<s>
The	O
TI-99/4	B-Device
and	O
TI-99/4A	B-Device
are	O
home	O
computers	O
released	O
by	O
Texas	O
Instruments	O
in	O
1979	O
and	O
1981	O
,	O
respectively	O
.	O
</s>
<s>
Based	O
on	O
the	O
Texas	B-General_Concept
Instruments	I-General_Concept
TMS9900	I-General_Concept
microprocessor	B-Architecture
originally	O
used	O
in	O
minicomputers	B-Architecture
,	O
the	O
TI-99/4	B-Device
was	O
the	O
first	O
16-bit	B-Device
home	O
computer	O
.	O
</s>
<s>
The	O
associated	O
video	B-General_Concept
display	I-General_Concept
controller	I-General_Concept
provides	O
color	O
graphics	O
and	O
sprite	O
support	O
which	O
were	O
only	O
comparable	O
with	O
those	O
of	O
the	O
Atari	B-Device
400	I-Device
and	I-Device
800	I-Device
released	O
a	O
month	O
after	O
the	O
TI-99/4	B-Device
.	O
</s>
<s>
The	O
calculator-style	O
keyboard	O
of	O
the	O
TI-99/4	B-Device
was	O
cited	O
as	O
a	O
weak	O
point	O
,	O
and	O
TI	O
's	O
reliance	O
on	O
ROM	B-Protocol
cartridges	I-Protocol
and	O
their	O
practice	O
of	O
limiting	O
developer	O
information	O
to	O
select	O
third	O
parties	O
resulted	O
in	O
a	O
lack	O
of	O
software	O
for	O
the	O
system	O
.	O
</s>
<s>
The	O
TI-99/4A	B-Device
was	O
released	O
in	O
June	O
1981	O
to	O
address	O
some	O
of	O
these	O
issues	O
with	O
a	O
simplified	O
internal	O
design	O
,	O
full-travel	O
keyboard	O
,	O
improved	O
graphics	O
,	O
and	O
a	O
unique	O
expansion	O
system	O
.	O
</s>
<s>
At	O
half	O
the	O
price	O
of	O
the	O
original	O
model	O
,	O
sales	O
picked	O
up	O
significantly	O
and	O
TI	O
supported	O
the	O
4A	O
with	O
peripherals	O
,	O
including	O
a	O
speech	B-Application
synthesizer	I-Application
and	O
a	O
"	O
Peripheral	O
Expansion	O
System	O
"	O
box	O
to	O
contain	O
hardware	O
add-ons	O
.	O
</s>
<s>
The	O
1981	O
US	O
launch	O
of	O
the	O
TI-99/4A	B-Device
followed	O
Commodore	O
's	O
VIC-20	B-Device
by	O
several	O
months	O
.	O
</s>
<s>
Commodore	O
CEO	O
Jack	O
Tramiel	O
did	O
not	O
like	O
TI	O
's	O
predatory	O
pricing	O
in	O
the	O
mid-1970s	O
and	O
retaliated	O
with	O
a	O
price	O
war	O
by	O
repeatedly	O
lowering	O
the	O
price	O
of	O
the	O
VIC-20	B-Device
and	O
forcing	O
TI	O
to	O
do	O
the	O
same	O
.	O
</s>
<s>
By	O
1983	O
,	O
the	O
99/4A	B-Device
was	O
selling	O
at	O
a	O
loss	O
for	O
under	O
.	O
</s>
<s>
Even	O
with	O
the	O
increased	O
user	O
base	O
created	O
by	O
the	O
heavy	O
discounts	O
,	O
Texas	O
Instruments	O
lost	O
US$330	O
million	O
in	O
the	O
third	O
quarter	O
of	O
1983	O
and	O
announced	O
the	O
discontinuation	O
of	O
the	O
TI-99/4A	B-Device
in	O
October	O
1983	O
.	O
</s>
<s>
The	O
TI-99/4	B-Device
was	O
intended	O
to	O
fit	O
in	O
the	O
middle	O
of	O
a	O
planned	O
range	O
of	O
TI-99	B-Device
computers	O
,	O
none	O
of	O
which	O
were	O
ultimately	O
released	O
but	O
prototypes	O
and	O
documentation	O
have	O
been	O
found	O
after	O
the	O
TI-99/4A	B-Device
was	O
discontinued	O
.	O
</s>
<s>
The	O
TI-99/4A	B-Device
is	O
a	O
self-contained	O
console	O
with	O
the	O
motherboard	B-Device
,	O
ROM	B-Protocol
cartridge	I-Protocol
slot	O
,	O
and	O
full-travel	O
keyboard	O
in	O
the	O
same	O
case	O
.	O
</s>
<s>
TI	B-Language
BASIC	I-Language
,	O
an	O
ANSI-compliant	O
BASIC	O
interpreter	O
based	O
on	O
Dartmouth	B-Language
BASIC	I-Language
,	O
is	O
built-in	O
and	O
includes	O
support	O
for	O
graphics	O
,	O
sound	O
,	O
and	O
file	O
system	O
access	O
.	O
</s>
<s>
Later	O
versions	O
of	O
the	O
99/4A	B-Device
,	O
identified	O
by	O
(	O
C	O
)	O
1983	O
TEXAS	O
INSTRUMENTS	O
V2.2	O
on	O
the	O
title	O
page	O
,	O
prevent	O
the	O
use	O
of	O
unlicensed	O
ROM	B-Protocol
cartridges	I-Protocol
from	O
third-party	O
manufacturers	O
such	O
as	O
Atarisoft	O
.	O
</s>
<s>
Peripherals	O
include	O
a	O
5¼	O
"	O
floppy	B-Device
disk	I-Device
drive	I-Device
and	O
controller	O
,	O
an	O
RS-232	O
card	O
with	O
two	O
serial	O
ports	O
and	O
one	O
parallel	O
port	O
,	O
a	O
P-code	B-Language
card	O
for	O
Pascal	B-Application
support	O
,	O
a	O
thermal	O
printer	O
,	O
a	O
300-baud	O
acoustic	B-Device
coupler	I-Device
,	O
a	O
tape	O
drive	O
using	O
standard	O
audio	O
cassettes	O
as	O
media	O
,	O
and	O
a	O
32	O
KB	O
memory	O
expansion	B-Device
card	I-Device
.	O
</s>
<s>
Both	O
TI-99/4	B-Device
models	O
use	O
the	O
16-bit	B-Device
TMS9900	B-General_Concept
CPU	B-General_Concept
running	O
at	O
3	O
MHz	O
.	O
</s>
<s>
The	O
TMS9900	B-General_Concept
is	O
a	O
single-chip	O
implementation	O
of	O
a	O
TI-990	B-Device
minicomputer	B-Architecture
.	O
</s>
<s>
Although	O
a	O
full	O
16-bit	B-Device
processor	I-Device
,	O
only	O
the	O
system	O
ROM	B-Device
and	O
256	O
bytes	O
of	O
scratchpad	O
RAM	B-Architecture
are	O
available	O
on	O
the	O
16-bit	B-Device
bus	O
.	O
</s>
<s>
In	O
order	O
to	O
build	O
a	O
complete	O
16-bit	B-Device
system	O
,	O
TI	O
would	O
have	O
had	O
to	O
redesign	O
many	O
of	O
their	O
existing	O
8-bit	O
support	O
chips	O
.	O
</s>
<s>
The	O
result	O
was	O
that	O
only	O
a	O
small	O
portion	O
of	O
the	O
system	O
was	O
16-bit	B-Device
,	O
and	O
used	O
a	O
second	O
8-bit	O
computer	B-General_Concept
bus	I-General_Concept
for	O
the	O
rest	O
.	O
</s>
<s>
One	O
of	O
the	O
key	O
features	O
of	O
the	O
TMS9900	B-General_Concept
from	O
the	O
minicomputer	B-Architecture
design	O
that	O
spawned	O
it	O
was	O
the	O
inclusion	O
of	O
several	O
sets	O
of	O
processor	B-General_Concept
registers	I-General_Concept
.	O
</s>
<s>
In	O
a	O
minicomputer	B-Architecture
setting	O
,	O
the	O
system	O
was	O
typically	O
running	O
a	O
time	B-General_Concept
sharing	I-General_Concept
or	O
multitasking	B-Operating_System
operating	I-Operating_System
system	I-Operating_System
,	O
or	O
being	O
used	O
for	O
real-time	B-General_Concept
computing	I-General_Concept
,	O
both	O
of	O
which	O
benefit	O
from	O
being	O
able	O
to	O
quickly	O
switch	O
among	O
programs	O
.	O
</s>
<s>
To	O
do	O
this	O
,	O
the	O
TMS9900	B-General_Concept
stored	O
several	O
sets	O
of	O
registers	O
in	O
main	O
memory	O
and	O
could	O
switch	O
between	O
the	O
sets	O
of	O
sixteen	O
16-bit	B-Device
registers	O
by	O
changing	O
the	O
single	O
workspace	O
pointer	B-General_Concept
register	I-General_Concept
,	O
thereby	O
allowing	O
very	O
rapid	O
context	B-Operating_System
switching	I-Operating_System
.	O
</s>
<s>
The	O
new	O
design	O
put	O
256	O
bytes	O
of	O
random	B-Architecture
access	I-Architecture
memory	I-Architecture
(	O
RAM	B-Architecture
)	O
on	O
the	O
16-bit	B-Device
bus	O
to	O
store	O
up	O
to	O
eight	O
sets	O
of	O
registers	O
.	O
</s>
<s>
This	O
area	O
of	O
RAM	B-Architecture
is	O
known	O
as	O
the	O
"	O
scratchpad	O
memory	O
"	O
.	O
</s>
<s>
As	O
the	O
processor	O
's	O
instructions	O
are	O
all	O
16-bit	B-Device
as	O
well	O
,	O
the	O
8	O
KB	O
internal	O
system	O
read	B-Device
only	I-Device
memory	I-Device
(	O
ROM	B-Device
)	O
was	O
also	O
on	O
the	O
16-bit	B-Device
side	O
.	O
</s>
<s>
Only	O
the	O
program	B-General_Concept
counter	I-General_Concept
,	O
status	O
register	O
,	O
and	O
workspace	O
pointer	B-General_Concept
registers	I-General_Concept
are	O
actually	O
implemented	O
on	O
the	O
chip	O
itself	O
.	O
</s>
<s>
Included	O
on	O
the	O
8-bit	O
side	O
of	O
the	O
system	O
is	O
the	O
majority	O
of	O
the	O
RAM	B-Architecture
and	O
almost	O
all	O
of	O
the	O
support	O
chips	O
,	O
especially	O
the	O
video	B-General_Concept
display	I-General_Concept
controller	I-General_Concept
(	O
VDP	O
)	O
.	O
</s>
<s>
The	O
system	O
's	O
RAM	B-Architecture
is	O
managed	O
by	O
the	O
VDP	O
,	O
which	O
provides	O
access	O
to	O
the	O
CPU	B-General_Concept
only	O
when	O
the	O
CPU	B-General_Concept
is	O
not	O
using	O
the	O
memory	O
.	O
</s>
<s>
According	O
to	O
IEEE	O
Spectrum	O
,	O
this	O
negates	O
the	O
performance	O
advantage	O
of	O
a	O
16-bit	B-Device
processor	I-Device
.	O
</s>
<s>
Graphics	O
in	O
the	O
99/4A	B-Device
are	O
generated	O
by	O
a	O
TMS9918A	B-Architecture
Video	O
Display	O
Processor	O
(	O
VDP	O
)	O
,	O
with	O
a	O
variant	O
for	O
PAL	B-Language
territories	O
.	O
</s>
<s>
It	O
serves	O
as	O
the	O
video	O
processor	O
for	O
the	O
ColecoVision	B-Device
and	O
SG-1000	B-Operating_System
consoles	O
,	O
and	O
an	O
earlier	O
model	O
is	O
part	O
of	O
the	O
MSX	B-Operating_System
computer	O
standard	O
.	O
</s>
<s>
The	O
TMS9918A	B-Architecture
supports	O
character-based	O
and	O
bitmap	O
display	O
modes	O
as	O
well	O
as	O
hardware	O
sprites	O
.	O
</s>
<s>
There	O
are	O
32	O
single-color	O
sprites	O
total	O
,	O
but	O
only	O
a	O
maximum	O
of	O
4	O
can	O
be	O
displayed	O
per	O
scan	B-Algorithm
line	I-Algorithm
.	O
</s>
<s>
16	O
KB	O
of	O
RAM	B-Architecture
is	O
provided	O
for	O
the	O
Video	O
Display	O
Processor	O
.	O
</s>
<s>
TI	B-Language
BASIC	I-Language
user	O
programs	O
.	O
</s>
<s>
TI-99	B-Device
peripherals	O
contain	O
device	O
drivers	O
in	O
ROMs	O
in	O
the	O
hardware	O
.	O
</s>
<s>
PAL-based	O
machines	O
output	O
a	O
more	O
complex	O
YUV	O
signal	O
which	O
is	O
also	O
modulated	O
to	O
UHF	O
externally	O
.	O
</s>
<s>
Two	O
digital	O
joysticks	B-Device
can	O
be	O
connected	O
through	O
a	O
single	O
DE-9	O
port	O
.	O
</s>
<s>
It	O
is	O
identical	O
to	O
the	O
Atari	B-Protocol
joystick	I-Protocol
port	I-Protocol
,	O
but	O
with	O
incompatible	O
pins	O
.	O
</s>
<s>
Aftermarket	O
adapters	O
allow	O
the	O
use	O
of	O
Atari	B-Device
compatible	I-Device
joysticks	I-Device
.	O
</s>
<s>
TI	O
sold	O
an	O
official	O
32	O
KB	O
RAM	B-Architecture
expansion	O
.	O
</s>
<s>
For	O
example	O
,	O
an	O
Extended	O
Basic	O
program	O
is	O
restricted	O
to	O
using	O
24	O
KB	O
with	O
the	O
remaining	O
8	O
KB	O
available	O
for	O
machine	B-Language
code	I-Language
routines	O
.	O
</s>
<s>
The	O
Mini	O
Memory	O
plug-in	O
module	O
contains	O
4	O
KB	O
of	O
battery-backed	O
RAM	B-Architecture
that	O
can	O
be	O
used	O
as	O
a	O
persistent	O
RAM	B-Architecture
disk	O
or	O
to	O
load	O
a	O
machine-code	O
program	O
.	O
</s>
<s>
The	O
TI-99/4A	B-Device
can	O
be	O
upgraded	O
via	O
expansion	B-Device
cards	I-Device
added	O
to	O
an	O
eight-slot	O
,	O
external	O
chassis	O
containing	O
its	O
own	O
linear	O
power	O
supply	O
and	O
a	O
full-height	O
5¼	O
"	O
floppy	B-Device
bay	O
.	O
</s>
<s>
The	O
PEB	O
carries	O
an	O
analog	O
sound	O
input	O
on	O
the	O
expansion	B-Device
bus	I-Device
,	O
allowing	O
the	O
Speech	B-Application
Synthesizer	I-Application
's	O
audio	O
to	O
be	O
carried	O
through	O
the	O
console	O
to	O
the	O
monitor	O
.	O
</s>
<s>
The	O
audio	O
is	O
also	O
carried	O
through	O
the	O
ribbon	O
cable	O
to	O
the	O
PEB	O
,	O
both	O
allowing	O
the	O
relocation	O
of	O
the	O
Speech	B-Application
Synthesizer	I-Application
to	O
the	O
PEB	O
and	O
the	O
possibility	O
of	O
audio	O
cards	O
offering	O
more	O
features	O
than	O
the	O
console	O
's	O
built-in	O
sound	O
.	O
</s>
<s>
Diskette	B-Device
drive	O
control	O
card	O
.	O
</s>
<s>
In	O
the	O
late	O
1970s	O
and	O
early	O
1980s	O
,	O
TI	O
was	O
a	O
pioneer	O
in	O
speech	B-Application
synthesis	I-Application
because	O
of	O
its	O
Texas	B-Application
Instruments	I-Application
LPC	I-Application
Speech	I-Application
Chips	I-Application
which	O
were	O
used	O
in	O
its	O
Speak	B-Application
&	I-Application
Spell	I-Application
toys	O
.	O
</s>
<s>
A	O
plug-in	O
speech	B-Application
synthesizer	I-Application
module	O
was	O
available	O
for	O
the	O
TI-99/4	B-Device
and	O
4A	O
.	O
</s>
<s>
Speech	B-Application
synthesizers	I-Application
were	O
offered	O
free	O
with	O
the	O
purchase	O
of	O
a	O
number	O
of	O
cartridges	B-Protocol
and	O
were	O
used	O
by	O
video	O
games	O
such	O
as	O
Alpiner	B-Application
and	O
Parsec	B-Application
.	O
</s>
<s>
Alpiners	B-Application
speech	O
includes	O
male	O
and	O
female	O
voices	O
and	O
can	O
be	O
sarcastic	O
when	O
the	O
player	O
makes	O
a	O
bad	O
move	O
.	O
</s>
<s>
The	O
synthesizer	O
uses	O
a	O
variant	O
of	O
linear	B-Algorithm
predictive	I-Algorithm
coding	I-Algorithm
and	O
has	O
a	O
small	O
in-built	O
vocabulary	O
.	O
</s>
<s>
The	O
original	O
intent	O
was	O
to	O
release	O
small	O
cartridges	B-Protocol
that	O
plugged	O
directly	O
into	O
the	O
synthesizer	O
unit	O
to	O
increase	O
the	O
device	O
's	O
vocabulary	O
.	O
</s>
<s>
However	O
,	O
the	O
success	O
of	O
software	O
text-to-speech	B-Application
in	O
the	O
Terminal	O
Emulator	O
II	O
cartridge	B-Protocol
cancelled	O
that	O
plan	O
.	O
</s>
<s>
In	O
1977	O
,	O
groups	O
within	O
Texas	O
Instruments	O
were	O
designing	O
a	O
video	B-Device
game	I-Device
console	I-Device
,	O
a	O
home	O
computer	O
to	O
compete	O
against	O
the	O
TRS-80	B-Device
and	O
Apple	B-Device
II	I-Device
,	O
and	O
a	O
high-end	O
business	O
personal	O
computer	O
with	O
a	O
hard	B-Device
drive	I-Device
.	O
</s>
<s>
According	O
to	O
Wally	O
Rhines	O
,	O
the	O
99/4	O
'	O
s	O
"	O
ultracheap	O
keyboard	O
"	O
(	O
with	O
calculator-style	O
keys	O
)	O
,	O
RF	O
modulator	O
,	O
and	O
ROM	B-Protocol
cartridges	I-Protocol
came	O
from	O
the	O
console	O
design	O
.	O
</s>
<s>
Meanwhile	O
,	O
the	O
third	O
team	O
was	O
merged	O
into	O
TI	O
's	O
Data	O
Systems	O
Division	O
,	O
which	O
had	O
a	O
line	O
of	O
minicomputer	B-Architecture
products	O
and	O
various	O
computer	B-General_Concept
terminals	I-General_Concept
;	O
they	O
viewed	O
the	O
all-in-one	O
machine	O
as	O
a	O
threat	O
and	O
the	O
project	O
was	O
eventually	O
killed	O
.	O
</s>
<s>
Others	O
within	O
the	O
company	O
persuaded	O
the	O
Lubbock	O
group	O
to	O
use	O
TI	O
's	O
TMS9900	B-General_Concept
CPU	B-General_Concept
.	O
</s>
<s>
This	O
was	O
in	O
keeping	O
with	O
TI	O
's	O
"	O
one	O
company	O
,	O
one	O
computer	O
architecture	O
"	O
concept	O
,	O
where	O
a	O
single	O
processor	O
model	O
would	O
scale	O
from	O
consoles	O
to	O
its	O
high-end	O
minicomputers	B-Architecture
.	O
</s>
<s>
The	O
TMS9900	B-General_Concept
is	O
a	O
single-chip	O
implementation	O
of	O
TI	O
's	O
16-bit	B-Device
TI-990	B-Device
mini	O
design	O
,	O
and	O
is	O
the	O
CPU	B-General_Concept
in	O
low-end	O
models	O
of	O
that	O
platform	O
.	O
</s>
<s>
Feature-limited	O
single-chip	O
versions	O
of	O
popular	O
minicomputer	B-Architecture
designs	O
from	O
the	O
1960s	O
were	O
popular	O
in	O
the	O
mid-1970s	O
and	O
newly	O
designed	O
16-bit	B-Device
and	O
32-bit	O
CPUs	O
like	O
the	O
Intel	B-Device
8088	I-Device
and	O
Motorola	B-Device
68000	I-Device
,	O
respectively	O
,	O
quickly	O
rendered	O
these	O
earlier	O
designs	O
obsolete	O
.	O
</s>
<s>
Many	O
of	O
the	O
TMS9900	B-General_Concept
's	O
quirky	O
features	O
,	O
like	O
processor	B-General_Concept
registers	I-General_Concept
in	O
main	O
memory	O
,	O
came	O
from	O
its	O
minicomputer	B-Architecture
roots	O
where	O
such	O
concepts	O
were	O
more	O
common	O
.	O
</s>
<s>
This	O
was	O
based	O
on	O
TI	O
's	O
version	O
of	O
the	O
8-bit	O
Intel	B-General_Concept
8080	I-General_Concept
supported	O
by	O
an	O
all-TI	O
chip	O
set	O
.	O
</s>
<s>
The	O
company	O
eventually	O
gave	O
up	O
and	O
bundled	O
a	O
modified	O
Zenith	O
Electronics	O
television	O
as	O
a	O
computer	B-Device
monitor	I-Device
,	O
eliminating	O
the	O
need	O
for	O
the	O
RF	O
modulator	O
that	O
generates	O
the	O
interference	O
by	O
connecting	O
directly	O
to	O
the	O
TV	O
's	O
circuitry	O
using	O
a	O
composite	O
video	O
signal	O
.	O
</s>
<s>
Very	O
little	O
software	O
was	O
available	O
,	O
as	O
few	O
developers	O
ported	O
their	O
products	O
to	O
its	O
16-bit	B-Device
CPU	B-General_Concept
.	O
</s>
<s>
In	O
July	O
1980	O
,	O
Adam	O
Osborne	O
reported	O
that	O
,	O
despite	O
poor	O
sales	O
,	O
TI	O
had	O
raised	O
the	O
price	O
of	O
a	O
complete	O
system	O
to	O
,	O
higher	O
than	O
the	O
popular	O
Apple	B-Device
II	I-Device
,	O
which	O
started	O
at	O
.	O
</s>
<s>
TI	O
sold	O
fewer	O
than	O
20,000	O
computers	O
by	O
summer	O
1981	O
,	O
less	O
than	O
one	O
tenth	O
Apple	O
or	O
Radio	O
Shack	O
's	O
volume	O
;	O
even	O
Atari	O
,	O
Inc.	O
,	O
which	O
reportedly	O
lost	O
on	O
sales	O
of	O
of	O
computers	O
,	O
had	O
an	O
Atari	B-Device
8-bit	I-Device
family	I-Device
installed	O
base	O
more	O
than	O
twice	O
as	O
large	O
.	O
</s>
<s>
Two	O
years	O
after	O
the	O
99/4	O
'	O
s	O
debut	O
,	O
TI	O
released	O
the	O
99/4A	B-Device
.	O
</s>
<s>
TI	O
continued	O
lowering	O
the	O
price	O
through	O
1981	O
,	O
first	O
to	O
,	O
and	O
then	O
to	O
in	O
early	O
1982	O
,	O
in	O
competition	O
with	O
Commodore	O
's	O
VIC-20	B-Device
.	O
</s>
<s>
By	O
mid-1982	O
,	O
Jerry	O
Pournelle	O
wrote	O
that	O
TI	O
was	O
"	O
practically	O
giving	O
away	O
the	O
TI-99/4A	B-Device
"	O
.	O
</s>
<s>
TI	O
celebrated	O
the	O
99/4A	B-Device
'	O
s	O
market	O
success	O
at	O
the	O
January	O
1983	O
Consumer	O
Electronics	O
Show	O
in	O
Las	O
Vegas	O
.	O
</s>
<s>
In	O
February	O
TI	O
responded	O
with	O
a	O
99/4A	B-Device
retail	O
price	O
of	O
.	O
</s>
<s>
In	O
April	O
,	O
the	O
VIC-20	B-Device
'	O
s	O
bundled	O
retail	O
price	O
reached	O
and	O
the	O
99/4A	B-Device
followed	O
suit	O
.	O
</s>
<s>
TI	O
was	O
forced	O
to	O
sell	O
the	O
99/4A	B-Device
for	O
about	O
the	O
same	O
price	O
as	O
the	O
VIC-20	B-Device
,	O
even	O
though	O
it	O
was	O
much	O
more	O
expensive	O
to	O
manufacture	O
.	O
</s>
<s>
TI	O
could	O
not	O
make	O
a	O
profit	O
on	O
the	O
TI-99/4A	B-Device
at	O
a	O
price	O
of	O
$99	O
,	O
but	O
hoped	O
that	O
selling	O
many	O
inexpensive	O
computers	O
would	O
increase	O
sales	O
of	O
more	O
profitable	O
software	O
and	O
peripherals	O
.	O
</s>
<s>
TI	O
did	O
not	O
provide	O
an	O
editor	O
,	O
assembler	B-Language
,	O
or	O
hardware	O
technical	O
information	O
when	O
it	O
released	O
the	O
computer	O
.	O
</s>
<s>
Green	O
's	O
company	O
,	O
Instant	O
Software	O
,	O
was	O
a	O
prolific	O
publisher	O
of	O
TRS-80	B-Device
software	O
,	O
but	O
could	O
not	O
find	O
anyone	O
to	O
port	O
software	O
to	O
the	O
TI	O
.	O
</s>
<s>
A	O
Spinnaker	O
Software	O
executive	O
said	O
that	O
the	O
99/4A	B-Device
had	O
"	O
the	O
worst	O
software	O
in	O
the	O
business	O
"	O
,	O
and	O
Ahl	O
noted	O
that	O
unlike	O
other	O
computers	O
,	O
it	O
did	O
not	O
have	O
"	O
Microsoft	B-Language
BASIC	I-Language
,	O
VisiCalc	B-Application
,	O
WordStar	B-Application
,	O
or	O
any	O
popular	O
games	O
"	O
.	O
</s>
<s>
TI	O
joysticks	B-Device
,	O
for	O
example	O
,	O
were	O
of	O
poor	O
quality	O
and	O
difficult	O
to	O
find	O
;	O
one	O
reseller	O
reported	O
that	O
its	O
best-selling	O
product	O
was	O
the	O
Atari	B-Device
CX40	I-Device
joystick	I-Device
adapter	O
cable	O
.	O
</s>
<s>
Kilobaud	O
Microcomputing	O
reported	O
that	O
a	O
Commodore	O
executive	O
promised	O
the	O
VIC-20	B-Device
would	O
have	O
"	O
enough	O
additional	O
documentation	O
to	O
enable	O
an	O
experienced	O
programmer/hobbyist	O
to	O
get	O
inside	O
and	O
let	O
his	O
imagination	O
work	O
"	O
.	O
</s>
<s>
Even	O
when	O
competitors	O
did	O
not	O
disclose	O
technical	O
information	O
,	O
because	O
their	O
computers	O
used	O
commercial	O
off-the-shelf	O
parts	O
like	O
the	O
MOS	B-General_Concept
6502	I-General_Concept
and	O
Zilog	B-General_Concept
Z-80	I-General_Concept
,	O
much	O
more	O
information	O
was	O
public	O
than	O
for	O
TI	O
's	O
proprietary	O
components	O
.	O
</s>
<s>
The	O
company	O
released	O
software	O
and	O
hardware	O
technical	O
information	O
when	O
the	O
IBM	B-Device
PC	I-Device
was	O
announced	O
in	O
1981	O
,	O
stating	O
that	O
"	O
the	O
definition	O
of	O
a	O
personal	O
computer	O
is	O
third-party	O
hardware	O
and	O
software	O
"	O
.	O
</s>
<s>
After	O
third-party	O
developers	O
 '	O
games	O
for	O
the	O
Atari	O
2600	O
became	O
very	O
successful	O
,	O
TI	O
at	O
the	O
June	O
1983	O
Consumer	O
Electronics	O
Show	O
announced	O
that	O
only	O
cartridges	B-Protocol
with	O
a	O
TI-licensed	O
lockout	O
chip	O
would	O
work	O
in	O
the	O
99/4A	B-Device
.	O
</s>
<s>
No	O
official	O
technical	O
documentation	O
from	O
TI	O
was	O
released	O
until	O
the	O
"	O
Editor/Assembler	O
"	O
development	O
suite	O
was	O
released	O
in	O
1981	O
,	O
and	O
no	O
system	O
schematics	O
were	O
ever	O
released	O
to	O
the	O
public	O
until	O
after	O
TI	O
had	O
discontinued	O
the	O
computer	O
.	O
</s>
<s>
The	O
low	O
price	O
affected	O
the	O
99/4A	B-Device
'	O
s	O
reputation	O
;	O
"	O
When	O
they	O
went	O
to	O
,	O
people	O
started	O
asking	O
'	O
What	O
's	O
wrong	O
with	O
it	O
?	O
</s>
<s>
Some	O
observers	O
predicted	O
after	O
the	O
second	O
quarter	O
's	O
loss	O
that	O
the	O
99/4A	B-Device
would	O
not	O
be	O
able	O
to	O
recover	O
;	O
even	O
if	O
the	O
company	O
did	O
not	O
plan	O
to	O
discontinue	O
the	O
computer	O
,	O
the	O
fear	O
that	O
it	O
would	O
become	O
orphaned	O
technology	O
might	O
cause	O
retailers	O
to	O
avoid	O
ordering	O
inventory	O
.	O
</s>
<s>
After	O
losing	O
after	O
taxes	O
in	O
the	O
third	O
calendar	O
quarter	O
of	O
1983	O
,	O
TI	O
announced	O
plans	O
to	O
discontinue	O
the	O
99/4A	B-Device
,	O
while	O
continuing	O
to	O
sell	O
the	O
TI	B-Device
Professional	I-Device
MS-DOS-compatible	O
computer	O
.	O
</s>
<s>
A	O
total	O
of	O
2.8	O
million	O
units	O
were	O
shipped	O
before	O
the	O
TI-99/4A	B-Device
was	O
discontinued	O
in	O
March	O
1984	O
.	O
</s>
<s>
The	O
99/4A	B-Device
became	O
the	O
first	O
in	O
a	O
series	O
of	O
home	O
computers	O
to	O
be	O
orphaned	O
by	O
their	O
manufacturer	O
over	O
the	O
next	O
few	O
years	O
,	O
along	O
with	O
the	O
Coleco	B-Device
Adam	I-Device
,	O
Mattel	B-Device
Aquarius	I-Device
,	O
Timex	B-Device
Sinclair	I-Device
1000	I-Device
,	O
and	O
IBM	B-Device
PCjr	I-Device
.	O
</s>
<s>
The	O
TMS9900	B-General_Concept
's	O
machine	B-Language
language	I-Language
instructions	O
must	O
be	O
word-aligned	O
,	O
so	O
at	O
least	O
16-bits	B-Device
are	O
needed	O
for	O
every	O
instruction	O
.	O
</s>
<s>
Additionally	O
,	O
programming	O
the	O
8-bit	O
side	O
of	O
the	O
system	O
from	O
16-bit	B-Device
code	O
is	O
somewhat	O
complex	O
.	O
</s>
<s>
This	O
is	O
a	O
compact	O
8-bit	O
language	O
interpreted	O
by	O
the	O
CPU	B-General_Concept
which	O
dynamically	O
translates	O
the	O
GPL	O
instructions	O
into	O
one	O
or	O
more	O
TMS9900	B-General_Concept
instructions	O
.	O
</s>
<s>
All	O
software	O
originally	O
distributed	O
on	O
ROM	B-Protocol
cartridges	I-Protocol
were	O
written	O
using	O
GPL	O
,	O
and	O
are	O
sometimes	O
referred	O
to	O
as	O
GROMs	O
.	O
</s>
<s>
On	O
the	O
Creative	O
Computing	O
Benchmark	O
,	O
it	O
runs	O
at	O
roughly	O
half	O
the	O
speed	O
of	O
the	O
Apple	B-Device
II	I-Device
.	O
</s>
<s>
TMS9918A	B-Architecture
VDP	O
,	O
40	O
pin	O
DIP	B-Algorithm
.	O
</s>
<s>
The	O
earlier	O
99/4	O
uses	O
the	O
TMS9918	B-Architecture
.	O
</s>
<s>
PAL	B-Language
systems	O
use	O
the	O
"	O
9929	O
"	O
versions	O
of	O
each	O
.	O
</s>
<s>
A	O
single	O
bit	O
is	O
available	O
in	O
hardware	O
for	O
collision	O
detection	O
,	O
and	O
the	O
console	O
supports	O
automatic	O
movement	O
via	O
an	O
interrupt	O
routine	O
in	O
the	O
ROM	B-Device
.	O
</s>
<s>
There	O
can	O
only	O
be	O
4	O
visible	O
sprites	O
per	O
scan	B-Algorithm
line	I-Algorithm
.	O
</s>
<s>
Bitmap	O
mode	O
:	O
256×192	O
pixels	O
(	O
no	O
more	O
than	O
two	O
colors	O
in	O
an	O
eight-pixel	O
row	O
,	O
full	O
15	O
color	O
palette	O
+	O
transparent	O
,	O
all	O
32	O
sprites	O
available	O
but	O
interrupt-based	O
motion	O
through	O
the	O
ROM	B-Device
routine	O
is	O
not	O
due	O
to	O
the	O
memory	O
layout	O
,	O
not	O
available	O
to	O
BASIC	O
or	O
the	O
original	O
9918	O
)	O
.	O
</s>
<s>
Roughly	O
100	O
games	O
were	O
published	O
for	O
the	O
TI-99/4A	B-Device
,	O
with	O
most	O
published	O
by	O
Texas	O
Instruments	O
.	O
</s>
<s>
Some	O
of	O
the	O
games	O
released	O
only	O
for	O
the	O
99/4A	B-Device
are	O
Parsec	B-Application
,	O
Alpiner	B-Application
,	O
Tombstone	B-Application
City	I-Application
:	I-Application
21st	I-Application
Century	I-Application
,	O
Tunnels	B-Application
of	I-Application
Doom	I-Application
,	O
and	O
The	B-Application
Attack	I-Application
.	O
</s>
<s>
TI	B-Application
Invaders	I-Application
and	O
Car	B-Application
Wars	I-Application
are	O
TI	O
's	O
renditions	O
of	O
Space	B-Application
Invaders	I-Application
and	O
Head	B-Application
On	I-Application
respectively	O
.	O
</s>
<s>
Munch	B-Application
Man	I-Application
is	O
similar	O
to	O
Pac-Man	B-Application
,	O
but	O
the	O
title	O
character	O
fills	O
the	O
maze	O
with	O
a	O
pattern	O
rather	O
than	O
emptying	O
it	O
of	O
dots	O
.	O
</s>
<s>
Tigervision	O
offered	O
a	O
solution	O
to	O
the	O
memory	O
limitation	O
of	O
the	O
standard	O
cartridge	B-Protocol
slot	O
in	O
the	O
form	O
of	O
a	O
24kB	O
memory	O
expansion	O
cartridge	B-Protocol
that	O
attached	O
to	O
the	O
side	O
expansion	O
interface	O
,	O
emulating	O
an	O
expansion	O
device	O
.	O
</s>
<s>
This	O
allowed	O
the	O
company	O
to	O
implement	O
a	O
larger	O
game	O
completely	O
in	O
machine	B-Language
code	I-Language
,	O
which	O
was	O
used	O
for	O
Espial	O
and	O
Miner	B-Application
2049er	I-Application
.	O
</s>
<s>
Exceltec	O
also	O
released	O
two	O
similar	O
side	O
cartridges	B-Protocol
:	O
Arcturus	O
and	O
Killer	O
Caterpillar	O
.	O
</s>
<s>
TI	O
not	O
only	O
discouraged	O
third-party	O
development	O
,	O
including	O
games	O
,	O
but	O
it	O
also	O
failed	O
to	O
license	O
popular	O
arcade	O
games	O
like	O
Zaxxon	B-Application
and	O
Frogger	B-Application
.	O
</s>
<s>
Though	O
it	O
is	O
similar	O
to	O
today	O
's	O
USB	B-Protocol
(	O
plug	O
and	O
play	O
,	O
hot-swappable	O
,	O
etc	O
.	O
</s>
<s>
The	O
TI-99/4	B-Device
was	O
intended	O
to	O
fit	O
in	O
the	O
middle	O
of	O
a	O
planned	O
range	O
of	O
TI-99	B-Device
computers	O
,	O
with	O
prototypes	O
and	O
documentation	O
created	O
for	O
other	O
models	O
.	O
</s>
<s>
Initial	O
plans	O
were	O
for	O
a	O
lower-end	O
TI-99/2	O
and	O
a	O
more	O
powerful	O
TI-99/8	O
.	O
</s>
<s>
Later	O
ideas	O
for	O
expanding	O
the	O
range	O
included	O
a	O
bargain-priced	O
TI-99/3	O
,	O
a	O
terminal	O
TI-99/7	O
,	O
and	O
a	O
direct	O
follow-up	O
to	O
the	O
TI-99/4A	B-Device
referred	O
to	O
as	O
either	O
TI-99/4B	O
or	O
TI-99/5	O
.	O
</s>
<s>
At	O
the	O
time	O
they	O
left	O
the	O
home	O
computer	O
market	O
,	O
TI	O
had	O
been	O
actively	O
developing	O
two	O
successors	O
to	O
the	O
TI-99/4A	B-Device
that	O
went	O
through	O
several	O
prototypes	O
but	O
never	O
entered	O
production	O
.	O
</s>
<s>
Some	O
of	O
these	O
prototypes	O
are	O
now	O
in	O
the	O
hands	O
of	O
TI-99/4A	B-Device
collectors	O
.	O
</s>
<s>
Both	O
machines	O
would	O
have	O
been	O
substantially	O
faster	O
than	O
the	O
original	O
TI-99/4A	B-Device
and	O
used	O
the	O
Hex-Bus	O
serial	O
interface	O
.	O
</s>
<s>
TI-99/2	O
,	O
a	O
4K	O
RAM	B-Architecture
,	O
32K	O
ROM	B-Device
computer	O
with	O
no	O
color	O
,	O
sound	O
,	O
or	O
joystick	B-Device
port	O
and	O
a	O
Mylar	O
keyboard	O
.	O
</s>
<s>
TI	O
designed	O
the	O
computer	O
in	O
four	O
and	O
a	O
half	O
months	O
to	O
sell	O
for	O
under	O
$100	O
and	O
compete	O
with	O
the	O
Sinclair	O
ZX81	O
and	O
Timex	B-Device
Sinclair	I-Device
1000	I-Device
.	O
</s>
<s>
Based	O
on	O
the	O
TMS9995	O
CPU	B-General_Concept
running	O
at	O
10.7MHz	O
and	O
with	O
a	O
built-in	O
RF	O
modulator	O
,	O
performance	O
greatly	O
increased	O
when	O
the	O
screen	O
was	O
blank	O
.	O
</s>
<s>
99/2	O
software	O
ran	O
on	O
the	O
99/4A	B-Device
,	O
but	O
not	O
vice	O
versa	O
.	O
</s>
<s>
Home-computer	O
prices	O
declined	O
so	O
quickly	O
,	O
however	O
,	O
that	O
by	O
mid-1983	O
the	O
99/4A	B-Device
sold	O
for	O
$99	O
.	O
</s>
<s>
TI-99/8	O
and	O
99/6	O
.	O
</s>
<s>
It	O
included	O
64kB	O
of	O
RAM	B-Architecture
expandable	O
to	O
15	O
megabytes	O
,	O
a	O
larger	O
keyboard	O
,	O
built-in	O
speech	B-Application
synthesis	I-Application
,	O
built-in	O
UCSD	B-Language
Pascal	I-Language
operating	O
environment	O
,	O
and	O
the	O
full	O
16-bit	B-Device
data	B-General_Concept
bus	I-General_Concept
available	O
on	O
the	O
expansion	B-Device
port	I-Device
.	O
</s>
<s>
The	O
Multi	B-Application
Emulator	I-Application
Super	I-Application
System	I-Application
is	O
capable	O
of	O
running	O
what	O
are	O
believed	O
to	O
be	O
the	O
system	O
's	O
ROMs	O
.	O
</s>
<s>
Portions	O
of	O
the	O
operating	B-General_Concept
system	I-General_Concept
and	O
BASIC	O
code	O
are	O
similar	O
to	O
the	O
99/8	O
.	O
</s>
<s>
Until	O
2006	O
,	O
there	O
was	O
an	O
annual	O
Chicago	O
TI	O
Faire	O
where	O
people	O
celebrated	O
the	O
TI-99	B-Device
family	O
of	O
computers	O
.	O
</s>
<s>
The	O
Myarc	O
Geneve	B-Device
9640	I-Device
is	O
an	O
enhanced	O
TI-99/4A	B-Device
clone	O
built	O
by	O
Myarc	O
as	O
a	O
card	O
to	O
fit	O
into	O
the	O
TI	O
Peripheral	O
Expansion	O
System	O
.	O
</s>
<s>
Released	O
in	O
1987	O
,	O
it	O
is	O
similar	O
to	O
the	O
unreleased	O
TI-99/8	O
system	O
.	O
</s>
<s>
It	O
includes	O
a	O
12MHz	O
TMS9995	O
processor	O
,	O
enhanced	O
graphics	O
with	O
80-column	O
text	O
mode	O
,	O
16-bit	B-Device
wide	O
RAM	B-Architecture
,	O
MDOS	B-Operating_System
,	O
and	O
is	O
compatible	O
with	O
nearly	O
all	O
TI	O
software	O
and	O
slot-mounted	O
hardware	O
.	O
</s>
<s>
The	O
Second	O
Generation	O
CPU	B-General_Concept
card	O
(	O
SGCPU	O
)	O
was	O
released	O
by	O
the	O
System	O
99	O
User	O
Group	O
in	O
1996	O
as	O
a	O
card	O
to	O
be	O
installed	O
in	O
the	O
PEB	O
.	O
</s>
<s>
In	O
2004	O
,	O
a	O
Universal	B-Protocol
Serial	I-Protocol
Bus	I-Protocol
card	O
and	O
Advanced	B-Protocol
Technology	I-Protocol
Attachment	I-Protocol
controller	O
for	O
IDE	B-Protocol
hard	B-Device
disks	I-Device
for	O
the	O
PEB	O
were	O
released	O
.	O
</s>
<s>
A	O
range	O
of	O
plug-in	B-Protocol
cartridge	I-Protocol
boards	O
have	O
been	O
developed	O
,	O
allowing	O
software	O
projects	O
to	O
be	O
distributed	O
on	O
cartridge	B-Protocol
.	O
</s>
<s>
It	O
uses	O
two	O
FPGAs	O
to	O
emulate	O
the	O
entire	O
architecture	O
of	O
the	O
Myarc	O
Geneve	B-Device
9640	I-Device
and	O
the	O
TMS9995	O
microprocessor	B-Architecture
.	O
</s>
<s>
It	O
incorporates	O
an	O
SD	O
card	O
reader	O
,	O
Ethernet	O
,	O
VGA	B-Protocol
output	O
,	O
and	O
64MB	O
RAM	B-Architecture
.	O
</s>
<s>
An	O
FPGA-based	O
TMS9918	B-Architecture
compatible	O
graphics	B-General_Concept
chip	I-General_Concept
,	O
called	O
the	O
F18A	O
,	O
is	O
a	O
drop-in	O
replacement	O
for	O
the	O
original	O
9918	O
VDP	O
,	O
but	O
features	O
VGA	B-Protocol
output	O
,	O
bypassing	O
the	O
TMS9918A	B-Architecture
's	O
native	O
composite	O
output	O
,	O
and	O
contains	O
other	O
enhancements	O
such	O
as	O
removal	O
of	O
the	O
restriction	O
of	O
4	O
sprites	O
per	O
scan	B-Algorithm
line	I-Algorithm
.	O
</s>
