everybody knows about sinclair and the
zx80
there's
the lovely zx80 and a lot of people know
that his story followed in the next year
the zx81 but there was a machine that
went before it wasn't from sinclair as a
company wasn't from sinclair research
from a company called science of
cambridge um and it's the mk14
and it looks exactly like that pretty
basic stuff not even case on this one so
this came out in 1977. i mean 1977
you've got to realize this is a couple
of years before
the zx80 two or three years before this
was launched so computing home computing
um personal computing was very much in
its infancy um
as you can see
and this isn't a great deal more than a
calculator in some ways
but it's the beginning of
everything in terms of uh sinclair and
what they would do later on um and
there's a nice little story that goes
along with it so as with um many things
sometimes the story is not quite what
you'd expect it to be
if we take
this magazine here computing today
computing today number one was actually
part of eti electronics today
international november 1978 this one's
dated
so very very early on but in there is an
advert for the mk 14. this thing was 39
pound 95 to buy plus eight percent v80
250 pound in today's money approximately
taking into account inflation so it
sounds really cheap but really it wasn't
um and i can put that into context so
39.95 for one of these um we have over
here a very early copy of personal
computer world 78 same kind of era at
the back
we have a machine for example the exedy
sorcerer brilliant machine but this
guy's very happy as you can see z80 base
32k computer i want you to spend less
than a thousand pound my sorcerer cost
me 950. yeah 950 pound is about five and
a half grand in today's money um you
know and yeah if you had that kind of
money you would be doing that kind of uh
thing on the picture seed one there does
it say a price there 1 674 for that
machine that's then money not today's
money so that's even more expensive they
were used in education uh they were used
for research um you know these we see we
do have to realize these were the micro
computers so mainframes and minis they
were they were hundreds of thousands of
hours to buy back then you know millions
of pounds in today's money so these were
you know relatively cheap relative being
the op the operative word there um but
very very expensive most people couldn't
afford these these kind of things um so
sinclair has always wanted to bring
machines out that broke that price
barrier and not just by a bit by a lot
the mk-14 was obviously vastly cut down
from any of those other machines that
are out there
you had this very very
simple touch keyboard there an led
display so basically a calculator
display you can only do sort of seven
segment digits with that it had 256
bytes of ram because there's not even a
kilobyte it's a quarter of a kilobyte um
so very very limited ram but then you
know with a keyboard like that how much
data are you really going to type into
these things how much did you need
um it was an 8-bit processor um had 12
bits of
address space then you could take a bit
further with an extra four bits as well
but you'd have to software program that
but it was pretty limited but it was a
machine that you could buy for 39.95
you could own this thing and you could
write the code that you wanted to write
so how did sinclair and i would say
chris curry at the time how did they
come about with actually
making this as a product
there was a guy called ian williamson
um and uh he came up with an idea for a
micro computer kit
um
and he saw the scamp design so we have
to look at the main chip
the main chip in there there is the
processor this is the scamp processor
it's actually written sc slash mp and it
stands for simple cost effective or one
word microprocessor two words
microprocessor is only one word these
days anyway um scmp but it got known as
the scamp um
and it was a you know an impressive
little processor made by national
semiconductor it williamson has seen the
various designs out there and this is a
development system for the scmp and we
also have quite a rare intro kit that
you could buy the this kit and make your
own scmp based system national
semiconductor to produce this so that
people in the industry could make their
designs around it and they had something
called a reference design so they had a
circuit diagram in williamson produced
this board again based on that original
design um took it to
uh clive and chris and said i've got an
idea for a product that you might be
interested in making but as the story
goes we do have a video on our youtube
channel which is an interview with ian
williamson so you can get this from the
horse's mouth but he showed this to the
guys and they were interested very much
interested sinclair was probably more
interested in the future of this what it
could become because it was very very
basic but chris thought yes this could
be a product um
so they said yeah this is we're
interested in that that's an interesting
thing that we might be able to market
um
but
when they went to national semiconductor
and said okay we want to buy a load of
your scamp chips um national assembly
said oh well what you what do you do
with those and they explained it and
they said well actually you know we've
already got the reference design you
know we could supply you with those
chips in the reference design you
basically just make that as a kit and
sell it
so uh chris had to sort of go back
with um you know tell him to his legs
and say to ian well actually you know
really sorry i know we've shook on it
but um we're actually going to go with
national semiconductor because they've
given us a fantastic deal um so we don't
need your design thank you very much um
jog on this guy's invented a design for
computer but there's one already
existing um yeah it was only based on
the the reference designs that national
semiconductor but what what it had done
is it foreseen this idea that actually
you know the design is basically there
you can build upon this and actually
there's a lot of people that might like
to make this kit so you know the it's
the idea the initial idea um um came
from ian that this could be a product so
that didn't kind of work out um free and
sadly um however you know he would then
go on to write the manual along with
rodney dale there was money to be made
in creating the manual and writing other
books for it as well so other books were
produced about programming the machine
and that kind of thing i think we've got
there you go understanding the
microprocessors with the mk 14 ian
williamson and rodney dale both of who
are trustees of the museum i should say
so yeah from the original design and
that's the kit that you can buy you can
see that there are
quite big similarities you've got the
same chip the original ceramic chip
there whereas these ones got the plastic
dips
same kind of memory
and then you have a display here an led
display with a keyboard well
that looks pretty similar to me
so you can see that um progression on
from the development kits through to
the board that was finally produced and
sold so this doesn't have the processor
in it the process is there you have this
prototyping area so what you can do is
you can put any components you like
there and wire them up and then to
program it you would put your board into
there you could have different boards
with different expansions ram or various
other io that kind of thing and you
could program it and make it do what you
want so this is the development system
and they gave you all the supporting
material yeah so the programming manuals
um there so you would have your manual
and you would learn about the
entire instruction set so again what
needs to be remembered here is that we
are programming uh in assembly language
in a machine code so you are typing in
hexadecimal numbers here that represent
those commands so at this time chris
curry was at um
science cambridge and was really
in charge of this product project um
so later on when chris was at acorn
interestingly we have an acorn
system one doesn't look that dissimilar
same kind of calculator display there
hex keypad different chip this one uses
a 6502 which would be the processor that
their next machines would use the bbc
micro the atom and that kind of thing
but you know it just shows how
everything starts somewhere um so the
system one again a very rare machine
starting very very basic typing
um you know
assembly language code in and and even
that you know you think that assembly
language would be a very high low level
language that a lot of people wouldn't
do
however
if we take a look at home computing
games programs on page
68 to life for the mk14 so here we have
a program listing for the
mk14 and you can see it's the assembly
language code but that's the hex that
you would type in so a memory location
of 20 you would type in c4 oe
and that would be effectively ldx
conway's game of life yeah so but it's
not really a game it's more of a
simulation but there you know the
machine could play this kind of this
basic game and you could play other
games on it you know the simple number
games that you could do trying to work
out what date this is oh there's summer
81. so 1981 and people were still
writing code for the mk14 that was
released in 77. so these things had a
reasonable life i'm not sure if anybody
did type that in but who knows somebody
probably did a lot of people were buying
these things as the kit so i have
another thing over here to show you this
is extremely rare
let's move that out there
so if you'd ordered one of these things
this is what you get so this is an
unboxing of mk14 this probably doesn't
happen very much online this is a
completely unmade kit as it would have
been delivered so part of this was the
construction process in the first place
getting the manual getting the circuit
diagram understanding what all the
components do
soldering them into their place on the
board soldering all of these connections
i don't know how many there are a good
couple of hundred there so you'd sort
all your components in place and if
you've done it well
you've got resistors there capacitors
and things uh crystal um if you've done
it well it will work um and you could
then start to program it really good
manual with it that had
um what you've got greatest common
divisor software pulse delay digital
alarm clock random noise decimal to hex
so you know there were lots of things
you could get it to do there's even a
monitor listing there and interestingly
the chip had an inbuilt uart so it had
serial communications actually built
onto the chip so it was possible then to
connect it up to a
another device then see the output
rather than just needing to rely on that
very very small calculator display
so there's lots of things you could do a
lot of this is just demo software just
to show you the ideas between behind
programming how you can use memory
locations so machine code what you're
doing is you're saying take this memory
location move it into the processor
add something to it move it back to a
memory location very very simple
step
language so that was defined as kind of
programming at the bare metal you know
you were talking directly to the chips
um
nothing in between so you knew every
single instruction and what it was for
and why it was there um talking to those
ships directly so that gives you a
really good understanding of programming
computers and if you understood how to
do this you can apply that to pretty
much to any processor the the commands
might change um but ultimately it's the
same logical thinking process
so you know you could type in those
things those programs and get them to
run
but
also it has to be remembered that on the
output here you've got a port exposing
the address and data bus and various
control lines and things and you could
then have it controlling other things
this was kind of the raspberry pi of its
day you know you had address lines there
you would put on an address decoder um
create yourself some io space and that
could be sort of an address latch or a
data bus slash that you could then store
data in and have eight outputs or 16
hours i mean you wanted same way input
you could have a latch that then red
inputs
so you've got some i o control so from
that these things were then used for a
number of purposes one we have in the
collection is a machine over here
vaguely looks a little bit like an mk14
we've got the same calculator display
there same kind of hex pad
but this is used for medical research so
this is just
an mk14 in a big wooden box
you can see the mk14 down there you can
see the expansion chip we have a tape
interface there and then we have some
other malarkey going on there not quite
sure what that is power supply you can
just plug it into the mains the power
supply drops it down to about eight
volts for the board itself and this was
used for medical research controlling
inputs and outputs monitoring um and
then analyzing those results it'd be
quite feasible that you could find out
what some of these reaction times is
depending on how much they're drunk um
yeah that would be a good use of this uh
this machine um i have no idea if that's
what it was useful but hey i might use
that now so i was going to say we don't
we need to do some research i think yeah
absolutely we'll do that later um but
some but yeah so so these had genuine
real world uses it might seem that one
of these things is pretty much unusable
but really not you know it was
ultimately usable if you wanted to
control something this
could have done it there's a real world
used for it they've made the box made it
portable
and very usable but then other people
were just using it for their own fun
learnings how to code controlling their
hornby railway i know people that had
done exactly that with it um
so yeah loads of different things and
yeah this was sort of 77 this was before
most people were into some
microcomputers as they were then um so
ahead of the curve
so sometimes if floppies would die so
you often would make backup copies
let's try this
one sounds more hopeful
and so there's this game called lander