Archive Magazine CD 1995/Archive Magazine CD 1995.iso/text/hints/volume_02/issue_05

Text File | 1995-02-16 | 13.8 KB | 307 lines

•   How to wipe a disc clean − Having explained in H & T in issue 2.1
how to use *LIB“” and *WIPE * ~C to wipe a disc clean, here is the
really quick way! Take a blank disc and do a *BACKUP onto the disc to be
purged − takes about 10 seconds all together, even with only a single
drive!
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•   Microlink Modem connections − We have at last sorted out the
connections necessary for the Microlink Multispeed modem. The problem is
that it seems to need two different connections depending on whether you
are using ArcTerm or Hearsay. Anyway, here are some connections that
seem to work OK. ArcTerm version first:
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Modem    Computer
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GND   1
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            }Ñ   5   GND
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GND   7
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RXD   2   Ñ   3   TXD
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TXD   3   Ñ   2   RXD
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RTS   4   Ñ   7   RTS
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CTS   5   Ñ   8   CTS
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            6   DSR
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DSR   6   Ñ{2 .5
            1   DCD
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DTR   20   Ñ   4   DTR
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Note that the Archimedes DCD is not connected to the modem DCD but to
the DSR to ensure that it is ON all the time. The modem DCD is only ON
whilst on-line. Here are the Hearsay connections:
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Modem    Computer
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GND   1
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          }Ñ   5   GND
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GND   7
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RXD   2   Ñ   3   TXD
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TXD   3   Ñ   2   RXD
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RTS   4   Ñ   7   RTS
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CTS   5   Ñ   6   DSR
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DSR   6 (NC)
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DTR   20 (NC)
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DCD   8   Ñ   9   RI
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            1   DCD}
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            4   DTR} linked
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            8   CTS}
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•   BBC Hard Discs − If you have BBC hard discs that use the 1 MHz bus,
you can run them on the Archimedes under the new 6502 emulator,
“65host”, that comes with RISC-OS. All you do is enter 65host and load
the BBC 1770 ADFS then, assuming you have an I/O podule, connect the
hard disc to the 2 MHz bus and away you go.
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(Surely it wouldn’t be too difficult, would it(?), to patch it into the
existing operating system to make the hard discs accessible in native
mode instead of limiting it to use with the emulator? Could anyone do
that for us? Ed.)
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•   Naff RTC Month − If you get this error message when running the
desktop, the chances are that it is time to change your batteries. Acorn
suggest changing them once a year.
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•   Repton 3 − first a comment − The characters included are exactly the
same as in the BBC version even though they are mode 9, so it looks like
mode 5 on the BBC. This is disappointing as the extra resolution and
colour are wasted unless you redefine the characters − a mammoth task as
there are 768 altogether! (Phil Armstrong, Doncaster)
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Phil also saysÉ I redesigned the first 48 characters which took quite
some time and I did encounter a few problems, namely my maps occasion
ally were wiped or the start position changed. To get round this
problem, I examined the data files and found:
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&0000 to &10A0   8 Map definitions and colours for each map
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&10A0 to &70A0   48 character definitions
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So if you lose your maps or wish to copy a character set to another set
of maps, follow these operations:
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*Load Newdata 10000    load new char-acters as saved by editor
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*Save Char 110A0 170A0   save character set alone
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*Load Olddata 10000   load file contain-ing required maps
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*Load Char 110A0   overlay new character set
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*Save Newfile 10000 170A0   save maps and characters together
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Newfile can then be loaded into the game. Changing characters does not
seem to affect the competition numbers the game gives you.
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•   Games on the 440 − Many games programs will not run on the 440 if
the screensize is set above 160k, so you should try *Configure Screen
size 5 before running the game.
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•   Pacmania − Two avid “Pacmaniacs”, Harjit Takshak and Linus Twizell,
have provided some Pacmania hints:
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Do a *LOAD PACMANIA 10000 then you can set the number of lives with
?&102C8 = n (but too many slows the games down) and ?&113D4 = n sets the
number of points per pill and ?&10234 = n sets the number of credits and
then CALL &10000 starts off the game.
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•   GammaPlot − It is possible to change the colour of a line on a line
graph by using the command *SG17,n,128 where n is the GCOL number (e.g.
48 = blue). This command can also be used in the Macro mode followed by
a line with GRAPH (just the graph) or CHART (graph and axis). The colour
will be saved, along with the graph, to disc.
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•   Printer problems − there have been one or two problems with spurious
operation of printers, especially with Integrex printers when doing
graphics dumps. These are caused by timing problems on the Archimedes’
parallel port control lines and can be solved by an internal circuit
board modification that Acorn have recognised as a field change, i.e. if
you are having problems, go to your local Archimedes dealer and ask if
he can do field change 2002 for you. (D.I.Y. field changes will void
your warranty, but if you want details anyway, send us an S.A.E.)
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•   Conditional booting (cf Archive 2.3, page 13) Philip Colmer says
that unfortunately *FX200,2 followed by reset is treated as a power-on
reset so the monotonic clock is reset. Probably a better way is
SYS“OS_Byte”,253,0,255 TO break% where break% is 0 for soft break, 1 for
power-on reset and 2 for a hard break − a bit more reliable than
checking a clock value.
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•   BCPL on ADFS − J Laski writesÉ I am a BCPL freak: due to the fact
that ADFS was not available when it was designed, the ROM system causes
files to be read/written with OSBGET/PUT rather than OSFILE/OSGBPB;
also, intermediate files in the compiler and editor use names such as
Backup$ which ADFS abhors.
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To get round this, patch the routine in the ROM (image disk) FSTYPE
(G39) always to return 7 (see manual p117). In both BCPLARG and BCPLCCG,
patch the second static load (LLL) in G1 from “OCODE$$” to “OCODE!!”. In
ED, in G318 patch the static load in G318 about 40 words before the SWL
near the end of the routine; this can best be found by looking for the
long forward jump about 30 Cintcodes from the beginning. (N.B. I use an
extended ED, so have only given rough positions; G318 is the last
routine called from G1.)
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If you feel you cannot make these changes yourself, and send me a disk
with proof that you have a legal copy of BCPL and a stamped self-
addressed mailer, and I will send you a modified version. I would
appreciate, but do not insist on, any utilities that you think might
amuse me.
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I am seeking a version of BCPL in ARM code and, if ACORN cannot be
persuaded to release their version, will do it myself, probably somewhat
‘adhocly’. If you have any views on desirable facilities, I should be
glad to read them. I shall shareware distribute with a licence fee
requested. (Dr J Laski, 18 Ebury Street, London, SW1W 0LU.
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•   “Colour Printouts − The Easy Way”  − I read with considerable
interest the article by W R (Basil) Davis on taking 35mm photographs of
the monitor screen. (Archive 1.9, page 52) I was able to put this to
practical use recently since I wished to design and produce some
graphics screens (using GammaPlot) and use these in a conference
presentation. I did consider using acetates with an overhead projector,
but decided 35mm slides would be more suitable.
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The following additional comments (which should be read in conjunction
with the original article) may assist other Archive readers contemplat
ing taking such pictures:
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1) Before embarking on photographing any screen displays, it is
important to remember that any apparently minor “blemish” will be
magnified considerably if your results are being projected using 35mm
slides. Careful thought should be given to the screen layout and the
choice of colours; provided they don’t clash, brighter foreground
colours are preferable, with black or a dark blue making an ideal
background. The normal Archimedes text is quite visible when projected
using 35mm slides; additionally I used a GammaPlot feature to enlarge
the standard text for titles etc. and, whilst this was quite acceptable
on a monitor screen, when projected it did appear noticeable “chunky”.
Next time I will use the Archimedes special fonts with GammaPlot
instead.
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2) In choosing the 35mm film to use, one important consideration may be
the speed with which you wish the results to be returned to you. Whilst
most colour print films can be developed overnight or even within an
hour or so, this is not the case with colour slide films. Most have to
be sent away for processing and a delay of 10−14 days is not untypical.
If you want colour slide film developed quickly it is best to use (non
“process paid”) Kodak Ektachrome film which good photographic shops
should get returned to them within 2−3 days. There are also a few
specialist laboratories which offer a 2−3 hour service.
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3) When determining the correct ‘peak white’ exposure using an automatic
camera, it is possible for the camera’s metering system to be too
sophisticated! I was using a Minolta 7000 AF camera and the exposure
settings fluctuated quite rapidly as the monitor screen picture was
scanned and refreshed. Checking the exposure using a different camera
confirmed the article’s “if all else fails” assumed exposure settings.
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4) Focusing may well be perfectly feasible when using a camera with
auto-focus. I found it best to set the initial focus with a screen
display visible, rather than a blank screen, and then switch the auto-
focus off − this is because the Minolta 7000 AF system tries to refocus
after every picture is taken. In setting the combination of shutter
speed and aperture, it is probably preferable to err towards the slower
shutter speed/smaller aperture (higher ‘f’ number) setting as this will
increase the ‘depth of field’ and give a greater safety margin if the
focusing is not quite right.
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5) As mentioned in the original article, a sturdy tripod is virtually
essential and a remote shutter release (or possibly the camera’s Delayed
Action feature − if fitted) must be used to avoid camera shake and
consequent blurred pictures. Additionally, switching off the room lights
when taking the photographs should avoid any extraneous reflections off
the monitor screen possibly spoiling the finished results.
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6) If you are using 35mm slides and the results are to be projected
using a professional (rather than domestic) slide projector, it is
definitely worthwhile having the slides ‘glass mounted’ − although this
does increase the cost! This prevents the heat from the projector lamp
“popping” the slide and causing part(s) of it to appear out of focus.
For those who are interested in further reading on the subject, there is
an article in January 1989’s issue of BBC Acorn User (pages 81-83) on
the subject of taking photographs of the computer screen, there is even
advice on taking pictures of commercial games software.    Rob Brown.
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•   Willie Stott has sent in a very complete set of facilities for
support of the Epson LQ series, including a download font designer. This
will only be of interest to those with the right hardware, but he has
used a neat idea to get control of any extra facilities that your
printer supports, but for which First Word Plus has no category. He
points out that foreign characters can be used as printer definitions.
The characters with ASCII values between &E0 and &EE appear on the
bottom line of the character window and you have to do three things:
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a)   Define the character as a suitable message to the printer in the
character translation table of the hex file, then turn it into a driver.
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b)   Design suitable character definitions (using VDU23,...) to
represent the action of the printer so that it is added to the compu
ter’s character table when FWP is booted up.
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c)   Include your definitions in the FWP boot file before the *key 1 ...
line.
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•   A tip from an unknown writer (maybe Paul knows who to acknowledge −
Sorry, no. Ed.): how would you like to be able to produce a spool file
of your FWP output? What? Not much!? You may be missing something, as
you could then move the file to another machine and get a printout via
that machine, e.g. via an IBM or a mainframe. The trick is to *SET
PrinterType$4 <spoolfilespec> before booting up FWP. Then select
“network port” from the printer box in FWP. The system variable
PrinterType$4 holds the pathname for network printer output. The
<spoolfilespec> needs to include the full adfs:$.filename format.
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•   Someone besides me is the kind of two-fingered typist that hits
<ctrl> at the same time as <A>. What should our correspondent do? File
his fingers down? Stick a piece of rough Velcro on the <ctrl> key? No,
contact the Archive office and have someone write a module to intercept
<ctrl-A> and make a beep. The trouble is that when you are just feeling
bold enough to try to modify a bit of assembler to help a friend, you
should not choose a keyboard buffer intercept. There is no way to try it
out safely, or even to get a decent service from the debugger as every
keypress goes via your duff code. You cannot even type “*rmkill”
successfully. The only key which really works is <reset>. Help!! All
serious programmers out there: where did I go wrong? Why does the IRQ
stack pointer unwind so fast? P.S. If you can include a <ctrl-f12> =
swapcase facility in the module, you will win a large “thank you” and a
small prize for the best solution. You can start with the PrintKey
module program in Archive1.10, page 45.
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•   There is a new version of FWP available from Acorn for those whose
copy does not pause at the ends of each page, even if the flag has been
correctly set in the printer driver. Return your disk to Customer
Support, Acorn Computers Ltd., Fulbourn Rd., Cherry Hinton, Cambridge
CB1 4JN. (Reprinted from BBC Acorn User, Feb ’89, p 10).
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It is rumoured that there is a genuinely new version on its way, perhaps
to coincide with RISC-OS.
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•   Johnathan Young has a cure for the FWP buzz (the one which comes out
of the speaker or down the external audio output, and sounds like the
onset of tinnitus): boot up and then exit EMR’s sound synth package. A
bit expensive for silence, but you get the music program free! Has
anyone an explanation or a better solution?
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