<s>
The	O
iPhone	B-Operating_System
4	O
is	O
a	O
smartphone	B-Application
that	O
was	O
designed	O
and	O
marketed	O
by	O
Apple	O
Inc	O
.	O
</s>
<s>
It	O
is	O
the	O
fourth	O
generation	B-Application
of	O
the	O
iPhone	B-Operating_System
lineup	O
,	O
succeeding	O
the	O
iPhone	B-Operating_System
3GS	I-Operating_System
and	O
preceding	O
the	O
4S	B-Operating_System
.	O
</s>
<s>
Following	O
a	O
number	O
of	O
notable	O
leaks	O
,	O
the	O
iPhone	B-Operating_System
4	O
was	O
first	O
unveiled	O
on	O
June	O
7	O
,	O
2010	O
,	O
at	O
Apple	O
's	O
Worldwide	O
Developers	O
Conference	O
in	O
San	O
Francisco	O
,	O
and	O
was	O
released	O
on	O
June	O
24	O
,	O
2010	O
,	O
in	O
the	O
United	O
States	O
,	O
United	O
Kingdom	O
,	O
France	O
,	O
Germany	O
,	O
and	O
Japan	O
.	O
</s>
<s>
The	O
iPhone	B-Operating_System
4	O
introduced	O
a	O
new	O
hardware	O
design	O
to	O
the	O
iPhone	B-Operating_System
family	O
,	O
which	O
Apple	O
's	O
CEO	B-Application
Steve	O
Jobs	O
touted	O
as	O
the	O
thinnest	O
smartphone	B-Application
in	O
the	O
world	O
at	O
the	O
time	O
;	O
it	O
consisted	O
of	O
a	O
stainless	O
steel	O
frame	O
which	O
doubled	O
as	O
an	O
antenna	O
,	O
with	O
internal	O
components	O
situated	O
between	O
two	O
panels	O
of	O
aluminosilicate	O
glass	O
.	O
</s>
<s>
The	O
iPhone	B-Operating_System
4	O
introduced	O
Apple	O
's	O
new	O
high-resolution	B-Algorithm
"	O
Retina	B-Operating_System
Display	I-Operating_System
"	O
(	O
with	O
a	O
pixel	B-Algorithm
density	I-Algorithm
of	O
326	O
pixels	B-Algorithm
per	I-Algorithm
inch	I-Algorithm
)	O
,	O
while	O
maintaining	O
the	O
same	O
physical	O
size	O
and	O
aspect	O
ratio	O
as	O
its	O
precursors	O
,	O
Apple	O
's	O
A4	O
system-on-chip	B-Architecture
,	O
along	O
with	O
iOS	B-Operating_System
4	I-Operating_System
—	O
which	O
notably	O
introduced	O
multitasking	O
functionality	O
and	O
app	O
folders	O
.	O
</s>
<s>
It	O
was	O
the	O
first	O
iPhone	B-Operating_System
at	O
the	O
time	O
to	O
include	O
a	O
front-facing	O
camera	O
,	O
which	O
made	O
possible	O
Apple	O
's	O
new	O
FaceTime	B-Operating_System
video	I-Operating_System
chat	O
service	O
,	O
and	O
the	O
first	O
to	O
be	O
released	O
in	O
a	O
version	O
for	O
CDMA	B-Protocol
networks	O
,	O
ending	O
T	O
's	O
period	O
as	O
the	O
exclusive	O
carrier	O
of	O
iPhone	B-Operating_System
products	O
in	O
the	O
United	O
States	O
.	O
</s>
<s>
The	O
iPhone	B-Operating_System
4	O
received	O
a	O
largely	O
positive	O
reception	O
,	O
with	O
critics	O
praising	O
its	O
revamped	O
design	O
and	O
more	O
powerful	O
hardware	O
,	O
in	O
comparison	O
to	O
previous	O
models	O
.	O
</s>
<s>
While	O
it	O
was	O
a	O
market	O
success	O
(	O
with	O
over	O
600,000	O
pre-orders	O
within	O
24	O
hours	O
)	O
,	O
the	O
release	O
of	O
the	O
iPhone	B-Operating_System
4	O
was	O
plagued	O
by	O
highly	O
publicized	O
reports	O
concerning	O
abnormalities	O
in	O
its	O
new	O
antenna	O
design	O
that	O
caused	O
the	O
device	O
to	O
lose	O
its	O
cellular	O
signal	O
if	O
held	O
in	O
a	O
certain	O
way	O
.	O
</s>
<s>
The	O
iPhone	B-Operating_System
4	O
spent	O
the	O
longest	O
time	O
as	O
Apple	O
's	O
flagship	O
iPhone	B-Operating_System
model	O
at	O
fifteen	O
months	O
.	O
</s>
<s>
Although	O
the	O
succeeding	O
4S	B-Operating_System
was	O
announced	O
in	O
October	O
2011	O
,	O
the	O
4	O
continued	O
to	O
be	O
sold	O
as	O
a	O
midrange	O
model	O
until	O
September	O
2012	O
,	O
and	O
thereafter	O
as	O
the	O
entry-level	O
offering	O
in	O
Apple	O
's	O
lineup	O
until	O
September	O
2013	O
with	O
the	O
announcement	O
of	O
the	O
iPhone	B-Operating_System
5S	I-Operating_System
and	O
iPhone	B-Operating_System
5C	I-Operating_System
.	O
</s>
<s>
The	O
iPhone	B-Operating_System
4	O
had	O
one	O
of	O
the	O
longest	O
lifespans	O
of	O
any	O
iPhone	B-Operating_System
ever	O
produced	O
,	O
spanning	O
close	O
to	O
four	O
years	O
and	O
available	O
in	O
some	O
developing	O
countries	O
until	O
early	O
2015	O
.	O
</s>
<s>
Before	O
the	O
official	O
unveiling	O
of	O
the	O
iPhone	B-Operating_System
4	O
on	O
June	O
7	O
,	O
2010	O
,	O
two	O
prototypes	B-Application
were	O
brought	O
to	O
the	O
attention	O
of	O
the	O
media	O
,	O
breaching	O
Apple	O
's	O
normally	O
secretive	O
development	O
process	O
.	O
</s>
<s>
On	O
January	O
27	O
,	O
2010	O
,	O
gadget	O
website	O
Engadget	B-Application
received	O
leaked	O
images	O
of	O
the	O
unreleased	O
first-generation	B-Operating_System
iPad	I-Operating_System
.	O
</s>
<s>
Unbeknownst	O
to	O
the	O
editors	O
and	O
readers	O
,	O
these	O
images	O
contained	O
two	O
unreleased	O
iPhone	B-Operating_System
4	O
models	O
.	O
</s>
<s>
On	O
April	O
19	O
,	O
2010	O
,	O
gadget	O
website	O
Gizmodo	O
reported	O
that	O
they	O
had	O
purchased	O
an	O
iPhone	B-Operating_System
prototype	B-Application
for	O
$5000	O
,	O
and	O
furthermore	O
,	O
had	O
conducted	O
a	O
product	O
teardown	O
of	O
the	O
device	O
.	O
</s>
<s>
The	O
prototype	B-Application
was	O
reported	O
to	O
have	O
been	O
lost	O
by	O
an	O
Apple	O
employee	O
,	O
Gray	O
Powell	O
,	O
in	O
Redwood	O
City	O
,	O
California	O
.	O
</s>
<s>
Shortly	O
after	O
Gizmodo	O
published	O
detailed	O
information	O
about	O
the	O
prototype	B-Application
,	O
Apple	O
's	O
legal	O
associates	O
formally	O
requested	O
for	O
the	O
phone	O
to	O
be	O
returned	O
to	O
Apple	O
,	O
and	O
Gizmodo	O
responded	O
with	O
the	O
intent	O
to	O
cooperate	O
.	O
</s>
<s>
On	O
April	O
23	O
,	O
officers	O
from	O
the	O
Rapid	O
Enforcement	O
Allied	O
Computer	O
Team	O
(	O
REACT	O
)	O
task	O
force	O
of	O
the	O
California	O
HTTAP	O
Program	O
raided	O
the	O
home	O
of	O
Jason	O
Chen	O
,	O
the	O
Gizmodo	O
editor	O
responsible	O
for	O
reviewing	O
the	O
prototype	B-Application
,	O
seizing	O
all	O
of	O
his	O
computers	O
and	O
hard	O
drives	O
.	O
</s>
<s>
Apple	O
had	O
already	O
received	O
the	O
iPhone	B-Operating_System
prototype	B-Application
before	O
the	O
raid	O
when	O
it	O
was	O
returned	O
by	O
Gizmodo	O
.	O
</s>
<s>
Pictures	O
and	O
video	O
of	O
a	O
second	O
prototype	B-Application
were	O
published	O
on	O
a	O
Vietnamese	O
website	O
,	O
Taoviet	O
,	O
on	O
May	O
12	O
,	O
2010	O
.	O
</s>
<s>
The	O
website	O
purchased	O
the	O
prototype	B-Application
for	O
$	O
4,000	O
.	O
</s>
<s>
DigiTimes	O
reported	O
that	O
the	O
screen	O
resolution	B-Algorithm
of	O
the	O
new	O
phone	O
was	O
960-by-640	O
,	O
which	O
was	O
confirmed	O
by	O
Apple	O
at	O
the	O
iPhone	B-Operating_System
4	O
's	O
official	O
announcement	O
.	O
</s>
<s>
The	O
iPhone	B-Operating_System
4	O
was	O
available	O
for	O
pre-order	O
on	O
June	O
15	O
,	O
2010	O
.	O
</s>
<s>
Customers	O
attempting	O
to	O
pre-order	O
the	O
iPhone	B-Operating_System
4	O
reported	O
problems	O
with	O
the	O
pre-order	O
process	O
on	O
the	O
US	O
and	O
UK	O
online	O
Apple	O
Stores	O
which	O
crashed	O
due	O
to	O
the	O
surge	O
in	O
traffic	O
.	O
</s>
<s>
The	O
same	O
issue	O
was	O
reported	O
with	O
AT&T	O
and	O
SoftBank	O
,	O
Apple	O
's	O
exclusive	O
partners	O
in	O
the	O
United	O
States	O
and	O
Japan	O
respectively	O
,	O
who	O
suspended	O
advance	O
sales	O
of	O
the	O
iPhone	B-Operating_System
4	O
as	O
demand	O
threatened	O
to	O
exceed	O
supply	O
.	O
</s>
<s>
Apple	O
and	O
its	O
partner	O
carriers	O
received	O
600,000	O
pre-orders	O
for	O
the	O
iPhone	B-Operating_System
4	O
in	O
the	O
first	O
24	O
hours	O
,	O
the	O
largest	O
number	O
of	O
pre-orders	O
Apple	O
had	O
received	O
in	O
a	O
single	O
day	O
for	O
any	O
device	O
up	O
to	O
that	O
point	O
.	O
</s>
<s>
Engadget	B-Application
reported	O
that	O
at	O
20:30	O
UTC	O
,	O
all	O
iPhone	B-Operating_System
4	O
pre-order	O
suppliers	O
had	O
sold	O
out	O
.	O
</s>
<s>
1.7million	O
iPhone	B-Operating_System
4	O
models	O
were	O
sold	O
in	O
its	O
first	O
three	O
days	O
of	O
availability	O
.	O
</s>
<s>
The	O
iPhone	B-Operating_System
4	O
was	O
also	O
released	O
through	O
Orange	O
in	O
Tunisia	O
and	O
was	O
available	O
in	O
eight	O
cities	O
at	O
the	O
launch	O
.	O
</s>
<s>
On	O
July	O
30	O
,	O
2010	O
,	O
iPhone	B-Operating_System
4	O
was	O
made	O
available	O
for	O
sale	O
in	O
Australia	O
,	O
New	O
Zealand	O
and	O
15	O
other	O
countries	O
with	O
free	O
bumper	O
cases	O
.	O
</s>
<s>
The	O
iPhone	B-Operating_System
4	O
was	O
released	O
in	O
South	O
Africa	O
on	O
September	O
22	O
on	O
the	O
Vodacom	O
and	O
MTN	O
networks	O
,	O
in	O
very	O
limited	O
quantities	O
.	O
</s>
<s>
The	O
iPhone	B-Operating_System
4	O
was	O
launched	O
in	O
Vietnam	O
on	O
September	O
30	O
on	O
VinaPhone	O
and	O
Viettel	O
,	O
at	O
first	O
in	O
3	O
major	O
cities	O
:	O
Hanoi	O
,	O
Ho	O
Chi	O
Minh	O
City	O
and	O
Da	O
Nang	O
,	O
and	O
then	O
all	O
over	O
the	O
country	O
by	O
the	O
end	O
of	O
October	O
.	O
</s>
<s>
The	O
iPhone	B-Operating_System
4	O
was	O
launched	O
in	O
India	O
on	O
May	O
27	O
,	O
2011	O
by	O
Aircel	O
and	O
Airtel	O
.	O
</s>
<s>
On	O
January	O
11	O
,	O
2011	O
,	O
Verizon	B-Application
Wireless	I-Application
announced	O
during	O
a	O
media	O
event	O
that	O
it	O
had	O
reached	O
an	O
agreement	O
with	O
Apple	O
and	O
would	O
begin	O
selling	O
a	O
CDMA	B-Protocol
iPhone	B-Operating_System
4	O
in	O
the	O
United	O
States	O
,	O
ending	O
Apple	O
's	O
exclusivity	O
agreement	O
with	O
AT&T	O
.	O
</s>
<s>
The	O
Verizon	B-Application
iPhone	B-Operating_System
went	O
on	O
sale	O
on	O
February	O
10	O
and	O
pre	O
orders	O
began	O
on	O
February	O
3	O
.	O
</s>
<s>
The	O
Verizon	B-Application
iPhone	B-Operating_System
includes	O
the	O
'	O
Personal	O
Hotspot	B-Application
"	O
feature	O
which	O
allows	O
a	O
user	O
to	O
use	O
the	O
iPhone	B-Operating_System
as	O
a	O
wireless	B-Application
hotspot	I-Application
,	O
with	O
up	O
to	O
five	O
devices	O
connecting	O
at	O
one	O
time	O
.	O
</s>
<s>
The	O
February	O
3	O
,	O
2011	O
,	O
presale	O
of	O
the	O
iPhone	B-Operating_System
4	O
broke	O
Verizon	B-Application
's	O
first	O
day	O
sales	O
records	O
for	O
a	O
single	O
device	O
.	O
</s>
<s>
On	O
June	O
24	O
,	O
2010	O
,	O
Apple	O
stated	O
that	O
the	O
white	O
iPhone	B-Operating_System
4	O
models	O
were	O
proving	O
more	O
"	O
challenging	O
to	O
manufacture	O
"	O
than	O
expected	O
,	O
and	O
initially	O
pushed	O
the	O
release	O
date	O
back	O
to	O
the	O
second	O
half	O
of	O
July	O
.	O
</s>
<s>
There	O
was	O
a	O
lot	O
of	O
speculation	O
surrounding	O
the	O
delay	O
of	O
the	O
white	O
iPhone	B-Operating_System
4	O
.	O
</s>
<s>
On	O
April	O
27	O
,	O
2011	O
,	O
Apple	O
announced	O
that	O
it	O
would	O
be	O
releasing	O
the	O
white	O
iPhone	B-Operating_System
4	O
model	O
on	O
April	O
28	O
,	O
2011	O
,	O
for	O
both	O
GSM	O
and	O
CDMA	B-Protocol
.	O
</s>
<s>
The	O
release	O
of	O
the	O
white	O
iPhone	B-Operating_System
4	O
was	O
carried	O
out	O
on	O
April	O
28	O
.	O
</s>
<s>
During	O
Apple	O
's	O
official	O
unveiling	O
of	O
the	O
iPhone	B-Operating_System
4S	I-Operating_System
on	O
October	O
4	O
,	O
2011	O
,	O
it	O
was	O
announced	O
that	O
Sprint	O
would	O
begin	O
carrying	O
the	O
reconfigured	O
CDMA	B-Protocol
iPhone	B-Operating_System
4	O
and	O
the	O
iPhone	B-Operating_System
4S	I-Operating_System
in	O
the	O
US	O
on	O
October	O
14	O
.	O
</s>
<s>
In	O
September	O
2013	O
,	O
after	O
the	O
release	O
of	O
the	O
iPhone	B-Operating_System
5S	I-Operating_System
and	O
iPhone	B-Operating_System
5C	I-Operating_System
,	O
Apple	O
stopped	O
selling	O
the	O
iPhone	B-Operating_System
4	O
in	O
most	O
of	O
their	O
stores	O
as	O
well	O
as	O
on	O
their	O
website	O
.	O
</s>
<s>
It	O
was	O
replaced	O
by	O
the	O
8GB	O
iPhone	B-Operating_System
4S	I-Operating_System
.	O
</s>
<s>
The	O
display	O
of	O
the	O
iPhone	B-Operating_System
4	O
was	O
manufactured	O
by	O
LG	O
under	O
an	O
exclusive	O
contract	O
with	O
Apple	O
.	O
</s>
<s>
It	O
features	O
an	O
LED	O
backlit	O
TFT	B-Device
LCD	I-Device
capacitive	O
touchscreen	B-Device
with	O
a	O
pixel	B-Algorithm
density	I-Algorithm
of	O
326	O
pixels	B-Algorithm
per	I-Algorithm
inch	I-Algorithm
(	O
ppi	B-Algorithm
)	O
on	O
a	O
(	O
diagonally	O
measured	O
)	O
,	O
960×640	O
display	O
.	O
</s>
<s>
The	O
screen	O
was	O
marketed	O
by	O
Apple	O
as	O
the	O
"	O
Retina	B-Operating_System
display	I-Operating_System
"	O
,	O
based	O
on	O
the	O
assertion	O
that	O
a	O
display	O
of	O
approximately	O
300	O
ppi	B-Algorithm
at	O
a	O
distance	O
of	O
from	O
one	O
's	O
eye	O
,	O
or	O
57	O
arcseconds	O
per	O
pixel	O
is	O
the	O
maximum	O
amount	O
of	O
detail	O
that	O
the	O
human	O
retina	O
can	O
perceive	O
.	O
</s>
<s>
With	O
the	O
iPhone	B-Operating_System
expected	O
to	O
be	O
used	O
at	O
a	O
distance	O
of	O
about	O
12inches	O
from	O
the	O
eyes	O
,	O
a	O
higher	O
resolution	B-Algorithm
would	O
allegedly	O
have	O
no	O
effect	O
on	O
the	O
image	O
's	O
apparent	O
quality	O
as	O
the	O
maximum	O
potential	O
of	O
the	O
human	O
eye	O
has	O
already	O
been	O
met	O
.	O
</s>
<s>
Soneira	O
stated	O
that	O
the	O
resolution	B-Algorithm
of	O
the	O
human	O
retina	O
is	O
higher	O
than	O
claimed	O
by	O
Apple	O
,	O
working	O
out	O
to	O
477	O
PPI	B-Algorithm
at	O
from	O
the	O
eyes	O
,	O
or	O
36	O
arcseconds	O
per	O
pixel	O
.	O
</s>
<s>
However	O
,	O
Phil	O
Plait	O
,	O
author	O
of	O
Bad	O
Astronomy	O
,	O
whose	O
career	O
includes	O
a	O
collaboration	O
with	O
NASA	O
regarding	O
the	O
camera	O
on	O
the	O
Hubble	O
Space	O
Telescope	O
,	O
responded	O
to	O
the	O
criticism	O
by	O
stating	O
that	O
"	O
if	O
you	O
have	O
[	O
better	O
than	O
20/20	O
]	O
eyesight	O
,	O
then	O
at	O
one	O
foot	O
away	O
the	O
iPhone	B-Operating_System
4	O
's	O
pixels	O
are	O
resolved	O
.	O
</s>
<s>
The	O
iPhone	B-Operating_System
4	O
features	O
an	O
additional	O
front-facing	O
VGA	B-Protocol
camera	O
,	O
and	O
a	O
backside-illuminated	O
5	B-Operating_System
megapixel	O
rear-facing	O
camera	O
with	O
a	O
3.85mm	O
f/2.8	O
lens	O
and	O
an	O
LED	O
flash	O
.	O
</s>
<s>
The	O
rear-facing	O
5-megapixel	O
camera	O
is	O
capable	O
of	O
recording	O
HD	O
video	O
in	O
720p	O
at	O
30	O
frames	O
per	O
second	O
.	O
</s>
<s>
Both	O
cameras	O
make	O
use	O
of	O
the	O
tap	O
to	O
focus	O
feature	O
,	O
part	O
of	O
iOS	B-Operating_System
4	I-Operating_System
,	O
for	O
photo	O
and	O
video	O
recording	O
.	O
</s>
<s>
The	O
rear-facing	O
camera	O
has	O
a	O
5×	O
digital	B-Algorithm
zoom	I-Algorithm
.	O
</s>
<s>
In	O
contrast	O
to	O
Steve	O
Jobs	O
 '	O
announcement	O
at	O
WWDC	O
2010	O
,	O
recent	O
Federal	O
Communications	O
Commission	O
documentation	O
showed	O
that	O
,	O
in	O
fact	O
,	O
the	O
iPhone	B-Operating_System
4	O
contains	O
a	O
penta-band	O
3G	B-Architecture
UMTS	B-Protocol
antenna	O
,	O
not	O
a	O
quad-band	O
3G	B-Architecture
UMTS	B-Protocol
radio	O
,	O
as	O
advertised	O
by	O
Apple	O
.	O
</s>
<s>
According	O
to	O
the	O
FCC	O
documentation	O
filed	O
by	O
Apple	O
,	O
the	O
radio	O
inside	O
the	O
iPhone	B-Operating_System
4	O
supports	O
800	O
,	O
850	O
,	O
900	O
,	O
1	O
,	O
900	O
,	O
and	O
2,100	O
MHz	O
.	O
</s>
<s>
As	O
with	O
most	O
of	O
Apple	O
's	O
mobile	O
products	O
at	O
the	O
time	O
,	O
the	O
iPhone	B-Operating_System
4	O
also	O
used	O
the	O
30	O
pin	O
dock	O
connector	O
as	O
its	O
only	O
external	O
data	O
port	O
.	O
</s>
<s>
The	O
iPhone	B-Operating_System
4	O
is	O
the	O
first	O
generation	B-Application
of	O
iPhone	B-Operating_System
to	O
have	O
a	O
second	O
microphone	B-Algorithm
used	O
for	O
noise	O
cancellation	O
.	O
</s>
<s>
It	O
is	O
located	O
on	O
the	O
top	O
of	O
the	O
unit	O
near	O
the	O
headphone	B-Device
jack	I-Device
;	O
the	O
main	O
microphone	B-Algorithm
is	O
on	O
the	O
bottom	O
left	O
.	O
</s>
<s>
The	O
iPhone	B-Operating_System
4	O
introduces	O
a	O
gyroscopic	O
sensor	O
that	O
detects	O
3-axis	O
angular	O
acceleration	O
around	O
the	O
X	O
,	O
Y	O
,	O
and	O
Z	O
axes	O
,	O
enabling	O
precise	O
calculation	O
of	O
yaw	O
,	O
pitch	O
,	O
and	O
roll	O
.	O
</s>
<s>
The	O
gyroscope	B-Application
complements	O
the	O
accelerometer	O
,	O
a	O
sensor	O
that	O
has	O
been	O
present	O
since	O
the	O
original	B-Operating_System
iPhone	I-Operating_System
,	O
which	O
detects	O
the	O
device	O
's	O
acceleration	O
,	O
shake	O
,	O
vibration	O
shock	O
,	O
or	O
fall	O
by	O
detecting	O
linear	O
acceleration	O
along	O
with	O
one	O
of	O
three	O
axes	O
(	O
X	O
,	O
Y	O
,	O
and	O
Z	O
)	O
.	O
</s>
<s>
The	O
combined	O
data	O
from	O
the	O
accelerometer	O
and	O
the	O
gyroscope	B-Application
provides	O
detailed	O
and	O
precise	O
information	O
about	O
the	O
device	O
's	O
6-axis	O
movement	O
in	O
space	O
.	O
</s>
<s>
The	O
3	O
axes	O
of	O
the	O
gyroscope	B-Application
combined	O
with	O
the	O
3	O
axes	O
of	O
the	O
accelerometer	O
enable	O
the	O
device	O
to	O
recognize	O
approximately	O
how	O
far	O
,	O
fast	O
,	O
and	O
in	O
which	O
direction	O
it	O
has	O
moved	O
in	O
space	O
.	O
</s>
<s>
The	O
iPhone	B-Operating_System
4	O
is	O
powered	O
by	O
the	O
Apple	O
A4	O
chip	O
,	O
which	O
was	O
designed	O
by	O
Intrinsity	O
and	O
,	O
like	O
all	O
prior	O
iPhone	B-Operating_System
models	O
,	O
manufactured	O
by	O
Samsung	O
.	O
</s>
<s>
This	O
system-on-a-chip	B-Architecture
is	O
composed	O
of	O
an	O
ARM	B-Architecture
Cortex-A8	I-Architecture
CPU	B-General_Concept
integrated	O
with	O
a	O
PowerVR	B-Device
SGX535	O
GPU	B-Architecture
.	O
</s>
<s>
The	O
Apple	O
A4	O
was	O
also	O
used	O
in	O
the	O
first-generation	B-Operating_System
iPad	I-Operating_System
(	O
released	O
in	O
2010	O
)	O
,	O
where	O
it	O
was	O
clocked	O
at	O
its	O
rated	O
speed	O
of	O
1GHz	O
.	O
</s>
<s>
The	O
Apple	O
A4	O
was	O
the	O
first	O
ever	O
CPU	B-General_Concept
designed	O
by	O
Apple	O
.	O
</s>
<s>
The	O
clock	O
speed	O
in	O
the	O
iPhone	B-Operating_System
4	O
was	O
never	O
disclosed	O
.	O
</s>
<s>
All	O
prior	O
models	O
of	O
the	O
iPhone	B-Operating_System
had	O
underclocked	B-Device
the	O
CPU	B-General_Concept
,	O
which	O
typically	O
extends	O
battery	O
life	O
and	O
lowers	O
heat	B-General_Concept
dissipation	I-General_Concept
.	O
</s>
<s>
The	O
iPhone	B-Operating_System
4	O
has	O
512MB	O
of	O
DRAM	O
.	O
</s>
<s>
As	O
on	O
prior	O
models	O
,	O
all	O
data	O
is	O
stored	O
in	O
flash	B-Device
memory	I-Device
,	O
8	O
,	O
16	O
or	O
32GB	O
,	O
and	O
not	O
on	O
the	O
SIM	O
.	O
</s>
<s>
The	O
iPhone	B-Operating_System
4	O
uses	O
a	O
micro-SIM	O
card	O
on	O
iPhone	B-Operating_System
4	O
devices	O
running	O
on	O
a	O
GSM	O
network	O
,	O
which	O
is	O
positioned	O
in	O
an	O
ejectable	O
tray	O
,	O
located	O
on	O
the	O
right	O
side	O
of	O
the	O
device	O
.	O
</s>
<s>
On	O
a	O
CDMA	B-Protocol
network	O
,	O
however	O
,	O
the	O
phone	O
connects	O
to	O
the	O
network	O
using	O
an	O
ESN	O
.	O
</s>
<s>
The	O
iPhone	B-Operating_System
4	O
features	O
a	O
redesigned	O
structure	O
,	O
designed	O
by	O
Jony	O
Ive	O
,	O
a	O
design	O
that	O
would	O
later	O
be	O
reused	O
and	O
adapted	O
for	O
the	O
iPhone	B-Operating_System
4S	I-Operating_System
,	O
5	B-Operating_System
,	O
5S	B-Operating_System
and	O
first-generation	B-Operating_System
iPhone	I-Operating_System
SE	I-Operating_System
.	O
</s>
<s>
The	O
redesign	O
reflects	O
the	O
utilitarianism	O
and	O
uniformity	O
of	O
existing	O
Apple	O
products	O
,	O
such	O
as	O
the	O
iPad	B-Device
and	O
the	O
iMac	B-Device
.	O
</s>
<s>
The	O
overall	O
dimensions	O
of	O
the	O
iPhone	B-Operating_System
4	O
have	O
been	O
reduced	O
from	O
their	O
predecessor	O
.	O
</s>
<s>
It	O
is	O
high	O
,	O
wide	O
,	O
and	O
deep	O
,	O
compared	O
to	O
the	O
iPhone	B-Operating_System
3GS	I-Operating_System
,	O
which	O
is	O
high	O
,	O
wide	O
,	O
and	O
deep	O
;	O
making	O
the	O
iPhone	B-Operating_System
4	O
24%	O
thinner	O
than	O
its	O
predecessor	O
,	O
the	O
iPhone	B-Operating_System
3GS	I-Operating_System
.	O
</s>
<s>
Steve	O
Jobs	O
claimed	O
it	O
to	O
be	O
"	O
the	O
thinnest	O
smartphone	B-Application
on	O
the	O
planet.	O
"	O
</s>
<s>
The	O
iPhone	B-Operating_System
4	O
is	O
structured	O
around	O
a	O
stainless	O
steel	O
frame	O
that	O
wraps	O
around	O
the	O
edge	O
of	O
the	O
phone	O
,	O
acting	O
both	O
as	O
the	O
primary	O
structure	O
for	O
the	O
device	O
and	O
as	O
the	O
iPhone	B-Operating_System
4	O
's	O
antennas	O
.	O
</s>
<s>
This	O
metal	O
band	O
features	O
two	O
slits	O
on	O
the	O
GSM	O
version	O
of	O
the	O
phone	O
,	O
one	O
at	O
the	O
lower	O
left	O
,	O
and	O
one	O
at	O
the	O
top	O
(	O
and	O
a	O
fake	O
slit	O
along	O
the	O
lower	O
right	O
,	O
to	O
cosmetically	O
mirror	O
the	O
one	O
at	O
the	O
lower	O
left	O
)	O
that	O
divide	O
the	O
band	O
into	O
two	O
antenna	O
sections	O
:	O
the	O
left	O
section	O
of	O
the	O
band	O
serves	O
as	O
the	O
Bluetooth	B-Protocol
,	O
Wi-Fi	O
,	O
and	O
GPS	O
antenna	O
,	O
and	O
the	O
right	O
and	O
lower	O
sections	O
of	O
the	O
band	O
act	O
as	O
the	O
antenna	O
for	O
GSM	O
and	O
UMTS	B-Protocol
connectivity	O
.	O
</s>
<s>
On	O
the	O
CDMA	B-Protocol
version	O
of	O
the	O
phone	O
,	O
there	O
are	O
four	O
slits	O
in	O
the	O
metal	O
band	O
.	O
</s>
<s>
The	O
top	O
portion	O
of	O
the	O
band	O
(	O
divided	O
by	O
the	O
top	O
left	O
and	O
right	O
slits	O
)	O
is	O
for	O
connecting	O
to	O
the	O
CDMA	B-Protocol
network	O
.	O
</s>
<s>
The	O
left	O
portion	O
of	O
the	O
metal	O
band	O
is	O
for	O
Bluetooth	B-Protocol
,	O
Wi-Fi	O
,	O
and	O
GPS	O
just	O
like	O
the	O
GSM	O
version	O
.	O
</s>
<s>
In	O
fall	O
2010	O
,	O
pentalobe	B-Operating_System
screws	I-Operating_System
started	O
to	O
replace	O
the	O
Philips	O
screws	O
used	O
in	O
post-repair	O
units	O
in	O
the	O
US	O
and	O
in	O
production	O
units	O
in	O
Japan	O
.	O
</s>
<s>
The	O
iPhone	B-Operating_System
4	O
shipped	O
with	O
iOS	B-Operating_System
4	I-Operating_System
,	O
which	O
was	O
the	O
newest	O
version	O
of	O
Apple	O
's	O
iOS	B-Application
mobile	B-Operating_System
operating	I-Operating_System
system	I-Operating_System
at	O
the	O
time	O
.	O
</s>
<s>
iOS	B-Operating_System
4	I-Operating_System
introduced	O
a	O
multitasking	O
system	O
,	O
allowing	O
apps	O
to	O
remain	O
"	O
suspended	O
"	O
in	O
memory	O
,	O
perform	O
certain	O
operations	O
in	O
the	O
background	O
,	O
and	O
allowing	O
users	O
to	O
switch	O
between	O
apps	O
using	O
an	O
on-screen	O
menu	O
.	O
</s>
<s>
It	O
also	O
introduced	O
FaceTime	B-Operating_System
,	O
which	O
allows	O
users	O
to	O
perform	O
video	B-Application
calls	I-Application
between	O
other	O
iPhone	B-Operating_System
,	O
iPad	B-Device
,	O
iPod	B-Device
Touch	I-Device
,	O
and	O
OS	B-Operating_System
X	I-Operating_System
users	O
.	O
</s>
<s>
The	O
iPhone	B-Operating_System
4	O
supports	O
up	O
to	O
iOS	B-Operating_System
7	I-Operating_System
,	O
released	O
in	O
September	O
2013	O
.	O
</s>
<s>
Due	O
to	O
the	O
relatively	O
aged	O
hardware	O
of	O
the	O
iPhone	B-Operating_System
4	O
,	O
most	O
features	O
available	O
on	O
newer	O
iPhone	B-Operating_System
models	O
are	O
not	O
available	O
on	O
the	O
device	O
;	O
as	O
of	O
iOS	B-Operating_System
7	I-Operating_System
,	O
they	O
include	O
Siri	B-Application
,	O
3D	O
maps	B-Application
and	O
turn-by-turn	O
navigation	O
,	O
AirDrop	B-Operating_System
,	O
AirPlay	O
mirroring	O
,	O
live	O
camera	O
filters	O
,	O
panorama	O
mode	O
and	O
certain	O
visual	O
effects	O
introduced	O
by	O
iOS	B-Operating_System
7	I-Operating_System
,	O
such	O
as	O
the	O
blurring	O
of	O
translucent	O
interface	O
elements	O
,	O
the	O
parallax	B-Device
effect	O
on	O
the	O
home	O
screen	O
,	O
and	O
live	O
wallpapers	O
.	O
</s>
<s>
While	O
still	O
subject	O
to	O
the	O
same	O
limitations	O
,	O
iOS	B-Application
7.1	O
did	O
bring	O
some	O
slight	O
performance	O
improvements	O
to	O
the	O
operating	O
system	O
on	O
the	O
iPhone	B-Operating_System
4	O
.	O
iOS	B-Operating_System
7	I-Operating_System
,	O
specifically	O
iOS	B-Application
7.1.2	O
,	O
is	O
the	O
last	O
version	O
of	O
iOS	B-Application
to	O
support	O
the	O
iPhone	B-Operating_System
4	O
.	O
</s>
<s>
Unlike	O
the	O
iPhone	B-Operating_System
4S	I-Operating_System
,	O
the	O
iPhone	B-Operating_System
4	O
did	O
not	O
receive	O
the	O
iOS	B-Application
8	O
update	O
due	O
to	O
performance	O
issues	O
.	O
</s>
<s>
Apple	O
updated	O
the	O
bumper	O
with	O
a	O
wider	O
volume	O
switch	O
hole	O
with	O
the	O
release	O
of	O
the	O
iPhone	B-Operating_System
4	O
for	O
CDMA	B-Protocol
networks	O
.	O
</s>
<s>
The	O
updated	O
bumper	O
is	O
also	O
compatible	O
with	O
iPhone	B-Operating_System
4S	I-Operating_System
,	O
the	O
next-generation	O
iPhone	B-Operating_System
that	O
has	O
the	O
same	O
exterior	O
design	O
and	O
measurements	O
as	O
the	O
CDMA	B-Protocol
model	O
of	O
the	O
iPhone	B-Operating_System
4	O
,	O
but	O
with	O
a	O
SIM	O
card	O
slot	O
as	O
well	O
.	O
</s>
<s>
Rhodri	O
Marsden	O
of	O
The	O
Independent	O
said	O
that	O
"	O
aside	O
from	O
the	O
introduction	O
of	O
face-to-face	O
video	B-Application
calling	I-Application
,	O
it	O
's	O
not	O
a	O
staggering	O
feature	O
set	O
,	O
"	O
instead	O
focusing	O
on	O
how	O
the	O
device	O
is	O
"	O
more	O
powerful	O
than	O
its	O
predecessor	O
,	O
speedier	O
,	O
easier	O
to	O
use	O
and	O
will	O
make	O
previously	O
laborious	O
tasks	O
seem	O
like	O
a	O
cinch	O
"	O
.	O
</s>
<s>
CNET	O
reacted	O
to	O
the	O
announcement	O
by	O
explaining	O
how	O
it	O
believes	O
that	O
iMovie	O
for	O
iOS	B-Application
was	O
the	O
"	O
most	O
exciting	O
part	O
of	O
this	O
year	O
's	O
WWDC	O
Keynote	O
"	O
.	O
</s>
<s>
The	O
article	O
noted	O
how	O
the	O
iPhone	B-Operating_System
4	O
,	O
unlike	O
current	O
cameras	O
,	O
can	O
record	O
HD	O
content	O
and	O
then	O
edit	O
it	O
from	O
the	O
same	O
device	O
,	O
labeling	O
it	O
a	O
"	O
true	O
mobile	O
editing	O
suite	O
"	O
.	O
</s>
<s>
Reviews	O
of	O
the	O
iPhone	B-Operating_System
4	O
were	O
largely	O
positive	O
.	O
</s>
<s>
Engadget	B-Application
named	O
it	O
the	O
"	O
best	O
smartphone	B-Application
on	O
the	O
market	O
"	O
in	O
June	O
2010	O
.	O
</s>
<s>
CNET	O
gave	O
the	O
iPhone	B-Operating_System
4	O
a	O
rating	O
of	O
8.6	O
out	O
of	O
10	O
,	O
one	O
of	O
the	O
highest	O
ratings	O
it	O
had	O
given	O
any	O
smartphone	B-Application
.	O
</s>
<s>
TechRadar	O
gave	O
the	O
device	O
4.5/5	O
stars	O
.	O
</s>
<s>
Consumer	O
Reports	O
said	O
the	O
signal	O
problem	O
was	O
the	O
reason	O
they	O
did	O
not	O
rate	O
it	O
a	O
"	O
recommended	O
"	O
model	O
,	O
although	O
the	O
other	O
tests	O
ranked	O
it	O
highest	O
among	O
smart	B-Application
phones	I-Application
.	O
</s>
<s>
Joshua	O
Topolsky	O
of	O
Engadget	B-Application
described	O
the	O
device	O
's	O
industrial	O
design	O
as	O
being	O
"	O
more	O
detailed	O
and	O
sophisticated	O
"	O
than	O
its	O
predecessor	O
.	O
</s>
<s>
Another	O
issue	O
reported	O
by	O
some	O
users	O
within	O
days	O
of	O
the	O
iPhone	B-Operating_System
4	O
release	O
was	O
that	O
during	O
calls	O
the	O
proximity	B-Device
sensor	I-Device
can	O
be	O
insensitive	O
,	O
so	O
that	O
facial	O
contact	O
with	O
the	O
touchscreen	B-Device
can	O
end	O
calls	O
,	O
mute	O
calls	O
,	O
and	O
dial	O
other	O
numbers	O
.	O
</s>
<s>
Some	O
users	O
reported	O
that	O
,	O
particularly	O
in	O
low-light	O
conditions	O
,	O
photos	O
taken	O
on	O
the	O
iPhone	B-Operating_System
4	O
sometimes	O
contained	O
blue	O
or	O
green	O
"	O
splotches.	O
"	O
</s>
<s>
Issues	O
with	O
white	B-Algorithm
balance	I-Algorithm
were	O
also	O
discovered	O
,	O
particularly	O
when	O
using	O
the	O
flash	O
.	O
</s>
<s>
Shortly	O
after	O
the	O
iPhone	B-Operating_System
4	O
was	O
launched	O
,	O
some	O
consumers	O
reported	O
that	O
signal	O
strength	O
of	O
the	O
phone	O
was	O
reduced	O
when	O
touching	O
the	O
lower	O
left	O
edge	O
of	O
the	O
phone	O
,	O
bridging	O
one	O
of	O
the	O
two	O
locations	O
which	O
separates	O
the	O
two	O
antennas	O
,	O
resulting	O
in	O
dropped	O
calls	O
in	O
some	O
areas	O
with	O
lower	O
signal	O
reception	O
.	O
</s>
<s>
Internally	O
,	O
senior	O
antenna	O
expert	O
Ruben	O
Caballero	O
raised	O
concerns	O
to	O
CEO	B-Application
Steve	O
Jobs	O
that	O
the	O
antenna	O
design	O
could	O
lead	O
to	O
dropped	O
calls	O
.	O
</s>
<s>
As	O
a	O
consequence	O
of	O
this	O
problem	O
,	O
it	O
was	O
reported	O
on	O
July	O
2	O
,	O
2010	O
that	O
several	O
iPhone	B-Operating_System
4	O
users	O
were	O
planning	O
on	O
suing	O
Apple	O
and	O
AT&T	O
for	O
fraud	O
by	O
concealment	O
,	O
negligence	O
,	O
intentional	O
misrepresentation	O
and	O
defective	O
design	O
.	O
</s>
<s>
The	O
legal	O
challenge	O
was	O
started	O
by	O
a	O
law	O
firm	O
,	O
who	O
set	O
up	O
a	O
website	O
to	O
recruit	O
disenchanted	O
iPhone	B-Operating_System
4	O
buyers	O
for	O
a	O
lawsuit	O
against	O
Apple	O
.	O
</s>
<s>
Apple	O
promised	O
to	O
correct	O
the	O
issue	O
and	O
release	O
a	O
software	O
update	O
within	O
a	O
few	O
weeks	O
that	O
would	O
address	O
the	O
"	O
mistake	O
"	O
,	O
which	O
had	O
been	O
present	O
since	O
the	O
original	B-Operating_System
iPhone	I-Operating_System
.	O
</s>
<s>
Consumer	O
Reports	O
initially	O
stated	O
that	O
the	O
iPhone	B-Operating_System
4	O
's	O
signal	O
issues	O
are	O
not	O
"	O
unique	O
,	O
and	O
may	O
not	O
be	O
serious	O
"	O
and	O
it	O
continued	O
to	O
mention	O
that	O
signal	O
loss	O
is	O
a	O
problem	O
that	O
is	O
faced	O
by	O
the	O
entire	O
smartphone	B-Application
industry	O
.	O
</s>
<s>
The	O
magazine	O
rejected	O
Apple	O
's	O
explanation	O
after	O
conducting	O
tests	O
in	O
a	O
controlled	O
environment	O
,	O
and	O
comparing	O
the	O
results	O
against	O
prior	O
generations	O
of	O
iPhone	B-Operating_System
.	O
</s>
<s>
It	O
sarcastically	O
pointed	O
out	O
that	O
using	O
a	O
piece	O
of	O
tape	O
to	O
cover	O
the	O
lower	O
left	O
antenna	O
gap	O
was	O
one	O
way	O
to	O
fix	O
the	O
problem	O
,	O
but	O
recommended	O
that	O
consumers	O
who	O
"	O
want	O
an	O
iPhone	B-Operating_System
that	O
works	O
well	O
without	O
a	O
masking-tape	O
fix	O
"	O
purchase	O
the	O
iPhone	B-Operating_System
3GS	I-Operating_System
instead	O
.	O
</s>
<s>
The	O
magazine	O
also	O
tested	O
the	O
iPhone	B-Operating_System
4	O
while	O
it	O
was	O
wearing	O
a	O
Bumper	O
,	O
a	O
frame-like	O
cover	O
sold	O
by	O
Apple	O
that	O
prevents	O
direct	O
contact	O
with	O
the	O
antenna	O
,	O
reporting	O
that	O
it	O
did	O
resolve	O
the	O
problem	O
.	O
</s>
<s>
CNN	B-Architecture
repeated	O
Consumer	O
Reports'''	O
statement	O
that	O
a	O
small	O
amount	O
of	O
duct	O
tape	O
had	O
proven	O
an	O
effective	O
fix	O
to	O
the	O
iPhone	B-Operating_System
4	O
's	O
dropped	O
call	O
issue	O
.	O
</s>
<s>
On	O
July	O
16	O
,	O
2010	O
,	O
at	O
a	O
press	O
conference	O
which	O
included	O
a	O
private	O
tour	O
of	O
Apple	O
's	O
antenna	O
design	O
lab	O
for	O
journalists	O
,	O
Steve	O
Jobs	O
announced	O
that	O
Apple	O
would	O
provide	O
all	O
iPhone	B-Operating_System
4	O
owners	O
with	O
a	O
free	O
case	O
to	O
help	O
solve	O
the	O
antenna	O
issue	O
and	O
a	O
refund	O
to	O
those	O
users	O
who	O
had	O
already	O
purchased	O
a	O
Bumper	O
.	O
</s>
<s>
Additionally	O
,	O
Jobs	O
cited	O
figures	O
from	O
AppleCare	O
which	O
showed	O
that	O
only	O
0.55	O
percent	O
of	O
all	O
iPhone	B-Operating_System
4	O
users	O
have	O
complained	O
to	O
the	O
company	O
about	O
the	O
issue	O
,	O
while	O
the	O
number	O
of	O
phones	O
returned	O
to	O
Apple	O
was	O
1.7	O
percent	O
–	O
4.3	O
percentage	O
points	O
less	O
than	O
the	O
number	O
of	O
iPhone	B-Operating_System
3GS	I-Operating_System
models	O
that	O
were	O
returned	O
in	O
the	O
first	O
month	O
of	O
the	O
phone	O
's	O
launch.Consumer	O
Reports	O
noted	O
that	O
the	O
solution	O
was	O
not	O
permanent	O
,	O
though	O
a	O
good	O
first	O
step	O
.	O
</s>
<s>
However	O
,	O
because	O
Jobs	O
did	O
not	O
specify	O
a	O
time	O
line	O
for	O
fixing	O
the	O
problem	O
,	O
and	O
the	O
offering	O
for	O
a	O
free	O
bumper	O
only	O
being	O
a	O
temporary	O
solution	O
,	O
PC	O
World''	O
decided	O
to	O
remove	O
the	O
iPhone	B-Operating_System
4	O
from	O
its	O
"	O
Top	O
10	O
Cell	O
Phones	O
"	O
chart	O
and	O
reassign	O
it	O
to	O
a	O
pending	O
rating	O
.	O
</s>
<s>
Despite	O
the	O
negative	O
media	O
attention	O
regarding	O
the	O
antenna	O
issues	O
,	O
72%	O
of	O
iPhone	B-Operating_System
4	O
users	O
say	O
that	O
they	O
are	O
"	O
very	O
satisfied	O
"	O
with	O
their	O
iPhone	B-Operating_System
4	O
according	O
to	O
an	O
August	O
2010	O
survey	O
by	O
ChangeWave	O
Research	O
.	O
</s>
<s>
The	O
iPhone	B-Operating_System
4	O
model	O
continued	O
to	O
be	O
sold	O
unchanged	O
up	O
until	O
September	O
2013	O
.	O
</s>
<s>
In	O
2011	O
,	O
two	O
iPhone	B-Operating_System
4	O
units	O
equipped	O
with	O
a	O
special	O
application	O
were	O
taken	O
to	O
the	O
International	O
Space	O
Station	O
aboard	O
the	O
Space	O
Shuttle	O
on	O
the	O
STS-135	O
mission	O
.	O
</s>
