<s>
Microsoft	O
's	O
Kuwaiti	B-Algorithm
algorithm	I-Algorithm
is	O
used	O
in	O
Windows	O
to	O
convert	O
between	O
Gregorian	O
calendar	O
dates	O
and	O
Islamic	O
calendar	O
dates	O
.	O
</s>
<s>
According	O
to	O
Rob	O
van	O
Gent	O
,	O
the	O
so-called	O
"	O
Kuwaiti	B-Algorithm
algorithm	I-Algorithm
"	O
is	O
simply	O
an	O
implementation	O
of	O
the	O
standard	O
Tabular	O
Islamic	O
calendar	O
algorithm	O
used	O
in	O
Islamic	O
astronomical	O
tables	O
since	O
the	O
11th	O
century	O
.	O
</s>
