<s>
UAE	B-Device
is	O
a	O
computer	B-Application
emulator	I-Application
which	O
emulates	B-Application
the	O
hardware	B-Architecture
of	O
Commodore	O
International	O
's	O
Amiga	B-Device
range	O
of	O
computers	O
.	O
</s>
<s>
Released	O
under	O
the	O
GNU	B-License
General	I-License
Public	I-License
License	I-License
,	O
UAE	B-Device
is	O
free	B-Application
software	I-Application
.	O
</s>
<s>
Bernd	O
Schmidt	O
conceived	O
of	O
an	O
emulator	B-Application
that	O
can	O
run	O
Amiga	B-Device
software	I-Device
when	O
he	O
found	O
that	O
such	O
a	O
task	O
was	O
widely	O
believed	O
to	O
be	O
impossible	O
.	O
</s>
<s>
Schmidt	O
had	O
written	O
previous	O
programs	O
for	O
Amiga	B-Device
,	O
and	O
was	O
further	O
motivated	O
by	O
the	O
desire	O
to	O
not	O
lose	O
games	O
,	O
demos	O
,	O
and	O
sound	O
modules	O
to	O
switching	O
operating	B-General_Concept
systems	I-General_Concept
.	O
</s>
<s>
UAE	B-Device
was	O
released	O
in	O
1995	O
and	O
was	O
originally	O
called	O
the	O
Unusable	B-Device
Amiga	I-Device
Emulator	I-Device
,	O
due	O
to	O
its	O
inability	O
to	O
boot	O
.	O
</s>
<s>
In	O
its	O
early	O
stages	O
,	O
it	O
was	O
known	O
as	O
Unix	B-Device
Amiga	I-Device
Emulator	I-Device
and	O
later	O
with	O
other	O
names	O
as	O
well	O
.	O
</s>
<s>
Today	O
,	O
what	O
the	O
name	O
of	O
the	O
software	O
product	O
,	O
stands	O
for	O
today	O
,	O
is	O
the	O
Universal	O
Amiga	B-Device
Emulator	B-Application
.	O
</s>
<s>
UAE	B-Device
is	O
almost	O
a	O
full-featured	O
Amiga	B-Device
emulator	B-Application
.	O
</s>
<s>
It	O
emulates	B-Application
most	O
of	O
its	O
functions	O
:	O
</s>
<s>
Processor	O
:	O
Motorola	O
68000/010/020/040	O
CPU	O
,	O
optionally	O
a	O
68881	B-General_Concept
FPU	O
,	O
and	O
as	O
of	O
WinUAE	B-Device
3.0.0	O
beta	O
15	O
,	O
an	O
enhanced	O
PowerPC	B-Architecture
JIT	O
core	O
using	O
the	O
QEMU	B-Application
CPU	O
libraries	O
.	O
</s>
<s>
64	O
MB	O
Zorro	B-Device
III	I-Device
Fast	O
RAM	O
,	O
independent	O
of	O
Chip	O
RAM	O
setting	O
(	O
68020+	O
only	O
)	O
.	O
</s>
<s>
Serial	B-Protocol
port	I-Protocol
,	O
and	O
Simple	O
parallel	O
port	O
is	O
only	O
sufficient	O
for	O
printing	O
.	O
</s>
<s>
For	O
software	O
,	O
UAE	B-Device
may	O
use	O
disk	B-Application
images	I-Application
made	O
from	O
original	O
Amiga	B-Device
floppy	B-Device
disks	I-Device
.	O
</s>
<s>
These	O
images	O
have	O
the	O
file	O
extension	O
of	O
"	O
ADF	O
"	O
(	O
Amiga	B-Device
Disk	O
File	O
)	O
.	O
</s>
<s>
Actual	O
Amiga	B-Device
disks	O
cannot	O
be	O
used	O
,	O
because	O
of	O
limitations	O
in	O
the	O
floppy	B-Device
controllers	I-Device
used	O
in	O
other	O
computers	O
.	O
</s>
<s>
Images	O
of	O
Amiga	B-Device
formatted	O
hard	B-Device
drives	I-Device
can	O
also	O
be	O
made	O
.	O
</s>
<s>
UAE	B-Device
also	O
supports	O
mapping	O
host	O
operating	B-General_Concept
system	I-General_Concept
's	O
directories	O
to	O
Amiga	B-Device
hard	B-Device
drives	I-Device
,	O
and	O
finally	O
,	O
physical	O
Amiga	B-Device
formatted	O
hard	B-Device
drives	I-Device
can	O
be	O
mounted	O
.	O
</s>
<s>
UAE	B-Device
does	O
not	O
include	O
the	O
original	O
Amiga	B-Application
operating	I-Application
system	I-Application
ROM	O
and	O
files	O
,	O
which	O
are	O
required	O
for	O
running	O
an	O
Amiga	B-Device
system	O
.	O
</s>
<s>
These	O
are	O
included	O
under	O
license	O
in	O
packages	O
like	O
Amiga	B-Application
Forever	I-Application
.	O
</s>
<s>
Original	O
Kickstart	O
3.1	O
ROM	O
images	O
are	O
also	O
included	O
with	O
AmigaOS4	B-Application
for	O
PowerPC	B-Architecture
since	O
version	O
4.1	O
Update	O
4	O
.	O
</s>
<s>
UAE	B-Device
also	O
supports	O
alternative	O
system	O
ROMs	O
,	O
such	O
as	O
those	O
derived	O
from	O
the	O
AROS	B-Application
project	O
,	O
however	O
these	O
do	O
not	O
provide	O
the	O
same	O
degree	O
of	O
software	O
compatibility	O
as	O
the	O
original	O
ROMs	O
.	O
</s>
<s>
UAE	B-Device
has	O
been	O
ported	O
to	O
many	O
host	O
operating	B-General_Concept
systems	I-General_Concept
,	O
including	O
Linux	B-Application
,	O
macOS	B-Application
,	O
FreeBSD	B-Operating_System
,	O
DOS	B-Device
,	O
Microsoft	B-Application
Windows	I-Application
,	O
RISC	B-Operating_System
OS	I-Operating_System
,	O
BeOS	B-Application
,	O
Palm	B-Operating_System
OS	I-Operating_System
,	O
Android	B-Application
,	O
the	O
Xbox	B-Application
console	I-Application
,	O
the	O
PSP	B-Operating_System
,	O
PSVita	B-Device
and	O
GP2X	B-Device
handhelds	O
,	O
iOS	B-Application
,	O
the	B-Operating_System
Wii	I-Operating_System
and	O
Dreamcast	B-Operating_System
consoles	O
,	O
and	O
even	O
to	O
AmigaOS	B-Application
,	O
MorphOS	B-Operating_System
and	O
AROS	B-Application
.	O
</s>
<s>
There	O
have	O
been	O
many	O
threads	O
in	O
the	O
past	O
on	O
Usenet	B-Application
and	O
other	O
public	O
forums	O
where	O
people	O
argued	O
about	O
the	O
possibility	O
of	O
writing	O
an	O
Amiga	B-Device
emulator	B-Application
.	O
</s>
<s>
Some	O
considered	O
UAE	B-Device
to	O
be	O
attempting	O
the	O
impossible	O
;	O
to	O
be	O
demanding	O
that	O
a	O
system	O
read	O
,	O
process	O
and	O
output	O
100	O
MB/s	O
of	O
data	O
when	O
the	O
fastest	O
PC	O
was	O
a	O
66MHz	O
486	B-General_Concept
,	O
while	O
keeping	O
various	O
emulated	B-Application
chips	O
(	O
the	O
Amiga	B-Device
chipset	O
)	O
all	O
in	O
sync	O
and	O
appearing	O
as	O
they	O
were	O
supposed	O
to	O
appear	O
to	O
software	O
.	O
</s>
<s>
UAE	B-Device
was	O
almost	O
entirely	O
unusable	O
in	O
its	O
first	O
releases	O
,	O
but	O
slowly	O
and	O
step	O
by	O
step	O
,	O
it	O
fleshed	O
out	O
its	O
support	O
of	O
the	O
Amiga	B-Device
chipset	O
and	O
by	O
the	O
end	O
of	O
1997	O
was	O
able	O
to	O
emulate	O
an	O
Amiga	B-Device
500	I-Device
at	O
a	O
quality	O
and	O
speed	O
that	O
were	O
sufficient	O
for	O
productivity	O
use	O
and	O
for	O
many	O
games	O
.	O
</s>
<s>
Since	O
then	O
,	O
UAE	B-Device
has	O
been	O
usable	O
,	O
thanks	O
partly	O
to	O
the	O
effort	O
taken	O
to	O
develop	O
it	O
and	O
partly	O
to	O
the	O
big	O
improvements	O
in	O
technology	O
that	O
brought	O
computers	O
many	O
times	O
faster	O
than	O
those	O
UAE	B-Device
was	O
initially	O
running	O
on	O
.	O
</s>
<s>
Many	O
Amiga	B-Application
games	I-Application
and	O
applications	O
can	O
run	O
smoothly	O
on	O
a	O
Pentium	O
II-era	O
system	O
.	O
</s>
<s>
The	O
realization	O
that	O
a	O
useful	O
Amiga	B-Device
emulator	B-Application
could	O
be	O
written	O
contributed	O
to	O
an	O
increase	O
in	O
enthusiasm	O
about	O
emulation	B-Application
,	O
which	O
started	O
or	O
sped-up	O
efforts	O
to	O
write	O
emulators	B-Application
for	O
other	O
and	O
often	O
less	O
popular	O
computer	O
and	O
electronic	O
game	O
architectures	O
.	O
</s>
<s>
A	O
major	O
improvement	O
was	O
made	O
in	O
2000	O
by	O
Bernd	O
Meyer	O
with	O
the	O
use	O
of	O
Just-in-time	O
compilation	O
,	O
which	O
significantly	O
improved	O
the	O
emulation	B-Application
speed	O
,	O
to	O
the	O
extent	O
that	O
average	O
PCs	O
could	O
now	O
emulate	O
some	O
Amiga	B-Device
software	I-Device
faster	O
than	O
any	O
real	O
Amiga	B-Device
could	O
run	O
it	O
.	O
</s>
<s>
UAE	B-Device
can	O
use	O
as	O
much	O
of	O
the	O
host	O
's	O
power	O
in	O
native	B-Language
mode	I-Language
as	O
possible	O
,	O
or	O
balance	O
it	O
with	O
other	O
requirements	O
of	O
the	O
host	O
OS	O
,	O
or	O
to	O
accurately	O
reflect	O
the	O
original	O
speed	O
,	O
depending	O
on	O
a	O
user	O
's	O
choice	O
.	O
</s>
<s>
UAE	B-Device
also	O
provides	O
an	O
RTG-compatible	O
"	O
video	B-Device
card	I-Device
"	O
for	O
the	O
Amiga	B-Device
side	O
of	O
the	O
emulation	B-Application
which	O
is	O
tailored	O
for	O
display	O
on	O
the	O
host	O
hardware	B-Architecture
,	O
so	O
as	O
not	O
to	O
be	O
limited	O
to	O
the	O
emulation	B-Application
of	O
the	O
original	O
Amiga	B-Device
video	O
hardware	B-Architecture
.	O
</s>
<s>
There	O
are	O
six	O
main	O
forks	B-Application
of	O
the	O
original	O
program	O
:	O
</s>
<s>
UAE4all	O
,	O
a	O
stripped	O
and	O
optimized	O
version	O
,	O
designed	O
to	O
emulate	O
an	O
OCS	O
Amiga	B-Device
on	O
low-end	O
devices	O
.	O
</s>
<s>
UAE4all2	O
add	O
AGA	O
and	O
hard	B-Device
disk	I-Device
support	O
.	O
</s>
<s>
Scripted	O
Amiga	B-Device
Emulator	B-Application
(	O
SAE	O
)	O
,	O
designed	O
to	O
run	O
in	O
a	O
modern	O
browser	O
using	O
JavaScript	B-Language
and	O
HTML5	B-Application
.	O
</s>
<s>
It	O
is	O
also	O
based	O
on	O
WinUAE	B-Device
and	O
was	O
released	O
on	O
1	O
.	O
</s>
<s>
UAE4ARM	O
,	O
designed	O
to	O
run	O
on	O
ARM	O
devices	O
including	O
the	O
Raspberry	B-Operating_System
Pi	I-Operating_System
.	O
</s>
<s>
It	O
's	O
the	O
only	O
fork	B-Application
supporting	O
Just-In-Time	O
on	O
ARM	O
devices	O
.	O
</s>
<s>
Others	O
supported	O
platforms	O
are	O
Pandora	O
,	O
Android	B-Application
and	O
libretro	O
.	O
</s>
<s>
The	O
most	O
active	O
fork	B-Application
is	O
WinUAE	B-Device
;	O
current	O
versions	O
of	O
this	O
still	O
contain	O
bugs	O
and	O
compatibility	O
issues	O
.	O
</s>
