<s>
The	O
Sinclair	B-Device
QL	I-Device
(	O
for	O
Quantum	O
Leap	O
)	O
is	O
a	O
personal	B-Device
computer	I-Device
launched	O
by	O
Sinclair	O
Research	O
in	O
1984	O
,	O
as	O
an	O
upper-end	O
counterpart	O
to	O
the	O
ZX	B-Operating_System
Spectrum	I-Operating_System
.	O
</s>
<s>
While	O
the	O
ZX	B-Operating_System
Spectrum	I-Operating_System
has	O
an	O
8-bit	O
Zilog	B-General_Concept
Z80	I-General_Concept
as	O
the	O
CPU	B-Device
,	O
the	O
QL	O
uses	O
a	O
Motorola	B-Device
68008	I-Device
.	O
</s>
<s>
The	O
68008	B-Device
is	O
a	O
member	O
of	O
the	O
Motorola	B-Device
68000	I-Device
family	O
with	O
32-bit	O
internal	O
data	O
registers	O
,	O
but	O
an	O
8-bit	O
external	B-General_Concept
data	I-General_Concept
bus	I-General_Concept
.	O
</s>
<s>
The	O
QL	O
was	O
originally	O
conceived	O
in	O
1981	O
under	O
the	O
code-name	O
ZX83	B-Device
,	O
as	O
a	O
portable	B-Device
computer	I-Device
for	O
business	O
users	O
,	O
with	O
a	O
built-in	O
ultra-thin	O
flat-screen	O
CRT	B-Device
display	I-Device
similar	O
to	O
the	O
later	O
TV80	O
pocket	O
TV	O
,	O
printer	O
and	O
modem	B-Application
.	O
</s>
<s>
The	O
industrial	O
design	O
was	O
done	O
by	O
Rick	O
Dickinson	O
,	O
who	O
already	O
designed	O
the	O
ZX81	O
and	O
ZX	B-Operating_System
Spectrum	I-Operating_System
range	O
of	O
products	O
.	O
</s>
<s>
The	O
QL	O
was	O
designed	O
to	O
be	O
more	O
powerful	O
than	O
the	O
IBM	B-Device
Personal	I-Device
Computer	I-Device
,	O
and	O
comparable	O
to	O
Apple	O
's	O
Macintosh	B-Device
.	O
</s>
<s>
While	O
the	O
CPU	B-Device
clock	O
speed	O
is	O
comparable	O
to	O
that	O
of	O
the	O
Macintosh	B-Device
,	O
and	O
the	O
later	O
Atari	B-Device
ST	I-Device
and	O
Amiga	O
,	O
the	O
8-bit	O
databus	B-General_Concept
and	O
cycle	B-General_Concept
stealing	I-General_Concept
of	O
the	O
ZX8301	O
gate	O
array	O
limit	O
the	O
QL	O
's	O
performance	O
.	O
</s>
<s>
Sinclair	O
had	O
commissioned	O
GST	O
Computer	O
Systems	O
to	O
produce	O
the	O
operating	B-General_Concept
system	I-General_Concept
for	O
the	O
machine	O
,	O
but	O
switched	O
to	O
Domesdos	B-Operating_System
,	O
developed	O
by	O
Tony	O
Tebby	O
as	O
an	O
in-house	O
alternative	O
,	O
before	O
launch	O
.	O
</s>
<s>
GST	O
's	O
OS	B-General_Concept
,	O
designed	O
by	O
Tim	O
Ward	O
,	O
was	O
later	O
made	O
available	O
as	O
68K/OS	B-Operating_System
,	O
in	O
the	O
form	O
of	O
an	O
add-on	O
ROM	B-Device
card	O
.	O
</s>
<s>
The	O
tools	O
developed	O
by	O
GST	O
for	O
the	O
QL	O
would	O
later	O
be	O
used	O
on	O
the	O
Atari	B-Device
ST	I-Device
,	O
where	O
GST	O
object	O
format	O
became	O
standard	O
.	O
</s>
<s>
At	O
the	O
time	O
of	O
the	O
rushed	O
launch	O
,	O
on	O
12	O
January	O
1984	O
,	O
the	O
QL	O
was	O
far	O
from	O
being	O
ready	O
for	O
production	O
—	O
there	O
being	O
no	O
complete	O
working	B-Application
prototype	I-Application
in	O
existence	O
.	O
</s>
<s>
Early	O
production	O
QLs	O
were	O
shipped	O
with	O
preliminary	O
versions	O
of	O
firmware	B-Application
containing	O
numerous	O
bugs	B-Error_Name
,	O
mainly	O
in	O
SuperBASIC	B-Language
.	O
</s>
<s>
Part	O
of	O
the	O
firmware	B-Application
is	O
held	O
on	O
an	O
external	O
16KiB	O
ROM	B-Device
cartridge	O
also	O
known	O
as	O
the	O
"	O
kludge	B-Architecture
"	O
or	O
"	O
dongle	B-Device
"	O
,	O
until	O
the	O
QL	O
was	O
redesigned	O
to	O
accommodate	O
the	O
necessary	O
48KiB	O
of	O
ROM	B-Device
internally	O
,	O
instead	O
of	O
the	O
32KiB	O
initially	O
specified	O
.	O
</s>
<s>
The	O
QL	O
also	O
suffers	O
from	O
reliability	O
problems	O
of	O
its	O
Microdrives	B-Device
.	O
</s>
<s>
These	O
problems	O
were	O
later	O
rectified	O
,	O
by	O
Sinclair	O
engineers	O
,	O
especially	O
on	O
Samsung	B-Application
produced	O
models	O
,	O
as	O
well	O
as	O
by	O
aftermarket	O
firms	O
such	O
as	O
Adman	O
Services	O
and	O
TF	O
Services	O
,	O
to	O
the	O
point	O
where	O
several	O
QL	O
users	O
report	O
the	O
Samsung	B-Application
Microdrives	B-Device
in	O
particular	O
working	O
perfectly	O
even	O
after	O
almost	O
17	O
years	O
of	O
service	O
;	O
but	O
in	O
any	O
case	O
too	O
late	O
to	O
redeem	O
the	O
negative	O
image	O
they	O
had	O
already	O
created	O
.	O
</s>
<s>
Apart	O
from	O
its	O
reliability	O
issues	O
,	O
the	O
target	O
business	O
market	O
was	O
becoming	O
wedded	O
to	O
the	O
IBM	B-Device
PC	I-Device
platform	O
,	O
whilst	O
the	O
majority	O
of	O
ZX	B-Operating_System
Spectrum	I-Operating_System
owners	O
were	O
uninterested	O
in	O
upgrading	O
to	O
a	O
machine	O
which	O
had	O
a	O
minimal	O
library	O
of	O
games	O
(	O
with	O
only	O
about	O
70	O
titles	O
,	O
compared	O
to	O
the	O
Spectrum	O
's	O
more	O
than	O
4700	O
)	O
.	O
</s>
<s>
Sinclair	O
's	O
persistence	O
with	O
the	O
non-standard	O
Microdrive	B-Device
and	O
uncomfortable	O
keyboard	O
did	O
not	O
endear	O
it	O
to	O
the	O
business	O
market	O
;	O
coupled	O
with	O
the	O
machine	O
's	O
resemblance	O
to	O
a	O
ZX	O
Spectrum+	O
,	O
they	O
led	O
many	O
to	O
perceive	O
the	O
QL	O
as	O
something	O
akin	O
to	O
a	O
toy	O
.	O
</s>
<s>
Software	O
publishers	O
were	O
also	O
reluctant	O
to	O
support	O
the	O
QL	O
because	O
Microdrive	B-Device
cartridges	O
were	O
the	O
only	O
available	O
distribution	O
medium	O
for	O
QL	O
.	O
</s>
<s>
Based	O
on	O
a	O
Motorola	B-Device
68008	I-Device
processor	O
clocked	O
at	O
7.5	O
MHz	O
,	O
the	O
QL	O
included	O
128	O
KiB	O
of	O
RAM	B-Architecture
,	O
which	O
is	O
officially	O
expandable	O
to	O
640	O
KiB	O
and	O
in	O
practice	O
,	O
896	O
KB	O
.	O
</s>
<s>
It	O
can	O
be	O
connected	O
to	O
a	O
monitor	B-Device
or	O
TV	O
for	O
display	O
.	O
</s>
<s>
Sinclair	O
recommended	O
the	O
"	O
SINCLAIR	O
VISION-QL	O
"	O
RGB	O
monitor	B-Device
for	O
usage	O
with	O
the	O
QL	O
.	O
</s>
<s>
Both	O
screen	O
modes	O
use	O
a	O
32	O
KiB	O
framebuffer	B-Algorithm
in	O
main	O
memory	O
.	O
</s>
<s>
The	O
hardware	O
is	O
capable	O
of	O
switching	O
between	O
two	O
different	O
areas	O
of	O
memory	O
for	O
the	O
frame	B-Algorithm
buffer	I-Algorithm
,	O
thus	O
allowing	O
double	O
buffering	O
.	O
</s>
<s>
However	O
,	O
this	O
would	O
use	O
64	O
KB	O
of	O
the	O
standard	O
machine	O
's	O
128	O
KiB	O
of	O
RAM	B-Architecture
and	O
there	O
is	O
no	O
support	O
for	O
this	O
feature	O
in	O
the	O
QL	O
's	O
original	O
firmware	B-Application
.	O
</s>
<s>
The	O
alternative	O
and	O
improved	O
operating	B-General_Concept
system	I-General_Concept
Minerva	B-Application
provides	O
full	O
support	O
for	O
the	O
second	O
frame	B-Algorithm
buffer	I-Algorithm
.	O
</s>
<s>
When	O
connected	O
to	O
a	O
normally-adjusted	O
TV	O
or	O
monitor	B-Device
,	O
the	O
QL	O
's	O
video	O
output	O
overscans	O
horizontally	O
.	O
</s>
<s>
This	O
is	O
reputed	O
to	O
have	O
been	O
due	O
to	O
the	O
timing	O
constants	O
in	O
the	O
ZX8301	O
chip	O
being	O
optimised	O
for	O
the	O
flat-screen	O
CRT	B-Device
display	I-Device
originally	O
intended	O
for	O
the	O
QL	O
.	O
</s>
<s>
Internally	O
,	O
the	O
QL	O
comprises	O
the	O
CPU	B-Device
,	O
two	O
ULAs	O
(	O
ZX8301	O
and	O
ZX8302	O
)	O
and	O
an	O
Intel	B-Device
8049	I-Device
microcontroller	B-Architecture
known	O
as	O
the	O
IPC	O
,	O
or	O
"	O
Intelligent	O
Peripheral	O
Controller	O
"	O
,	O
responsible	O
for	O
keyboard	O
,	O
joystick	B-Device
ports	O
,	O
RS-232	O
inputs	O
and	O
sound	O
output	O
.	O
</s>
<s>
The	O
ZX8302	O
,	O
or	O
"	O
Peripheral	O
Chip	O
"	O
,	O
interfaces	O
to	O
the	O
RS-232	O
ports	O
(	O
transmit	O
only	O
)	O
Microdrives	B-Device
,	O
QLAN	O
ports	O
,	O
real-time	O
clock	O
and	O
the	O
8049	B-Device
via	O
a	O
synchronous	O
serial	O
link	O
.	O
</s>
<s>
The	O
8049	B-Device
included	O
at	O
a	O
late	O
stage	O
in	O
the	O
QL	O
's	O
design	O
(	O
the	O
ZX8302	O
originally	O
being	O
intended	O
to	O
perform	O
its	O
functions	O
)	O
runs	O
at	O
7.5	O
MHz	O
and	O
acts	O
as	O
a	O
keyboard/joystick	O
interface	O
,	O
RS-232	O
receive	O
buffer	O
and	O
audio	O
generator	O
.	O
</s>
<s>
When	O
comparing	O
technical	O
specifications	O
among	O
microcomputers	B-Architecture
in	O
the	O
traditional	O
sense	O
of	O
the	O
term	O
,	O
the	O
QL	O
qualifies	O
as	O
the	O
fastest	O
for	O
having	O
a	O
15	O
MHz	O
clock	O
that	O
alternates	O
between	O
Motorola	O
's	O
68008	B-Device
&	O
Intel	O
's	O
8049	B-Device
.	O
</s>
<s>
Two	O
built-in	O
Microdrive	B-Device
tape-loop	O
cartridge	O
drives	O
provide	O
mass	O
storage	O
,	O
in	O
place	O
of	O
the	O
more	O
expensive	O
floppy	B-Device
disk	I-Device
drives	I-Device
found	O
on	O
similar	O
systems	O
of	O
the	O
era	O
.	O
</s>
<s>
Microdrives	B-Device
had	O
been	O
introduced	O
for	O
the	O
ZX	B-Operating_System
Spectrum	I-Operating_System
in	O
July	O
1983	O
,	O
although	O
the	O
QL	O
uses	O
a	O
different	O
logical	O
tape	O
format	O
.	O
</s>
<s>
Interfaces	O
include	O
an	O
expansion	O
slot	O
,	O
ROM	B-Device
cartridge	O
socket	O
,	O
dual	O
RS-232	O
ports	O
,	O
proprietary	O
QLAN	O
local	B-General_Concept
area	I-General_Concept
network	I-General_Concept
ports	O
,	O
dual	O
joystick	B-Device
ports	O
and	O
an	O
external	O
Microdrive	B-Device
bus	O
.	O
</s>
<s>
The	O
QL	O
uses	O
British	O
Telecom	O
type	O
631W	O
plugs	O
of	O
similar	O
design	O
to	O
British	O
telephone	O
sockets	O
for	O
serial	O
cables	O
except	O
for	O
QLs	O
built	O
by	O
Samsung	B-Application
for	O
export	O
markets	O
,	O
which	O
have	O
DE-9	B-Protocol
sockets	O
.	O
</s>
<s>
Joysticks	B-Device
connect	O
to	O
the	O
QL	O
with	O
similar	O
type	O
630W	O
plugs	O
.	O
</s>
<s>
Physically	O
,	O
the	O
QL	O
is	O
the	O
same	O
black	O
colour	O
as	O
the	O
preceding	O
ZX81	O
and	O
ZX	B-Operating_System
Spectrum	I-Operating_System
,	O
but	O
introduced	O
a	O
new	O
angular	O
styling	O
theme	O
and	O
keyboard	O
design	O
which	O
would	O
later	O
be	O
seen	O
in	O
the	O
ZX	O
Spectrum+	O
.	O
</s>
<s>
QDOS	B-Operating_System
,	O
a	O
pre-emptive	B-Operating_System
multitasking	I-Operating_System
operating	I-Operating_System
system	I-Operating_System
primarily	O
designed	O
by	O
Tony	O
Tebby	O
,	O
is	O
included	O
on	O
ROM	B-Device
,	O
as	O
is	O
an	O
advanced	O
structured	O
BASIC	O
interpreter	B-Application
,	O
named	O
SuperBASIC	B-Language
designed	O
by	O
Jan	O
Jones	O
,	O
which	O
is	O
also	O
used	O
as	O
the	O
command-line	O
interpreter	B-Application
.	O
</s>
<s>
The	O
QL	O
is	O
bundled	O
with	O
an	O
office	O
suite	O
,	O
consisting	O
of	O
a	O
word	O
processor	O
,	O
spreadsheet	O
,	O
database	O
,	O
and	O
business	O
graphics	O
written	O
by	O
Psion	B-Application
.	O
</s>
<s>
It	O
is	O
the	O
first	O
OS	B-General_Concept
to	O
feature	O
a	O
Windows-style	O
GUI	B-Application
,	O
predating	O
Apple	O
Computer	O
by	O
a	O
month	O
.	O
</s>
<s>
The	O
QL	O
's	O
CPU	B-Device
,	O
ZX8301	O
and	O
ZX8302	O
ASICs	O
and	O
Microdrives	B-Device
form	O
the	O
basis	O
of	O
One	B-Device
Per	I-Device
Desk	I-Device
(	O
OPD	O
)	O
.	O
</s>
<s>
Built	O
by	O
International	O
Computers	O
Limited	O
(	O
ICL	O
)	O
,	O
it	O
was	O
also	O
marketed	O
by	O
British	O
Telecom	O
as	O
the	O
Merlin	B-Device
Tonto	I-Device
and	O
by	O
Telecom	O
Australia	O
as	O
the	O
Computerphone	B-Device
.	O
</s>
<s>
The	O
result	O
of	O
a	O
three-year	O
collaboration	O
between	O
Sinclair	O
Research	O
,	O
ICL	O
and	O
British	O
Telecom	O
,	O
the	O
One	B-Device
Per	I-Device
Desk	I-Device
adds	O
a	O
telephone	O
handset	O
at	O
one	O
end	O
of	O
the	O
keyboard	O
,	O
and	O
rudimentary	O
Computer-Telephony	O
Integration	O
(	O
CTI	O
)	O
software	O
.	O
</s>
<s>
Linus	O
Torvalds	O
has	O
attributed	O
his	O
eventually	O
developing	O
the	O
Linux	B-Operating_System
kernel	I-Operating_System
,	O
likewise	O
having	O
pre-emptive	B-Operating_System
multitasking	I-Operating_System
,	O
in	O
part	O
to	O
having	O
owned	O
a	O
Sinclair	B-Device
QL	I-Device
in	O
the	O
1980s	O
.	O
</s>
<s>
His	O
frustration	O
with	O
the	O
Sinclair	O
led	O
,	O
years	O
later	O
,	O
to	O
his	O
purchase	O
of	O
a	O
more	O
standard	O
IBM	B-Device
PC	I-Device
compatible	O
on	O
which	O
he	O
would	O
develop	O
Linux	B-Application
.	O
</s>
<s>
These	O
included	O
CST	O
and	O
DanSoft	O
,	O
creators	O
of	O
the	O
Thor	B-Device
line	O
of	O
compatible	O
systems	O
;	O
Miracle	O
Systems	O
,	O
creator	O
of	O
the	O
Gold	O
Card	O
and	O
Super	O
Gold	O
Card	O
processor/memory	O
upgrade	O
cards	O
and	O
the	O
QXL	O
PC-based	O
hardware	O
emulator	B-Application
;	O
and	O
Qubbesoft	O
,	O
with	O
the	O
Aurora	O
,	O
the	O
first	O
replacement	O
QL	O
mainboard	B-Device
,	O
with	O
enhanced	O
graphics	O
modes	O
.	O
</s>
<s>
In	O
the	O
late	O
1990s	O
,	O
two	O
partly	O
QL-compatible	O
motherboards	B-Device
named	O
Q40	B-Device
and	O
Q60	B-Device
(	O
collectively	O
referred	O
to	O
as	O
Qx0	B-Device
)	O
were	O
designed	O
by	O
Peter	O
Graf	O
and	O
marketed	O
by	O
D&D	O
Systems	O
.	O
</s>
<s>
The	O
Q40	B-Device
and	O
Q60	B-Device
,	O
based	O
on	O
the	O
Motorola	B-Device
68040	I-Device
and	O
68060	B-General_Concept
CPUs	B-Device
respectively	O
,	O
are	O
much	O
more	O
powerful	O
than	O
the	O
original	O
QL	O
and	O
have	O
the	O
ability	O
among	O
other	O
things	O
(	O
such	O
as	O
multimedia	O
,	O
high	O
resolution	O
graphics	O
,	O
Ethernet	O
networking	O
etc	O
.	O
)	O
</s>
<s>
to	O
run	O
the	O
Linux	B-Application
operating	I-Application
system	I-Application
.	O
</s>
<s>
Patched	O
or	O
reengineered	O
versions	O
of	O
QDOS	B-Operating_System
were	O
produced	O
,	O
most	O
notably	O
Minerva	B-Application
which	O
gradually	O
evolved	O
into	O
a	O
completely	O
rewritten	O
operating	B-General_Concept
system	I-General_Concept
,	O
offering	O
improved	O
speed	O
,	O
with	O
multitasking	O
SuperBASIC	B-Language
interpreters	B-Application
.	O
</s>
<s>
Tony	O
Tebby	O
went	O
on	O
to	O
produce	O
another	O
updated	O
operating	B-General_Concept
system	I-General_Concept
,	O
SMSQ/E	B-Operating_System
,	O
which	O
has	O
continued	O
to	O
be	O
developed	O
for	O
the	O
Sinclair	B-Device
QL	I-Device
and	O
emulators	B-Application
,	O
offering	O
many	O
more	O
features	O
.	O
</s>
<s>
Quite	O
a	O
few	O
emulators	B-Application
and	O
virtual	O
QLs	O
became	O
available	O
over	O
time	O
of	O
which	O
Q-emuLator	O
(	O
Windows/Mac	O
)	O
,	O
QPC2	O
(	O
Windows	O
)	O
,	O
SMSQmulator	O
(	O
Java	O
)	O
,	O
ZEsarUX	O
(	O
Windows/Mac/Linux	O
)	O
and	O
sQLux	O
(	O
Windows/Mac/Linux	O
)	O
are	O
actively	O
maintained	O
.	O
</s>
<s>
Several	O
distributions	O
of	O
emulators	B-Application
,	O
applications	O
and	O
information	O
have	O
been	O
produced	O
,	O
of	O
which	O
Black	O
Phoenix	O
and	O
QL/E	O
are	O
the	O
most	O
actively	O
maintained	O
.	O
</s>
