<s>
MAD	O
(	O
Michigan	B-Language
Algorithm	I-Language
Decoder	I-Language
)	O
is	O
a	O
programming	O
language	O
and	O
compiler	B-Language
for	O
the	O
IBM	B-Device
704	I-Device
and	O
later	O
the	O
IBM	B-Device
709	I-Device
,	O
IBM	B-Device
7090	I-Device
,	O
IBM	B-Device
7040	I-Device
,	O
UNIVAC	O
1107	O
,	O
UNIVAC	O
1108	O
,	O
Philco	O
210-211	O
,	O
and	O
eventually	O
the	O
IBM	B-Device
S/370	I-Device
mainframe	B-Architecture
computers	I-Architecture
.	O
</s>
<s>
Developed	O
in	O
1959	O
at	O
the	O
University	O
of	O
Michigan	O
by	O
Bernard	O
Galler	O
,	O
Bruce	O
Arden	O
and	O
Robert	O
M	O
.	O
Graham	O
,	O
MAD	O
is	O
a	O
variant	O
of	O
the	O
ALGOL	B-Language
language	I-Language
.	O
</s>
<s>
It	O
was	O
widely	O
used	O
to	O
teach	O
programming	O
at	O
colleges	O
and	O
universities	O
during	O
the	O
1960s	O
and	O
played	O
a	O
minor	O
role	O
in	O
the	O
development	O
of	O
CTSS	B-Operating_System
,	O
Multics	B-Application
,	O
and	O
the	O
Michigan	B-Application
Terminal	I-Application
System	I-Application
computer	B-General_Concept
operating	I-General_Concept
systems	I-General_Concept
.	O
</s>
<s>
The	O
original	O
version	O
of	O
the	O
chatbot	B-Application
ELIZA	B-Application
was	O
written	O
in	O
MAD-SLIP	B-Application
.	O
</s>
<s>
The	O
archives	O
at	O
the	O
Bentley	O
Historical	O
Library	O
of	O
the	O
University	O
of	O
Michigan	O
contain	O
reference	O
materials	O
on	O
the	O
development	O
of	O
MAD	O
and	O
MAD/I	B-Language
,	O
including	O
three	O
linear	O
feet	O
of	O
printouts	O
with	O
hand-written	O
notations	O
and	O
original	O
printed	O
manuals	O
.	O
</s>
<s>
There	O
are	O
three	O
MAD	O
compilers	B-Language
:	O
</s>
<s>
Original	O
MAD	O
,	O
the	O
compiler	B-Language
developed	O
in	O
1959	O
at	O
the	O
University	O
of	O
Michigan	O
for	O
the	O
IBM	B-Device
704	I-Device
and	O
later	O
the	O
IBM	B-Device
709	I-Device
and	O
IBM	B-Device
7090	I-Device
mainframe	B-Architecture
computers	I-Architecture
running	O
the	O
University	B-Application
of	I-Application
Michigan	I-Application
Executive	I-Application
System	I-Application
(	O
UMES	B-Application
)	O
and	O
the	O
Compatible	B-Operating_System
Time-Sharing	I-Operating_System
System	I-Operating_System
(	O
CTSS	B-Operating_System
)	O
operating	B-General_Concept
systems	I-General_Concept
.	O
</s>
<s>
MAD/I	B-Language
,	O
an	O
"	O
extended	O
"	O
version	O
of	O
MAD	O
for	O
the	O
IBM	B-Application
System/360	I-Application
series	O
of	O
computers	O
running	O
under	O
the	O
Michigan	B-Application
Terminal	I-Application
System	I-Application
(	O
MTS	B-Application
)	O
.	O
</s>
<s>
Work	O
on	O
the	O
new	O
compiler	B-Language
started	O
in	O
1965	O
as	O
part	O
of	O
the	O
ARPA	O
sponsored	O
CONCOMP	O
project	O
at	O
the	O
University	O
of	O
Michigan	O
.	O
</s>
<s>
As	O
work	O
progressed	O
it	O
gradually	O
became	O
clear	O
that	O
MAD/I	B-Language
was	O
a	O
new	O
language	O
independent	O
of	O
the	O
original	O
7090	O
version	O
of	O
MAD	O
.	O
</s>
<s>
GOM	O
(	O
Good	B-Language
Old	I-Language
MAD	I-Language
)	O
,	O
a	O
reimplementation	O
of	O
the	O
original	O
7090	O
MAD	O
for	O
the	O
IBM	B-Device
System/370	I-Device
series	O
of	O
mainframe	B-Architecture
computers	I-Architecture
running	O
the	O
Michigan	B-Application
Terminal	I-Application
System	I-Application
(	O
MTS	B-Application
)	O
.	O
</s>
<s>
While	O
MAD	O
was	O
motivated	O
by	O
ALGOL	B-Language
58	I-Language
,	O
it	O
does	O
not	O
resemble	O
ALGOL	B-Language
58	I-Language
in	O
any	O
significant	O
way	O
.	O
</s>
<s>
Programs	O
written	O
in	O
MAD	O
included	O
MAIL	O
,	O
RUNOFF	B-Protocol
,	O
one	O
of	O
the	O
first	O
text	O
processing	O
systems	O
,	O
and	O
several	O
other	O
utilities	O
all	O
under	O
Compatible	B-Operating_System
Time-Sharing	I-Operating_System
System	I-Operating_System
(	O
CTSS	B-Operating_System
)	O
.	O
</s>
<s>
Work	O
was	O
done	O
on	O
a	O
design	O
for	O
a	O
MAD	O
compiler	B-Language
for	O
Multics	B-Application
,	O
but	O
it	O
was	O
never	O
implemented	O
.	O
</s>
<s>
I	O
think	O
that	O
the	O
most	O
fun	O
I	O
had	O
programming	O
was	O
a	O
summer	O
job	O
at	O
Project	O
MAC	O
at	O
MIT	O
in	O
the	O
summer	O
of	O
1966	O
,	O
where	O
I	O
worked	O
on	O
a	O
program	O
that	O
created	O
a	O
job	O
tape	O
for	O
the	O
brand	O
new	O
GE	O
645	O
in	O
the	O
earliest	O
days	O
of	O
Multics	B-Application
.	O
</s>
<s>
I	O
was	O
writing	O
in	O
MAD	O
,	O
which	O
was	O
much	O
easier	O
and	O
more	O
pleasant	O
than	O
the	O
FORTRAN	B-Application
and	O
COBOL	O
that	O
I	O
had	O
written	O
earlier	O
,	O
and	O
I	O
was	O
using	O
CTSS	B-Operating_System
,	O
the	O
first	O
time-sharing	O
system	O
,	O
which	O
was	O
infinitely	O
easier	O
and	O
more	O
pleasant	O
than	O
punch	O
cards	O
.	O
</s>
<s>
MAD	O
was	O
quite	O
fast	O
compared	O
to	O
some	O
of	O
the	O
other	O
compilers	B-Language
of	O
its	O
day	O
.	O
</s>
<s>
Because	O
a	O
number	O
of	O
people	O
were	O
interested	O
in	O
using	O
the	O
FORTRAN	B-Application
language	I-Application
and	O
yet	O
wanted	O
to	O
obtain	O
the	O
speed	O
of	O
the	O
MAD	O
compiler	B-Language
,	O
a	O
system	O
called	O
MADTRAN	O
(	O
written	O
in	O
MAD	O
)	O
was	O
developed	O
.	O
</s>
<s>
MADTRAN	O
was	O
simply	O
a	O
translator	O
from	O
FORTRAN	B-Application
to	O
MAD	O
,	O
which	O
then	O
produced	O
machine	O
code	O
.	O
</s>
<s>
MAD/I	B-Language
has	O
a	O
syntactic	O
structure	O
similar	O
to	O
ALGOL	B-Language
60	I-Language
together	O
with	O
important	O
features	O
from	O
the	O
original	O
MAD	O
and	O
from	O
PL/I	B-Language
.	O
</s>
<s>
MAD/I	B-Language
was	O
designed	O
as	O
an	O
extensible	O
language	O
.	O
</s>
<s>
It	O
was	O
available	O
for	O
use	O
under	O
MTS	B-Application
and	O
provided	O
many	O
new	O
ideas	O
which	O
made	O
their	O
way	O
into	O
other	O
languages	O
,	O
but	O
MAD/I	B-Language
compilations	B-Language
were	O
slow	O
and	O
MAD/I	B-Language
never	O
extended	O
itself	O
into	O
widespread	O
use	O
when	O
compared	O
to	O
the	O
original	O
7090	O
MAD	O
.	O
</s>
<s>
The	O
MTS	B-Application
Message	O
System	O
was	O
written	O
in	O
GOM	O
.	O
</s>
<s>
In	O
a	O
pre-release	O
version	O
of	O
the	O
original	O
MAD	O
,	O
as	O
a	O
reference	O
to	O
MAD	O
's	O
namesake	O
,	O
MAD	O
magazine	O
,	O
when	O
a	O
program	O
contained	O
too	O
many	O
compile	B-Language
time	O
errors	O
the	O
compiler	B-Language
would	O
print	O
a	O
full-page	O
picture	O
of	O
Alfred	O
E	O
.	O
Neuman	O
using	O
ASCII	O
art	O
.	O
</s>
<s>
However	O
,	O
it	O
was	O
included	O
in	O
the	O
production	O
version	O
for	O
the	O
IBM	B-Device
7040	I-Device
.	O
</s>
<s>
By	O
the	O
time	O
we	O
designed	O
the	O
language	O
that	O
we	O
thought	O
would	O
be	O
worth	O
doing	O
and	O
for	O
which	O
we	O
could	O
do	O
a	O
compiler	B-Language
,	O
we	O
could	O
n't	O
call	O
it	O
Algol	B-Language
anymore	O
;	O
it	O
really	O
was	O
different	O
.	O
</s>
<s>
That	O
's	O
when	O
we	O
adopted	O
the	O
name	O
MAD	O
,	O
for	O
the	O
Michigan	B-Language
Algorithm	I-Language
Decoder	I-Language
.	O
</s>
<s>
Alternatively	O
,	O
contractions	O
can	O
be	O
used	O
,	O
and	O
the	O
compiler	B-Language
will	O
expand	O
them	O
in	O
the	O
listing	O
:	O
</s>
<s>
MAD	O
and	O
GOM	O
,	O
but	O
not	O
MAD/I	B-Language
,	O
are	O
composed	O
of	O
the	O
following	O
elements	O
:	O
</s>
<s>
Internal	O
functions	O
are	O
compiled	B-Language
as	O
part	O
of	O
the	O
program	O
in	O
which	O
they	O
are	O
used	O
and	O
share	O
declarations	O
and	O
variables	O
with	O
the	O
main	O
program	O
.	O
</s>
<s>
External	O
functions	O
are	O
compiled	B-Language
separately	O
and	O
do	O
not	O
share	O
declarations	O
and	O
variables	O
.	O
</s>
