<s>
The	O
Cambridge	B-Device
Z88	I-Device
is	O
a	O
Zilog	O
Z80-based	O
portable	B-Device
computer	I-Device
released	O
in	O
1987	O
by	O
Cambridge	O
Computer	O
,	O
the	O
company	O
formed	O
for	O
such	O
purpose	O
by	O
Clive	O
Sinclair	O
.	O
</s>
<s>
It	O
was	O
approximately	O
A4	O
paper	O
sized	O
and	O
lightweight	O
at	O
,	O
running	O
on	O
four	O
AA	B-Algorithm
batteries	I-Algorithm
for	O
20	O
hours	O
of	O
use	O
.	O
</s>
<s>
It	O
was	O
packaged	O
with	O
a	O
built-in	O
combined	O
word	O
processing/spreadsheet/database	O
application	O
called	O
PipeDream	O
(	O
functionally	O
equivalent	O
to	O
a	O
1987	O
BBC	B-Device
Micro	I-Device
ROM	B-Device
called	O
Acornsoft	O
View	O
Professional	O
)	O
,	O
along	O
with	O
several	O
other	O
applications	B-Application
and	O
utilities	O
,	O
such	O
as	O
a	O
Z80-version	O
of	O
the	O
BBC	B-Language
BASIC	I-Language
programming	I-Language
language	I-Language
.	O
</s>
<s>
The	O
Z88	O
evolved	O
from	O
Sir	O
Clive	O
Sinclair	O
's	O
Pandora	O
portable	B-Device
computer	I-Device
project	O
which	O
had	O
been	O
under	O
development	O
at	O
Sinclair	O
Research	O
during	O
the	O
mid-1980s	O
.	O
</s>
<s>
The	O
Z88	O
is	O
a	O
portable	B-Device
computer	I-Device
weighing	O
,	O
based	O
on	O
a	O
low-power	O
CMOS	B-Device
version	O
of	O
the	O
popular	O
Zilog	B-General_Concept
Z80	I-General_Concept
microprocessor	B-Architecture
.	O
</s>
<s>
It	O
comes	O
with	O
32kB	O
of	O
internal	O
pseudo-static	O
RAM	B-Architecture
and	O
128kB	O
of	O
ROM	B-Device
containing	O
the	O
operating	B-General_Concept
system	I-General_Concept
(	O
called	O
OZ	O
)	O
.	O
</s>
<s>
The	O
memory	O
can	O
be	O
expanded	O
up	O
to	O
3.5MB	O
of	O
RAM	B-Architecture
,	O
the	O
contents	O
of	O
which	O
are	O
preserved	O
across	O
sessions	O
.	O
</s>
<s>
The	O
machine	O
uses	O
a	O
membrane	B-Device
keyboard	I-Device
,	O
which	O
is	O
almost	O
silent	O
in	O
use	O
;	O
an	O
optional	O
electronic	O
"	O
click	O
"	O
can	O
be	O
turned	O
on	O
to	O
indicate	O
keystrokes	O
.	O
</s>
<s>
The	O
Z88	O
is	O
powered	O
by	O
four	O
AA	B-Algorithm
batteries	I-Algorithm
,	O
giving	O
up	O
to	O
20	O
hours	O
of	O
use	O
.	O
</s>
<s>
It	O
has	O
three	O
memory	O
card	O
slots	O
,	O
which	O
accommodate	O
proprietary	O
RAM	B-Architecture
,	O
EPROM	B-General_Concept
or	O
flash	B-Device
cards	I-Device
,	O
the	O
third	O
slot	O
being	O
equipped	O
with	O
a	O
built-in	O
EPROM	B-General_Concept
programmer	I-General_Concept
.	O
</s>
<s>
The	O
Z88	O
has	O
a	O
built-in	O
eight-line	O
,	O
64	O
×	O
640	O
pixel	O
super-twisted	B-General_Concept
nematic	I-General_Concept
display	I-General_Concept
which	O
has	O
greater	O
contrast	O
than	O
conventional	O
twisted	O
nematic	O
LCDs	O
.	O
</s>
<s>
The	O
64kB	O
addressable	O
by	O
the	O
Z80	B-General_Concept
processor	O
are	O
divided	O
in	O
four	O
banks	O
of	O
16kB	O
each	O
.	O
</s>
<s>
The	O
first	O
512kB	O
are	O
reserved	O
for	O
ROM	B-Device
;	O
the	O
next	O
512kB	O
are	O
reserved	O
for	O
internal	O
RAM	B-Architecture
.	O
</s>
<s>
Since	O
1998	O
,	O
a	O
1MiB	O
Flash	B-Device
memory	I-Device
card	O
is	O
available	O
which	O
provides	O
convenient	O
non-volatile	B-General_Concept
storage	I-General_Concept
.	O
</s>
<s>
Unlike	O
traditional	O
EPROM	B-General_Concept
cards	O
(	O
erased	O
with	O
an	O
external	O
ultraviolet	B-Application
light	O
)	O
,	O
this	O
one	O
can	O
be	O
electrically	O
erased	O
in	O
the	O
computer	O
's	O
slot	O
.	O
</s>
<s>
It	O
is	O
possible	O
to	O
read	O
,	O
write	O
and	O
erase	O
flash	B-Device
cards	I-Device
in	O
the	O
three	O
slots	O
and	O
the	O
internal	O
one	O
.	O
</s>
<s>
It	O
is	O
also	O
possible	O
for	O
an	O
experienced	O
user	O
to	O
replace	O
the	O
built-in	O
32kB	O
RAM	B-Architecture
chip	I-Architecture
with	O
a	O
bigger	O
128	O
or	O
512kB	O
static	O
RAM	B-Architecture
chip	I-Architecture
.	O
</s>
<s>
However	O
,	O
the	O
latter	O
requires	O
some	O
extra	O
board	O
modifications	O
,	O
and	O
512kB	O
is	O
the	O
biggest	O
size	O
that	O
can	O
be	O
addressed	O
by	O
the	O
Z88	O
for	O
the	O
internal	O
RAM	B-Architecture
.	O
</s>
<s>
A	O
similar	O
modification	O
is	O
possible	O
for	O
the	O
internal	O
ROM	B-Device
slot	O
.	O
</s>
<s>
A	O
512kB	O
flash	B-Device
chip	I-Device
can	O
replace	O
the	O
original	O
ROM	B-Device
,	O
allowing	O
an	O
upgrade	O
of	O
the	O
operating	B-General_Concept
system	I-General_Concept
.	O
</s>
