<s>
Bus	B-Device
and	I-Device
Tag	I-Device
is	O
an	O
"	O
IBM	O
standard	O
for	O
a	O
computer	O
peripheral	O
interface	O
"	O
,	O
and	O
was	O
commonly	O
used	O
to	O
connect	O
their	O
mainframe	O
computers	O
to	O
peripheral	O
devices	O
such	O
as	O
line	O
printers	O
,	O
disk	B-Device
storage	I-Device
,	O
magnetic	B-Architecture
tape	I-Architecture
drives	I-Architecture
and	O
IBM	B-Operating_System
3270	I-Operating_System
display	O
controllers	O
.	O
</s>
<s>
Bus	B-Device
and	I-Device
Tag	I-Device
cables	O
are	O
"	O
daisy	B-Application
chained	I-Application
"	O
;	O
and	O
one	O
interface	O
can	O
attach	O
up	O
to	O
eight	O
peripheral	O
control	O
units	O
.	O
</s>
<s>
Bus	B-Device
and	I-Device
Tag	I-Device
channels	I-Device
handle	O
data	O
rates	O
up	O
to	O
4.5MB	O
per	O
second	O
.	O
</s>
<s>
Bus	B-Device
and	I-Device
Tag	I-Device
architecture	O
was	O
also	O
used	O
by	O
other	O
computer	O
manufacturers	O
to	O
attach	O
IBM	O
peripherals	O
to	O
their	O
systems	O
.	O
</s>
<s>
Bus	B-Device
and	I-Device
Tag	I-Device
was	O
introduced	O
with	O
System/360	B-Application
in	O
1964	O
,	O
and	O
was	O
also	O
used	O
with	O
System/370	B-Device
.	O
</s>
<s>
With	O
the	O
introduction	O
of	O
serial	B-Protocol
,	O
fiber	B-Architecture
optic	I-Architecture
ESCON	B-Device
in	O
the	O
1990s	O
Bus	B-Device
and	I-Device
Tag	I-Device
channels	I-Device
were	O
re-christened	O
"	O
parallel	O
channels	O
"	O
,	O
and	O
were	O
gradually	O
superseded	O
.	O
</s>
<s>
Equipment	O
is	O
available	O
to	O
allow	O
connection	O
of	O
older	O
devices	O
using	O
Bus	B-Device
and	I-Device
Tag	I-Device
to	O
mainframe	O
FICON	B-Architecture
or	O
ESCON	B-Device
channels	O
.	O
</s>
<s>
Originally	O
the	O
System/360	B-Application
had	O
two	O
types	O
of	O
channel	O
;	O
the	O
byte	O
multiplexor	O
channel	O
and	O
the	O
selector	O
channel	O
.	O
</s>
<s>
In	O
1970	O
,	O
IBM	O
announced	O
the	O
2880	O
block	O
multiplexor	O
channel	O
for	O
the	O
360/85	B-Device
and	O
360/195	B-Device
,	O
in	O
support	O
of	O
the	O
IBM	B-Device
2305	I-Device
fixed	O
head	O
disk	B-Device
.	O
</s>
<s>
In	O
the	O
same	O
year	O
,	O
IBM	O
announced	O
the	O
System/370	B-Device
,	O
which	O
included	O
block	O
multiplexor	O
channels	O
.	O
</s>
<s>
The	O
following	O
schematic	O
shows	O
a	O
complex	O
system	O
with	O
two	O
CPUs	O
and	O
multiple	O
peripherals	O
connected	O
using	O
bus	B-Device
and	I-Device
tag	I-Device
cabling	O
.	O
</s>
