<s>
Enhanced	B-Architecture
Small	I-Architecture
Disk	I-Architecture
Interface	I-Architecture
(	O
ESDI	O
)	O
is	O
an	O
obsolete	O
disk	O
interface	O
designed	O
by	O
Maxtor	O
Corporation	O
in	O
the	O
early	O
1980s	O
to	O
be	O
a	O
follow-on	O
to	O
the	O
ST-412/506	B-Device
interface	O
.	O
</s>
<s>
ESDI	O
improved	O
on	O
ST-506	B-Device
by	O
moving	O
certain	O
parts	O
that	O
were	O
traditionally	O
kept	O
on	O
the	O
controller	O
(	O
such	O
as	O
the	O
data	O
separator	O
)	O
into	O
the	O
drives	O
themselves	O
,	O
and	O
also	O
generalizing	O
the	O
control	O
bus	O
such	O
that	O
more	O
kinds	O
of	O
devices	O
(	O
such	O
as	O
removable	O
disks	O
and	O
tape	O
drives	O
)	O
could	O
be	O
connected	O
.	O
</s>
<s>
ESDI	O
uses	O
the	O
same	O
cabling	O
as	O
ST-506	B-Device
(	O
one	O
34-pin	O
common	O
control	O
cable	O
,	O
and	O
a	O
20-pin	O
data	O
channel	O
cable	O
for	O
each	O
device	O
)	O
,	O
and	O
thus	O
could	O
easily	O
be	O
retrofitted	O
to	O
ST-506	B-Device
applications	O
.	O
</s>
<s>
ESDI	O
was	O
popular	O
in	O
the	O
mid-to-late	O
1980s	O
,	O
when	O
SCSI	B-Architecture
and	O
IDE	B-Protocol
technologies	O
were	O
young	O
and	O
immature	O
,	O
and	O
ST-506	B-Device
was	O
neither	O
fast	O
nor	O
flexible	O
enough	O
.	O
</s>
<s>
ESDI	O
could	O
handle	O
data	O
rates	O
of	O
10	O
,	O
15	O
,	O
or	O
20	O
Mbit/s	O
(	O
as	O
opposed	O
to	O
ST-506	B-Device
'	O
s	O
top	O
speed	O
of	O
7.5	O
Mbit/s	O
)	O
,	O
and	O
many	O
high-end	O
SCSI	B-Architecture
drives	O
of	O
the	O
era	O
were	O
actually	O
high-end	O
ESDI	O
drives	O
with	O
SCSI	B-Architecture
bridges	O
integrated	O
on	O
the	O
drive	O
.	O
</s>
<s>
By	O
1990	O
,	O
SCSI	B-Architecture
had	O
matured	O
enough	O
to	O
handle	O
high	O
data	O
rates	O
and	O
multiple	O
types	O
of	O
drives	O
,	O
and	O
ATA	O
was	O
quickly	O
overtaking	O
ST-506	B-Device
in	O
the	O
desktop	O
market	O
.	O
</s>
