<s>
The	O
TI-85	B-Device
is	O
a	O
graphing	B-Application
calculator	I-Application
made	O
by	O
Texas	O
Instruments	O
based	O
on	O
the	O
Zilog	B-General_Concept
Z80	I-General_Concept
microprocessor	B-Architecture
.	O
</s>
<s>
Designed	O
in	O
1992	O
as	O
TI	O
's	O
second	O
graphing	B-Application
calculator	I-Application
(	O
the	O
first	O
was	O
the	O
TI-81	B-Device
)	O
,	O
it	O
was	O
replaced	O
by	O
the	O
TI-86	B-Device
,	O
which	O
has	O
also	O
been	O
discontinued	O
.	O
</s>
<s>
The	O
TI-85	B-Device
was	O
significantly	O
more	O
powerful	O
than	O
the	O
TI-81	B-Device
,	O
as	O
it	O
was	O
designed	O
as	O
a	O
calculator	O
primarily	O
for	O
use	O
in	O
engineering	O
and	O
calculus	O
courses	O
.	O
</s>
<s>
Texas	O
Instruments	O
had	O
included	O
a	O
version	O
of	O
BASIC	O
on	O
the	O
device	O
to	O
allow	O
programming	B-General_Concept
.	O
</s>
<s>
Each	O
calculator	O
came	O
with	O
a	O
cable	O
to	O
connect	O
calculators	O
(	O
simply	O
a	O
three-conductor	O
cable	O
with	O
2.5mm	O
phone	B-Device
connectors	I-Device
on	O
each	O
end	O
)	O
.	O
</s>
<s>
Another	O
cable	O
known	O
as	O
the	O
TI-Graph	O
Link	O
was	O
also	O
sold	O
,	O
along	O
with	O
appropriate	O
software	O
,	O
to	O
connect	O
the	O
calculator	O
to	O
a	O
personal	B-Device
computer	I-Device
.	O
</s>
<s>
These	O
cables	O
made	O
it	O
possible	O
to	O
save	O
programs	O
and	O
make	O
backups	B-Protocol
.	O
</s>
<s>
Enthusiasts	O
analyzed	O
memory	O
backups	B-Protocol
and	O
discovered	O
that	O
entries	O
in	O
the	O
calculator	O
's	O
CUSTOM	O
menu	O
pointed	O
at	O
specific	O
memory	O
locations	O
.	O
</s>
<s>
With	O
this	O
knowledge	O
,	O
a	O
hack	O
was	O
devised	O
where	O
a	O
special	O
string	O
could	O
be	O
inserted	O
into	O
the	O
backup	B-Protocol
at	O
the	O
proper	O
location	O
to	O
allow	O
the	O
calculator	O
to	O
execute	O
assembly	B-Language
language	I-Language
programs	O
.	O
</s>
<s>
This	O
development	O
made	O
the	O
TI-85	B-Device
the	O
first	O
TI	O
graphing	B-Application
calculator	I-Application
that	O
could	O
execute	O
assembly	B-Language
programs	O
.	O
</s>
<s>
Programs	O
written	O
in	O
assembly	B-Language
would	O
be	O
stored	O
as	O
string	O
expressions	O
and	O
accessed	O
through	O
the	O
CUSTOM	O
menu	O
.	O
</s>
<s>
Games	O
such	O
as	O
Tetris	B-Device
and	O
Boulder	O
Dash	O
are	O
available	O
,	O
as	O
are	O
programs	O
with	O
more	O
practical	O
uses	O
,	O
such	O
as	O
versions	O
of	O
the	O
periodic	O
table	O
.	O
</s>
<s>
Total	O
memory	O
capacity	O
was	O
about	O
32	O
kilobytes	O
,	O
with	O
28226	O
bytes	B-Application
available	O
for	O
use	O
.	O
</s>
<s>
The	O
assembly	B-Device
language	I-Device
shell	I-Device
ZShell	O
is	O
also	O
available	O
for	O
the	O
TI-85	B-Device
.	O
</s>
<s>
Probably	O
in	O
response	O
to	O
the	O
widespread	O
use	O
of	O
assembly	B-Language
programs	O
,	O
TI	O
officially	O
introduced	O
assembly	B-Language
access	O
in	O
later	O
models	O
,	O
such	O
as	O
the	O
TI-83	B-Device
and	O
TI-86	B-Device
,	O
along	O
with	O
expanded	O
memory	O
.	O
</s>
<s>
The	O
TI-86	B-Device
is	O
very	O
similar	O
to	O
the	O
TI-85	B-Device
,	O
sharing	O
the	O
same	O
display	B-General_Concept
resolution	I-General_Concept
(	O
128×64	O
)	O
,	O
processor	O
,	O
and	O
processor	O
speed	O
(	O
6MHz	O
)	O
.	O
</s>
