<s>
In	O
computing	O
,	O
mass	B-Device
storage	I-Device
refers	O
to	O
the	O
storage	O
of	O
large	O
amounts	O
of	O
data	O
in	O
a	O
persisting	B-Application
and	O
machine-readable	B-General_Concept
fashion	O
.	O
</s>
<s>
In	O
general	O
,	O
the	O
term	O
is	O
used	O
as	O
large	O
in	O
relation	O
to	O
contemporaneous	O
hard	B-Device
disk	I-Device
drives	I-Device
,	O
but	O
it	O
has	O
been	O
used	O
large	O
in	O
relation	O
to	O
primary	O
memory	O
as	O
for	O
example	O
with	O
floppy	B-Device
disks	I-Device
on	O
personal	B-Device
computers	I-Device
.	O
</s>
<s>
Devices	O
and/or	O
systems	O
that	O
have	O
been	O
described	O
as	O
mass	B-Device
storage	I-Device
include	O
tape	B-Device
libraries	I-Device
,	O
RAID	B-Architecture
systems	O
,	O
and	O
a	O
variety	O
of	O
computer	B-Device
drives	I-Device
such	O
as	O
hard	B-Device
disk	I-Device
drives	I-Device
,	O
magnetic	B-Architecture
tape	I-Architecture
drives	I-Architecture
,	O
magneto-optical	B-Device
disc	I-Device
drives	O
,	O
optical	B-Device
disc	I-Device
drives	O
,	O
memory	B-Device
cards	I-Device
,	O
and	O
solid-state	B-Device
drives	I-Device
.	O
</s>
<s>
It	O
also	O
includes	O
experimental	O
forms	O
like	O
holographic	B-Algorithm
memory	I-Algorithm
.	O
</s>
<s>
Mass	B-Device
storage	I-Device
includes	O
devices	O
with	O
removable	B-Device
and	O
non-removable	O
media	O
.	O
</s>
<s>
It	O
does	O
not	O
include	O
random	B-Architecture
access	I-Architecture
memory	I-Architecture
(	O
RAM	B-Architecture
)	O
.	O
</s>
<s>
There	O
are	O
two	O
broad	O
classes	O
of	O
mass	B-Device
storage	I-Device
:	O
local	O
data	O
in	O
devices	O
such	O
as	O
smartphones	B-Application
or	O
computers	O
,	O
and	O
enterprise	O
servers	O
and	O
data	B-Operating_System
centers	I-Operating_System
for	O
the	O
cloud	O
.	O
</s>
<s>
For	O
local	O
storage	O
,	O
SSDs	B-Device
are	O
on	O
the	O
way	O
to	O
replacing	O
HDDs	O
.	O
</s>
<s>
Considering	O
the	O
mobile	O
segment	O
from	O
phones	O
to	O
notebooks	B-Device
,	O
the	O
majority	O
of	O
systems	O
today	O
is	O
based	O
on	O
NAND	O
Flash	O
.	O
</s>
<s>
As	O
for	O
Enterprise	O
and	O
data	B-Operating_System
centers	I-Operating_System
,	O
storage	O
tiers	O
have	O
established	O
using	O
a	O
mix	O
of	O
SSD	B-Device
and	O
HDD	B-Device
.	O
</s>
<s>
The	O
notion	O
of	O
"	O
large	O
"	O
amounts	O
of	O
data	O
is	O
of	O
course	O
highly	O
dependent	O
on	O
the	O
time	O
frame	O
and	O
the	O
market	O
segment	O
,	O
as	O
storage	O
device	O
capacity	O
has	O
increased	O
by	O
many	O
orders	O
of	O
magnitude	O
since	O
the	O
beginnings	O
of	O
computer	O
technology	O
in	O
the	O
late	O
1940s	O
and	O
continues	O
to	O
grow	O
;	O
however	O
,	O
in	O
any	O
time	O
frame	O
,	O
common	O
mass	B-General_Concept
storage	I-General_Concept
devices	I-General_Concept
have	O
tended	O
to	O
be	O
much	O
larger	O
and	O
at	O
the	O
same	O
time	O
much	O
slower	O
than	O
common	O
realizations	O
of	O
contemporaneous	O
primary	O
storage	O
technology	O
.	O
</s>
<s>
Papers	O
at	O
the	O
1966	O
Fall	O
Joint	O
Computer	O
Conference	O
(	O
FJCC	O
)	O
used	O
the	O
term	O
mass	B-Device
storage	I-Device
for	O
devices	O
substantially	O
larger	O
than	O
contemporaneous	O
hard	B-Device
disk	I-Device
drives	I-Device
.	O
</s>
<s>
Similarly	O
,	O
a	O
1972	O
analysis	O
identified	O
mass	B-Device
storage	I-Device
systems	I-Device
from	O
Ampex	O
(	O
Terabit	O
Memory	O
)	O
using	O
video	O
tape	O
,	O
Precision	O
Industries	O
(	O
Unicon	O
690-212	O
)	O
using	O
lasers	O
and	O
International	O
Video	O
(	O
IVC-1000	O
)	O
using	O
video	O
tape	O
and	O
states	O
"	O
In	O
the	O
literature	O
,	O
the	O
most	O
common	O
definition	O
of	O
mass	B-Device
storage	I-Device
capacity	O
is	O
a	O
trillion	O
bits.	O
"	O
.	O
</s>
<s>
The	O
first	O
IEEE	O
conference	O
on	O
mass	B-Device
storage	I-Device
was	O
held	O
in	O
1974	O
and	O
at	O
that	O
time	O
identified	O
mass	B-Device
storage	I-Device
as	O
"	O
capacity	O
on	O
the	O
order	O
of	O
1012	O
bits	O
"	O
(	O
1	O
gigabyte	O
)	O
.	O
</s>
<s>
In	O
the	O
mid-1970s	O
IBM	O
used	O
the	O
term	O
to	O
in	O
the	O
name	O
of	O
the	O
IBM	B-Device
3850	I-Device
Mass	I-Device
Storage	I-Device
System	I-Device
,	O
which	O
provided	O
virtual	O
disks	B-Device
backed	O
up	O
by	O
Helical	O
scan	O
magnetic	B-Architecture
tape	I-Architecture
cartridges	O
,	O
slower	O
than	O
disk	B-Device
drives	I-Device
but	O
with	O
a	O
capacity	O
larger	O
than	O
was	O
affordable	O
with	O
disks	B-Device
.	O
</s>
<s>
The	O
term	O
mass	B-Device
storage	I-Device
was	O
used	O
in	O
the	O
PC	O
marketplace	O
for	O
devices	O
,	O
such	O
as	O
floppy	B-Device
disk	I-Device
drives	I-Device
,	O
far	O
smaller	O
than	O
devices	O
that	O
were	O
not	O
considered	O
mass	B-Device
storage	I-Device
in	O
the	O
mainframe	O
marketplace	O
.	O
</s>
<s>
Mass	B-General_Concept
storage	I-General_Concept
devices	I-General_Concept
are	O
characterized	O
by	O
:	O
</s>
<s>
Magnetic	O
disks	B-Device
are	O
the	O
predominant	O
storage	B-General_Concept
media	I-General_Concept
in	O
personal	B-Device
computers	I-Device
.	O
</s>
<s>
Optical	B-Device
discs	I-Device
,	O
however	O
,	O
are	O
almost	O
exclusively	O
used	O
in	O
the	O
large-scale	O
distribution	O
of	O
retail	O
software	O
,	O
music	O
and	O
movies	O
because	O
of	O
the	O
cost	O
and	O
manufacturing	O
efficiency	O
of	O
the	O
molding	O
process	O
used	O
to	O
produce	O
DVD	O
and	O
compact	O
discs	O
and	O
the	O
nearly-universal	O
presence	O
of	O
reader	B-Device
drives	I-Device
in	O
personal	B-Device
computers	I-Device
and	O
consumer	O
appliances	O
.	O
</s>
<s>
Flash	B-Device
memory	I-Device
(	O
in	O
particular	O
,	O
NAND	O
flash	O
)	O
has	O
an	O
established	O
and	O
growing	O
niche	O
as	O
a	O
replacement	O
for	O
magnetic	O
hard	B-Device
disks	I-Device
in	O
high	O
performance	O
enterprise	O
computing	O
installations	O
due	O
to	O
its	O
robustness	O
stemming	O
from	O
its	O
lack	O
of	O
moving	O
parts	O
,	O
and	O
its	O
inherently	O
much	O
lower	O
latency	O
when	O
compared	O
to	O
conventional	O
magnetic	B-Device
hard	I-Device
drive	I-Device
solutions	O
.	O
</s>
<s>
Flash	B-Device
memory	I-Device
has	O
also	O
long	O
been	O
popular	O
as	O
removable	B-Device
storage	I-Device
such	O
as	O
USB	B-Protocol
sticks	O
,	O
where	O
it	O
de	O
facto	O
makes	O
up	O
the	O
market	O
.	O
</s>
<s>
It	O
has	O
also	O
made	O
its	O
way	O
onto	O
laptops	B-Device
in	O
the	O
form	O
of	O
SSDs	B-Device
,	O
sharing	O
similar	O
reasons	O
with	O
enterprise	O
computing	O
:	O
Namely	O
,	O
markedly	O
high	O
degrees	O
of	O
resistance	O
to	O
physical	O
impact	O
,	O
which	O
is	O
again	O
,	O
due	O
to	O
the	O
lack	O
of	O
moving	O
parts	O
,	O
as	O
well	O
as	O
a	O
performance	O
increase	O
over	O
conventional	O
magnetic	O
hard	B-Device
disks	I-Device
and	O
markedly	O
reduced	O
weight	O
and	O
power	O
consumption	O
.	O
</s>
<s>
The	O
design	O
of	O
computer	B-General_Concept
architectures	I-General_Concept
and	O
operating	B-General_Concept
systems	I-General_Concept
are	O
often	O
dictated	O
by	O
the	O
mass	B-Device
storage	I-Device
and	O
bus	B-General_Concept
technology	O
of	O
their	O
time	O
.	O
</s>
<s>
Mass	B-General_Concept
storage	I-General_Concept
devices	I-General_Concept
used	O
in	O
desktop	O
and	O
most	O
server	O
computers	O
typically	O
have	O
their	O
data	O
organized	O
in	O
a	O
file	B-Application
system	I-Application
.	O
</s>
<s>
The	O
choice	O
of	O
file	B-Application
system	I-Application
is	O
often	O
important	O
in	O
maximizing	O
the	O
performance	O
of	O
the	O
device	O
:	O
general	O
purpose	O
file	B-Application
systems	I-Application
(	O
such	O
as	O
NTFS	B-Application
and	O
HFS	B-Application
,	O
for	O
example	O
)	O
tend	O
to	O
do	O
poorly	O
on	O
slow-seeking	O
optical	O
storage	O
such	O
as	O
compact	O
discs	O
.	O
</s>
<s>
Some	O
relational	B-Application
databases	I-Application
can	O
also	O
be	O
deployed	O
on	O
mass	B-General_Concept
storage	I-General_Concept
devices	I-General_Concept
without	O
an	O
intermediate	O
file	B-Application
system	I-Application
or	O
storage	O
manager	O
.	O
</s>
<s>
Oracle	B-General_Concept
and	O
MySQL	B-Application
,	O
for	O
example	O
,	O
can	O
store	O
table	O
data	O
directly	O
on	O
raw	O
block	O
devices	O
.	O
</s>
<s>
On	O
removable	B-Device
media	I-Device
,	O
archive	O
formats	O
(	O
such	O
as	O
tar	B-Application
archives	I-Application
on	O
magnetic	B-Architecture
tape	I-Architecture
,	O
which	O
pack	O
file	O
data	O
end-to-end	O
)	O
are	O
sometimes	O
used	O
instead	O
of	O
file	B-Application
systems	I-Application
because	O
they	O
are	O
more	O
portable	O
and	O
simpler	O
to	O
stream	O
.	O
</s>
<s>
On	O
embedded	O
computers	O
,	O
it	O
is	O
common	O
to	O
memory	B-General_Concept
map	I-General_Concept
the	O
contents	O
of	O
a	O
mass	B-Device
storage	I-Device
device	I-Device
(	O
usually	O
ROM	B-Device
or	O
flash	B-Device
memory	I-Device
)	O
so	O
that	O
its	O
contents	O
can	O
be	O
traversed	O
as	O
in-memory	O
data	O
structures	O
or	O
executed	O
directly	O
by	O
programs	O
.	O
</s>
