Old Hardware Emulated :OZvm - The Cambridge Z88 Portable Computer
The Emulation of Handheld Computers From The 80's.
The Interesting Path to The Z88 and the genius who delivered it, Sir Clive Sinclair
Before covering the machine in detail, I feel compelled to provide a brief
history of Sir Clive Sinclair, the one who conceived this computer, because he's a very interesting and prominent person in
his own right.The Cambridge Z88 was one of his brainchild's. He was a
technological visionary and a leading character in the British computing
scene in the early 80's. Sinclair's products garnered mass appeal and
made computing accessible for those that otherwise wouldn't had the
opportunity to experiment with computers. Sinclair's idea of low-cost
computing played a role in this country as well.A idea was embraced by Jack Tramiel and put forth in the Commodore VIC-20 and C64. The idea of technology for the masses, and not the classes.
Computers during this time were still extremely expensive.
Machines like the TRS-80 started at around $600, while computers such as
the Atari 800, the Commodore PET, and Apple 2 were more expensive
still. Let's not even mention the price tag of those IBM Compatibles! In
the 1970's, his company, Sinclair Radionics, created affordable digital
watches and pocket calculators for that were much cheaper in price than
there competitors.
This company was also working on a low-cost, portable TV. His
ultimate dream was to build a affordable electric car that could be
accessible to the masses. A dream that was placed on hold when his
company went into financial dire straits. Many of these products had high
failure rates that painted the products of Sinclair Radionics as "crap"
by the public as large. The NEB (National Enterprise Board), brought a
stake in the company to help finance the development of new products.
Eventually, they became the majority share in the company and when the
company couldn't return from profitability, Sinclair Radionics was
broken up, with Clive Sinclair getting a cut of it.
Timex-Sinclair 1000. Paid $1.08 from a Salvation Army Thrift Store in South Texas.
Realizing
that Sinclair Radionics was failing, Clive Sinclair had a separate
company, Science of Cambridge, which would continue his commercial
pursuits. It was this company that eventually created the legendary
computers like the ZX-Spectrum. Renaming themselves Sinclair Research
after the collapse of Radionics, the company released a microcomputer
kit, followed up by the Sinclair ZX81. That computer was known here in
the US as the Timex-Sinclair. Sinclair Research partnered with Timex,
the watch company to sell the computers here. These machines never
gained a foothold here as the home market was dominated by Commodore
with there VIC-20 and C64. Machines like the ZX81 and later the
ZX-Spectrum became the fixture of the British microcomputer scene
though. Many were introduced to programming and game design for the
first time through these little computers.
While this part of the article is lengthy, it's not intended as
being a detailed history of Sinclair's career or that of his companies.
If anyone wants more information, one can trail Wikipedia or the various
websites on the net detailing the impact of these products. I would
also recommend the movie Micro Men, which is a dramatized
documentary about Sinclair and his rivalry with Acorn Electronics. One
could compare this movie as the British equivalent of Pirates of Silicon Valley. To be honest though, I've enjoyed Micro Men
much better than that other movie though.
The interesting thing about Sinclair is that he only see's
computers as a tool, and not as a ends in themselves. In interviews, he
stated that he doesn't use the Internet nor have email. The reason for
this is that he views them as distractions in the pursuit of invention.
He envisioned tools that can benefit humanity as a whole.
When it comes to computing, he envisioned a affordable computer
that would be useful for those on the go. This idea wasn't totally
original as one saw machines like the Sharp Pocket Computers and the
Tandy TRS-80 Model 100 computers that existed previously. However, his
computer would incorporate software that was much more powerful than its
contemporaries, and would serve a much more universal purpose. Many of
the handheld computers made by Sharp and Casio usually served
specialized niches purposes in mathematical and scientific field work or
were used in the financial and insurance markets. The Tandy TRS-80
Model 100 found a lot of love with authors and journalist, but was still
specific in need.
The Cambridge Z88
Let's now
examine this portable computer. The Z88 was powered by a CMOS version of
the 8-bit Zilog Z80 processor. This processor was widely used in many
8-bit computers of there day like the Tandy TRS-80 home computers and
the various CP/M microcomputers. By default, the computer shipped with
32KB of RAM, while the operating system, named OZ, was stored on a 128KB
ROM chip. The computer could be expanded up to 3.5MB's of RAM.
The Z88 used a membrane keyboard. A click sound could be turned on
to provide feedback from the key-press. The computer is powered by 4 AA
batteries, which can provide up to 20 hours of battery life. Also,
there are three memory card slots, which could accommodate memory
expansion, EPROM or FLASH cards. These expansion cards could have memory
and/or storage capacities ranging from 32KB to 1MB.
The Cambridge Z88 also sported a enhanced LCD display which
provided greater contrast in the screen compared to most of standard
displays LCD displays. The screen had a resolution of 64 by 640 pixels,
providing 8 lines on text.
OZvm emulating the Cambridge Z88.
Software
The Cambridge
Z88 came preloaded with a variety of software that was bundled on the
ROM chip. A organizer, Diary, allowed the users to organize there
schedule. Terminal, a communications programs, allowed file transfer to
and from the device via RS-232 serial port.
One could argue that the most widely used program on the Z88 is
PipeDream. PipeDream is a combination word-processor/spreadsheet
application. One could argue that this was the most important piece of
software on the Z88 as it's a powerful program which allows the user to
compose documents on the go. This Cambridge Z88 became the computer of
choice for journalist the world over due to its portability, powerful
software, and initiative environment. The software was also useful for
those that just wanted a general-purpose word-processor without having a
full-blown desktop or owning a electric typewriters from IBM or
Smith-Corona.
The computer shipped with BASIC. This was a typical practice with
most computers of there day. The version of BASIC included was of the
BBC dialect, which was widely used on many British microcomputers of
there day. It first gained massive use on the Acorn BBC Micro, and then
ported to various other computers over the years.
The PipeDream word-processor/spreadsheet application for the Z88.
BBC BASIC for the Cambridge Z88.
There was also a collection of utilities that came with the computer as well, like a calendar, calculator, and alarm.
Calendar
Calculator
A strong enthusiast
community formed around this computer. Many wrote there own applications
for the Z88 as well. Some are still using this computer and supporting
it today. Not only that, emulation allows those that never had the
opportunity to use this computer to try it out.
Emulation
I used the
OZvm emulator to emulate this machine. The name is taken from OZ, which
was the name of the operating system for the Z88. As noted on the
homepage for the emulator, the software is geared towards software
development. One can write applications for this computer without
needing the actual hardware. This could be considered good as hardware
gets scarcer over time. Not only that, for those that do have the
physical machines, they can rest knowing that its still being supported
by a active, home-brew community. This community is even releasing new
versions of the OZ that can be updated over the original OS as well.
The website centering around this development and support is at:
While the emulator is at:
OZvm has been ported to Windows, Mac OS, and Linux. I'm using the
Windows port of the emulator for the screenshots provided above. All I
have to say is that it works. One can try out the applications that came
with the Z88. One can test out the different versions of OZ as well. As
mentioned before, the home-brew community uses this emulator for
software development as well, writing new applications for the Z88. OZvm
is open-source as well.
Final Thoughts
As mentioned
in previous articles, those who never exposed to these computers from
the past might feel out of place. These machines were from a different
era that centered around productivity, with multimedia being a distant
pipedream (I couldn't help myself). These articles intended to focus on
such platforms from a emulation perspective. As real hardware ages,
emulation will eventually be the only way to document the history of
computing as a whole. Especially for the portable computers, like the
Cambridge Z88.
These portable computers would play a role in the development of
the recreational technology of our smartphones and tablets that we so
know and love today. That tech had to come from somewhere, right! The
Cambridge Z88 had to come from a visionary, right! Hats off to the
genius that's Sir Clive Sinclair and the innovative work done that
helped bring computing to the masses.
Articles of Interest
Wikipedia - Cambridge Z88: https://en.wikipedia.org/wiki/Cambridge_Z88
Old Computers - Cambridge Z88: http://oldcomputers.net/cambridge-z88.html
Z88 Emulator - "OZvm": https://cambridgez88.jira.com/wiki/spaces/OZVM/overview
BBC BASIC: https://en.wikipedia.org/wiki/BBC_BASIC
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