<s>
Tandy	O
Corporation	O
released	O
several	O
computer	O
product	O
lines	O
starting	O
in	O
1977	O
,	O
under	O
both	O
TRS-80	B-Device
and	O
Tandy	O
branding	O
.	O
</s>
<s>
TRS-80	B-Device
was	O
a	O
brand	O
associated	O
with	O
several	O
desktop	O
microcomputer	B-Architecture
lines	O
sold	O
by	O
Tandy	O
Corporation	O
through	O
their	O
Radio	O
Shack	O
stores	O
.	O
</s>
<s>
It	O
was	O
first	O
used	O
on	O
the	B-Device
original	I-Device
TRS-80	I-Device
(	O
later	O
known	O
as	O
the	O
Model	O
I	O
)	O
,	O
one	O
of	O
the	O
earliest	O
mass-produced	O
personal	O
computers	O
.	O
</s>
<s>
However	O
,	O
Tandy	O
later	O
used	O
the	O
TRS-80	B-Device
name	O
on	O
a	O
number	O
of	O
different	O
computer	O
lines	O
,	O
many	O
of	O
which	O
were	O
technically	O
unrelated	O
to	O
(	O
and	O
incompatible	O
with	O
)	O
the	O
original	O
Model	O
I	O
and	O
its	O
replacements	O
.	O
</s>
<s>
The	B-Device
original	I-Device
TRS-80	I-Device
Micro	B-Architecture
Computer	I-Architecture
System	O
(	O
later	O
known	O
as	O
the	O
Model	O
I	O
to	O
distinguish	O
it	O
from	O
successors	O
)	O
was	O
launched	O
in	O
1977	O
and	O
-	O
alongside	O
the	O
Apple	B-Device
II	I-Device
and	O
Commodore	B-Device
PET	I-Device
-	O
was	O
one	O
of	O
the	O
earliest	O
mass-produced	O
personal	O
computers	O
.	O
</s>
<s>
By	O
1979	O
,	O
the	O
TRS-80	B-Device
had	O
the	O
largest	O
selection	O
of	O
software	O
in	O
the	O
microcomputer	B-Architecture
market	O
.	O
</s>
<s>
In	O
July	O
1980	O
the	O
mostly-compatible	O
TRS-80	B-Device
Model	O
III	O
was	O
launched	O
,	O
and	O
the	O
original	O
Model	O
I	O
was	O
discontinued	O
.	O
</s>
<s>
Disk-based	O
Model	O
4	O
's	O
had	O
64	O
KB	O
of	O
RAM	O
standard	O
;	O
an	O
optional	O
bank	O
of	O
additional	O
64	O
KB	O
was	O
accessible	O
to	O
applications	O
software	O
using	O
bank	B-General_Concept
switching	I-General_Concept
technology	O
.	O
</s>
<s>
A	O
more	O
modern	O
version	O
of	O
Microsoft	O
's	O
BASIC	O
interpreter	O
more	O
closely	O
resembled	O
the	O
MS-DOS	B-Application
GW-BASIC	B-Language
,	O
featuring	O
PC-like	O
functionality	O
.	O
</s>
<s>
The	O
Model	O
4	O
could	O
run	O
the	O
industry-standard	O
CP/M	B-Application
operating	I-Application
system	I-Application
without	O
hardware	O
modification	O
(	O
as	O
was	O
needed	O
for	O
the	O
Model	O
III	O
)	O
.	O
</s>
<s>
This	O
afforded	O
the	O
user	O
access	O
to	O
popular	O
application	O
software	O
such	O
as	O
MicroPro	B-Application
's	O
WordStar	B-Application
,	O
Ashton-Tate	O
'	O
s	O
dBase	B-Application
II	I-Application
,	O
and	O
Sorcim	O
's	O
SuperCalc	B-Application
.	O
</s>
<s>
Early	O
versions	O
of	O
the	O
Model	O
4	O
mainboard	O
were	O
designed	O
to	O
accept	O
a	O
Zilog	B-Device
Z800	I-Device
16-bit	O
CPU	O
upgrade	O
board	O
to	O
replace	O
the	O
Z80	O
8-bit	O
CPU	O
but	O
this	O
option	O
was	O
never	O
released	O
,	O
as	O
Zilog	O
failed	O
to	O
bring	O
the	O
new	O
CPU	O
to	O
market	O
.	O
</s>
<s>
In	O
October	O
1979	O
Tandy	O
began	O
shipping	O
the	O
TRS-80	B-Device
Model	O
II	O
,	O
which	O
was	O
targeted	O
to	O
the	O
small-business	O
market	O
.	O
</s>
<s>
This	O
was	O
somewhat	O
mitigated	O
by	O
the	O
availability	O
of	O
the	O
CP/M	B-Application
from	O
third	O
parties	O
.	O
</s>
<s>
The	O
Model	O
II	O
was	O
replaced	O
in	O
1982	O
by	O
the	O
TRS-80	B-Device
Model	O
12	O
.	O
</s>
<s>
In	O
February	O
1982	O
,	O
Tandy	O
released	O
the	O
TRS-80	B-Device
Model	O
16	O
,	O
as	O
the	O
follow-on	O
to	O
the	O
Model	O
II	O
;	O
an	O
upgrade	O
kit	O
was	O
available	O
for	O
Model	O
II	O
systems	O
.	O
</s>
<s>
The	O
Model	O
16	O
adds	O
a	O
6MHz	O
,	O
16-bit	O
Motorola	B-Device
68000	I-Device
processor	I-Device
and	O
memory	O
card	O
.	O
</s>
<s>
In	O
early	O
1983	O
,	O
Tandy	O
switched	O
from	O
TRSDOS-16	O
to	O
Xenix	B-Application
.	O
</s>
<s>
The	O
Model	O
16	O
evolved	O
into	O
the	O
Model	O
16B	O
with	O
256	O
KB	O
in	O
July	O
1983	O
,	O
and	O
later	O
the	O
Tandy	O
6000	O
,	O
gaining	O
an	O
internal	O
hard	O
drive	O
along	O
the	O
way	O
and	O
switching	O
to	O
an	O
8MHz	O
68000	B-Device
.	O
</s>
<s>
Tandy	O
also	O
produced	O
the	O
TRS-80	B-Device
Color	O
Computer	O
(	O
CoCo	O
)	O
,	O
based	O
on	O
the	O
Motorola	B-Device
6809	I-Device
processor	O
.	O
</s>
<s>
It	O
competed	O
directly	O
with	O
the	O
Commodore	O
64	O
,	O
Apple	B-Device
II	I-Device
,	O
and	O
Atari	B-Device
8-bit	I-Device
family	I-Device
of	O
computers	O
.	O
</s>
<s>
OS-9	B-Operating_System
,	O
a	O
multitasking	O
,	O
multi-user	O
operating	O
system	O
was	O
supplied	O
for	O
this	O
machine	O
.	O
</s>
<s>
In	O
addition	O
to	O
the	O
above	O
,	O
Tandy	O
produced	O
the	O
TRS-80	B-Device
Model	O
100	O
series	O
of	O
laptop	O
computers	O
.	O
</s>
<s>
This	O
series	O
comprised	O
the	O
TRS-80	B-Device
Model	O
100	O
,	O
Tandy	O
102	O
,	O
Tandy	O
200	O
and	O
Tandy	O
600	O
.	O
</s>
<s>
It	O
was	O
possible	O
to	O
use	O
the	O
Model	O
100	O
with	O
most	O
phones	O
in	O
the	O
world	O
with	O
the	O
use	O
of	O
an	O
optional	O
acoustic	B-Device
coupler	I-Device
that	O
fit	O
over	O
a	O
standard	O
telephone	O
handset	O
.	O
</s>
<s>
The	O
combination	O
of	O
the	O
acoustic	B-Device
coupler	I-Device
,	O
the	O
machine	O
's	O
outstanding	O
battery	O
life	O
(	O
it	O
could	O
be	O
used	O
for	O
days	O
on	O
a	O
set	O
of	O
4	O
AA	O
cells	O
)	O
,	O
and	O
its	O
simple	O
text	O
editor	O
made	O
the	O
Model	O
100/102	O
popular	O
with	O
journalists	O
in	O
the	O
early	O
1980s	O
.	O
</s>
<s>
The	O
MC-10	B-Device
was	O
a	O
short-lived	O
and	O
little-known	O
Tandy	O
computer	O
,	O
similar	O
in	O
appearance	O
to	O
the	O
Sinclair	O
ZX81	O
.	O
</s>
<s>
It	O
was	O
a	O
small	O
system	O
based	O
on	O
the	O
Motorola	B-Device
6803	I-Device
processor	O
and	O
featured	O
4	O
KB	O
of	O
RAM	O
.	O
</s>
<s>
A	O
modified	O
version	O
of	O
the	O
MC-10	B-Device
was	O
sold	O
in	O
France	O
as	O
the	O
Matra	B-Device
Alice	I-Device
.	O
</s>
<s>
A	O
magazine	O
was	O
published	O
which	O
offered	O
programs	O
for	O
both	O
the	O
CoCo	O
and	O
MC-10	B-Device
but	O
very	O
few	O
programs	O
were	O
available	O
for	O
purchase	O
.	O
</s>
<s>
Programs	O
for	O
the	O
MC-10	B-Device
were	O
not	O
compatible	O
with	O
the	O
CoCo	O
.	O
</s>
<s>
Both	O
the	O
TRS-80	B-Device
and	O
Tandy	O
brands	O
were	O
used	O
for	O
a	O
range	O
of	O
"	O
Pocket	O
Computers	O
"	O
sold	O
by	O
Tandy	O
.	O
</s>
<s>
The	O
TRS-80	B-Device
PT-210	O
Portable	O
Data	O
Terminal	O
was	O
released	O
in	O
late	O
1982	O
for	O
.	O
</s>
<s>
It	O
included	O
an	O
acoustic	B-Device
coupler	I-Device
,	O
300	O
baud	O
modem	O
,	O
thermal	O
printer	O
,	O
and	O
typewriter-style	O
keyboard	O
.	O
</s>
<s>
In	O
the	O
early	O
1980s	O
,	O
Tandy	O
began	O
producing	O
a	O
line	O
of	O
computers	O
that	O
were	O
at	O
first	O
"	O
MS-DOS	B-Application
compatible	O
"	O
--able	O
to	O
run	O
MS-DOS	B-Application
and	O
certain	O
applications	O
,	O
but	O
not	O
fully	O
compatible	O
with	O
every	O
nuance	O
of	O
the	O
original	O
IBM	B-Device
PC	I-Device
systems--and	O
later	O
mostly	O
,	O
but	O
not	O
100%	O
,	O
IBM	B-Device
PC	I-Device
compatible	O
.	O
</s>
<s>
The	O
first	O
of	O
these	O
was	O
the	O
Tandy	B-Device
2000	I-Device
,	O
a	O
pure	O
MS-DOS	B-Application
compatible	O
machine	O
with	O
no	O
IBM	B-Device
PC	I-Device
ROM	O
BIOS	O
or	O
pretense	O
of	O
PC	O
hardware	O
compatibility	O
.	O
</s>
<s>
Such	O
machines	O
were	O
common	O
in	O
the	O
early	O
1980s	O
;	O
the	O
NEC	B-Operating_System
APC	I-Operating_System
is	O
another	O
example	O
.	O
</s>
<s>
The	O
Tandy	B-Device
2000	I-Device
system	O
was	O
similar	O
to	O
the	O
Texas	O
Instruments	O
Professional	O
Computer	O
in	O
that	O
it	O
offered	O
better	O
graphics	O
,	O
a	O
faster	O
processor	O
(	O
80186	O
)	O
and	O
higher	O
capacity	O
disk	O
drives	O
(	O
80	O
track	O
double	O
sided	O
800k	O
5.25	O
drives	O
)	O
than	O
the	O
original	O
IBM	B-Device
PC	I-Device
.	O
</s>
<s>
However	O
,	O
around	O
the	O
time	O
of	O
its	O
introduction	O
,	O
the	O
industry	O
began	O
moving	O
away	O
from	O
MS-DOS	B-Application
compatible	O
computers	O
and	O
towards	O
fully	O
IBM	B-Device
PC	I-Device
compatible	O
clones	O
;	O
later	O
Tandy	O
offerings	O
moved	O
toward	O
full	O
PC	O
hardware	O
compatibility	O
.	O
</s>
<s>
This	O
industry	O
shift	O
was	O
mainly	O
spurred	O
by	O
the	O
observation	O
that	O
most	O
MS-DOS	B-Application
software	O
was	O
being	O
written	O
for	O
the	O
IBM	B-Device
PC	I-Device
and	O
relied	O
not	O
only	O
on	O
the	O
services	O
provided	O
by	O
MS-DOS	B-Application
itself	O
but	O
also	O
on	O
others	O
provided	O
by	O
the	O
IBM	O
ROM	O
BIOS	O
and	O
,	O
where	O
the	O
services	O
provided	O
by	O
neither	O
DOS	O
nor	O
the	O
IBM	O
BIOS	O
were	O
adequate	O
,	O
on	O
direct	O
low-level	O
control	O
of	O
the	O
IBM	B-Device
PC	I-Device
hardware	O
(	O
especially	O
the	O
video	O
)	O
.	O
</s>
<s>
The	O
Tandy	B-Device
2000	I-Device
was	O
followed	O
later	O
by	O
the	O
less	O
expensive	O
Tandy	O
1000	O
,	O
marketed	O
as	O
highly	O
compatible	O
with	O
the	O
IBM	B-Device
PC	I-Device
but	O
actually	O
designed	O
to	O
be	O
an	O
enhanced	O
IBM	O
PCjr-compatible	O
computer	O
.	O
</s>
<s>
With	O
inopportune	O
timing	O
(	O
for	O
Tandy	O
)	O
,	O
IBM	O
discontinued	O
the	O
unsuccessful	O
PCjr	B-Device
shortly	O
before	O
the	O
Tandy	O
1000	O
was	O
scheduled	O
for	O
introduction	O
.	O
</s>
<s>
While	O
the	O
progressive	O
Tandy	O
1000	O
models	O
fairly	O
quickly	O
departed	O
from	O
PCjr	B-Device
hardware	O
compatibility	O
,	O
they	O
all	O
retained	O
the	O
enhanced	O
CGA	O
video	O
modes	O
of	O
the	O
IBM	B-Device
PCjr	I-Device
(	O
supported	O
by	O
no	O
other	O
IBM	O
or	O
clone	O
machine	O
)	O
,	O
and	O
some	O
later	O
models	O
added	O
an	O
original	O
640x200	O
16-color	O
video	O
mode	O
.	O
</s>
<s>
In	O
1987	O
Tandy	O
introduced	O
the	O
1400LT	O
,	O
a	O
clamshell-style	O
MS-DOS	B-Application
compatible	O
laptop	O
computer	O
with	O
an	O
integral	O
monochrome	O
LCD	O
display	O
and	O
two	O
3.5	O
inch	O
diskette	O
drives	O
.	O
</s>
