<s>
K	B-Application
is	O
a	O
proprietary	O
array	B-Data_Structure
processing	O
programming	O
language	O
developed	O
by	O
Arthur	O
Whitney	O
and	O
commercialized	O
by	O
Kx	O
Systems	O
.	O
</s>
<s>
The	O
language	O
serves	O
as	O
the	O
foundation	O
for	O
kdb+	B-Application
,	O
an	O
in-memory	B-General_Concept
,	O
column-based	O
database	O
,	O
and	O
other	O
related	O
financial	O
products	O
.	O
</s>
<s>
The	O
language	O
,	O
originally	O
developed	O
in	O
1993	O
,	O
is	O
a	O
variant	O
of	O
APL	B-Language
and	O
contains	O
elements	O
of	O
Scheme	B-Language
.	O
</s>
<s>
Before	O
developing	O
K	B-Application
,	O
Arthur	O
Whitney	O
had	O
worked	O
extensively	O
with	O
APL	B-Language
,	O
first	O
at	O
I	O
.	O
P	O
.	O
Sharp	O
Associates	O
alongside	O
Ken	O
Iverson	O
and	O
Roger	O
Hui	O
,	O
and	O
later	O
at	O
Morgan	O
Stanley	O
developing	O
financial	O
applications	O
.	O
</s>
<s>
At	O
Morgan	O
Stanley	O
,	O
Whitney	O
helped	O
to	O
develop	O
A+	B-Language
,	O
a	O
variant	O
of	O
APL	B-Language
,	O
to	O
facilitate	O
migrating	O
APL	B-Language
applications	O
from	O
IBM	O
mainframe	B-Architecture
computers	I-Architecture
to	O
a	O
network	O
of	O
Sun	O
workstations	B-Device
.	O
</s>
<s>
A+	B-Language
had	O
a	O
smaller	O
set	O
of	O
primitive	O
functions	O
and	O
was	O
designed	O
for	O
speed	O
and	O
to	O
handle	O
large	O
sets	O
of	O
time	O
series	O
data	O
.	O
</s>
<s>
In	O
1993	O
,	O
Whitney	O
left	O
Morgan	O
Stanley	O
and	O
developed	O
the	O
first	O
version	O
of	O
the	O
K	B-Application
language	I-Application
.	O
</s>
<s>
For	O
the	O
next	O
four	O
years	O
he	O
developed	O
various	O
financial	O
and	O
trading	O
applications	O
using	O
K	B-Application
for	O
UBS	O
.	O
</s>
<s>
In	O
1998	O
,	O
Kx	O
Systems	O
released	O
kdb+	B-Application
,	O
a	O
database	O
built	O
on	O
K	B-Application
.	O
kdb	B-Application
was	O
an	O
in-memory	B-General_Concept
,	O
column-oriented	B-General_Concept
database	I-General_Concept
and	O
included	O
ksql	O
,	O
a	O
query	O
language	O
with	O
an	O
SQL-like	O
syntax	O
.	O
</s>
<s>
Since	O
then	O
,	O
several	O
financial	O
products	O
have	O
been	O
developed	O
with	O
K	B-Application
and	O
kdb+	B-Application
.	O
</s>
<s>
kdb+	B-Application
/tick	O
and	O
kdb+	B-Application
/taq	O
were	O
developed	O
in	O
2001	O
.	O
kdb+	B-Application
,	O
a	O
64-bit	O
version	O
of	O
kdb+	B-Application
was	O
released	O
in	O
2003	O
and	O
kdb+	B-Application
/tick	O
and	O
kdb+	B-Application
/taq	O
were	O
released	O
in	O
2004	O
.	O
kdb+	B-Application
included	O
Q	B-Application
,	O
a	O
language	O
that	O
merged	O
the	O
functions	O
of	O
the	O
underlying	O
K	B-Application
language	I-Application
and	O
ksql	O
.	O
</s>
<s>
Whitney	O
released	O
a	O
derivative	O
of	O
K	B-Application
called	O
Shakti	O
in	O
2018	O
.	O
</s>
<s>
K	B-Application
shares	O
key	O
features	O
with	O
APL	B-Language
.	O
</s>
<s>
They	O
are	O
both	O
interpreted	B-Application
,	O
interactive	B-General_Concept
languages	O
noted	O
for	O
concise	O
and	O
expressive	O
syntax	O
.	O
</s>
<s>
These	O
primitive	O
functions	O
include	O
mathematical	O
operations	O
that	O
work	O
on	O
arrays	O
as	O
whole	O
data	O
objects	O
,	O
and	O
array	B-Data_Structure
operations	O
,	O
such	O
as	O
sorting	O
or	O
reversing	O
the	O
order	O
of	O
an	O
array	B-Data_Structure
.	O
</s>
<s>
Like	O
APL	B-Language
,	O
the	O
primitive	O
functions	O
and	O
operators	O
are	O
represented	O
by	O
single	O
or	O
double	O
characters	O
;	O
however	O
,	O
unlike	O
APL	B-Language
,	O
K	B-Application
restricts	O
itself	O
to	O
the	O
ASCII	B-Protocol
character	I-Protocol
set	I-Protocol
(	O
as	O
does	O
another	O
APL	B-Language
variant	O
,	O
J	B-Language
)	O
.	O
</s>
<s>
To	O
allow	O
for	O
this	O
,	O
the	O
set	O
of	O
primitive	O
functions	O
for	O
K	B-Application
is	O
smaller	O
and	O
heavily	O
overloaded	B-Language
,	O
with	O
each	O
of	O
the	O
ASCII	B-Protocol
symbols	O
representing	O
two	O
or	O
more	O
distinct	O
functions	O
or	O
operations	O
.	O
</s>
<s>
As	O
a	O
result	O
,	O
K	B-Application
expressions	O
can	O
be	O
opaque	O
and	O
difficult	O
to	O
parse	O
for	O
humans	O
.	O
</s>
<s>
The	O
second	O
core	O
distinction	O
of	O
K	B-Application
is	O
that	O
functions	O
are	O
first-class	O
objects	O
,	O
a	O
concept	O
borrowed	O
from	O
Scheme	B-Language
.	O
</s>
<s>
First-class	B-Application
functions	I-Application
can	O
be	O
used	O
in	O
the	O
same	O
contexts	O
where	O
a	O
data	O
value	O
can	O
be	O
used	O
.	O
</s>
<s>
Function	O
expressions	O
are	O
specified	O
in	O
K	B-Application
using	O
curly	O
brackets	O
.	O
</s>
<s>
In	O
K	B-Application
,	O
named	O
functions	O
are	O
simply	O
function	O
expressions	O
stored	O
to	O
a	O
variable	O
in	O
the	O
same	O
way	O
any	O
data	O
value	O
is	O
stored	O
to	O
a	O
variable	O
.	O
</s>
<s>
K	B-Application
is	O
an	O
interpreted	B-Application
language	I-Application
where	O
every	O
statement	O
is	O
evaluated	O
and	O
its	O
results	O
displayed	O
immediately	O
.	O
</s>
<s>
K	B-Application
is	O
the	O
foundation	O
for	O
a	O
family	O
of	O
financial	O
products	O
.	O
</s>
<s>
Kdb+	B-Application
is	O
an	O
in-memory	B-General_Concept
,	O
column-based	O
database	O
with	O
much	O
of	O
the	O
same	O
functions	O
of	O
a	O
relational	B-Application
database	I-Application
management	I-Application
system	I-Application
.	O
</s>
<s>
The	O
database	O
supports	O
SQL	B-Language
,	O
SQL-92	B-Language
and	O
ksql	O
,	O
a	O
query	O
language	O
with	O
a	O
syntax	O
similar	O
to	O
SQL	B-Language
and	O
designed	O
for	O
column	O
based	O
queries	O
and	O
array	B-Data_Structure
analysis	O
.	O
</s>
<s>
Kdb+	B-Application
is	O
available	O
for	O
several	O
operating	B-General_Concept
systems	I-General_Concept
,	O
including	O
Solaris	B-Application
,	O
Linux	B-Application
,	O
macOS	B-Application
,	O
and	O
Windows	B-Application
(	O
32-bit	O
or	O
64-bit	O
)	O
.	O
</s>
