<s>
The	O
MOS	B-General_Concept
Technology	I-General_Concept
6509	I-General_Concept
,	O
an	O
enhanced	O
version	O
of	O
the	O
popular	O
6502	B-General_Concept
microprocessor	I-General_Concept
,	O
is	O
capable	O
of	O
addressing	O
up	O
to	O
1	O
megabyte	O
of	O
RAM	B-Architecture
via	O
bank	B-General_Concept
switching	I-General_Concept
.	O
</s>
<s>
While	O
numerous	O
6502-based	O
processors	O
can	O
perform	O
bank	B-General_Concept
switching	I-General_Concept
,	O
they	O
achieve	O
this	O
via	O
separate	O
logic	O
.	O
</s>
<s>
The	O
6509	O
has	O
a	O
reputation	O
for	O
being	O
difficult	O
to	O
program	O
,	O
due	O
to	O
its	O
bank	B-General_Concept
switching	I-General_Concept
scheme	O
.	O
</s>
<s>
It	O
is	O
used	O
in	O
the	O
Commodore	B-Device
CBM-II	I-Device
line	O
of	O
computers	O
.	O
</s>
