<s>
Programmed	B-Application
Airline	I-Application
Reservations	I-Application
System	I-Application
(	O
PARS	O
)	O
is	O
an	O
IBM	O
proprietary	B-Application
large	O
scale	O
airline	O
reservation	O
application	O
,	O
a	O
computer	B-Application
reservations	I-Application
system	I-Application
,	O
executing	O
under	O
the	O
control	O
of	O
IBM	B-Application
Airline	I-Application
Control	I-Application
Program	I-Application
(	O
ACP	B-Application
)	O
(	O
and	O
later	O
its	O
successor	O
,	O
Transaction	B-Operating_System
Processing	I-Operating_System
Facility	I-Operating_System
(	O
TPF	B-Operating_System
)	O
)	O
.	O
</s>
<s>
By	O
the	O
1960s	O
,	O
with	O
the	O
American	O
Airlines	O
SABRE	B-Application
reservations	O
system	O
up	O
and	O
running	O
,	O
IBM	O
offered	O
its	O
expertise	O
to	O
other	O
airlines	O
,	O
and	O
soon	O
developed	O
Deltamatic	O
for	O
Delta	O
Air	O
Lines	O
on	O
the	O
IBM	B-Device
7074	I-Device
,	O
and	O
PANAMAC	O
for	O
Pan	O
American	O
World	O
Airways	O
using	O
an	O
IBM	B-Device
7080	I-Device
.	O
</s>
<s>
By	O
1967/8	O
IBM	O
generalized	O
its	O
airline	O
reservations	O
work	O
into	O
the	O
PARS	O
system	O
,	O
which	O
ran	O
on	O
the	O
larger	O
members	O
of	O
the	O
IBM	B-Application
System/360	I-Application
family	O
and	O
which	O
could	O
support	O
the	O
largest	O
airlines	O
 '	O
needs	O
at	O
that	O
time	O
(	O
e.g.	O
</s>
<s>
The	O
high	O
performance	O
PARS	O
operating	O
system	O
evolved	O
from	O
ACP	B-Application
(	O
Airlines	B-Application
Control	I-Application
Program	I-Application
)	O
to	O
TPF	B-Operating_System
(	O
Transaction	B-Operating_System
Processing	I-Operating_System
Facility	I-Operating_System
)	O
.	O
</s>
<s>
In	O
the	O
early	O
days	O
of	O
automated	O
reservations	O
systems	O
in	O
the	O
1960s	O
and	O
1970s	O
the	O
combination	O
of	O
ACP	B-Application
and	O
PARS	O
provided	O
unprecedented	O
scale	O
and	O
performance	O
from	O
an	O
on-line	O
real-time	O
system	O
,	O
and	O
for	O
a	O
considerable	O
period	O
ranked	O
among	O
the	O
largest	O
networks	O
and	O
systems	O
of	O
the	O
era	O
.	O
</s>
<s>
In	O
the	O
early	O
1970s	O
major	O
US	O
banks	O
were	O
developing	O
major	O
on-line	O
teleprocessing	O
applications	O
systems	O
and	O
were	O
in	O
urgent	O
need	O
of	O
ACP	B-Application
's	O
high	O
performance	O
capabilities	O
.	O
</s>
<s>
ACP	B-Application
was	O
made	O
available	O
by	O
IBM	O
to	O
the	O
banking	O
industry	O
in	O
the	O
mid-1970s	O
.	O
</s>
<s>
IranAir	O
,	O
the	O
Iranian	O
National	O
Airline	O
,	O
discontinued	O
using	O
IBM-ACP/IPARS	O
at	O
the	O
beginning	O
of	O
2000	O
due	O
to	O
Year	O
2000	O
(	O
Y2K	O
)	O
problem	O
.	O
</s>
