<s>
The	O
classic	O
Macintosh	B-Device
startup	I-Device
sequence	O
includes	O
hardware	O
tests	O
which	O
may	O
trigger	O
the	O
startup	O
chime	O
,	O
Happy	O
Mac	B-Device
,	O
Sad	O
Mac	B-Device
,	O
and	O
Chimes	O
of	O
Death	O
.	O
</s>
<s>
On	O
Macs	B-Device
running	O
macOS	B-Operating_System
Big	I-Operating_System
Sur	I-Operating_System
or	O
later	O
the	O
startup	O
sound	O
is	O
enabled	O
by	O
default	O
,	O
but	O
can	O
be	O
disabled	O
by	O
the	O
user	O
within	O
System	O
Preferences	O
(	O
Big	B-Operating_System
Sur	I-Operating_System
or	O
Monterey	B-Device
)	O
or	O
System	O
Settings	O
(	O
Ventura	B-Operating_System
)	O
.	O
</s>
<s>
The	O
Macintosh	B-Device
startup	I-Device
chime	O
is	O
played	O
on	O
power-up	O
,	O
before	O
trying	O
to	O
boot	B-Operating_System
an	O
operating	B-General_Concept
system	I-General_Concept
.	O
</s>
<s>
The	O
specific	O
sound	O
differs	O
depending	O
on	O
the	O
ROM	O
,	O
which	O
greatly	O
varies	O
depending	O
on	O
Macintosh	B-Device
model	O
.	O
</s>
<s>
The	O
first	O
sound	O
version	O
in	O
the	O
first	O
three	O
Macintosh	B-Device
models	O
is	O
a	O
simple	O
square-wave	O
"	O
beep	O
"	O
,	O
and	O
all	O
subsequent	O
sounds	O
are	O
various	O
chords	O
.	O
</s>
<s>
Mark	O
Lentczner	O
created	O
the	O
software	O
that	O
plays	O
the	O
arpeggiated	O
chord	O
in	O
the	O
Macintosh	B-Device
II	I-Device
.	O
</s>
<s>
Variations	O
of	O
this	O
sound	O
were	O
deployed	O
until	O
Jim	O
Reekes	O
created	O
the	O
startup	O
chime	O
in	O
the	O
Quadra	B-Device
700	I-Device
through	O
the	O
Quadra	B-Device
800	I-Device
.	O
</s>
<s>
He	O
is	O
also	O
the	O
creator	O
of	O
the	O
iconic	O
(	O
or	O
"	O
earconic	O
"	O
,	O
as	O
he	O
calls	O
it	O
)	O
"	O
bong	O
"	O
startup	O
chime	O
in	O
most	O
Macintoshes	B-Device
since	O
the	O
Quadra	B-Device
840AV	I-Device
.	O
</s>
<s>
A	O
slightly	O
lower-pitched	O
version	O
of	O
this	O
chime	O
is	O
in	O
all	O
PCI-based	O
Power	B-Device
Macs	I-Device
until	O
the	O
iMac	B-Device
G3	I-Device
.	O
</s>
<s>
The	O
Macintosh	B-Device
LC	I-Device
,	O
LC	B-Device
II	O
,	O
and	O
Macintosh	B-Device
Classic	I-Device
II	I-Device
do	O
not	O
use	O
the	O
Reekes	O
chime	O
,	O
instead	O
using	O
an	O
F	O
major	O
chord	O
that	O
just	O
produces	O
a	O
"	O
ding	O
"	O
sound	O
.	O
</s>
<s>
The	O
first	O
generation	O
of	O
Power	B-Device
Macintosh	I-Device
computers	O
also	O
do	O
not	O
use	O
the	O
Reekes	O
chime	O
,	O
instead	O
using	O
a	O
chord	O
strummed	O
on	O
a	O
Yamaha	O
12-string	O
acoustic	O
guitar	O
by	O
jazz	O
guitarist	O
Stanley	O
Jordan	O
.	O
</s>
<s>
Further	O
,	O
the	O
Power	B-Device
Macintosh	I-Device
5200	I-Device
–	I-Device
6300	I-Device
computers	O
(	O
excluding	O
the	O
5400	O
and	O
5500	O
,	O
which	O
have	O
the	O
"	O
bong	O
"	O
chime	O
like	O
the	O
one	O
in	O
the	O
PCI-based	O
Power	B-Device
Macs	I-Device
)	O
use	O
a	O
unique	O
chime	O
,	O
which	O
is	O
also	O
in	O
the	O
television	O
commercials	O
for	O
the	O
Power	B-Device
Macintosh	I-Device
and	O
PowerBook	B-Device
series	O
from	O
1995	O
until	O
1998	O
,	O
and	O
the	O
20th	B-Device
Anniversary	I-Device
Macintosh	I-Device
uses	O
another	O
unique	O
sound	O
.	O
</s>
<s>
For	O
models	O
built	O
prior	O
to	O
the	O
introduction	O
of	O
the	O
Power	B-Device
Macintosh	I-Device
in	O
1994	O
,	O
the	O
failure	O
of	O
initial	O
self-diagnostic	O
tests	O
results	O
in	O
a	O
Sad	O
Mac	B-Device
icon	O
,	O
an	O
error	O
code	O
,	O
and	O
distinctive	O
Chimes	O
of	O
Death	O
sounds	O
.	O
</s>
<s>
The	O
chime	O
for	O
all	O
Mac	B-Device
computers	I-Device
from	O
1998	O
to	O
early	O
2016	O
is	O
the	O
same	O
chime	O
used	O
first	O
in	O
the	O
iMac	B-Device
G3	I-Device
.	O
</s>
<s>
Since	O
2012	O
,	O
the	O
Mac	B-Device
startup	I-Device
chime	O
is	O
a	O
registered	O
trademark	O
in	O
the	O
United	O
States	O
,	O
and	O
is	O
featured	O
in	O
the	O
2008	O
Pixar	O
film	O
WALL-E	B-Application
when	O
the	O
titular	O
robot	O
character	O
is	O
fully	O
recharged	O
by	O
solar	O
panels	O
as	O
well	O
as	O
in	O
the	O
2007	O
Brad	O
Paisley	O
song	O
"	O
Online	O
"	O
.	O
</s>
<s>
Starting	O
with	O
the	O
2016	O
MacBook	O
Pro	O
,	O
all	O
new	O
Macs	B-Device
were	O
shipped	O
without	O
a	O
startup	O
chime	O
,	O
with	O
the	O
Macs	B-Device
silently	O
booting	B-Operating_System
when	O
powered	O
on	O
.	O
</s>
<s>
In	O
2020	O
,	O
the	O
startup	O
chime	O
would	O
be	O
added	O
to	O
these	O
models	O
with	O
the	O
release	O
of	O
macOS	B-Operating_System
Big	I-Operating_System
Sur	I-Operating_System
,	O
which	O
allows	O
it	O
to	O
be	O
enabled	O
or	O
disabled	O
in	O
System	O
Preferences	O
.	O
</s>
<s>
On	O
the	O
macOS	B-Operating_System
Big	I-Operating_System
Sur	I-Operating_System
11.0.1	O
beta	O
,	O
it	O
was	O
discovered	O
that	O
the	O
new	O
lower	O
pitched	O
chime	O
was	O
brought	O
to	O
all	O
older	O
supported	O
Macs	B-Device
.	O
</s>
<s>
In	O
a	O
firmware	O
update	O
included	O
in	O
the	O
macOS	B-Application
Catalina	O
2020-001	O
Security	O
Update	O
,	O
and	O
the	O
macOS	B-Application
Mojave	O
2020-007	O
Security	O
Update	O
,	O
the	O
new	O
startup	O
chime	O
in	O
Big	B-Operating_System
Sur	I-Operating_System
is	O
brought	O
to	O
all	O
Big	O
Sur-supported	O
Macs	B-Device
including	O
the	O
unsupported	O
2013	O
iMac	B-Device
.	O
</s>
<s>
A	O
Happy	O
Mac	B-Device
is	O
the	O
normal	O
bootup	B-Operating_System
(	O
startup	O
)	O
icon	O
of	O
an	O
Apple	B-Device
Macintosh	I-Device
computer	I-Device
running	O
older	O
versions	O
of	O
the	O
Mac	B-Device
operating	B-General_Concept
system	I-General_Concept
.	O
</s>
<s>
It	O
was	O
designed	O
by	O
Susan	O
Kare	O
in	O
the	O
1980s	O
,	O
drawing	O
inspiration	O
from	O
the	O
design	O
of	O
the	O
Compact	O
Macintosh	B-Device
series	O
and	O
from	O
the	O
Batman	O
character	O
Two-Face	O
.	O
</s>
<s>
The	O
icon	O
remained	O
unchanged	O
until	O
the	O
introduction	O
of	O
New	B-Device
World	I-Device
ROM	I-Device
Macs	B-Device
,	O
when	O
it	O
was	O
updated	O
to	O
8-bit	O
color	O
.	O
</s>
<s>
The	O
Happy	O
Mac	B-Device
indicates	O
that	O
booting	B-Operating_System
has	O
successfully	O
begun	O
,	O
whereas	O
a	O
Sad	O
Mac	B-Device
(	O
along	O
with	O
the	O
"	O
Chimes	O
of	O
Death	O
"	O
melody	O
or	O
one	O
or	O
more	O
beeps	O
)	O
indicates	O
a	O
hardware	O
problem	O
.	O
</s>
<s>
When	O
a	O
Macintosh	B-Device
boots	O
into	O
the	O
classic	B-Application
Mac	I-Application
OS	I-Application
(	O
Mac	B-Operating_System
OS	I-Operating_System
9	I-Operating_System
or	O
lower	O
)	O
,	O
the	O
system	O
will	O
play	O
its	O
startup	O
chime	O
,	O
the	O
screen	O
will	O
turn	O
gray	O
,	O
and	O
the	O
Happy	O
Mac	B-Device
icon	O
will	O
appear	O
,	O
followed	O
by	O
the	O
Mac	B-Application
OS	I-Application
splash	O
screen	O
(	O
or	O
the	O
small	O
"	O
Welcome	B-Device
to	I-Device
Macintosh	I-Device
"	O
screen	O
in	O
System	O
7.5	O
and	O
earlier	O
)	O
,	O
which	O
underwent	O
several	O
stylistic	O
changes	O
.	O
</s>
<s>
Mac	B-Application
OS	I-Application
versions	O
8.6	O
and	O
later	O
also	O
includes	O
the	O
version	O
number	O
in	O
this	O
splash	O
screen	O
(	O
for	O
example	O
,	O
"	O
Welcome	O
to	O
Mac	B-Application
OS	I-Application
8.6	O
"	O
)	O
.	O
</s>
<s>
On	O
early	O
Macs	B-Device
without	O
an	O
internal	B-Device
hard	I-Device
drive	I-Device
,	O
the	O
computer	O
boots	O
up	O
to	O
a	O
point	O
where	O
it	O
needs	O
to	O
load	O
the	O
operating	B-General_Concept
system	I-General_Concept
from	O
a	O
floppy	B-Device
disk	I-Device
.	O
</s>
<s>
Until	O
the	O
user	O
inserts	O
the	O
correct	O
disk	O
,	O
the	O
Mac	B-Device
displays	O
a	O
floppy	B-Device
icon	O
with	O
a	O
blinking	O
question	O
mark	O
.	O
</s>
<s>
In	O
later	O
Macs	B-Device
,	O
a	O
folder	O
icon	O
with	O
a	O
question	O
mark	O
that	O
repeatedly	O
changes	O
to	O
the	O
Finder	B-Application
icon	I-Application
is	O
shown	O
if	O
a	O
System	B-Operating_System
Folder	I-Operating_System
or	O
boot	B-Operating_System
loader	O
file	O
cannot	O
be	O
found	O
on	O
the	O
startup	O
disk	O
.	O
</s>
<s>
With	O
Mac	B-Operating_System
OS	I-Operating_System
X	I-Operating_System
10.1	I-Operating_System
,	O
a	O
new	O
Happy	O
Mac	B-Device
was	O
included	O
.	O
</s>
<s>
This	O
is	O
also	O
the	O
last	O
version	O
with	O
a	O
Happy	O
Mac	B-Device
icon	O
;	O
in	O
version	B-Operating_System
10.2	I-Operating_System
,	O
the	O
Happy	O
Mac	B-Device
symbol	O
was	O
replaced	O
with	O
the	O
Apple	O
logo	O
.	O
</s>
<s>
In	O
OS	B-Application
X	I-Application
Lion	I-Application
10.7	B-Application
,	O
the	O
Apple	O
logo	O
was	O
slightly	O
shrunk	O
and	O
a	O
drop-in	O
shadow	O
was	O
added	O
.	O
</s>
<s>
In	O
OS	B-Device
X	I-Device
Yosemite	I-Device
10.10	O
,	O
the	O
white	O
screen	O
with	O
a	O
gray	O
Apple	O
logo	O
was	O
replaced	O
with	O
a	O
black	O
screen	O
with	O
a	O
white	O
Apple	O
logo	O
and	O
the	O
spinning	O
wheel	O
was	O
replaced	O
with	O
a	O
loading	O
bar	O
.	O
</s>
<s>
However	O
,	O
this	O
only	O
applies	O
to	O
Macs	B-Device
from	O
2013	O
and	O
later	O
,	O
including	O
the	O
2012	O
Retina	O
MacBook	O
Pros	O
,	O
and	O
requires	O
a	O
firmware	O
update	O
to	O
be	O
applied	O
.	O
</s>
<s>
All	O
earlier	O
Macs	B-Device
still	O
use	O
the	O
old	O
screen	O
.	O
</s>
<s>
The	O
shadow	O
on	O
the	O
Apple	O
logo	O
was	O
removed	O
in	O
OS	B-Operating_System
X	I-Operating_System
El	I-Operating_System
Capitan	I-Operating_System
10.11	O
.	O
</s>
<s>
In	O
2016	O
and	O
later	O
Macs	B-Device
(	O
excluding	O
the	O
Early	O
2016	O
MacBook	O
)	O
,	O
the	O
Apple	O
logo	O
appears	O
immediately	O
when	O
the	O
screen	O
turns	O
on	O
.	O
</s>
<s>
The	O
Face	O
ID	O
logo	O
for	O
the	O
iPhone	B-Operating_System
X	I-Operating_System
was	O
based	O
on	O
the	O
Happy	O
Mac	B-Device
.	O
</s>
<s>
With	O
the	O
introduction	O
of	O
Mac	B-Application
OS	I-Application
X	I-Application
,	O
in	O
addition	O
to	O
the	O
blinking	O
system	B-Operating_System
folder	I-Operating_System
icon	O
,	O
a	O
prohibition	O
icon	O
was	O
added	O
to	O
show	O
an	O
incorrect	O
OS	O
version	O
is	O
found	O
.	O
</s>
<s>
The	O
bomb	B-Device
screen	I-Device
in	O
the	O
classic	B-Application
Mac	I-Application
OS	I-Application
was	O
replaced	O
with	O
a	O
kernel	B-Operating_System
panic	I-Operating_System
,	O
which	O
was	O
originally	O
colored	O
white	O
but	O
was	O
changed	O
to	O
black	O
in	O
version	B-Operating_System
10.3	I-Operating_System
.	O
</s>
<s>
A	O
Sad	O
Mac	B-Device
is	O
a	O
symbol	O
in	O
older-generation	O
Apple	B-Device
Macintosh	I-Device
computers	I-Device
(	O
hardware	O
using	O
the	O
Old	B-Device
World	I-Device
ROM	I-Device
and	O
not	O
Open	B-Architecture
Firmware	I-Architecture
,	O
which	O
are	O
those	O
predating	O
onboard	O
USB	O
)	O
,	O
starting	O
with	O
the	O
original	O
128K	O
Macintosh	B-Device
and	O
ending	O
with	O
the	O
last	O
NuBus-based	O
Power	B-Device
Macintosh	I-Device
models	O
(	O
including	O
the	O
first-generation	O
6100	B-Device
,	O
7100	B-Device
,	O
8100	B-Device
,	O
as	O
well	O
as	O
the	O
PowerBook	B-Device
5300	I-Device
and	O
1400	B-Device
)	O
,	O
to	O
indicate	O
a	O
severe	O
hardware	O
or	O
software	O
problem	O
that	O
prevented	O
startup	O
from	O
occurring	O
successfully	O
.	O
</s>
<s>
The	O
Sad	O
Mac	B-Device
icon	O
is	O
displayed	O
,	O
along	O
with	O
a	O
set	O
of	O
hexadecimal	O
codes	O
that	O
indicate	O
the	O
type	O
of	O
problem	O
at	O
startup	O
.	O
</s>
<s>
This	O
is	O
in	O
place	O
of	O
the	O
normal	O
Happy	O
Mac	B-Device
icon	O
,	O
which	O
indicates	O
that	O
the	O
startup-time	O
hardware	O
tests	O
were	O
successful	O
.	O
</s>
<s>
In	O
68k	O
models	O
made	O
after	O
the	O
Macintosh	B-Device
II	I-Device
,	O
the	O
Chimes	O
of	O
Death	O
are	O
played	O
.	O
</s>
<s>
Models	O
prior	O
to	O
the	O
Macintosh	B-Device
II	I-Device
crash	O
silently	O
and	O
display	O
the	O
Sad	O
Mac	B-Device
,	O
without	O
playing	O
any	O
tone	O
.	O
</s>
<s>
PowerPC	B-Architecture
Macs	B-Device
play	O
a	O
sound	O
effect	O
of	O
a	O
car	O
crash	O
,	O
and	O
computers	O
equipped	O
with	O
the	O
PowerPC	B-Architecture
upgrade	O
card	O
use	O
the	O
three	O
note	O
brass	O
fanfare	O
death	O
chime	O
(	O
A	O
,	O
E-natural	O
,	O
and	O
E-flat	O
)	O
,	O
followed	O
by	O
the	O
sound	O
of	O
a	O
drum	O
,	O
same	O
as	O
the	O
Macintosh	B-Device
Performa	I-Device
6200	I-Device
and	O
Macintosh	B-Device
Performa	I-Device
6300	I-Device
.	O
</s>
<s>
A	O
Sad	O
Mac	B-Device
may	O
be	O
deliberately	O
generated	O
at	O
startup	O
by	O
pressing	O
the	O
interrupt	B-Application
switch	I-Application
on	O
Macintosh	B-Device
computers	I-Device
that	O
had	O
one	O
installed	O
,	O
or	O
by	O
pressing	O
Command	O
and	O
Power	O
keys	O
shortly	O
after	O
the	O
startup	O
chime	O
.	O
</s>
<s>
On	O
some	O
Macintoshes	B-Device
such	O
as	O
PowerBook	B-Device
540c	O
,	O
if	O
the	O
user	O
presses	O
the	O
command	O
and	O
power	O
keys	O
before	O
the	O
boot	B-Operating_System
screen	O
displays	O
,	O
it	O
will	O
play	O
the	O
"	O
chimes	O
of	O
death	O
"	O
.	O
</s>
<s>
The	O
chimes	O
are	O
a	O
fraction	O
of	O
normal	O
speed	O
and	O
there	O
is	O
no	O
Sad	O
Mac	B-Device
displayed	O
.	O
</s>
<s>
Old	B-Device
World	I-Device
ROM	I-Device
Power	B-Device
Macintosh	I-Device
and	O
PowerBook	B-Device
models	O
based	O
on	O
the	O
PCI	B-Protocol
architecture	O
do	O
not	O
use	O
a	O
Sad	O
Mac	B-Device
icon	O
and	O
will	O
instead	O
only	O
play	O
the	O
error/car	O
-crash	O
sound	O
on	O
a	O
hardware	O
failure	O
(	O
such	O
as	O
missing	O
or	O
bad	O
memory	O
,	O
unusable	O
CPU	O
,	O
or	O
similar	O
)	O
.	O
</s>
<s>
Mac	B-Operating_System
OS	I-Operating_System
X	I-Operating_System
10.2	I-Operating_System
Jaguar	I-Operating_System
and	O
later	O
instead	O
use	O
the	O
Universal	O
"	O
no	O
"	O
symbol	O
to	O
denote	O
a	O
hardware	O
or	O
software	O
error	O
that	O
renders	O
the	O
computer	O
non-bootable	O
.	O
</s>
<s>
The	O
Chimes	O
of	O
Death	O
are	O
the	O
Macintosh	B-Device
equivalent	O
of	O
a	O
beep	B-Device
code	I-Device
on	O
IBM	O
PC	O
compatibles	O
.	O
</s>
<s>
On	O
all	O
Macintosh	B-Device
models	O
predating	O
the	O
adoption	O
of	O
PCI	B-Protocol
and	O
Open	B-Architecture
Firmware	I-Architecture
,	O
the	O
Chimes	O
of	O
Death	O
are	O
often	O
accompanied	O
by	O
a	O
Sad	O
Mac	B-Device
icon	O
in	O
the	O
middle	O
of	O
the	O
screen	O
.	O
</s>
<s>
Different	O
Macintosh	B-Device
series	O
have	O
different	O
death	O
chimes	O
.	O
</s>
<s>
The	O
Macintosh	B-Device
II	I-Device
is	O
the	O
first	O
to	O
use	O
the	O
death	O
chimes	O
,	O
a	O
loud	O
and	O
eerie	O
upward	O
major	O
arpeggio	O
,	O
with	O
different	O
chimes	O
on	O
many	O
models	O
.	O
</s>
<s>
The	O
Macintosh	B-Device
Quadra	I-Device
,	O
Centris	B-Device
,	O
Performa	B-Device
(	O
including	O
the	O
6200	O
and	O
6300	O
,	O
which	O
were	O
also	O
Power	B-Device
Macintosh	I-Device
models	O
,	O
only	O
occurring	O
after	O
the	O
screen	O
lights	O
up	O
)	O
,	O
LC	B-Device
,	O
and	O
the	O
Macintosh	B-Device
Classic	I-Device
II	I-Device
play	O
a	O
generally	O
softer	O
and	O
lower	O
pitched	O
version	O
of	O
the	O
upward	O
major	O
arpeggio	O
,	O
followed	O
by	O
three	O
or	O
four	O
notes	O
,	O
with	O
slight	O
variation	O
depending	O
on	O
the	O
model	O
of	O
the	O
Macintosh	B-Device
.	O
</s>
<s>
The	O
PowerBook	B-Device
5300	I-Device
,	O
190	O
,	O
and	O
1400	B-Device
use	O
the	O
second	O
half	O
of	O
the	O
8-note	O
arpeggio	O
as	O
found	O
on	O
the	O
Quadra	O
and	O
Centris	B-Device
models	O
,	O
or	O
the	O
entire	O
death	O
chime	O
if	O
the	O
error	O
occurs	O
before	O
the	O
screen	O
lights	O
up	O
.	O
</s>
<s>
The	O
Macintosh	B-Device
Quadra	I-Device
660AV	O
and	O
Centris	B-Device
660AV	O
use	O
a	O
sound	O
of	O
a	O
single	O
pass	O
of	O
Roland	O
D-50	O
'	O
s	O
"	O
Digital	O
Native	O
Dance	O
"	O
sample	O
loop	O
,	O
and	O
the	O
NuBus	B-Device
based	O
Power	B-Device
Macintosh	I-Device
models	O
(	O
including	O
6100	B-Device
,	O
7100	B-Device
,	O
and	O
8100	B-Device
)	O
series	O
use	O
a	O
car	O
crash	O
sound	O
.	O
</s>
<s>
The	O
Power	B-Device
Macintosh	I-Device
and	O
Performa	B-Device
6200	I-Device
and	O
6300	O
series	O
,	O
before	O
the	O
screen	O
comes	O
on	O
for	O
these	O
models	O
,	O
along	O
with	O
the	O
Power	B-Device
Macintosh	I-Device
upgrade	O
card	O
,	O
use	O
an	O
eerily	O
dramatic	O
3-note	O
brass	O
fanfare	O
with	O
a	O
rhythm	O
of	O
drums	O
and	O
cymbals	O
;	O
the	O
former	O
plays	O
the	O
8-note	O
arpeggio	O
instead	O
when	O
the	O
screen	O
is	O
on	O
.	O
</s>
<s>
The	O
pre-G3	O
PCI	B-Protocol
Power	B-Device
Macs	I-Device
,	O
the	O
beige	O
G3	O
Power	B-Device
Macs	I-Device
,	O
the	O
G3	O
All-In-One	O
,	O
and	O
the	O
PowerBook	B-Device
2400	O
,	O
3400	O
,	O
and	O
G3	O
all	O
use	O
a	O
sound	O
of	O
glass	O
shattering	O
;	O
these	O
models	O
do	O
not	O
display	O
a	O
Sad	O
Mac	B-Device
icon	O
.	O
</s>
<s>
Since	O
the	O
introduction	O
of	O
the	O
iMac	B-Device
in	O
1998	O
,	O
the	O
Chimes	O
of	O
Death	O
are	O
no	O
longer	O
used	O
in	O
favor	O
of	O
a	O
series	O
of	O
tones	O
to	O
indicate	O
hardware	O
errors	O
.	O
</s>
