<s>
Typeahead	B-Device
is	O
a	O
feature	O
of	O
computers	O
and	O
software	O
(	O
and	O
some	O
typewriters	O
)	O
that	O
enables	O
users	O
to	O
continue	O
typing	O
regardless	O
of	O
program	O
or	O
computer	O
operation	O
—	O
the	O
user	O
may	O
type	O
in	O
whatever	O
speed	O
is	O
desired	O
,	O
and	O
if	O
the	O
receiving	O
software	O
is	O
busy	O
at	O
the	O
time	O
it	O
will	O
be	O
called	O
to	O
handle	O
this	O
later	O
.	O
</s>
<s>
This	O
programming	O
technique	O
for	O
handling	O
uses	O
what	O
is	O
known	O
as	O
a	O
keyboard	B-Device
buffer	I-Device
.	O
</s>
<s>
Typeahead	B-Device
has	O
its	O
roots	O
in	O
the	O
age	O
of	O
typewriters	O
.	O
</s>
<s>
The	O
IBM	O
Selectric	O
typewriter	O
,	O
first	O
released	O
in	O
1961	O
,	O
had	O
a	O
mechanical	O
key	O
lockout	O
feature	O
designed	O
to	O
smooth	O
out	O
typists	O
 '	O
irregular	O
keystrokes	O
that	O
,	O
to	O
many	O
users	O
,	O
felt	O
like	O
typeahead	B-Device
.	O
</s>
<s>
Achieving	O
true	O
typeahead	B-Device
requires	O
maintaining	O
a	O
so-called	O
"	O
typeahead	B-Device
buffer	I-Device
"	O
—	O
a	O
FIFO	B-Operating_System
queue	O
,	O
for	O
instance	O
—	O
whose	O
role	O
it	O
is	O
to	O
store	O
a	O
limited	O
amount	O
of	O
keyboard	B-Device
input	O
until	O
it	O
is	O
called	O
for	O
.	O
</s>
<s>
Installing	O
such	O
a	O
buffer	B-General_Concept
can	O
be	O
done	O
at	O
both	O
the	O
hardware	O
and	O
the	O
software	O
levels	O
;	O
most	O
modern	O
operating	O
systems	O
,	O
such	O
as	O
Unix	B-Application
,	O
implement	O
this	O
using	O
software	O
,	O
calling	O
kernel	B-Operating_System
interrupts	B-Application
.	O
</s>
<s>
In	O
some	O
network	B-Architecture
operations	O
,	O
one	O
might	O
attempt	O
to	O
dispatch	O
information	O
over	O
a	O
network	B-Architecture
,	O
regardless	O
whether	O
the	O
receiving	O
program	O
manages	O
to	O
keep	O
up	O
,	O
using	O
the	O
recipient	O
's	O
typeahead	B-Device
functions	O
.	O
</s>
