Informal approach is very rewarding
AFTER staying behind many hours after the children had gone
home from school, I decided to buy a BBC Micro of my own (1.2
OS but minus a disc interface).
I have bought all the back issues of The Micro User and spent
hours reading and typing programs, probably learning more from
my mistakes and working with a friend rather than wading through
the User Guide or some of your more learned articles. (I was never
much of a reader.)
I have particularly enjoyed loading or typing in programs and
then altering them, such as by replacing entries requiring use
of Return by using GET$.
In a French vocabulary test, I added music at the beginning
and end with a procedure, and programmed keys to add lines to
skip past the music should the user choose the option of a silent
quiz.
For the "counting" program (Electron User, November
issue) I added a procedure including some of the sounds from "Sounds
Exciting" to make the computer give a cheeky (though inoffensive
I add) response should the user choose not to play once the program
is loaded and running, and a line to ask if the user will press
the space-bar to restart after having a go.
I found Tim Hartnell's "Personal Computer Handbook"
helpful in getting into computing, providing simple listings which
could easily be manipulated.
As a dabbler I have enjoyed this informal approach. I hope you
will continue in your excellent magazine to cater for the likes
of me as well as those who fully understand the subject. - Michael
Bowie, Norbury, SW16.
Pixel problem
CAN you help me solve a couple of problems which I have had
with my BBC Micro since I bought it last year?
There are three small areas of the screen, approximately a pixel
size each, which will not conform to the colours set up on adjacent
locations.
And there is an occasional hiss on the speaker, similar to that
obtained on a radio during a storm, which also seems to affect
the picture.
I asked my local dedicated computer shop - not a chemists or
stationers - if they would rectify these difficulties on two separate
occasions, when they were fitting the 1.2 operating system and
latterly the speech synthesiser, and while I was advised that
all was well when the machines were collected the problems persist.
- David Rickwood, Tonbridge, Kent.
• Your machine is faulty. We had a similar one. The cause is
probably either a RAM fault, 6845 fault or ULA fault.
Anyway — it's easily fixed. Take it back!
Cheaper links
I WA S very interested by your article on linking BBC Micros
(Micro User, October). One to one (line) or one to several (star)
networks are handy, but the software and hardware rapidly become
too complicated using your scheme. You're still using the BBC
like a traditional micro!
Don't forget that it has independent input and output serial
buffers, and interrupts to prompt action when the buffers need
attention. These would allow machines to be linked in a cheap
asynchronous loop.
With only three wires between stations, carrying signal, ground
and busy, you can use inexpensive audio connectors for the join.
A stereo jack-plug at one side for receive and a socket at the
other for send meet the RS 423 DIN in the middle. Stretching and
closing the loop simply needs through-wired stereo extenders.
With the OUT of one BBC connected to the IN of the next, the
data would have to be sent in addressed, buffer-sized packets
to prevent a lock-up.
The addressing could be quite simple. If each block is preceded
by two (three) bytes, then you could specify one, many or all
of 16 (24) machines without complex decoding.
Just AND the address with your own, which has a single bit set.
If not yours, then send the message on.
If yours, then clear that bit and send the message on. If both
bytes of address come in as zero, then it has been all the way
around and you can dump it after checking its survival.
To do this properly, of course, the I/O would need interrupt
programming, but a cheap eprom should have ample capacity by using
the facilities in the BBC's OS.
The important step is to standardise the network. I'd like to
be able to type something like *LINK 11 to set up the system and
state my address, then transmit data as if through *TAPE.
Both origin and target address(es) are put in the file name,
and the intervening machines automatically (and invisibly) pass
the blocks from receive to send buffers. The target(s) must amend
the address, then copy the data to both the send and input buffers.
The simplest way to get the information into a program would
be to check the *LINK status as part of the command loop, then
INPUT any data in the queue. - Nik Kelly, Liverpool.
The Australian angle
FIRSTLY, I'd like to congratulate you on a great magazine, even
if it is a bit slow in getting all the way out here. (It's mid-October
and the August issue is not out yet!)
The Micro User has taken into account all levels of Beeb users
and tailored the magazine accordingly. Good stuff!
Meanwhile, the BBC Micro remains at a ridiculously high price
out here in Australia.
Converting to your pounds sterling, here the BBC costs around
£1,000, while a disc drive is around £600.
Comparing to Britain, the Beeb works out at least twice as expensive
as in your country.
Instead of the BBC Micro competing against the likes of the
Spectrum, Atari, Commodore 64 etc, as in England, its price pushes
it up into the Apple He market.
So in Australia you'd be shelling out the same money as for
a business computer.
I've been in shops and seen the salesmen singing the Beeb's
praises but once the price is mentioned the customer's usual response
is "No thank you".
Features it may have, but an extremely over-priced value it
also possesses in Australia. Maybe with a bit of luck, something
might happen and the prices will drop.
Darren Fishman, Victoria, Australia.
Fair enough!
AS a regular (and avid) reader of your magazine I looked forward
to the London Fair with great anticipation.
Being a confirmed southerner who believes that all life stops
at Watford (now extended to Cambridge) I was wondering what the
inhabitants of wild and distant Stockport could put on for us
in the big city.
Suffice it to say, I have now included it on my map of 'civilised
spots outside London'!
When is the next Fair in London? - R. Southall, Surbiton,
Surrey.
• You'll be pleased to know we're moving south again next month
for the Electron & BBC Micro User Show. It opens on March
29. Read all about it on Pages 104-105.
Power packed
MY BBC Micro is an early Model A (Issue 3 board) which I have
fully upgraded to a Model B in all respects except the power supply.
I have also fitted the disc interface, my drive being driven
from its own integral power supply.
Given that I still have the original Model A supply unit, how
many sideways ROMs will it safely power? At present, apart from
the OS 1.2, the DFS and the Basic chips, I have plugged in a word
processing chip. And what about the speech chips ? - M.T. Michaelides,
The Netherlands.
• I don't know the answer. Put it this way — the one I've got
at work powers all four. Mike Cook.
Dipping into disc storage
REGARDING your response to a letter from Simon Taurins in the
October issue of The Micro User, there are inexpensive ways of
using the disc storage facilities of the RML 380Z from a BBC Micro.
Firstly, there is a one BBC-RML link originating from David
Benzie of the ITMA project at the College of St Mark and St John,
Plymouth.
Secondly MACE, the West Midlands MEP Regional Centre, have devised
a network system that uses the RML to serve BBCs. Their address
is: Four Dwellings School, Dwellings Lane, Quinton, Birmingham
B32 1RT.
Further information on either should be available from any MEP
Regional Centre. - Neil Stanley, MEP Regional Information Centre,
Merseyside.
Suppressed display
I NOTE in the December issue of The Micro User a method to supress
display while using the printer. If one uses *FX3,10 this disables
the VDU driver and enables the printer without recourse to VDU
2 or CTRL B.
This instruction directs output to the printer only. *FX 3,0
redirects all output back to the TV.
I have not investigated the possibility that the *FX 3,10 (combining
*FX 3,8 & *FX 3,2) may prevent control characters being sent
to the printer. However if one is only interested in sending text
then the above calls give the easier method. - Michael Swatton,
Basildon, Essex.
• Thank you for your suggestions. Unfortunately, *FX 3,10 does
seem to prevent sending control codes.
Speedy loader
THE article by Paul Beverley (October 1983 issue of Micro User)
seemed to answer a problem experienced when running teacher training
courses — how to load programs quickly with only one disc unit.
Initial trials were unsuccessful, though instructions were followed
precisely. A rival magazine also featured a similar idea, again
incompletely.
Falling back on the User Guide, I was able to use Paul's simple
wiring diagram and the following programmed keys to successfully
splurt programs:
*KEY 9 *FX8,6¦M*FX3,7¦ML.¦*FX3¦M
*KEY 0 NEW¦M*FX7,6¦M*FX2,1¦M
Using these keys, a program loaded from disc on the transmitting
(Tx) machine (do not run in case function keys are redefined)
can be running on the receiving (Rx) machine within seconds by
pressing FO on Rx and pressing F9 on Tx. The program lines now
scroll on Rx.
When the "syntax error" message appears press Break,
then OLD Return, RUN Return on Rx.
The cable can then be transferred to a second Rx.
This method is almost as quick, and is subject to far fewer
problems than the MACE system which uses a 380-Z as a server.
One immediate advantage of this arrangement is the preparation
of cassette copies of disc programs on several different Rx computers.
- Alan Shaw, Clitheroe, Lancs.
Long distance gamesmanship
HAVING recently graduated to the BBC Micro I wish to contact
other users via my computer and play games with distant opponents.
I would also be interested in downloading software and accessing
data banks like teletext.
Could you please give details on whether a telephone line and
modem is needed and the facilities offered.
The ones I have been considering are Econet, a teletext adaptor
and Micronet.
Also if I have not taken up too much room already I would like
to know what the different LOAD/SAVE baud rates do apart from
speeding up or slowing down program transfer. Does this mean it
can communicate with other types of computer? - Martin Dimoglou,
Colchester, Essex.
• Econet would not suit your purposes. Both Micronet and the
BBC Teletext service allow you to download programs and access
databases - Prestel and Ceefax respectively.
Micronet needs a modem plus telephone line. Teletext just needs
the Acorn adaptor and a good television aerial.
As for the interactive games, people are busy working on this
— see our Link-up article in the October issue of The Micro User.
The different baud rates do effect the rate of loading and saving
programs. However, for technical reasons, the slower rates are
less susceptible to "noise" — that is, interference
— and so they're often used for long distance data transmissions
where it's important that the data survives.
Basicode II network
I AM interested in making contact with people who use 300 baud
modems together with the BBC Micro. In Holland we have a whole
communication net between micros. Using Basicode
II we can talk to many types of micros, including Apples, TRS
80s and Spectrums.
My address is: Hans Doeleman, Fuij 49, 1141CK, Monnickendam,
Netherlands.
• Readers who would like to know more about Basicode II, the
revolutionary computer language that enables micro to speak to
micro, should see the article about it in the October issue of
The Micro User.
Structured for the birds!
ROY Atherton's letter in the November issue of The Micro User
deplored the use of GOTO and GOSUB. Might I politely suggest he
does both, more especially the latter, now Winter is here.
The BBC Micro is a tool as is, say, a pen, and it matters not
whether the latter is a quill, fountain pen or ball point, nor
whether the script is block print, joined Form 3 script, copperplate
gothic, pharmaceutical/ medico script or advanced scribble - as
long as it does the job.
This yuk about "structured" programming is for the
birds!
I have thousands of my own very good full colour programs which
all work fantastically well, and they are all full of GOTO; GOSUB;
ON . . GOTO/GOSUB as well as PROCX and FNX with or without recursive
techniques.
But perhaps Mr Atherton is unaware of the fact that there is
a limit (on the BBC Model B) to the recursions - approximately
2,000 - then Bang!
One must use the techniques available and to hell with elegance,
which is a highly subjective term anyway.
The modern toilet is absolutely functional and elegant, but
it remains for all to see and recognise at once as merely a glazed
ceramic avocado green or blush pink privy and all the structuring
in the world cannot alter that fact and all the structurings Mr
Atherton refers to are ultimately fancy forms of GOTO and GOSUB.
- J. Frank Hughes, Henllan, Denbigh.
I HAVE followed the great GOTO controversy with some interest
as I took my first faltering steps in programming in Fortran IV
(I'm not really old, honest), where GOTO was a fairly sophisticated
instruction.
It remains a valid instruction in Basic and has its uses. In
particular, consider the structure "IF<condition>THEN-<line
number>". the execution of this is indistinguishable from
"IF<condition>THEN GOTO-<line number>".
The GOTO is implicit and thus is used by everyone, except only
the most pompous of programming pedants.
It is time they admitted their feet of clay and got on with
showing beginners how to programme clearly using all the instructions
available to the best advantage of each. - Dr G.T. Freshwater,
Lerwick, Shetland.
Tape for her, too
I TAKE The Micro User and have been very pleased with what I
have learned through its pages. I do however take issue with the
wording of the advert for the Christmas tape. Why "in his
stocking"?
For goodness sake why not say "in their stocking"
and avoid compounding the prevalent idea that computing is for
the male sex.
I'm not a particularly avid feminist but this really did irritate
me as I'm doing my best to initiate my three daughters into the
world of computers without giving them the idea they're odd! —
Janice Lee, Penarth, S. Glamorgan.
• Point taken - we normally catch these things before they go
through. However, very few of the letters and articles we receive
are from women and I doubt that the occasional use of an inappropriate
pronoun is entirely responsible.
Disc Executor
WE would like to take the opportunity to reply to the misleading
allegations made in your recent review of our tape to disc transfer
program Disc Executor.
Disc Executor is compatible with Watford Electronic's DFS and
will transfer all Acornsoft games to disc, including those which
are locked.
According to our research Acornsoft programs are the most popular.
Disc Executor will also run those programs which have data files
such as Acornsoft's Tree of Knowledge and Shirley Conran's Magic
Garden.
It will transfer and run a large majority of the commercial
software available at the present time including those from Program
Power, Superior Software, A & F Software, Software Invasion,
etc.
It will also allow full length adventures to be transfered to
disc, something which can not be achieved using moving routines!
Disc Executor is designed to simplify the transfer of programs
from tape to disc. It is intended for the person who has just
upgraded to disc drives or simply doesn't have the time or expertise
to write moving routines.
It does not move programs in memory but contains its own DFS
routines on disc which allow it to be completely independent of
the disc workspace and allows programs such as Felix in the Factory
to be loaded directly into memory.
Once the disc is full it is an easy operation to delete any
of the programs. In this way Disc Executor can be used to transfer
your favourite game of the month to disc and replace it with another
whenever you become tired of it.
The response from the public to Disc Executor both at the BBC
Micro User Show in London in December and from our mail order
customers has convinced us that Disc Executor does what the user
requires. - Stephen Green, Vision Software, Liverpool.
• There were no misleading allegations made in the review of
Disc Executor and the product sent in was accurately reviewed.
Let us state Micro User's position. If software houses wish
to have their products reviewed in a satisfactory light, they
should ensure that they send in a satisfactory version for review,
rather than, as often happens, releasing a later, "enhanced"
version.
We can only review products as they are, not as the vendor would
like them to be.
In this case we are glad to say that the later version of Disc
Executor does in fact support all the claims made in your letter,
as do several enthusiastic users of your product who have contacted
us since the review.
Hi-fi connection
I WOULD like to be able to connect my BBC Micro to my hi-fi
and in doing so bypass the micro's internal amplifier. Is this
possible? I did read somewhere of two
terminals which may serve this purpose. Perhaps you would be
able to advise regarding this matter. - A.G. McMahon, London.
• To judge by the number of queries we had on this at our London
show, everyone wants to to this!
To obtain the signal you require for the external amplifier,
simply take the feed from the link marked PL16 on the bottom left
edge of the printed circuit board.
Hong Kong assembly
I HAVE obtained a copy of the August issue because I wanted
the article on transfer from tape to disc. In the issue I found
Colin Malone's letter about the origin of BBC Micros.
Please pass on to Mr Malone the fact that my BBC B was assembled
in Hong Kong, that I bought it in Walton-on-Thames at the end
of July and that I am expecting him to replace it with one built
in the UK.
Which brings me on to the BBC Micro and Weights and Measures
and the sale of goods legislation.
Surely each new component, whether it is OS 1.2, Basic II or
Main board 7, is the equivalent of admitting that the previously
issued machines were in some way inadequate.
As such they should be replaced free of charge or the money
returned. I can think of no other area where this would not apply.
How about some forthright comments and help on behalf of all
BBC Micro purchasers? I believe you owe it to your loyal readers.
- R.D. Jackson, Sevenoaks, Kent.
Time call
BECA USE of children, etc, l am unable to take possession of
"my" BBC Micro until after 9pm, and as a result I become
carried away into the early hours of the morning. Trying to get
up for work the following day is becoming a problem.
What I want to do is to program the Micro's internal clock to
interrupt whatever I am doing at, say, lam with the message:
"The time is now lam, Go to bed!"
I know it should be possible from what I picked up at the BBC
Micro User Show in Manchester but I don't know how to do it.
Could you please tell me in absolute beginners language. I only
have three weeks' experience. - Michael Pastore, Droylsden,
Manchester.
• Your wish is our command. If you turn to Mike Cook's Body
Building article on Page 116 you'll see a real time clock described.
Acacia Computers market a rather elegant desk diary that should
more than fit the bill. We'll be carrying a full review soon.
Big bang
HELP! Anyone worked out an effective program for a nuclear explosion?
- Alan Frost, Eastbourne.
• We are assured that the super-powers already have such a program
well in hand.
And finally, with tongue firmly in cheek . . .
Slaving over a hot assembler
Dear Trev,
Don't be surprised if someday soon you read about me in your
morning paper. The story will probably go along the lines that
I'm helping police with their inquiries into the mysterious disappearance
of my wife.
Certain tapes will no doubt have been removed from my house
for expert examination.
It will all be because I'm trying to learn machine code. And
Andrea isn't helping.
Normally I'd be tucked away in the spare bedroom out of sight
but A.'s having it redecorated. She's hired a little man with
an allergy to cheques who tells me that he's "got a video
games machine" as well.
Anyway, me and my beeb are stuck down in the front room under
A.'s all-seeing eye as I struggle through "Machine Code for
Morons". And A. has started to Try To Take An Interest In
Hubby's Hobby.
I swear I'm going to cancel those women's magazines. It's because
of them that all the time I've been slaving over a hot assembler,
A.'s been there asking every kind of question but the ones I know
the answer to!
My big mistake was to let out a shout of joy when I'd finally
got my first machine code program to work. All it did was to print
"HELLO" on the screen but to me it was a work of genius.
Of course A. didn't see it that way.
"What's so good about that?" she asked.
"It's all done in machine code", I replied proudly.
"But why do it in machine code when you can do it in Banal
or whatever it is you normally use?"
"Because it's faster", I said ignoring the dig.
"Faster!" she snorted, "It's taken you hours
to do that".
Then, like the fool I so regularly am, I started to explain
the basics of machine code. I told her how the BBC Micro's built-in
assembler saved me having to mess around with the op codes and
made things that much simpler.
"But that's cheating!" she yelled. "It's not
you that's doing the machine code, it's the micro".
With that she departed to the kitchen leaving me with the parting
shot that all these registers and assemblies reminded her of school.
That was bad enough, but worse was to come. As I was plinging
away on my micro I heard her singing the Hokey Cokey in the kitchen.
Nothing wrong with that, of course, just a little eccentric.
No, it's not the song that's had me looking round for a blunt
instrument that won't show fingerprints. It's the words she's
singing to the tune:
You increment Y, you increment X,
And load the accumulator with zero zero hex ...
I despair! Yours, Bob.
