310	I-Device
disk	B-Device
drive	I-Device
stores	O
sectors	B-Application
of	O
320	O
words	O
(	O
640	O
bytes	O
)	O
plus	O
a	O
one-word	O
sector	O
address	O
.	O
</s>
<s>
A	O
cylinder	O
consists	O
of	O
two	O
tracks	B-Device
on	O
the	O
top	O
and	O
bottom	O
surfaces	O
of	O
the	O
2315	O
,	O
or	O
of	O
one	O
platter	O
on	O
the	O
1316	O
disk	B-Device
pack	O
used	O
in	O
the	O
2311	O
.	O
</s>
<s>
Each	O
disk	B-Device
cylinder	O
contains	O
eight	O
sectors	B-Application
.	O
</s>
<s>
A	O
sector	O
is	O
logically	O
divided	O
by	O
the	O
monitor	O
into	O
sixteen	O
disk	B-Device
blocks	O
of	O
20	O
words	O
(	O
40	O
bytes	O
)	O
each	O
.	O
</s>
<s>
The	O
disk	B-Device
block	O
is	O
the	O
unit	O
of	O
allocation	O
for	O
files	O
.	O
</s>
<s>
All	O
cartridges	O
contain	O
information	O
on	O
cylinder	O
0	O
,	O
including	O
the	O
defective	O
cylinder	O
table	O
,	O
cartridge	O
id	O
,	O
and	O
a	O
bootstrap	B-Operating_System
program	I-Operating_System
(	O
bootstrap	B-Operating_System
code	I-Operating_System
)	O
.	O
</s>
<s>
On	O
nonsystem	O
cartridges	O
,	O
the	O
bootstrap	O
simply	O
prints	O
an	O
error	O
message	O
and	O
waits	O
if	O
an	O
attempt	O
is	O
made	O
to	O
boot	B-Operating_System
from	O
this	O
cartridge	O
.	O
</s>
<s>
On	O
a	O
system	O
cartridge	O
this	O
is	O
the	O
cold-start	O
program	O
,	O
followed	O
by	O
a	O
communications	O
area	O
and	O
the	O
resident	B-Application
monitor	I-Application
in	O
sectors	B-Application
one	O
and	O
two	O
.	O
</s>
<s>
Sectors	B-Application
three	O
through	O
five	O
contain	O
the	O
System	O
Location	O
Equivalence	O
Table	O
(	O
SLET	O
)	O
—	O
a	O
directory	O
of	O
all	O
phases	O
of	O
all	O
monitor	O
programs	O
.	O
</s>
<s>
It	O
contains	O
the	O
Disk	B-Device
Monitor	O
program	O
,	O
and	O
optionally	O
the	O
FORTRAN	B-Application
compiler	B-Language
,	O
the	O
Assembler	B-Language
,	O
and	O
a	O
core	O
image	O
buffer	O
used	O
for	O
linking	O
relocatable	O
programs	O
.	O
</s>
<s>
Rarely	O
modified	O
files	O
thus	O
migrate	O
towards	O
the	O
start	O
of	O
the	O
disk	B-Device
as	O
new	O
files	O
or	O
new	O
versions	O
are	O
appended	O
,	O
and	O
frequently	O
modified	O
files	O
are	O
stored	O
towards	O
the	O
end	O
of	O
the	O
disk	B-Device
.	O
</s>
<s>
It	O
may	O
contain	O
one	O
temporary	O
file	O
created	O
by	O
the	O
system	O
or	O
the	O
user	O
,	O
such	O
as	O
the	O
output	O
of	O
a	O
compiler	B-Language
or	O
an	O
application	O
program	O
.	O
</s>
<s>
All	O
disk	B-Device
files	O
are	O
contiguous	O
disk	B-Device
blocks	O
,	O
thus	O
there	O
is	O
no	O
fragmentation	B-Application
.	O
</s>
<s>
With	O
limited	O
disk	B-Device
space	O
,	O
program	O
source	O
files	O
are	O
normally	O
kept	O
as	O
decks	O
of	O
cards	O
.	O
</s>
<s>
Users	O
having	O
larger	O
requirements	O
may	O
have	O
a	O
disk	B-Device
of	O
their	O
own	O
containing	O
the	O
operating	B-General_Concept
system	I-General_Concept
,	O
but	O
only	O
their	O
files	O
,	O
and	O
would	O
have	O
to	O
replace	O
the	O
"	O
pool	O
"	O
system	O
disk	B-Device
with	O
theirs	O
and	O
restart	O
the	O
system	O
when	O
their	O
programs	O
are	O
to	O
be	O
run	O
.	O
</s>
<s>
A	O
system	O
with	O
a	O
second	O
disk	B-Device
drive	I-Device
that	O
can	O
be	O
devoted	O
entirely	O
to	O
one	O
user	O
's	O
code	O
and	O
data	O
provides	O
some	O
relief	O
.	O
</s>
<s>
A	O
disk	B-Device
pack	O
or	O
cartridge	O
is	O
initialized	O
for	O
use	O
on	O
the	O
1130	O
by	O
the	O
Disk	B-Device
Pack	O
Initialization	O
Routine	O
(	O
DIPR	O
)	O
.	O
</s>
<s>
This	O
routine	O
scans	O
the	O
disk	B-Device
,	O
and	O
writes	O
sector	O
addresses	O
on	O
all	O
cylinders	O
,	O
flags	O
defective	O
sectors	B-Application
,	O
and	O
writes	O
a	O
cartridge	O
id	O
on	O
cylinder	O
zero	O
.	O
</s>
<s>
DIPR	O
is	O
a	O
Standalone	B-General_Concept
program	I-General_Concept
,	O
which	O
is	O
loaded	O
from	O
cards	O
or	O
paper	O
tape	O
,	O
and	O
accepts	O
the	O
cartridge	O
id	O
from	O
the	O
system	O
console	O
.	O
</s>
<s>
The	O
Disk	B-Application
Utility	I-Application
Program	I-Application
(	O
DUP	O
)	O
provides	O
commands	O
for	O
transferring	O
programs	O
,	O
subroutines	O
and	O
data	O
.	O
</s>
<s>
It	O
is	O
invoked	O
by	O
the	O
job	B-Application
control	I-Application
//	O
DUP	O
card	B-Architecture
,	O
followed	O
by	O
one	O
or	O
more	O
control	O
cards	O
:	O
</s>
<s>
Other	O
commands	O
,	O
mainly	O
for	O
use	O
by	O
the	O
system	O
administrator	O
,	O
define	O
or	O
expand	O
the	O
Fixed	O
Area	O
,	O
delete	O
the	O
FORTRAN	B-Application
compiler	B-Language
and/or	O
Assembler	B-Language
from	O
the	O
system	O
,	O
and	O
restore	O
correct	O
sector	O
addresses	O
to	O
Working	O
Storage	O
if	O
they	O
have	O
been	O
modified	O
.	O
</s>
<s>
Alternatively	O
,	O
a	O
program	O
can	O
go	O
through	O
this	O
process	O
each	O
time	O
it	O
is	O
to	O
be	O
run	O
,	O
and	O
for	O
infrequently	O
used	O
programs	O
this	O
is	O
preferred	O
in	O
order	O
to	O
conserve	O
disk	B-Device
space	O
.	O
</s>
<s>
The	O
following	O
control	O
card	B-Architecture
instructs	O
DUP	O
to	O
take	O
the	O
current	O
contents	O
of	O
working	O
storage	O
and	O
move	O
it	O
to	O
the	O
user	O
area	O
naming	O
it	O
PROGZ	O
.	O
</s>
<s>
Disk	B-Device
memory	I-Device
is	O
used	O
to	O
store	O
the	O
operating	B-General_Concept
system	I-General_Concept
,	O
object	O
code	O
,	O
and	O
data	O
,	O
but	O
source	O
code	O
is	O
kept	O
on	O
punched	B-Architecture
cards	I-Architecture
.	O
</s>
<s>
The	O
basic	O
1130	O
came	O
with	O
an	O
IBM	B-Device
2310	I-Device
voice-coil	O
actuated	O
disk	B-Device
drive	I-Device
,	O
called	O
"	O
Ramkit	O
"	O
,	O
from	O
IBM	O
's	O
General	O
Products	O
Division	O
in	O
San	O
Jose	O
.	O
</s>
<s>
There	O
is	O
a	O
special	O
type	O
element	O
available	O
for	O
APL	B-Language
,	O
a	O
powerful	O
array-oriented	O
programming	O
language	O
using	O
a	O
special	O
symbolic	O
notation	O
.	O
</s>
<s>
A	O
row	O
of	O
16	O
toggle	O
switches	O
on	O
the	O
console	O
typewriter	O
can	O
be	O
individually	O
tested	O
from	O
within	O
programs	O
,	O
using	O
the	O
special	O
Fortran	B-Application
statement	O
IF	O
(	O
SENSE	O
SWITCH	O
i	O
)	O
,	O
for	O
example	O
.	O
</s>
<s>
Magnetic	O
tape	O
–	O
From	O
1968	O
,	O
IBM	O
2415	O
Magnetic	B-Architecture
tape	I-Architecture
data	I-Architecture
storage	I-Architecture
drives	O
were	O
available	O
as	O
an	O
RPQ	O
.	O
</s>
<s>
Graphics	O
–	O
IBM	B-Device
2250	I-Device
Graphic	O
Display	O
Unit	O
.	O
</s>
<s>
Color	O
Pen	O
Plotter	O
–	O
IBM	B-Device
1627	I-Device
drum	O
plotter	O
.	O
</s>
<s>
The	O
IBM	B-Device
1130	I-Device
MTCA	O
,	O
for	O
Multiple	O
Terminal	O
Control	O
Adapter	O
,	O
announced	O
in	O
1970	O
allowed	O
up	O
to	O
four	O
2741	O
terminals	O
to	O
be	O
connected	O
to	O
an	O
IBM	B-Device
1130	I-Device
,	O
for	O
use	O
with	O
APL	B-Language
.	O
</s>
<s>
The	O
card	B-Architecture
reader	O
has	O
no	O
memory	O
buffers	O
,	O
but	O
instead	O
gives	O
the	O
CPU	O
a	O
level-zero	O
(	O
highest	O
priority	O
)	O
interrupt	B-Application
after	O
each	O
individual	O
column	O
of	O
the	O
card	B-Architecture
has	O
been	O
read	O
.	O
</s>
<s>
If	O
the	O
CPU	O
does	O
not	O
respond	O
and	O
store	O
the	O
twelve	O
bits	O
of	O
data	O
before	O
another	O
such	O
interrupt	B-Application
indicates	O
that	O
the	O
next	O
column	O
has	O
been	O
read	O
,	O
data	O
will	O
be	O
lost	O
.	O
</s>
<s>
The	O
CPU	O
has	O
to	O
translate	O
it	O
to	O
or	O
from	O
the	O
EBCDIC	B-Language
code	O
in	O
which	O
the	O
CPU	O
processes	O
the	O
text	O
.	O
</s>
<s>
Instructions	B-General_Concept
had	O
short	O
(	O
one-word	O
)	O
and	O
long	O
(	O
two-word	O
)	O
formats	O
.	O
</s>
<s>
Most	O
computational	O
,	O
load	O
,	O
and	O
store	O
instructions	B-General_Concept
referenced	O
one	O
register	O
(	O
usually	O
ACC	O
)	O
and	O
a	O
memory	O
location	O
.	O
</s>
<s>
Standard	O
-	O
and	O
extended-precision	B-Algorithm
floating-point	I-Algorithm
(	O
32	O
and	O
48bits	O
)	O
and	O
decimal	B-Device
data	O
were	O
supported	O
through	O
the	O
use	O
of	O
subroutines	O
.	O
</s>
<s>
The	O
memory	O
addresses	O
of	O
the	O
index	O
registers	O
permitted	O
direct	O
moves	O
between	O
them	O
,	O
such	O
as	O
with	O
LDX	O
I1	O
2/0002XR2./0003XR3./0008The	O
address	O
of	O
the	O
handler	O
for	O
the	O
Level	O
0	O
(	O
highest	O
priority	O
)	O
interrupt	B-Application
—	O
1442	O
card	B-Architecture
reader/punch	O
"	O
column	O
ready	O
"	O
interrupt./0009The	O
address	O
of	O
the	O
handler	O
for	O
the	O
Level	O
1	O
interrupt	B-Application
—	O
1132	O
printer	O
and	O
Synchronous	O
Communications	O
Adapter	O
.	O
</s>
<s>
The	O
1130	O
has	O
no	O
hardware	O
support	O
for	O
a	O
stack	B-General_Concept
.	O
</s>
<s>
Placing	O
the	O
return	O
address	O
in-line	O
was	O
a	O
common	O
technique	O
of	O
computers	O
at	O
that	O
time	O
,	O
such	O
as	O
the	O
Hewlett-Packard	O
HP	B-Device
2100	I-Device
,	O
the	O
DEC	B-Device
PDP-8	I-Device
,	O
and	O
the	O
Scientific	O
Data	O
Systems	O
SDS	B-Device
920	I-Device
.	O
</s>
<s>
END	O
SIMPL	O
Instructs	O
the	O
assembler	B-Language
that	O
the	O
source	O
for	O
routine	O
SIMPLE	O
is	O
complete	O
.	O
</s>
<s>
As	O
shown	O
,	O
a	O
subprogram	O
's	O
entry	O
point	O
is	O
DC	O
*	O
-*	O
,	O
an	O
assembler	B-Language
pseudo	O
operation	O
that	O
is	O
used	O
to	O
Define	O
a	O
Constant	O
(	O
occupying	O
one	O
word	O
of	O
storage	O
)	O
with	O
the	O
value	O
specified	O
by	O
the	O
expression	O
.	O
</s>
<s>
Re-entrancy	B-Operating_System
is	O
problematic	O
for	O
the	O
same	O
reason	O
:	O
An	O
interrupt	B-Application
service	O
routine	O
must	O
refrain	O
from	O
calling	O
any	O
subprogram	O
that	O
might	O
have	O
been	O
the	O
code	O
that	O
was	O
interrupted	O
.	O
</s>
<s>
Floating-point	O
functions	O
employ	O
the	O
floating-point	O
accumulator	O
(	O
a	O
two	O
word	O
area	O
set	O
aside	O
by	O
the	O
floating-point	O
library	O
,	O
three	O
words	O
for	O
extended	B-Algorithm
precision	I-Algorithm
)	O
,	O
and	O
so	O
on	O
.	O
</s>
<s>
(	O
Fortran	B-Application
subprograms	O
use	O
index	O
register	O
XR1	O
for	O
the	O
addresses	O
of	O
parameters	O
and	O
the	O
return	O
address	O
,	O
but	O
register	O
XR2	O
is	O
unused	O
.	O
)	O
</s>
<s>
RETN	O
B	O
L	O
*	O
-*	O
This	O
instruction	O
was	O
modified	O
two	O
instructions	B-General_Concept
ago	O
;	O
return	O
.	O
</s>
<s>
These	O
instructions	B-General_Concept
are	O
two	O
words	O
long	O
,	O
so	O
such	O
a	O
design	O
would	O
negate	O
the	O
code	O
size	O
savings	O
of	O
LIBF	O
.	O
</s>
<s>
It	O
is	O
common	O
in	O
1130	O
programming	O
to	O
modify	O
the	O
address	O
fields	O
of	O
instructions	B-General_Concept
and	O
,	O
in	O
fact	O
,	O
to	O
modify	O
entire	O
instructions	B-General_Concept
.	O
</s>
<s>
The	O
Fortran	B-Application
compiler	B-Language
produces	O
self-modifying	B-Application
code	I-Application
when	O
generating	O
code	O
for	O
any	O
subprograms	O
(	O
subroutines	O
or	O
functions	O
)	O
that	O
have	O
parameters	O
.	O
</s>
<s>
The	O
compiler	B-Language
builds	O
a	O
table	O
of	O
every	O
location	O
where	O
the	O
subprogram	O
references	O
one	O
of	O
its	O
parameters	O
,	O
and	O
compiles	B-Language
as	O
the	O
first	O
instruction	O
in	O
the	O
body	O
of	O
the	O
subprogram	O
a	O
call	O
to	O
a	O
subprogram	O
called	O
SUBIN	O
that	O
uses	O
the	O
table	O
to	O
modify	O
the	O
address	O
field	O
of	O
every	O
reference	O
to	O
a	O
parameter	O
to	O
be	O
the	O
actual	O
address	O
of	O
the	O
parameter	O
during	O
the	O
current	O
invocation	O
.	O
</s>
<s>
When	O
a	O
Fortran	B-Application
program	O
calls	O
a	O
subprogram	O
,	O
the	O
addresses	O
of	O
any	O
parameters	O
appear	O
in-line	O
following	O
the	O
call	O
.	O
</s>
<s>
For	O
example	O
,	O
the	O
Fortran	B-Application
statement	O
CALL	O
SIMPL(X )	O
might	O
compile	B-Language
into	O
:	O
</s>
<s>
The	O
compiler	B-Language
instead	O
used	O
direct	O
addressing	O
.	O
</s>
<s>
The	O
size	O
of	O
this	O
table	O
is	O
the	O
sum	O
of	O
5	O
,	O
the	O
number	O
of	O
parameters	O
,	O
and	O
the	O
number	O
of	O
references	O
;	O
if	O
this	O
sum	O
exceeds	O
511	O
,	O
compilation	B-Language
will	O
fail	O
.	O
</s>
<s>
Modifying	O
entire	O
instructions	B-General_Concept
was	O
a	O
common	O
technique	O
at	O
the	O
time	O
.	O
</s>
<s>
For	O
example	O
,	O
although	O
the	O
1130	O
has	O
an	O
OR	O
instruction	O
,	O
the	O
syntax	O
of	O
Fortran	B-Application
provides	O
no	O
way	O
to	O
write	O
it	O
.	O
</s>
<s>
An	O
integer	O
function	O
IOR	O
can	O
be	O
defined	O
,	O
enabling	O
logical	O
OR	O
to	O
be	O
part	O
of	O
a	O
Fortran	B-Application
expression	O
such	O
as	O
:	O
</s>
<s>
The	O
Fortran	B-Application
compiler	B-Language
places	O
the	O
addresses	O
of	O
I	O
and	O
J	O
in-line	O
and	O
expects	O
the	O
result	O
in	O
the	O
accumulator	O
.	O
</s>
<s>
Using	O
IOR(I,J )	O
in	O
a	O
Fortran	B-Application
expression	O
compiles	B-Language
the	O
following	O
four	O
words	O
:	O
</s>
<s>
In	O
fact	O
,	O
the	O
assembler	B-Language
IOR	O
function	O
does	O
not	O
compute	O
I	O
or	O
J	O
at	O
all	O
.	O
</s>
<s>
The	O
BSI	O
instruction	O
is	O
no	O
longer	O
there	O
;	O
what	O
is	O
now	O
there	O
is	O
the	O
two	O
instructions	B-General_Concept
it	O
has	O
just	O
written	O
.	O
</s>
<s>
If	O
the	O
Fortran	B-Application
line	O
illustrated	O
above	O
is	O
executed	O
again	O
,	O
it	O
runs	O
faster	O
than	O
it	O
did	O
the	O
first	O
time	O
.	O
</s>
<s>
A	O
function	O
that	O
self-modifies	O
,	O
as	O
IOR	O
does	O
,	O
can	O
not	O
be	O
used	O
in	O
a	O
Fortran	B-Application
subprogram	O
on	O
any	O
of	O
the	O
parameters	O
to	O
that	O
subprogram	O
(	O
though	O
it	O
could	O
be	O
used	O
to	O
combine	O
local	O
variables	O
)	O
because	O
it	O
is	O
incompatible	O
with	O
the	O
SUBIN	O
subprogram	O
discussed	O
above	O
.	O
</s>
<s>
On	O
subsequent	O
calls	O
to	O
the	O
Fortran	B-Application
subprogram	O
,	O
the	O
table	O
of	O
references	O
to	O
parameters	O
would	O
be	O
in	O
error	O
and	O
SUBIN	O
would	O
patch	O
the	O
wrong	O
word	O
,	O
in	O
this	O
case	O
placing	O
the	O
new	O
address	O
of	O
I	O
over	O
the	O
OR	O
operation	O
code	O
.	O
</s>
<s>
1130	O
FORTRAN	B-Application
offers	O
two	O
floating	O
point	O
formats	O
:	O
a	O
32-bit	O
"	O
standard	O
precision	O
"	O
format	O
and	O
a	O
40-bit	O
"	O
extended	B-Algorithm
precision	I-Algorithm
"	O
format	O
.	O
</s>
<s>
Standard	O
precision	O
format	O
contains	O
a	O
24-bit	O
two	B-General_Concept
's	I-General_Concept
complement	I-General_Concept
significand	B-Algorithm
while	O
extended	B-Algorithm
precision	I-Algorithm
utilizes	O
a	O
32-bit	O
two	B-General_Concept
's	I-General_Concept
complement	I-General_Concept
significand	B-Algorithm
.	O
</s>
<s>
The	O
extended	O
format	O
occupies	O
three	O
16-bit	B-Device
words	O
,	O
with	O
the	O
high-order	O
eight	O
bits	O
of	O
the	O
first	O
word	O
unused	O
.	O
</s>
<s>
The	O
characteristic	O
in	O
both	O
formats	O
is	O
an	O
8-bit	O
field	O
containing	O
the	O
power	O
of	O
two	O
biased	B-Algorithm
by	O
128	O
.	O
</s>
<s>
The	O
*	O
EXTENDED	B-Algorithm
PRECISION	I-Algorithm
compiler	B-Language
option	O
card	B-Architecture
tells	O
the	O
FORTRAN	B-Application
compiler	B-Language
to	O
use	O
40	O
bits	O
instead	O
of	O
32	O
bits	O
for	O
all	O
floating	O
point	O
data	O
,	O
there	O
is	O
no	O
provision	O
for	O
mixing	O
formats	O
.	O
</s>
<s>
Data	O
to	O
be	O
manipulated	O
and	O
the	O
instructions	B-General_Concept
that	O
manipulate	O
them	O
have	O
to	O
reside	O
together	O
in	O
core	O
memory	O
.	O
</s>
<s>
Fortran	B-Application
provides	O
several	O
techniques	O
to	O
write	O
large	O
programs	O
despite	O
this	O
limitation	O
.	O
</s>
<s>
Fortran	B-Application
let	O
any	O
subprogram	O
be	O
designated	O
as	O
"	O
LOCAL	O
"	O
(	O
Load-on-Call	O
)	O
.	O
</s>
<s>
Each	O
LOCAL	O
subprogram	O
is	O
an	O
overlay	B-General_Concept
;	O
it	O
is	O
part	O
of	O
the	O
disk-resident	O
executable	O
program	O
but	O
is	O
only	O
loaded	O
into	O
core	O
memory	O
(	O
if	O
not	O
already	O
there	O
)	O
during	O
the	O
time	O
it	O
is	O
called	O
.	O
</s>
<s>
An	O
entire	O
Fortran	B-Application
program	O
can	O
pass	O
control	O
to	O
a	O
subsequent	O
phase	O
,	O
exiting	O
to	O
the	O
Supervisor	O
with	O
an	O
instruction	O
to	O
load	O
the	O
follow-on	O
phase	O
into	O
core	O
memory	O
.	O
</s>
<s>
A	O
large	O
program	O
might	O
be	O
split	O
into	O
three	O
parts	O
,	O
separately	O
compiled	B-Language
,	O
called	O
PART1	O
,	O
PART2	O
,	O
and	O
PART3	O
.	O
</s>
<s>
Execution	O
is	O
started	O
by	O
//	O
XEQ	O
PART1	O
and	O
at	O
a	O
suitable	O
point	O
,	O
PART1	O
would	O
execute	O
the	O
Fortran	B-Application
statement	O
CALL	O
LINK(PART2 )	O
and	O
so	O
forth	B-Application
.	O
</s>
<s>
As	O
mentioned	O
above	O
,	O
the	O
Fortran	B-Application
compiler	B-Language
itself	O
was	O
written	O
this	O
way	O
,	O
with	O
each	O
phase	O
of	O
compilation	B-Language
achieved	O
by	O
a	O
separate	O
program	O
.	O
</s>
<s>
Programs	O
,	O
such	O
as	O
Fortran	B-Application
programs	O
,	O
reside	O
at	O
low	O
core	O
memory	O
addresses	O
(	O
just	O
above	O
the	O
Supervisor	O
)	O
.	O
</s>
<s>
Fortran	B-Application
allocates	O
space	O
at	O
the	O
highest	O
addresses	O
for	O
any	O
variables	O
and	O
arrays	O
declared	O
COMMON	O
.	O
</s>
<s>
The	O
examples	O
can	O
be	O
executed	O
on	O
the	O
IBM	B-Device
1130	I-Device
emulator	O
available	O
at	O
.	O
</s>
<s>
The	O
following	O
listing	O
shows	O
a	O
card	B-Architecture
deck	I-Architecture
that	O
compiles	B-Language
and	O
runs	O
an	O
assembler	B-Language
program	I-Language
that	O
lists	O
a	O
deck	O
of	O
cards	O
to	O
the	O
line	O
printer	O
.	O
</s>
<s>
In	O
this	O
job	O
,	O
the	O
assembler	B-Language
leaves	O
the	O
result	O
of	O
its	O
assembly	O
in	O
the	O
temporary	O
area	O
of	O
the	O
system	O
disk	B-Device
,	O
and	O
the	O
XEQ	O
command	O
executes	O
the	O
content	O
of	O
the	O
temporary	O
area	O
.	O
</s>
<s>
The	O
odd-looking	O
END	O
START	O
has	O
two	O
meanings	O
:	O
end	O
of	O
assembler	B-Language
source	O
,	O
and	O
the	O
name	O
of	O
the	O
entry	O
point	O
of	O
the	O
routine	O
,	O
which	O
has	O
the	O
label	O
START	O
.	O
</s>
<s>
Assembler	B-Language
source	O
starts	O
with	O
column	O
21	O
of	O
the	O
card	B-Architecture
,	O
not	O
column	O
one	O
.	O
</s>
<s>
In	O
systems	O
without	O
a	O
disk	B-Device
drive	I-Device
,	O
the	O
assembler	B-Language
would	O
punch	O
code	O
into	O
the	O
start	O
of	O
the	O
card	B-Architecture
just	O
read	O
(	O
the	O
card	B-Architecture
reader	O
was	O
actually	O
a	O
reader-punch	O
,	O
with	O
the	O
punch	O
station	O
after	O
the	O
read	O
station	O
)	O
and	O
then	O
read	O
the	O
next	O
card	B-Architecture
.	O
</s>
<s>
To	O
handle	O
forward	O
branches	O
and	O
the	O
like	O
,	O
the	O
assembler	B-Language
's	O
second	O
pass	O
literally	O
involved	O
a	O
second	O
pass	O
of	O
the	O
cards	O
through	O
the	O
reader/punch	O
.	O
</s>
<s>
If	O
source	O
changes	O
were	O
needed	O
the	O
programmer	O
would	O
duplicate	O
the	O
cards	O
to	O
obtain	O
a	O
deck	O
with	O
columns	O
1-20	O
blank	O
ready	O
for	O
the	O
next	O
run	O
through	O
the	O
assembler	B-Language
.	O
</s>
<s>
The	O
card	B-Architecture
buffer	O
requires	O
80	O
words	O
,	O
one	O
for	O
each	O
card	B-Architecture
column	O
.	O
</s>
<s>
Driver	O
CARD0	O
reads	O
each	O
card	B-Architecture
column	O
literally	O
,	O
using	O
12	O
of	O
the	O
16	B-Device
bits	I-Device
in	O
the	O
buffer	O
word	O
,	O
with	O
a	O
bit	O
set	O
to	O
on	O
for	O
each	O
hole	O
punched	O
in	O
the	O
corresponding	O
row	O
for	O
that	O
column	O
.	O
</s>
<s>
The	O
pattern	O
of	O
punches	O
typically	O
describes	O
a	O
text	O
character	O
using	O
the	O
Hollerith	B-Architecture
code	I-Architecture
.	O
</s>
<s>
The	O
console	O
keyboard	O
also	O
gives	O
input	O
to	O
the	O
program	O
in	O
the	O
Hollerith	B-Architecture
code	I-Architecture
,	O
the	O
only	O
case	O
of	O
two	O
devices	O
using	O
the	O
same	O
character	O
encoding	O
.	O
</s>
<s>
The	O
printer	O
routine	O
,	O
however	O
,	O
works	O
with	O
text	O
in	O
8-bit	O
EBCDIC	B-Language
with	O
two	O
characters	O
per	O
word	O
,	O
requiring	O
a	O
40-word	O
buffer	O
.	O
</s>
<s>
Despite	O
appearances	O
,	O
the	O
statement	O
CALL	O
HLEBC	O
is	O
not	O
executed	O
because	O
HLEBC	O
is	O
not	O
a	O
subroutine	O
but	O
an	O
IBM-supplied	O
Hollerith-to-EBCDIC	O
conversion	O
table	O
.	O
</s>
<s>
Again	O
,	O
the	O
program	O
loops	O
until	O
the	O
printer	B-Application
driver	I-Application
reports	O
completion	O
,	O
then	O
the	O
program	O
reads	O
the	O
next	O
card	B-Architecture
.	O
</s>
<s>
To	O
stop	O
the	O
card	B-Architecture
reader	O
as	O
soon	O
as	O
possible	O
,	O
a	O
program	O
could	O
check	O
for	O
the	O
Hollerith	B-Architecture
code	I-Architecture
of	O
/	O
before	O
even	O
converting	O
the	O
card	B-Architecture
to	O
EBCDIC	B-Language
.	O
</s>
<s>
The	O
call	O
to	O
CARD0	O
to	O
read	O
a	O
card	B-Architecture
initiates	O
that	O
operation	O
and	O
immediately	O
returns	O
to	O
the	O
caller	O
,	O
which	O
could	O
proceed	O
with	O
other	O
activity	O
.	O
</s>
<s>
However	O
,	O
the	O
example	O
program	O
makes	O
no	O
attempt	O
to	O
overlap	O
input	B-General_Concept
and	I-General_Concept
output	I-General_Concept
using	O
buffers	O
even	O
though	O
it	O
has	O
two	O
separate	O
work	O
areas	O
;	O
it	O
simply	O
loops	O
back	O
to	O
CIMP	O
to	O
test	O
afresh	O
.	O
</s>
<s>
After	O
CARD0	O
has	O
sensed	O
the	O
card	B-Architecture
reader	O
's	O
operation-complete	O
interrupt	B-Application
,	O
it	O
returns	O
one	O
word	O
further	O
on	O
,	O
thus	O
skipping	O
the	O
jump	O
back	O
to	O
CIMP	O
and	O
leaving	O
the	O
loop	O
.	O
</s>
<s>
The	O
example	O
routines	O
do	O
not	O
run	O
the	O
I/O	B-General_Concept
devices	I-General_Concept
at	O
top	O
speed	O
.	O
</s>
<s>
Notably	O
,	O
the	O
card	B-Architecture
reader	O
,	O
only	O
a	O
few	O
milliseconds	O
after	O
reporting	O
completion	O
on	O
reading	O
a	O
card	B-Architecture
,	O
will	O
commence	O
its	O
stop	O
sequence	O
,	O
after	O
which	O
a	O
new	O
read	O
command	O
will	O
have	O
to	O
wait	O
to	O
initiate	O
another	O
read	O
cycle	O
.	O
</s>
<s>
The	O
IBM	B-Device
1442	I-Device
reader	O
could	O
read	O
400	O
cards/minute	O
at	O
full	O
speed	O
,	O
but	O
just	O
a	O
little	O
hesitancy	O
in	O
the	O
read	O
commands	O
would	O
halve	O
its	O
throughput	O
or	O
worse	O
.	O
</s>
<s>
A	O
Fortran	B-Application
program	O
could	O
not	O
complete	O
even	O
the	O
simplest	O
input	O
processing	O
in	O
time	O
,	O
and	O
so	O
could	O
not	O
read	O
cards	O
at	O
full	O
speed	O
.	O
</s>
<s>
One	O
common	O
Fortran	B-Application
DO	O
loop	O
to	O
read	O
cards	O
made	O
the	O
motor	O
stop	O
and	O
start	O
so	O
frequently	O
as	O
to	O
accelerate	O
wear	O
.	O
</s>
<s>
With	O
buffering	O
,	O
the	O
card	B-Architecture
reader	O
control	O
could	O
be	O
overlapped	O
with	O
processing	O
,	O
and	O
the	O
reader	O
could	O
be	O
run	O
at	O
full	O
speed	O
through	O
large	O
data	O
decks	O
,	O
but	O
memory	O
for	O
the	O
more	O
complex	O
program	O
and	O
for	O
buffers	O
was	O
often	O
at	O
a	O
premium	O
.	O
</s>
<s>
Even	O
with	O
assembler	B-Language
and	O
double	O
buffering	O
,	O
a	O
program	O
to	O
list	O
a	O
deck	O
of	O
cards	O
from	O
the	O
IBM	B-Device
2501	I-Device
reader	O
(	O
1,000	O
cards/minute	O
)	O
on	O
the	O
line	O
printer	O
could	O
not	O
keep	O
up	O
,	O
as	O
the	O
translation	O
from	O
card	B-Architecture
hole	O
patterns	O
to	O
EBCDIC	B-Language
for	O
the	O
printer	O
as	O
done	O
by	O
EBPRT	O
was	O
too	O
slow	O
;	O
the	O
more	O
complex	O
ZIPCO	O
and	O
HLEBC	O
were	O
needed	O
instead	O
,	O
as	O
in	O
the	O
example	O
.	O
</s>
<s>
The	O
following	O
image	O
shows	O
a	O
simple	O
APL	B-Language
\	O
1130	O
session	O
.	O
</s>
<s>
In	O
the	O
same	O
year	O
as	O
the	O
1130	O
's	O
introduction	O
,	O
Digital	O
Equipment	O
Corporation	O
introduced	O
the	O
smaller	O
,	O
cheaper	O
,	O
and	O
better-selling	O
12-bit	O
PDP-8	B-Device
,	O
recognized	O
as	O
the	O
first	O
successful	O
minicomputer	B-Architecture
.	O
</s>
<s>
The	O
initial	O
architecture	O
was	O
18	O
bits	O
but	O
was	O
changed	O
to	O
16	B-Device
bits	I-Device
due	O
to	O
the	O
influence	O
of	O
the	O
System/360	B-Application
development	O
.	O
</s>
<s>
Notable	O
software	O
designer	O
Grady	O
Booch	O
got	O
his	O
first	O
exposure	O
to	O
programming	O
on	O
an	O
IBM	B-Device
1130	I-Device
:	O
</s>
<s>
After	O
we	O
chatted	O
for	O
a	O
while	O
,	O
he	O
handed	O
me	O
a	O
Fortran	B-Application
 [ manual ] 	O
.	O
</s>
<s>
The	O
fellow	O
,	O
to	O
my	O
delight	O
,	O
found	O
me	O
programming	O
time	O
on	O
an	O
IBM	B-Device
1130	I-Device
on	O
weekends	O
and	O
late-evening	O
hours	O
.	O
</s>
<s>
LISP	B-Language
guru	O
Guy	O
Steele	O
wrote	O
a	O
LISP	B-Language
interpreter	O
for	O
the	O
IBM	B-Device
1130	I-Device
when	O
he	O
was	O
in	O
high	O
school	O
(	O
Boston	O
Latin	O
School	O
,	O
which	O
had	O
an	O
IBM	B-Device
1130	I-Device
for	O
student	O
use	O
)	O
.	O
</s>
<s>
His	O
code	O
and	O
documentation	O
for	O
LISP	B-Language
1.6	O
,	O
along	O
with	O
a	O
summary	O
of	O
current	O
work	O
in	O
getting	O
it	O
to	O
run	O
under	O
simulation	O
,	O
is	O
available	O
at	O
.	O
</s>
<s>
Chuck	O
Moore	O
wanted	O
to	O
call	O
his	O
new	O
language	O
"	O
Fourth	O
"	O
but	O
the	O
IBM	B-Device
1130	I-Device
operating	B-General_Concept
system	I-General_Concept
was	O
limited	O
to	O
five-character	O
names	O
,	O
so	O
it	O
wound	O
up	O
being	O
called	O
FORTH	B-Application
.	O
</s>
<s>
Dan	O
Bricklin	O
,	O
creator	O
of	O
the	O
VisiCalc	B-Application
program	O
,	O
got	O
his	O
start	O
in	O
programming	O
when	O
he	O
learned	O
and	O
used	O
the	O
IBM	B-Device
1130	I-Device
as	O
part	O
of	O
the	O
National	O
Science	O
Foundation	O
Computer/Math	O
Summer	O
Project	O
for	O
high	O
school	O
students	O
,	O
given	O
at	O
the	O
University	O
of	O
Pennsylvania	O
in	O
1966	O
.	O
</s>
<s>
An	O
IBM	B-Device
1130	I-Device
with	O
8	O
kilowords	O
of	O
core	O
was	O
used	O
for	O
the	O
world	O
's	O
first	O
full-time	O
Search	O
for	O
Extraterrestrial	O
Intelligence	O
research	O
at	O
The	O
Ohio	O
State	O
University	O
Radio	O
Observatory	O
.	O
</s>
<s>
Charles	O
Goldfarb	O
,	O
the	O
father	O
of	O
SGML	B-Language
,	O
describes	O
a	O
job	O
installing	O
a	O
typesetting	O
system	O
based	O
on	O
an	O
IBM	B-Device
1130	I-Device
that	O
"	O
eventually	O
changed	O
my	O
career	O
"	O
,	O
driving	O
him	O
towards	O
generic	O
markup	O
:	O
</s>
<s>
The	O
system	O
was	O
an	O
IBM	B-Device
1130	I-Device
computer	O
,	O
a	O
machine	O
the	O
size	O
of	O
a	O
desk	O
with	O
8	O
KB	O
of	O
main	O
memory	O
,	O
a	O
512	O
KB	O
disk	B-Device
drive	I-Device
,	O
a	O
Teletype	O
CX	O
paper	O
tape	O
reader	O
and	O
BRPE	O
paper	O
tape	O
punch	O
,	O
and	O
a	O
Photon	O
713	O
photomechanical	O
typesetter	O
.	O
</s>
<s>
Alan	O
Kay	O
used	O
the	O
IBM	B-Device
1130	I-Device
in	O
early	O
GUI	O
work	O
for	O
his	O
Ph.D.	O
thesis	O
in	O
1969	O
.	O
</s>
<s>
Hutchinson	O
Central	O
Technical	O
High	O
School	O
(	O
"	O
Hutch	O
Tech	O
"	O
)	O
in	O
Buffalo	O
,	O
NY	O
used	O
the	O
IBM	B-Device
1130	I-Device
in	O
the	O
nation	O
's	O
first	O
four-year	O
high	O
school	O
computer	O
science	O
curriculum	O
in	O
1969	O
.	O
</s>
<s>
An	O
engineer	O
from	O
IBM	O
was	O
hired	O
by	O
Signetics	O
and	O
incorporated	O
a	O
number	O
of	O
architectural	O
features	O
from	O
the	O
IBM	B-Device
1130	I-Device
into	O
the	O
Signetics	B-General_Concept
2650	I-General_Concept
single-chip	O
processor	O
.	O
</s>
<s>
That	O
,	O
since	O
the	O
1130	O
was	O
a	O
small	O
scientific	O
machine	O
,	O
the	O
number	O
was	O
chosen	O
by	O
multiplying	O
360	O
(	O
as	O
in	O
IBM	B-Application
360	I-Application
)	O
by	O
π	O
.	O
</s>
<s>
That	O
the	O
1130	O
was	O
IBM	O
's	O
11th	O
Computer	B-General_Concept
Design	I-General_Concept
,	O
and	O
it	O
had	O
30	O
instructions	B-General_Concept
.	O
</s>
<s>
Others	O
have	O
speculated	O
that	O
the	O
existence	O
of	O
the	O
IBM	B-Device
1130	I-Device
explains	O
why	O
no	O
computer	O
designated	O
"	O
11/30	O
"	O
ever	O
appeared	O
in	O
the	O
PDP-11	B-Device
family	O
of	O
machines	O
.	O
</s>
