<s>
Beta	B-Device
Disk	I-Device
Interface	I-Device
is	O
a	O
disk	O
interface	O
for	O
ZX	B-Operating_System
Spectrum	I-Operating_System
computers	O
,	O
developed	O
by	O
Technology	B-Device
Research	I-Device
Ltd	I-Device
.	O
(	O
United	O
Kingdom	O
)	O
in	O
1984	O
and	O
released	O
in	O
1985	O
,	O
with	O
a	O
price	O
of	O
£109.25	O
(	O
or	O
£249.75	O
with	O
one	O
disk	O
drive	O
)	O
.	O
</s>
<s>
Beta	B-Device
128	I-Device
Disk	I-Device
Interface	I-Device
is	O
a	O
1987	O
version	O
,	O
supporting	O
ZX	B-Operating_System
Spectrum	I-Operating_System
128	O
machines	O
(	O
due	O
to	O
different	O
access	O
point	O
addresses	O
)	O
.	O
</s>
<s>
Beta	B-Device
Disk	I-Device
Interfaces	I-Device
were	O
distributed	O
with	O
the	O
TR-DOS	B-Operating_System
operating	O
system	O
in	O
ROM	O
,	O
also	O
attributed	O
to	O
Technology	B-Device
Research	I-Device
Ltd	I-Device
..	O
</s>
<s>
The	O
interface	O
was	O
based	O
on	O
the	O
WD1793	B-Device
chip	O
.	O
</s>
<s>
Latest	O
firmware	B-Application
version	O
is	O
5.03	O
(	O
1986	O
)	O
.	O
</s>
<s>
The	O
Beta	B-Device
Disk	I-Device
Interface	I-Device
handles	O
single	O
and	O
double	O
sided	O
,	O
40	O
or	O
80	O
tracks	O
double	O
density	O
floppy	B-Device
disks	I-Device
,	O
and	O
up	O
to	O
4	O
drives	O
.	O
</s>
<s>
This	O
interface	O
was	O
popular	O
for	O
its	O
simplicity	O
,	O
and	O
the	O
Beta	B-Device
128	I-Device
Disk	I-Device
Interface	I-Device
was	O
cloned	B-General_Concept
all	O
around	O
the	O
USSR	O
.	O
</s>
<s>
The	O
first	O
known	O
USSR	O
clones	B-General_Concept
were	O
ones	O
produced	O
by	O
НПВО	O
"	O
Вариант	O
"	O
(	O
NPVO	O
"	O
Variant	O
"	O
,	O
Leningrad	B-Device
)	O
in	O
1989	O
.	O
</s>
<s>
Beta	B-Device
128	I-Device
schematics	O
are	O
included	O
in	O
various	O
Soviet/Russian	O
ZX	B-Operating_System
Spectrum	I-Operating_System
clones	B-General_Concept
,	O
but	O
some	O
variants	O
only	O
support	O
two	O
drives	O
.	O
</s>
<s>
Between	O
2018	O
and	O
2021	O
,	O
Beta	B-Device
Disk	I-Device
clones	B-General_Concept
were	O
produced	O
in	O
the	O
Czech	O
Republic	O
,	O
with	O
the	O
names	O
such	O
as	O
Beta	B-Device
Disk	I-Device
128C	O
,	O
128X	O
and	O
128	O
mini	O
.	O
</s>
