<s>
The	O
PALM	O
(	O
Program	O
All	O
Logic	O
in	O
Microcode	B-Device
)	O
is	O
a	O
16-bit	O
central	B-General_Concept
processing	I-General_Concept
unit	I-General_Concept
(	O
CPU	O
)	O
developed	O
by	O
IBM	O
.	O
</s>
<s>
It	O
was	O
used	O
in	O
the	O
IBM	B-Device
5100	I-Device
Portable	I-Device
Computer	I-Device
,	O
a	O
predecessor	O
of	O
the	O
IBM	B-Device
PC	I-Device
,	O
and	O
the	O
IBM	B-Device
5110	I-Device
and	O
IBM	B-Device
5120	I-Device
follow-on	O
machines	O
.	O
</s>
<s>
IBM	O
referred	O
to	O
PALM	O
as	O
a	O
microprocessor	O
,	O
though	O
they	O
used	O
that	O
term	O
to	O
mean	O
a	O
processor	O
that	O
executes	O
microcode	B-Device
to	O
implement	O
a	O
higher-level	O
instruction	B-General_Concept
set	I-General_Concept
,	O
rather	O
than	O
its	O
conventional	O
definition	O
of	O
a	O
CPU	O
on	O
an	O
integrated	O
circuit	O
.	O
</s>
<s>
The	O
PALM	O
processor	O
was	O
a	O
circuit	O
board	O
containing	O
13	O
bipolar	O
gate	O
arrays	O
packaged	B-Algorithm
in	O
square	O
metal	O
cans	O
,	O
3	O
conventional	O
transistor	B-General_Concept
–	I-General_Concept
transistor	I-General_Concept
logic	I-General_Concept
(	O
TTL	B-General_Concept
)	O
ICs	O
in	O
dual	B-Algorithm
in-line	I-Algorithm
packages	I-Algorithm
,	O
and	O
1	O
round	O
metal	O
can	O
part	O
.	O
</s>
<s>
The	O
PALM	O
was	O
used	O
to	O
implement	O
an	O
emulator	O
,	O
which	O
in	O
turn	O
could	O
run	O
machine	O
instructions	O
originally	O
written	O
for	O
other	O
machines	O
;	O
this	O
is	O
how	O
IBM	B-Application
System/360	I-Application
APL	B-Language
ran	O
on	O
the	O
5100	O
.	O
</s>
<s>
PALM	O
has	O
a	O
16-bit	O
data	O
bus	O
,	O
with	O
two	O
additional	O
bits	O
used	O
for	O
parity	B-Error_Name
.	O
</s>
<s>
The	O
IBM	B-Device
5100	I-Device
could	O
be	O
configured	O
with	O
up	O
to	O
64+KB	O
(	O
APL	B-Language
+	O
BASIC	O
ROMs	O
make	O
64+KB	O
)	O
of	O
Executable	O
ROS	O
(	O
ROM	B-Device
)	O
and	O
up	O
to	O
64KB	O
of	O
RAM	B-Architecture
.	O
</s>
<s>
A	O
simple	O
bank	B-General_Concept
switching	I-General_Concept
scheme	O
was	O
used	O
to	O
extend	O
the	O
address	O
space	O
.	O
</s>
<s>
In	O
1973	O
,	O
the	O
IBM	O
Los	O
Gatos	O
Scientific	O
Center	O
developed	O
a	O
portable	O
computer	O
prototype	O
called	O
SCAMP	O
(	O
Special	O
Computer	O
APL	B-Language
Machine	O
Portable	O
)	O
based	O
on	O
the	O
PALM	O
processor	O
with	O
a	O
Philips	O
compact	O
cassette	O
drive	O
,	O
small	O
CRT	O
display	O
,	O
and	O
full-function	O
keyboard	O
.	O
</s>
