<s>
The	O
UNIVAC	B-Device
Solid	I-Device
State	I-Device
was	O
a	O
magnetic	O
drum-based	O
solid-state	O
computer	O
announced	O
by	O
Sperry	O
Rand	O
in	O
December	O
1958	O
as	O
a	O
response	O
to	O
the	O
IBM	B-Device
650	I-Device
.	O
</s>
<s>
It	O
was	O
one	O
of	O
the	O
first	O
computers	O
to	O
be	O
(	O
nearly	O
)	O
entirely	O
solid-state	O
,	O
using	O
700	O
transistors	B-Application
,	O
and	O
3000	O
magnetic	O
amplifiers	O
(	O
FERRACTOR	O
)	O
for	O
primary	O
logic	O
,	O
and	O
20	O
vacuum	O
tubes	O
largely	O
for	O
power	O
control	O
.	O
</s>
<s>
The	O
SS	O
I	O
had	O
only	O
the	O
standard	O
5,000	O
-word	O
drum	B-General_Concept
memory	I-General_Concept
described	O
in	O
this	O
article	O
and	O
no	O
tape	O
drives	O
.	O
</s>
<s>
The	O
memory	B-General_Concept
drum	I-General_Concept
had	O
a	O
regular	O
access	O
speed	O
AREA	O
and	O
a	O
FAST	O
ACCESS	O
AREA	O
.	O
</s>
<s>
There	O
were	O
3	O
of	O
these	O
registers	O
A	O
X	O
L	O
,	O
to	O
add	O
the	O
values	O
contained	O
in	O
drum	B-General_Concept
memory	I-General_Concept
locations	O
the	O
programmer	O
would	O
transfer	O
the	O
contents	O
of	O
the	O
specific	O
drum	O
location	O
to	O
register	O
A	O
,	O
then	O
the	O
second	O
operand	O
would	O
be	O
copied	O
to	O
the	O
X	O
register	O
.	O
</s>
<s>
Both	O
variants	O
included	O
a	O
card	B-Device
reader	I-Device
,	O
a	O
card	B-Device
punch	I-Device
,	O
and	O
the	O
line	O
printer	O
described	O
in	O
this	O
article	O
.	O
</s>
<s>
There	O
was	O
no	O
Operating	O
System	O
as	O
we	O
have	O
come	O
to	O
know	O
them	O
in	O
recent	O
years	O
;	O
every	O
program	O
was	O
completely	O
self-contained	O
,	O
including	O
the	O
boot	B-Application
loader	I-Application
that	O
initiated	O
execution	O
.	O
</s>
<s>
The	O
UNIVAC	B-Device
Solid	I-Device
State	I-Device
was	O
a	O
two-address	O
,	O
bi-quinary	B-Algorithm
coded	I-Algorithm
decimal	I-Algorithm
computer	O
using	O
signed	O
10-digit	O
words	O
.	O
</s>
<s>
Main	O
memory	O
storage	O
was	O
provided	O
by	O
a	O
5000-word	O
magnetic	B-General_Concept
drum	I-General_Concept
spinning	O
at	O
17,667	O
RPM	O
in	O
a	O
helium	O
atmosphere	O
.	O
</s>
<s>
The	O
Solid	O
State	O
was	O
one	O
of	O
the	O
first	B-Architecture
computers	I-Architecture
to	O
use	O
some	O
solid-state	O
components	O
.	O
</s>
<s>
However	O
,	O
much	O
of	O
the	O
computer	O
's	O
logic	O
was	O
made	O
out	O
of	O
magnetic	O
amplifiers	O
,	O
not	O
transistors	B-Application
.	O
</s>
<s>
The	O
decision	O
to	O
use	O
magnetic	O
amplifiers	O
was	O
made	O
because	O
the	O
point-contact	O
germanium	O
transistors	B-Application
then	O
available	O
had	O
highly	O
variable	O
characteristics	O
and	O
were	O
not	O
sufficiently	O
reliable	O
.	O
</s>
<s>
The	O
magnetic	O
amplifiers	O
required	O
clock	O
pulses	O
of	O
heavy	O
current	O
that	O
could	O
not	O
be	O
produced	O
by	O
the	O
transistors	B-Application
of	O
the	O
day	O
.	O
</s>
<s>
The	O
powerful	O
high-voltage	O
signal	O
was	O
stepped	O
down	O
to	O
a	O
36-volt	O
,	O
high-current	O
clock	O
by	O
oil-filled	O
transformers	B-Algorithm
that	O
were	O
distributed	O
about	O
the	O
machine	O
.	O
</s>
<s>
132	O
solenoid-operated	O
flat-faced	O
print	O
hammers	O
comprised	O
a	O
print	O
line	O
,	O
with	O
ten	O
characters	O
to	O
the	O
inch	O
.	O
</s>
<s>
When	O
a	O
desired	O
character	O
arrived	O
at	O
the	O
printing	O
position	O
,	O
as	O
indicated	O
by	O
timing	O
marks	O
on	O
the	O
end	O
of	O
the	O
drum	O
,	O
a	O
thyratron	O
would	O
fire	O
and	O
energize	O
a	O
print	O
column	O
solenoid	B-Algorithm
,	O
propelling	O
its	O
hammer	O
to	O
the	O
back	O
face	O
of	O
the	O
printing	O
paper	O
.	O
</s>
<s>
The	O
card	B-Device
punch	I-Device
had	O
a	O
maximum	O
rate	O
of	O
150	O
cards	O
per	O
minute	O
.	O
</s>
<s>
Timing	O
was	O
quite	O
critical	O
throughout	O
the	O
operation	O
of	O
the	O
card	B-Device
punch	I-Device
,	O
the	O
card	B-Device
reader	I-Device
and	O
the	O
printer	O
,	O
all	O
being	O
based	O
on	O
electromechanical	O
principles	O
.	O
</s>
<s>
The	O
basic	O
card	B-Device
punch	I-Device
mechanism	O
was	O
manufactured	O
by	O
Bull	O
,	O
a	O
French	O
company	O
which	O
owned	O
patents	O
on	O
80	O
column	O
punch	B-Device
card	O
machines	O
.	O
</s>
<s>
The	O
machine	O
came	O
in	O
two	O
versions	O
,	O
the	O
P147	O
and	O
the	O
P67	O
,	O
the	O
main	O
difference	O
being	O
electromagnetic	O
clutch	O
or	O
a	O
solenoid	B-Algorithm
operated	O
mechanical	O
"	O
dog	O
"	O
clutch	O
to	O
initiate	O
a	O
punch	B-Device
cycle	O
.	O
</s>
<s>
The	O
card	B-Device
punch	I-Device
had	O
a	O
preread	O
station	O
,	O
a	O
punch	B-Device
station	O
and	O
a	O
checkread	O
station	O
.	O
</s>
<s>
While	O
the	O
Bull	O
punch	B-Device
was	O
used	O
with	O
the	O
UNIVAC	B-Device
Solid	I-Device
State	I-Device
80	I-Device
for	O
80	O
column	O
cards	O
the	O
UNIVAC	B-Device
Solid	I-Device
State	I-Device
90	O
used	O
the	O
Univac	O
manufactured	O
"	O
Tower	O
Punch	B-Device
"	O
for	O
90	O
column	O
cards	O
.	O
</s>
<s>
The	O
Tower	O
Punch	B-Device
operating	O
at	O
150	O
cards	O
per	O
minute	O
used	O
mechanical	O
pin	O
sensing	O
in	O
the	O
pre	O
punch	B-Device
read	O
and	O
the	O
post	O
punch	B-Device
read	O
stations	O
giving	O
the	O
ability	O
to	O
read	O
a	O
card	O
,	O
punch	B-Device
additional	O
information	O
into	O
the	O
card	O
,	O
and	O
check	O
read	O
the	O
results	O
in	O
the	O
post	O
punch	B-Device
station	O
.	O
</s>
