Archive Magazine CD 1995/Archive Magazine CD 1995.iso/text/hints/volume_01/issue_03

Text File | 1995-02-16 | 16.9 KB | 342 lines

•   RAM upgrades − If you want to up-grade the ram yourself, rather than
trying to remove the main p.c.b. to get at the sockets where the new
chips are to go, you can remove the front fascia. To do this, remove the
lid, then disconnect the wires that go to the speaker and the ‘power on’
LED by pulling the four-pin socket off the pins on the board. The tongue
at the front of this socket is a clip that holds the socket in place, so
ease this forwards and the socket should slip off easily.  Then you can
remove the fascia itself by undoing the five screws, three underneath
and one at each side. Care should be taken with the eject button on the
disc drive as this can break off fairly easily if roughly handled. (Some
say, will inevitably break off, but a bit of super-glue or the like is
all you need to stick it back in place.) You will then have to remove
the bridge that supports the disc drive(s). This can be done by removing
one screw underneath the computer (do this first) then two screws at the
side. Plug in the chips and reverse the process, again being careful of
the disc eject button.
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•   Fitting a second drive is supposed to be a ‘dealer only’ upgrade,
but as long as you know a bit about electronics and vaguely what happens
inside computers, it is not too difficult to fit it yourself. However,
you should watch out that the front fascia plate is not too high. If it
is, it will bear on the disc and may cause an error when you try to
access the disc. I discovered this when I found that the drives worked
OK until I put the new two-hole fascia in place. My solution, when this
happened, was “brute force and ignorance”! The metal bracket on which
the drive is supported has a little bit of “give” in it − enough to
raise the front of the drive by the couple of millimetres necessary to
lift it away from the fascia.
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The other important thing to know is that to configure your second drive
as drive 1 you need to move the tiny black slider switch at the side of
the drive. It is a four position switch and usually comes in position 0,
so one click will move it to position 1.
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•   Anti-Buzz Fix  − There are, apparently, two different buzzes. One is
what occurs after you have pressed <escape> or <break> and the other a
much more annoying buzz which not all computers seem to have. The first
buzz is a software problem which is fixed in the 1.2 Arthur, so I am
told, but the other requires a hardware fix which is supposed to be done
by dealers as a free modification, but if you are deft with a soldering
iron and are willing to risk your warranty, here’s what to doÉ
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The solution, according to Acorn’s technical services department isÉ
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“Solder a 100µF, 10 volt electrolytic capacitor across pins 7 (positive)
and 4 (negative) of IC68. The capacitor should be kept as close to the
p.c.b. as possible and should be secured to the board with glue or hot
wax.”
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The bad news is that IC 68 is underneath the bar that supports the disc
drive(s)! The easiest way to get at it is actually, (1) take off the
lid, (2) unplug the lead that  goes to the speaker and power-on LED
(beware, the socket on the ends of the cable has a lip that locks it
onto the pins on the board − ease the lip forward before trying to pull
the socket off), (3) take off the front fascia (one screw at each side
and three under the front edge) and (4) unscrew the drive-support bridge
(one screw underneath and two at the side).
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•   Problems with monitors − Some folk are having problems with certain
monitors. If the problem is lack of contrast, use an oscilloscope to
check the voltage output levels from the Archimedes. If they are less
than 0.7 volts peak-to-peak you may need to change the values of the
output resistors. Acorn have changed resistors R20, R41 and R59 from 68
ohms to 43 ohms, so if you want to increase the output voltage, you
could either change the resistors or solder a 120 ohm resistor in
parallel with each.
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The other problem with some monitors, especially the NEC and Fujitsu
multisync monitors, is of getting a greenish tinge on white areas. This
comes about because Acorn put the sync signal onto the green line which
is apparently what certain monitors expect. To remove this sync signal,
simply remove resistor R39 − a quick snip with a good pair of side-
cutters should do it, but make sure you get the right resistor!
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(When I tried to do these modifications, I found it wasn’t too easy to
decide which resistor was which because the numbers are actually
underneath the resistors. If you look at the line of resistors coming
away from the video output socket you will see that they are: R1, R3,
R18, R20 (68R), R35, R37, R39 (1k2), R41 (68R), R45, R50, R52, R59
(68R), R60, R63 and R67.)
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•   Archimedes on Econet − As far as we can gather, the Econet hardware
to be added to the basic 305 or 310 is just the same as the module which
you would purchase for the Master or Compact − certainly, the part
supplied by Acorn to one of our readers had the same part number as the
Master equivalent. One problem which Econet users may find on earlier
systems is that even if you only want to use the disc system, you still
have to have a clock signal available, otherwise the computer hangs up!
Presumably this will be corrected in the 1.2 operating system! If you
are used to using !BOOT files on the network, you will need to change
them all to !ARMBOOT as well as having !BOOT files for the BBC. The
Archimedes will work quite well on a Level 3 server but there are no net
utilities like VIEW, REMOTE, NOTIFY, ROFF etc. The only one provided is
an enhanced FREE which includes RDFREE with it. Acorn have “no plans”
for providing these utilities. This, for schools, is quite a problem as
you cannot get to see what is going on around the net. However, software
transfer around the net is very easy. (These comments were kindly
provided by Mr V Smith of King Edwards School, Lytham.)
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•   Control key abbreviations − Lazy typists like me will like to know
that if you want to type, say, MODE12 perhaps to list a program that was
running in different screen mode or within a window, you can be
abbreviate it to <ctrl-V><ctrl-L>. What you are doing is the equivalent
of VDU22,12. On the BBC micro this was not a good idea because BASIC was
unaware of the change of mode and would start to over-write screen
memory with variables, but it is OK on the Archimedes because the screen
memory is protected by having configured a certain amount of screen RAM.
If you try it and then type PRINT MODE, it knows it is in mode 12. Other
mode numbers can be worked out − mode 0 would be <cvtrl-V><ctrl-@>, 1 is
A, 2-B, 3-C, 4-D, 5-E, 6-F, 7-G, 8-H, 9-I, 10-J, 11-K, 12-L, 13-M, 14-N,
15-O, 16-P, 17-Q, 18-R, 19-S, 20-T, 21-U.
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This can be extended to things like changing background colour, say to
blue, with <ctrl-S><ctrl-@><ctrl-D><ctrl-@><ctrl-@><ctrl-@> (where
<ctrl-@> is actually done with <ctrl-shift-2>) but there comes a limit
where it is quicker to type in the command rather than remembering the
control codes. You can even do all the plotting functions in this way −
try, for example, <ctrl-Y><e><ctrl-C><ctrl-C><ctrl-C><ctrl-C>. (That’s a
lower case “e”, not <ctrl-e> so switch caps lock off and just press <e>.
If nothing happens, do a mode change first to a graphics mode, say MODE
12, then try it.)
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To change mode when in the Arthur Supervisor, you could use, say, ECHO
|| V || L or ECHO || S || @ || D || @ || @ || @ or you could use ECHO
<19><0><4><0><0><0> but you can again just type in the <ctrl> sequences
as mentioned above.
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•   Special effects in View − You can use *ECHO or use the control key
sequences mentioned above when you are using View. Also, if you want to
put the ‘format block’, ‘move block’ and ‘delete block’ commands onto
function keys 10 to 12 (instead of using the <print> key) you can use:
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*KEY 10 || ! || L
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*KEY 11 || ! || \
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*KEY 12 || ! ,
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Despite what it says in the User Guide about the pageup and pagedown
keys not being used, they seem to work in View and they do actually move
you a page at a time up and down.
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•   *RMtidy − Beware that on the 0.20 Arthur, this can cause the machine
to crash whenm you subsequently try to us *RMLOAD.
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•   There is apparently another undocumented screen mode which will be
available on Arthur 1.2 − mode 21 which is 640 x 512 in 256 colours,
though it will obviously only be usable on a multi-sync monitor and uses
320k of RAM! Also, on the 400 series there will be two extra high
resolution monochrome modes for 64kHz monitors − mode 22 which is 160 x
122 text with 1280 x 976 graphics and mode 23 which is text only at 144
x 54. These use the extra hardware that is on the 400 series boards
though it looks as if there should be space for the chips on the 300
boards if you are prepared to risk fitting them yourself. There are no
sockets, so you would have to solder-suck all the holes first, and it’s
a multi-layer board.
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•   Delete on keypad − If you compare the keypads of the Master and the
Archimedes, you will see that where the Archimedes has a fullstop, the
Master has a delete key. If you think it would be useful to have the
delete function on the keypad, turn the num lock LED off and try
pressing the fullstop key!
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•   Function key definitions − If you want to know what the current key
definitions are, *SHOW K* will print them on the screen. The only slight
confusion is that they appear in alphabetic order − KEY$0, KEY$1,
KEY$10,  KEY$11,  KEY$12,  KEY$13, KEY$14, KEY$15,  KEY$2,  KEY$3 etc!
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Function key 0, as you probably know by now, is put onto the PRINT key,
but where are the other function keys − 13, 14 and 15? The only one I
have found is 13 which is on the INSERT key The other thing to watch is
that although there is a separate key for function key 10 (the break key
on the BBC micro), when you press <break>, KEY$10 is expanded as it was
on the BBC micro! (That was on 0.2. Has it changed in later versions of
the OS?)
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•   Diary & notepad − The diary and notepad can be saved onto disc by
putting the pointer on the pad or the calendar and clicking the middle
button. It then asks for confirmation that you want to save it. The
notepad is saved as “notepad” and the diary as “Diary87” (or whatever
year it is for). To load them back in again later, you have to open up
the disc and click on the required file before clicking on the diary or
notepad with the middle button and selecting LOAD. When saving, the name
is fixed by the desktop program, but once it has been saved, you can
rename the file if you want to save more than one, though obviously this
applies more to the note-pad as I know that some of you are still having
to use the notepad as a word-processor! Having said all that, I have to
admit that when I was trying this out, I had problems saving the
calendar − I kept getting “Disc full” or “Disc in need of compaction”
errors. Any offers of explanation?
1.3
•   The SYSTEMDEVS module is a set of logical device drivers that can be
used from Arthur. They make the device appear to the programmer as if
they were a file system. In Arthur 0.20 you have to load the module from
the Welcome disc, but in 0.30 onwards it should be in ROM. They include
LPT:, KEYBD:, PRINTER:, VDU and RAWVDU: so a simple command to copy a
file to screen would be *COPY FILE VDU: and any non-printing characters
appear in the format used to program the function keys, i.e. using pad
characters so that, for example, ASCII 12 comes out as || L.
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What is the point of these facilities? Well, you can use them to
redirect the flow of data into or out of a program or relating to an
Arthur command. Thus you can say *EX {>info } which sends the output
from the EX command to a file called “info” and *CAT {>>info } will then
ADD the catalogue information onto the end of the info file, or *CAT
{printer: } would print out the catalogue. *BASIC {<data } PROG would
run the BASIC program PROG and take it input information from the DATA
file rather than from the keyboard. Another possible application is for
debugging a program that is sending data to a disc file. Rather than
stopping the program and examining the disc file periodically, you could
change the line in the program where you set up the file for output and
use instead X% = OPENOUT “PRINT:” then subsequent PRINT#X%’s or
BPUT#X%’s would go to the printer. If the output is un-printable (or do
I mean non-printing?!) characters then you could set the printer into a
hex dump format which many dot matrix printers have these days. Then a
final suggestion for an application would be when using network and
ADFS. To avoid switching between the two, you could say X%=OPENOUT
“ADFS:$.TEST”. This means that you could presumably have files open on
both the network and the disk at the same time, but not having a network
for my solitary Archimedes, I cannot check this!
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(These comments were derived from an article in “Eureka” the Auckland
BBC User Groups’ Archimedes Newsletter. Many thanks to the editor, Tony
Krzyzewski. Write to him if you want more details of Eureka c/o Barsons
Computers, P O Box 26287, Epsom, Auckland, New Zealand.)
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•   ROMs that work under the emulator.
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Acornsoft’s Comal, Prolog and Lisp seem at first look to be OK, and one
reader comments that Logotron’s Logo is OK but that the graphics are
“funny” − whatever that means.
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Damon Hoggett reckons that to get the View series ROM’s to work, you
need to *LOAD them at &10000 and then poke the following addresses to
&EA (a NOP instruction) as explained last month. View B3.0: &128A2,
ViewSheet B1.0: &10690, 691 and 692 and ViewStore 1.0: &12BCE, BCF and
BD0 then you *SAVE filename 10000+4000 8000 8000. We made a mistake with
the mention last month of Viewstore 1.1 (page 23). The poke should be
?&12BE2=&EA, not 1ABE2 and you should also poke the next two bytes,
&12BE3 and E4.
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BBCSoft’s Monitor ROM seems to work OK with the emulator. You can
apparently assemble, disassemble and single-step through 6502 machine
code without problems.
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Some folk are saying the Inter-Chart works under the emulator, though
not option 9 to import data.
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•   BASIC editor on 0.20 OS − If you are in BASIC and you type EDIT,
BASIC issues a *ARMBE command, so if that module is not already loaded
into memory, it will look in the operating system ROM and then in the
current directory on the current drive for the ARMBE module. If it is
not there, it will come up with “Bad command”. However, if it finds it,
it will load it into memory. Then to enter the editor, you just type
EDIT again. So, until you get your 1.2 OS(!) it is a good idea to copy
the ARMBE module into the directory in which you keep your BASIC
programs so that it is ready to use at any time.
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•   No room in RMA − If you are in BASIC and try to *RMLOAD a module,
you may get “No room in RMA” even if the configuration is set to allow
enough space for that particular module. But if you QUIT first into the
Arthur supervisor you can do the RMLOAD and then go back into BASIC and
OLD to get your program back. However, I think I would tend to save the
program first just in case!
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•   BASIC V tips from Colin Dean, author of ‘Advanced BASIC’ (Tubelink’s
BASIC V look-alike for the BBC & Master)
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In the LIST IF command, if you put a space between the IF and the
<string> that follows it, you get a different effect. For example if you
have two lines:
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10RECTANGLE 1,2,3,4
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20 RECTANGLE 5,6,7,8
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Then “LIST IF RECTANGLE” shows line 20 only, whereas “LIST IFRECTANGLE”
shows both.
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A neat way to test more than one expression at once, without having to
use heavily nested IF’s is to use “CASE TRUE OF”. For example,
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CASE TRUE OF
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  WHEN X=3 AND Y=4:PRINT“X=3 and Y=4”
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  WHEN X>7, Z=0:PRINT“X>7 OR Z=0”
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ENDCASE
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However, you should beware of mixing numerics and logicals in CASE
expressions. For example,
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X = 6
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CASE X OF
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  WHEN TRUE : PRINT “TRUE”
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  WHEN FALSE : PRINT “FALSE”
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  OTHERWISE PRINT “SPURIOUS”
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ENDCASE
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this prints “SPURIOUS” because ‘6’ is neither true (−1) or false (0).
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•   Improved boot file for WWPlus − The !BOOT file on the Archimedes
Wordwise Plus discs is a BASIC program which checks whether the 6502
emulator is installed and if not loads it off the Welcome disc. If
instead you copy 65arthur onto your Wordwise Plus discs you can use a
simpler boot file which just says:
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QUIT
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65ARTHUR
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WW+
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and then do a *OPT 4 3 so that the computer EXEC’s the boot file instead
of running it. If you are using the disc version of CP-ROM, just add
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:SELECT SEGMENT 8
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:LOAD TEXT “$.CP-ROM.CPstart”
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*FX138,0,152
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to the boot file and it will start up the CP-ROM as well.
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•   Have you seen the whale?! − When playing Zarch, one or two folk have
discovered a whale that appears in the sea (or is it a shark or a sea-
monster?). You get 1000 points if you exterminate it and sometimes it
“beaches” itself and becomes a much easier target. By the way, how are
the scores going? I’ve just about managed to avoid being called a wet
lettuce or a stuffed aubergine, but one reader, Malcolm Roberts says his
son has reached 53,291.
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(STOP PRESS! I’ve just seen it too − very fleetingly. It was bluish with
a zig-zag fin on its back!)
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