<s>
TACL	B-Language
(	O
Tandem	B-Language
Advanced	I-Language
Command	I-Language
Language	I-Language
)	O
is	O
the	O
scripting	B-Language
programming	I-Language
language	I-Language
which	O
acts	O
as	O
the	O
shell	B-Operating_System
in	O
Tandem	O
Computers/NonStop	O
computers	O
.	O
</s>
<s>
Tandem	O
's	O
strategy	O
was	O
the	O
emerging	O
concept	O
of	O
"	O
continuous	O
availability	O
"	O
for	O
applications	O
requiring	O
near-total	O
uptime	O
,	O
in	O
which	O
single	O
points	O
of	O
failure	O
were	O
minimized	O
through	O
mirrored	O
storage	O
devices	O
,	O
controllers	O
and	O
software	O
,	O
and	O
operating	O
systems	O
engineered	O
specifically	O
for	O
fault	O
tolerance	O
(	O
using	O
the	O
Guardian	O
operating	O
system	O
,	O
later	O
NonStop	B-Architecture
Kernel	I-Architecture
or	O
NSK	O
,	O
and	O
later	O
NonStop	B-Architecture
OS	I-Architecture
)	O
.	O
</s>
<s>
In	O
computing	O
,	O
a	O
single	B-Architecture
point	I-Architecture
of	I-Architecture
failure	I-Architecture
refers	O
to	O
any	O
scenario	O
in	O
which	O
the	O
failure	O
of	O
a	O
single	O
component	O
,	O
application	O
or	O
process	O
could	O
result	O
in	O
broader	O
impacts	O
such	O
as	O
data	O
loss	O
or	O
the	O
cascading	O
failure	O
of	O
the	O
system	O
.	O
</s>
<s>
Today	O
they	O
are	O
known	O
as	O
"	O
HPE	B-Architecture
Nonstop	I-Architecture
"	O
,	O
with	O
products	O
such	O
as	O
the	O
HP	B-Architecture
Integrity	I-Architecture
NonStop	I-Architecture
Blade	O
systems	O
.	O
</s>
<s>
In	O
2022	O
,	O
HPE	B-Architecture
NonStop	I-Architecture
platforms	O
underpin	O
many	O
of	O
the	O
largest	O
banks	O
,	O
casinos	O
,	O
retailers	O
,	O
telephone	O
companies	O
,	O
email	O
systems	O
,	O
and	O
stock	O
exchanges	O
worldwide	O
.	O
</s>
<s>
TACL	B-Language
continues	O
to	O
be	O
the	O
scripting	B-Language
language	I-Language
used	O
on	O
NonStop	B-Architecture
Servers	O
.	O
</s>
<s>
Many	O
high-uptime	O
computer	O
systems	O
that	O
were	O
produced	O
after	O
the	O
Tandem	O
NonStop	B-Architecture
platform	O
rely	O
on	O
a	O
pair	O
of	O
concurrently	O
running	O
,	O
parallel	O
but	O
independent	O
processes	O
.	O
</s>
<s>
The	O
Tandem	O
NonStop	B-Architecture
design	O
philosophy	O
differs	O
as	O
each	O
CPU	O
performs	O
its	O
own	O
work	O
and	O
may	O
contain	O
a	O
dormant	O
"	O
backup	O
"	O
process	O
in	O
another	O
CPU	O
.	O
</s>
<s>
The	O
name	O
"	O
NonStop	B-Architecture
"	O
refers	O
to	O
this	O
fault-tolerant	O
design	O
.	O
</s>
<s>
HPE	B-Architecture
NonStop	I-Architecture
systems	O
can	O
support	O
operations	O
involving	O
high	O
transactions-per-second	O
and	O
are	O
therefore	O
used	O
in	O
critical	O
applications	O
such	O
as	O
banking	O
,	O
stock	O
trading	O
platforms	O
and	O
telecommunications	O
systems	O
.	O
</s>
<s>
Upon	O
the	O
NonStop	B-Architecture
OS	I-Architecture
platform	O
there	O
are	O
at	O
least	O
two	O
programming	O
languages	O
—	O
TAL	B-Language
(	O
Transaction	B-Language
Application	I-Language
Language	I-Language
)	O
as	O
the	O
compiled	O
language	O
,	O
and	O
TACL	B-Language
as	O
the	O
interpreted	O
language	O
.	O
</s>
<s>
NonStop	B-Architecture
OS	I-Architecture
software	O
includes	O
compilers	O
for	O
other	O
languages	O
(	O
including	O
Java	B-Language
,	O
C	O
,	O
C++	B-Language
,	O
COBOL	B-Application
,	O
SCOBOL	O
,	O
etc	O
.	O
</s>
<s>
)	O
,	O
which	O
may	O
be	O
used	O
to	O
support	O
functions	O
in	O
languages	O
other	O
than	O
TAL/TACL	O
if	O
required	O
.	O
</s>
<s>
TACL	B-Language
remains	O
as	O
the	O
default	O
scripting	B-Language
language	I-Language
on	O
these	O
machines	O
.	O
</s>
<s>
HPE	O
later	O
introduced	O
a	O
ksh-based	O
shell	B-Operating_System
command	O
interface	O
,	O
however	O
this	O
does	O
not	O
contain	O
every	O
capability	O
offered	O
by	O
TACL	B-Language
such	O
as	O
the	O
netstat	O
command	O
.	O
</s>
<s>
TACL	B-Language
built-ins	O
reflect	O
the	O
multi-CPU	O
nature	O
of	O
NSK	O
.	O
</s>
<s>
TACL	B-Language
instructions	O
can	O
be	O
stored	O
in	O
a	O
simple	O
text	O
file	O
as	O
MACROS	O
,	O
ROUTINES	O
,	O
or	O
DEFINES	O
which	O
the	O
TACL	B-Language
interpreter	O
can	O
execute	O
as	O
scripts	O
.	O
</s>
<s>
TACL	B-Language
is	O
also	O
used	O
as	O
a	O
job	B-Application
control	I-Application
language	I-Application
for	O
batch	O
jobs	O
.	O
</s>
<s>
The	O
TACL	B-Language
language	O
has	O
a	O
large	O
number	O
of	O
built-in	O
utilities	O
which	O
allow	O
the	O
user	O
to	O
capture	O
and	O
parse	O
output	O
from	O
various	O
system	O
utilities	O
.	O
</s>
<s>
This	O
allows	O
users	O
to	O
build	O
TACL	B-Language
programs	O
that	O
can	O
monitor	O
system	O
events	O
through	O
the	O
use	O
of	O
filters	O
that	O
monitor	O
the	O
system	O
and	O
application	O
event	O
logs	O
.	O
</s>
<s>
How	O
to	O
run	O
the	O
TACL	B-Language
routine	O
:	O
</s>
<s>
Execute	O
the	O
routine	O
by	O
naming	O
the	O
file	O
at	O
the	O
TACL	B-Language
prompt	O
:	O
</s>
