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IBM 7090 User Manual

IBM 7090
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7.
O.
00
REFERENCE
INFORMATION
7.1.00
CONDENSED LOOIC
7.1.01
Adders
(Systems
02.02.01.1-02.02.37.1)
The
adders
consist
of
transistor
switching
circuits
for
combining
binary
numbers
into
a
binary
sum.
The
7090
can
only
add,
therefore
control
lines
are
needed
to
develop
true
and
complement
conditions.
ACC
to
ADD
SR
to
ADD
XR
to
ADD
COMP
ACC
to
ADD
02.12.24.1
02.12.17.1
02.12.19.1
02.12.23.1
Adders
are
used
for
many
different
types
of
operations
and
some
controls
will
affect
only
certain
adders.
The
adders
have
three
types
of
outputs:
sum,
carry,
and
looka-
head.
Section
3
covers
the
theory
of
the
adder
outputs.
7.1.02
Address
Register
(Systems
03.06.00.1-03.06.04.1)
The
address
register
is
a
15-position
register
of
triggers.
It
is
labeled
3
through
17.
The
address
register
signals
the
desired
address
to
the
core
control
circuits
(Figure
7.1-1).
Control
lines
for
the
address
register
are:
Address
Switches
to
AR
AR
to
PC
03.06.05.1
03.06.05.1
7.1.03
Program
Register
(Systems
03.04.00.1-03.04.03.1)
The
program
register
is
made
up
of
ten
positions,
and
is
used
for
decoding
the
instructions
during
I
time.
Lines
controlling
the
input
and
output
of
the
program
register
(Figure
7.1-2)
are:
SR
to
PR
OPKto
PR
SB
to
PR
Reset
PR
02.11.
40.1
02.12.09.1
02.05.10.1
02.11.40.1
7.1.
04
Sense
Indicators
(Systems
02.06.00.1-02.06.35.1)
The
sense
indicator
register
is
a
36-position
register
of
triggers.
There
are
two
triggers
to
each
position
(Figure
7.
1-3)
.
Lines
controlling
the
sense
indicators
are:
Invert
SI
Set
IND
COMP
SI
to
SR
SI
to
SR
02.12.61.1
02.12.63.1
02.12.12.1
02.12.62.1
166

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IBM 7090 Specifications

General IconGeneral
CategoryMainframe Computer
Introduced1959
Transistor-basedYes
Word Length36 bits
Add Time4.8 microseconds
MemoryCore memory
Memory (words)32, 768 words