<s>
FASTRAND	B-Device
was	O
a	O
magnetic	B-General_Concept
drum	I-General_Concept
mass	O
storage	O
system	O
built	O
by	O
Sperry	O
Rand	O
Corporation	O
(	O
later	O
Sperry	O
Univac	O
)	O
for	O
their	O
UNIVAC	B-Device
1100	I-Device
series	I-Device
and	O
418/490/494	O
series	O
computers	O
.	O
</s>
<s>
A	O
FASTRAND	B-Device
subsystem	O
consisted	O
of	O
one	O
or	O
two	O
Control	O
Units	O
and	O
up	O
to	O
eight	O
FASTRAND	B-Device
units	O
.	O
</s>
<s>
A	O
dual-access	O
FASTRAND	B-Device
subsystem	O
included	O
two	O
complete	O
control	O
units	O
,	O
and	O
provided	O
parallel	O
data	O
paths	O
that	O
allowed	O
simultaneous	O
operations	O
on	O
any	O
two	O
FASTRAND	B-Device
units	O
in	O
the	O
subsystem	O
.	O
</s>
<s>
A	O
voice	O
coil	O
actuator	O
moved	O
a	O
bar	O
containing	O
multiple	O
single	O
track	O
recording	O
heads	B-Device
,	O
so	O
these	O
drums	O
operated	O
much	O
like	O
moving	O
head	O
disk	O
drives	O
with	O
multiple	O
disks	O
.	O
</s>
<s>
The	O
heads	B-Device
"	O
flew	O
"	O
on	O
self-acting	O
hydrodynamic	O
air	O
bearings	O
.	O
</s>
<s>
An	O
optional	O
feature	O
called	O
Fastband	O
included	O
24	O
additional	O
tracks	O
with	O
fixed	O
read/write	B-Device
heads	I-Device
.	O
</s>
<s>
The	O
Fastrands	B-Device
were	O
very	O
heavy	O
(	O
5,000	O
pounds	O
)	O
and	O
large	O
,	O
approximately	O
8	O
 '	O
long	O
.	O
</s>
<s>
Due	O
to	O
their	O
weight	O
,	O
FASTRAND	B-Device
units	O
were	O
usually	O
not	O
installed	O
on	O
"	O
false	O
floor	O
"	O
,	O
and	O
required	O
special	O
rigging	O
and	O
mounts	O
to	O
move	O
and/or	O
install	O
.	O
</s>
<s>
There	O
were	O
three	O
models	O
of	O
FASTRAND	B-Device
drives	O
:	O
</s>
<s>
FASTRAND	B-Device
I	O
had	O
a	O
single	O
drum	O
.	O
</s>
<s>
Very	O
few	O
of	O
these	O
devices	B-Device
were	O
delivered	O
.	O
</s>
<s>
FASTRAND	B-Device
II	O
(	O
the	O
majority	O
of	O
units	O
produced	O
)	O
had	O
two	O
counter-rotating	O
drums	O
to	O
eliminate	O
the	O
gyroscopic	O
effect	O
.	O
</s>
<s>
One	O
actuator	O
bar	O
with	O
heads	B-Device
was	O
located	O
between	O
the	O
drums	O
.	O
</s>
<s>
FASTRAND	B-Device
III	O
,	O
introduced	O
in	O
1970	O
,	O
was	O
physically	O
identical	O
to	O
the	O
FASTRAND	B-Device
II	O
,	O
but	O
increased	O
the	O
recording	B-Device
density	I-Device
by	O
50%	O
.	O
</s>
<s>
Despite	O
the	O
name	O
,	O
FASTRAND	B-Device
was	O
slow	O
.	O
</s>
<s>
The	O
head	O
positioning	O
time	O
was	O
significant	O
,	O
so	O
software	O
allocated	O
storage	O
by	O
tracks	O
(	O
1,792	O
words	O
,	O
10,752	O
characters	O
or	O
8,064	O
eight-bit	O
bytes	O
)	O
or	O
"	O
positions	O
"	O
,	O
a	O
group	O
of	O
64	O
tracks	O
(	O
114,688	O
words	O
,	O
688,128	O
characters	O
or	O
510,096	O
eight-bit	O
bytes	O
)	O
which	O
were	O
under	O
the	O
heads	B-Device
at	O
a	O
single	O
time	O
.	O
</s>
<s>
The	O
track	O
storage	O
units	O
were	O
checkboarded	O
so	O
that	O
,	O
with	O
precise	O
computation	O
of	O
the	O
program	O
's	O
processing	O
time	O
,	O
one	O
could	O
create	O
software	O
with	O
processing	O
time	O
per	O
unit	O
of	O
Fastrand	B-Device
blocks	O
that	O
resulted	O
in	O
a	O
program	O
running	O
in	O
synchronism	O
with	O
the	O
data	O
transfer	O
rate	O
of	O
the	O
drum	O
.	O
</s>
