what we've got here is a piece of
software that martin polyakov of
periodic videos commissioned
back in the 80s enabled people a level
students to test their chemistry
knowledge and if you look on periodic
videos perhaps they were running out of
storage space you'll see a video where
martin and i get this up and running on
the bbc micro and actually start it
working it was an interesting exercise
and we'll have a look later how we can
actually get the software off the bbc
micro onto something that we can run on
a modern computer a pc a mac even a
iphone or anything else which has got
the right sort of emulator
it's relatively easy to look at images
and videos and those sorts of things but
programs are harder right most images
perhaps and this is perhaps not
necessarily a good idea
um we tend to compress so we can press
them so they take up less space and so
we've got something like a jpeg we can
access it because it's so ubiquitous we
can just access it but
i shoot raw my slr
thinking about it i'm not so certain
that
22 years down the line
raw files will be that easy to access
now chances are i shoot with a
pretty common
canon dslr so chances are that yes that
will still be supported
but it's making me think about it
actually should i go and convert them
into something more convenient so it's
counted your intuitive in some respects
so your real shooting raw to preserve as
much possible quality as you can and
actually you might preserve the files
for longer if you put them into a
compressed format because they're more
common exactly so it's best keeping them
in both and it's actually the same for a
piece of software is that we need to be
able to decode
the data so to any media
we need to be able to decode it and use
it now for something like an image file
for a video that's a relative
straightforward you could write one when
it gets to something like martin's
chemistry games we can access the data
on the disk
we can start to see what some of these
are
this looks like it's a basic program so
that's loading that
so that's that's one of the programs
well let's have a look at some of the
others so this obviously looks like the
periodic table calcium
selenium titanium i suspect this is the
one that you had to guess what was in
there
we could start to see what's going on
here and start to see bits of it because
we can understand it as soon as you've
compressed it you need to know how it's
compressed before you can run it so it's
a good argument that you should keep
your data in an uncompressed format but
then of course that takes up even more
space and storage is plentiful but it's
not exactly cheap so you probably don't
want to compress it but if you're going
to do that do it in a file format
that will be
common i mean
text files put them inside zip files
don't use some weird and wonderful wacky
compression format that you've found
that'll save you one percent extra on
the file size 10 years down the line
chances are we'll probably still be able
to unzip the zip file possibly not the
weird and wacky format that you might
have used when it comes to program zone
a system like this not only we need to
copy the data and the program
we also need to emulate the complete
system that we're going to run it on
so for example if i wanted to get
martin's games working
on my mac or on a pc
not only do i need to copy the data off
this disk and that in itself is an
interesting issue because
i have a five and a quarter inch floppy
drive in the bbc micro
but i don't have one in my mac and i
don't have a usb
5 inch floppy drive in fact that
would has
take so that there's probably never been
one produced you get three and a half
inch floppy drives with usb output but
not five and a quarter
so we still need to find an interesting
way of getting the data off now we could
find a pc with a five and a quarter inch
floppy drive i've got one over there the
drive doesn't work unfortunately but we
then need to write software to
understand the disk format what i
actually did to do this
is
this machine is networked this is on an
earlier networking system called
echonate which acorn developed which i
can then get it onto the archimedes and
that's got a three and a half inch
floppy disk drive which i can use a pc
format to copy it
over to the mac so if we look
here i wrote this program what this
actually does is it reads each sector
sector bisector track by track off the
floppy disk we get that and we just
write it out to a file
one sector after another and we store it
on the network until eventually we've
got a copy of the file
sitting
on the archimedes
in this case it's called chem
dot image and chem two data image i then
copied them via a floppy disk onto my
mac using
the floppy drive over here
and then
i can use a bbc emulator
how many emulators can you run at the
same time
um
quite a lot in fact i have a machine
running a bbc emulator a mac plus
emulator mt4 and an amiga emulator at
the moment so you can run quite a lot on
a standard machine
then that must be running at full speed
but you can get things there modern
machines can emulate these things
pretty well i've taken an open source
emulator for the bbc micro called bbm i
didn't write it i just hacked it to run
nicely on my mac and so if we start the
emulator and we can
boot it
and we should see
exactly the same software running on the
modern computer but again we're having
to take it and emulate the whole machine
to run it so when we archive software we
probably want to at least archive
something that can run the software as
well in this case an emulator
will be sufficient and you can write
these emulators anything there's even a
javascript bbc micro emulator which
means that we could put this in the web
page and then you'd be able to run it
off that
break key can then let go break
wow and it starts up this is really
exciting that sound computer was a lot
more visceral in those days they made
noises and they sort of you heard them
going
so it's not quite centered on the screen