<s>
Scroll	B-Device
Lock	I-Device
( ⤓	O
or	O
⇳	O
)	O
is	O
a	O
lock	B-Device
key	I-Device
(	O
typically	O
with	O
an	O
associated	O
status	O
light	O
)	O
on	O
most	O
IBM-compatible	O
computer	B-Device
keyboards	I-Device
.	O
</s>
<s>
The	O
key	O
is	O
not	O
frequently	O
used	O
,	O
and	O
therefore	O
some	O
reduced	O
or	O
specialized	O
keyboards	B-Device
lack	O
altogether	O
.	O
</s>
<s>
This	O
behavior	O
is	O
a	O
remnant	O
of	O
the	O
original	O
IBM	B-Device
PC	I-Device
keyboards	I-Device
,	O
which	O
did	O
not	O
have	O
a	O
dedicated	O
key	O
.	O
</s>
<s>
The	O
key	O
was	O
meant	O
to	O
lock	O
all	O
scrolling	O
techniques	O
,	O
and	O
is	O
a	O
vestige	O
of	O
the	O
original	O
IBM	B-Device
PC	I-Device
keyboard	I-Device
.	O
</s>
<s>
In	O
the	O
original	O
design	O
,	O
was	O
intended	O
to	O
modify	O
the	O
behavior	O
of	O
the	O
arrow	B-Device
keys	I-Device
.	O
</s>
<s>
When	O
the	O
mode	O
was	O
on	O
,	O
the	O
arrow	B-Device
keys	I-Device
would	O
scroll	O
the	O
contents	O
of	O
a	O
text	O
window	O
instead	O
of	O
moving	O
the	O
cursor	B-Application
.	O
</s>
<s>
In	O
this	O
usage	O
,	O
is	O
a	O
toggling	O
lock	B-Device
key	I-Device
like	O
Num	B-Device
Lock	I-Device
or	O
Caps	B-Device
Lock	I-Device
,	O
which	O
have	O
a	O
state	O
that	O
persists	O
after	O
the	O
key	O
is	O
released	O
.	O
</s>
<s>
Modern	O
programs	O
honoring	O
this	O
behavior	O
include	O
IBM	B-Operating_System
Lotus	I-Operating_System
Notes	I-Operating_System
,	O
Forté	B-Protocol
Agent	I-Protocol
,	O
Image-Line	B-Application
FL	I-Application
Studio	I-Application
,	O
Renoise	B-Application
,	O
Microsoft	B-Application
Excel	I-Application
,	O
Microsoft	B-Operating_System
Project	I-Operating_System
,	O
LibreOffice	B-Operating_System
Calc	I-Operating_System
,	O
and	O
occasionally	O
Microsoft	B-Application
Word	I-Application
.	O
</s>
<s>
Some	O
text	O
editors	O
(	O
such	O
as	O
Notepad++	B-Language
,	O
Microsoft	B-Application
Visual	I-Application
Studio	I-Application
)	O
exhibit	O
similar	O
behavior	O
when	O
the	O
arrow	B-Device
keys	I-Device
are	O
used	O
with	O
pressed	O
.	O
</s>
<s>
Most	O
GUI	B-Application
environments	O
neglect	O
,	O
which	O
means	O
scrolling	O
must	O
be	O
accomplished	O
with	O
a	O
mouse	B-Device
,	O
using	O
means	O
such	O
as	O
scrollbars	O
or	O
scroll	O
wheels	O
,	O
or	O
an	O
"	O
autoscroll	O
"	O
feature	O
activated	O
by	O
the	O
middle	O
mouse	B-Device
button	O
(	O
which	O
may	O
be	O
part	O
of	O
the	O
scroll	O
wheel	O
)	O
.	O
</s>
<s>
Some	O
web	O
browsers	O
including	O
Google	B-Application
Chrome	I-Application
,	O
Firefox	B-Application
,	O
and	O
Internet	B-Application
Explorer	I-Application
support	O
a	O
Caret	B-Application
browsing	I-Application
mode	O
which	O
can	O
be	O
toggled	O
by	O
.	O
</s>
<s>
While	O
the	O
window	O
scrolling	O
behavior	O
with	O
Caret	B-Application
navigation	I-Application
disabled	O
(	O
the	O
default	O
)	O
is	O
similar	O
to	O
that	O
suggested	O
for	O
Scroll	B-Device
Lock	I-Device
,	O
enabling	O
Caret	B-Application
navigation	I-Application
will	O
enable	O
a	O
cursor	B-Application
scrolling	O
behavior	O
as	O
if	O
Scroll	B-Device
Lock	I-Device
were	O
disabled	O
.	O
</s>
<s>
Pressing	O
the	O
key	O
in	O
the	O
Linux	B-Application
console	I-Application
while	O
the	O
text	O
is	O
scrolling	O
through	O
the	O
screen	O
freezes	O
the	O
console	O
output	O
(	O
but	O
not	O
input	O
)	O
during	O
which	O
no	O
further	O
text	O
is	O
sent	O
to	O
the	O
screen	O
,	O
while	O
the	O
program	O
continues	O
running	O
as	O
usual	O
.	O
</s>
<s>
This	O
allows	O
the	O
user	O
to	O
pause	O
the	O
display	O
and	O
read	O
long	O
messages	O
that	O
scroll	O
through	O
the	O
screen	O
too	O
quickly	O
to	O
read	O
,	O
such	O
as	O
when	O
the	O
system	O
is	O
booting	B-Operating_System
up	I-Operating_System
(	O
provided	O
the	O
keyboard	B-Device
driver	B-Application
has	O
already	O
been	O
loaded	O
)	O
.	O
</s>
<s>
If	O
not	O
configured	O
otherwise	O
,	O
and	O
can	O
be	O
used	O
instead	O
of	O
Scroll	B-Device
Lock	I-Device
in	O
any	O
terminal	O
in	O
Linux	O
to	O
freeze	O
and	O
unfreeze	O
the	O
terminal	O
output	O
respectively	O
.	O
</s>
<s>
The	O
behavior	O
must	O
be	O
distinguished	O
from	O
pressing	O
the	O
Pause	B-Device
key	I-Device
during	O
POST	B-Device
or	O
under	O
DOS	B-Device
,	O
which	O
,	O
by	O
default	O
,	O
has	O
the	O
effect	O
of	O
temporarily	O
halting	O
the	O
running	O
process	O
.	O
</s>
<s>
On	O
the	O
FreeBSD	B-Operating_System
system	O
console	O
,	O
the	O
key	O
additionally	O
enables	O
scrolling	O
:	O
after	O
pressing	O
Scroll	B-Device
Lock	I-Device
,	O
one	O
can	O
use	O
and	O
to	O
scroll	O
up	O
or	O
down	O
.	O
</s>
<s>
Pressing	O
Scroll	B-Device
Lock	I-Device
again	O
disables	O
this	O
mode	O
and	O
moves	O
back	O
to	O
the	O
bottom	O
of	O
the	O
output	O
.	O
</s>
<s>
The	O
Linux	B-Application
console	I-Application
implemented	O
this	O
behaviour	O
by	O
using	O
and	O
,	O
not	O
requiring	O
to	O
be	O
active	O
;	O
this	O
behavior	O
was	O
removed	O
due	O
to	O
a	O
vulnerability	O
(	O
CVE-2020-14390	O
)	O
.	O
</s>
<s>
In	O
Multiuser	B-Operating_System
DOS	I-Operating_System
,	O
System	O
Manager	O
,	O
and	O
REAL/32	B-Operating_System
,	O
activating	O
during	O
boot	B-Operating_System
will	O
always	O
enter	O
a	O
special	O
diagnostic	O
mode	O
,	O
where	O
the	O
operating	O
system	O
and	O
loaded	O
device	B-Application
drivers	I-Application
will	O
display	O
detailed	O
status	O
and	O
debugging	O
information	O
about	O
themselves	O
and	O
their	O
interaction	O
with	O
the	O
operating	O
system	O
,	O
sometimes	O
up	O
to	O
several	O
screenfulls	O
per	O
loaded	O
driver	B-Application
.	O
</s>
<s>
DR-DOS	O
7.02	O
and	O
higher	O
provides	O
a	O
CONFIG.SYS	B-Device
directive	O
named	O
SCROLLOCK	B-Device
=	O
ON|OFF	O
to	O
change	O
the	O
Scroll	B-Device
Lock	I-Device
status	O
on	O
the	O
fly	O
.	O
</s>
<s>
Activating	O
during	O
boot	B-Operating_System
will	O
enter	O
a	O
DIAG	O
mode	O
as	O
well	O
,	O
wherein	O
some	O
special	O
drivers	O
may	O
display	O
more	O
verbose	O
messages	O
,	O
but	O
in	O
contrast	O
to	O
the	O
situation	O
under	O
the	O
Multiuser	B-Operating_System
DOS	I-Operating_System
family	O
normal	O
DOS	B-Device
drivers	O
do	O
not	O
typically	O
display	O
additional	O
information	O
.	O
</s>
<s>
The	O
operating	O
system	O
,	O
however	O
,	O
will	O
temporarily	O
suspend	O
any	O
automatic	O
timeouts	B-Device
(	O
TIMEOUT	B-Device
=	O
<seconds>,<character>,<switch>	O
)	O
in	O
CONFIG.SYS	B-Device
trace	B-Device
(	O
TRACE	B-Device
=	O
ON|OFF	O
)	O
and	O
/	O
single-stepping	O
modes	O
for	O
as	O
long	O
as	O
is	O
active	O
.	O
</s>
<s>
In	O
the	O
Microsoft	B-Device
Windows	I-Device
NT	I-Device
family	O
starting	O
with	O
Windows	O
2000	O
,	O
a	O
debugging	O
feature	O
can	O
be	O
enabled	O
,	O
that	O
allows	O
the	O
user	O
to	O
manually	O
crash	O
the	O
system	O
,	O
generating	O
a	O
memory	O
dump	O
for	O
analysis	O
of	O
the	O
current	O
state	O
of	O
the	O
operating	O
system	O
.	O
</s>
<s>
In	O
Microsoft	B-Language
Visual	I-Language
Basic	I-Language
5.0	I-Language
and	O
6.0	B-Language
,	O
pauses	O
the	O
running	O
program	O
in	O
the	O
integrated	O
development	O
environment	O
,	O
as	O
does	O
its	O
alias	O
.	O
</s>
<s>
In	O
conjunction	O
with	O
the	O
alternative	O
DOS	B-Device
keyboard	B-Device
and	O
console	O
drivers	O
FreeKEYB	O
and	O
K3PLUS	O
,	O
also	O
served	O
as	O
part	O
of	O
a	O
copy	B-General_Concept
&	I-General_Concept
paste	I-General_Concept
facility	O
between	O
applications	O
.	O
</s>
<s>
Compared	O
to	O
the	O
standard	O
keyboard	B-Device
driver	B-Application
KEYB	O
these	O
drivers	O
offered	O
several	O
extensions	O
including	O
an	O
extended	B-Device
keystroke	I-Device
buffer	I-Device
with	O
key	O
stacking	O
facility	O
,	O
macro	O
recorder	O
,	O
and	O
a	O
second	O
cursor	B-Application
called	O
CopyCursor	O
,	O
which	O
could	O
be	O
invoked	O
on	O
demand	O
(	O
by	O
default	O
on	O
pressing	O
or	O
the	O
middle	O
mouse	B-Device
button	O
)	O
and	O
freely	O
moved	O
on	O
the	O
screen	O
using	O
the	O
cursor	B-Device
keys	I-Device
or	O
the	O
mouse	B-Device
,	O
even	O
outside	O
the	O
area	O
reachable	O
by	O
the	O
standard	O
cursor	B-Application
in	O
the	O
running	O
application	O
.	O
</s>
<s>
Once	O
invoked	O
,	O
pressing	O
(	O
or	O
the	O
left	O
mouse	B-Device
button	O
)	O
the	O
characters	O
under	O
the	O
CopyCursor	O
could	O
be	O
stuffed	O
,	O
one	O
after	O
another	O
,	O
into	O
the	O
keyboard	B-Device
buffer	I-Device
,	O
from	O
where	O
they	O
would	O
be	O
read	O
by	O
the	O
running	O
application	O
as	O
emulated	O
key	O
(	O
or	O
Alt	O
Numpad	O
)	O
input	O
,	O
thereby	O
typically	O
showing	O
up	O
at	O
the	O
location	O
of	O
the	O
standard	O
cursor	B-Application
.	O
</s>
<s>
Normal	O
keyboard	B-Device
input	O
was	O
still	O
possible	O
while	O
the	O
CopyCursor	O
was	O
enabled	O
,	O
and	O
the	O
user	O
could	O
switch	O
between	O
the	O
two	O
cursors	B-Application
by	O
toggling	O
the	O
hotkey	O
again	O
.	O
</s>
<s>
Pressing	O
or	O
would	O
exit	O
the	O
CopyCursor	O
,	O
so	O
that	O
,	O
on	O
its	O
next	O
invocation	O
,	O
it	O
would	O
show	O
up	O
at	O
the	O
position	O
of	O
the	O
standard	O
cursor	B-Application
again	O
rather	O
than	O
at	O
its	O
previous	O
location	O
.	O
</s>
<s>
With	O
activated	O
,	O
keypresses	O
would	O
still	O
reach	O
the	O
normal	O
keystroke	B-Device
buffer	I-Device
,	O
while	O
CopyCursor	O
input	O
would	O
be	O
stacked	O
up	O
internally	O
for	O
later	O
use	O
in	O
a	O
second	O
queue	O
,	O
dynamically	O
maintained	O
within	O
the	O
extended	B-Device
keystroke	I-Device
buffer	I-Device
.	O
</s>
<s>
It	O
was	O
also	O
possible	O
to	O
use	O
this	O
as	O
input	O
into	O
the	O
macro	O
recorder	O
for	O
later	O
use	O
as	O
scrap	B-Application
macro	I-Application
.	O
</s>
<s>
Since	O
this	O
was	O
an	O
integral	O
part	O
of	O
these	O
keyboard	B-Device
drivers	O
,	O
it	O
was	O
fully	O
transparent	O
to	O
running	O
software	O
and	O
therefore	O
worked	O
with	O
virtually	O
any	O
DOS	B-Device
programs	O
,	O
including	O
at	O
the	O
command	O
prompt	O
,	O
temporary	O
shelled	O
programs	O
,	O
and	O
task	O
switchers	O
.	O
</s>
<s>
IBM	B-Device
PC	I-Device
documentation	O
called	O
an	O
"	O
inactive	O
key	O
"	O
.	O
</s>
<s>
When	O
PC	O
Magazine	O
asked	O
an	O
executive	O
of	O
keyboard	B-Device
manufacturer	O
Key	O
Tronic	O
about	O
the	O
key	O
's	O
purpose	O
in	O
a	O
1983	O
interview	O
,	O
he	O
replied	O
"	O
I	O
do	O
n't	O
know	O
,	O
but	O
we	O
put	O
it	O
on	O
ours	O
,	O
too	O
"	O
.	O
</s>
<s>
The	O
indicator	O
light	O
is	O
sometimes	O
used	O
for	O
other	O
purposes	O
such	O
as	O
a	O
keyboard	B-Device
layout	O
indicator	O
in	O
some	O
Linux	B-Application
distributions	I-Application
or	O
other	O
applications	O
,	O
because	O
doing	O
so	O
is	O
less	O
likely	O
to	O
cause	O
problems	O
than	O
manipulating	O
other	O
keys/lights	O
.	O
</s>
<s>
Keyboard	B-Device
,	I-Device
video	I-Device
,	I-Device
mouse	I-Device
switches	I-Device
(	O
KVM	O
)	O
often	O
use	O
the	O
Scroll	B-Device
Lock	I-Device
key	I-Device
on	O
the	O
keyboard	B-Device
connected	O
to	O
the	O
KVM	B-Device
switch	I-Device
for	O
selecting	O
between	O
computers	O
.	O
</s>
<s>
On	O
KVM	B-Device
switches	I-Device
with	O
On-screen	O
display	O
(	O
OSD	O
)	O
,	O
a	O
"	O
double	O
click	O
"	O
of	O
the	O
Scroll	B-Device
Lock	I-Device
key	I-Device
often	O
brings	O
up	O
the	O
OSD	O
,	O
allowing	O
the	O
user	O
to	O
select	O
the	O
desired	O
computer	O
from	O
a	O
list	O
or	O
access	O
the	O
configuration	O
menu	O
of	O
the	O
KVM	O
.	O
</s>
<s>
Some	O
models	O
,	O
especially	O
those	O
which	O
lack	O
an	O
OSD	O
,	O
switch	O
to	O
the	O
input	O
corresponding	O
to	O
the	O
number	O
key	O
pressed	O
after	O
Scroll	B-Device
Lock	I-Device
,	O
or	O
in	O
the	O
case	O
of	O
some	O
2-port	O
switches	O
,	O
the	O
up	O
and	O
down	O
arrow	B-Device
keys	I-Device
.	O
</s>
<s>
Simple	O
models	O
with	O
only	O
two	O
or	O
four	O
inputs	O
may	O
immediately	O
switch	O
to	O
the	O
next	O
input	O
following	O
a	O
double	O
press	O
of	O
the	O
Scroll	B-Device
Lock	I-Device
key	I-Device
.	O
</s>
<s>
Some	O
laptops	O
and	O
keyboards	B-Device
do	O
not	O
have	O
a	O
physical	O
key	O
.	O
</s>
<s>
Another	O
way	O
to	O
press	O
the	O
key	O
is	O
to	O
use	O
an	O
on-screen	O
keyboard	B-Device
.	O
</s>
<s>
This	O
will	O
provide	O
access	O
to	O
an	O
emulation	O
of	O
a	O
standard	O
101/102	O
-key	O
keyboard	B-Device
.	O
</s>
