Answer: Shadow RAM choice
In answer to Keith Taylor's question in AMPLINEX 017: I
don't think there is a Shadow RAM board for the BBC that doesn't have its
drawbacks. However, one that seems to have less operating problems than most is
the Integra-B from Computech.
It can be set to access Shadow RAM, and AMPLE seems to make
full use of it. The Shadow modes can be disabled, so that games and other
non-Shadow applications can be run.
Its one big handicap though, is the price - £135. But for
that you do get Shadow RAM, Sideways RAM and extra ROM slots, as well as other
goodies. Unfortunately, Hybrid's Sideways RAM utilities (in the AMPLE Toolbox)
will only work on a Master 128, not on a B+ or expanded Model B.
Patrick Black
Answer: The 'M.M5' module
Further to the question in AMPLINEX 016 about the meaning of
various words in the M5 module: AEN, PEN and ONEN select respectively
amplitude, pitch and both envelopes for subsequent GATE effect.
For example, PEN ON GATE will start just the pitch envelope.
This is used, for example in 'Mexico Suite third movement'. A useful definition
is:
"pgate" [PEN GATE]
Hybrid Technology
Question: FOR(...)FOR command
When I have a piece of music on the screen containing a
FOR(...)FOR command, and I try to use the f1 'play' key, it always produces a
'! Bad context' error, forcing me to MAKE it and type in its name as a command.
Can anyone help, please?
David Bloxham
Answer: Mozart's musical dice-game
In response to Vincent Fojut's query in AMPLINEX 017 concerning
Mozart's musical dice game: a more recent source of information on this topic may
be found in the book 'Creative sound on the BBC' (pages 185-194) published by
Acornsoft and written by David Ellis and Chris Jordan. I suggest this as an
excellent source in the first instance.
It provides quite a comprehensive introduction, together
with diagrams to show the essential structure of the random 'generator', and a
program, written in BASIC, but with the musical notation in the DATA statements
- known affectionately as Music Composition Language (MCL) - having a relatively
familiar appearance!
If any AMPLINEX members interested in music programming have
not yet seen this book I recommend they get hold of a copy and browse through.
Len Chirgwin
'Creative sound on the BBC microcomputer Model B' by David
Ellis and Chris Jordan published by Acornsoft in 1985 at £9.95p (ISBN 0907876226)
contains both a description of the dice game attributed to Mozart and a
complete program in BASIC which uses the internal sound chip of the BBC B. Some
time ago, Micro User were offering the book at a discount. Although not currently
advertised, they may still be able to supply.
Alan Minns
Answer: Music City on Prestel
Philip Hunter AMPLINEX 017 asks about Music City. This used
to have Music 500 and 5000 files, but it closed some time ago. It has recently
been resurrected, but is now dedicated to MIDI - no AMPLE files. As far as I know
there isn't an area on Prestel catering for AMPLE any more.
However, a modem will give access to AMPLE DCT, who have a
very good Music 500(0) section. They are at Dudley College of Technology, and
their phone number is (0384) 239944. There is a free area and Maestro, for
which there is an annual access fee of £3.50p (for MCPS copyright charges).
You pay the cost of the phone call, but nothing else. They
do like contributions though!
Patrick Black
Music City indeed no longer supports the Music 5000 system.
It used to: in fact, it is where I got my first break, but that was two years
ago, when it was run by Ian Guinan and Guy Oldhams. Music City now concentrates
mainly on MIDI, Amiga and ST thingumajigs, under new government.
The only music board I know of that supports the Music 5000
is that run by 'Panda' man David King: AMPLE-DCT. The address for contributions
or information) is:
David King
Dudley College of Technology
The Broadway
DUDLEY
West Midlands
DY1 4AS
Dudley College of Technology
The Broadway
DUDLEY
West Midlands
DY1 4AS
The DCT database covers a wide variety of other areas too,
not just music.
Phil Comber
Questions: Letters after modules
When MCAT is used, it displays the module name, version
number and then some letters. What do the letters mean?
David Bloxham
Answer: AMPLINEX Staff Printer (1)
Like Jack Wrigley (AMPLINEX 017) I was also very interested
in the Staff printing utility published in AMPLINEX 016, but was annoyed to
find that it did not seem to work on a BBC B with Aries B32 Shadow RAM.
However, it is quite straightforward to alter the program to do so.
Lines 9 and 10 in the file U.ASP can be deleted as these
select the Shadow RAM on a Master. Line 11 must be left in as it expands the
space available for user-defined characters, which are used by the Staff
Printer to define the symbols on the staff.
In the file U.ASP2, I found that the program would work
perfectly if the
PROCass:CALL code%
in line 40 was REMarked out.
Julian Benton
Answer: AMPLINEX Staff Printer (2)
In reply to Neil Walker's query about the AMPLINEX Staff
Printer (AMPLINEX 017), the short answer is no. The purpose of the 'CALL code%'
command is to provide a cyan/black stippled border to the screen windows. In
the machine code, the subroutine call to &FFB3 is machine specific - it
does not exist on the humble Model B! I seem to remember that its purpose is to
write a byte to the video memory. Although no harm is done if this routine is
omitted, it can be implemented fairly simply for the Aries system.
With apologies to Bob Ord, I have removed some redundant
code from his dump routine to reduce its length and added a short piece of code
to give the stippled border. This new U.ASPcode file (included on this disc) is
suitable only for the Aries system and replaces the original one. To use it,
modify the U.ASP2 program by deleting the whole of PROCass starting at line 290
and at line 40 replace 'PROCass:CALL code%' by 'CALL &ACE'.
Bob Ord is to be congratulated on getting such a complex
program to work. Alas, when I came to test my modification, two problems arose.
1) In decoding a program word, he searches for the word
'SCORE' following the '%STAFF' command - but not all STAFF words begin with
SCORE. This may be corrected by modifying line 2110 thus:
2110 REPEAT:m%=m%+1:UNTIL?m%=&51
2) If the program encounters a double octave jump, such as
'!!a', it will stop with a 'Subscript' error. If lines 950 and 960 are replaced
by the following, both '!' and '!!' are handled correctly.
955 IFd%-&DC ELSEz%=m%?1:z%=m%? (1-(z%=&DC)):t%=1-((z%MOD2)*2):
IFb%cptr%=cptr%+7*t%ELSE pptr%=pptr%+7*t%
Jack Wrigley's problem (AMPLINEX 017) is a little more
complex. Yes, the '*FX114' and '*SHADOW' lines must be removed but retain the
'*FX20,3'. This explodes the character font and raises the value of OSHWM by
three pages to make room for the special characters used in the staff printing
- this is why PAGE is reset to &1C00. But now, because the Aries Shadow RAM
is initiated by default, OSHWM is raised by a further page to provide workspace
for the Aries system. It is necessary to specify PAGE at &1D00 in order to make
room.
This may not leave enough memory for the variables. It would
be better to allocate a specific page (e.g. &1800) for the Aries workspace
thus:
*XOFF
<BREAK>
*XON 20 18
MODE 7
<BREAK>
*XON 20 18
MODE 7
The program should then run properly.
Alan Minns
Editor's note:
The comments following some of the questions above are only
my opinions on the subject and should not be taken as definitive answers.
Your comments are most welcome on any of the questions
posed, whether they supplement, confirm or correct any I have expressed.
Related files on this disc:
Published in AMPLINEX 018, July 1990
