Commodore Computer 4023 Bedienungsanleitung PDF herunterladen (Seite 9)

4023 GRAPHICS BUG by Tony Goceliak

In my article regarding the b-series screen dump, there is

one other set of inconsistencies which I would like to point out,

even though the majority of users would never notice the

imperfection. The difficulty is in a non-systematic series of

inconsistencies regarding the graphic symbols which produce

horizontal lines. Specifically, if you were to place your b into

graphics mode and type ?chr$(164) you would see one of the

series, of which there are eight unique members via screen

display, but only seven unique representatives on your 4023,

with one duplication, and not so obviously, one omission.

[To make things much easier, I have included a short basic

program entitled ’4023 bug demo’ which exposes the inconsis

tency much better than I will by words alone].

When the b is placed in graphics mode, pressing the

appropriate keys, or alternatively, printing the appropriate

chr$(...) will display the series of eight possible horizontal bar

symbols on screen. [They cannot be displayed from text mode].

If arranged in either ascending or descending order, they can

make a ’staircase’ of uniform slope. Upon sending the same

string of characters to the printer, a similar, but not exact

staircase will result. It is human nature to try to make patterns

out of nothing, and to try to make things fit, so my demo program

follows this up with a different string, including a chr$(254) [the

programmable character, suitably defined of course] which

should demonstrate the now ’sticks out like a sore thumb’

differences. All in all, no less than six of the eight characters

are incorrect! It would normally take a microscope to detect the

fact that these six characters produce print which is one dot too

high, but I recently wrote a program which produced a graph

on my b using exactly these characters, and when I produced a

hard copy, it just wasn’t right. (I admit, I DID use a micro

scope!)

Please bear in mind that this demonstration in the escape

becomes magnified in the vertical dimension only by a factor of

eight, so the difference which appears at a glance is not so easy

to spot when your 4023 spits it out. Now, as to why I have not

’sorted these things out’ in my screen dump. First, notice that

I have kept referring to 4023 and not 8023 throughout this article.

8023’s handle these characters perfectly! A ’corrected’ set

would make an 8023 misbehave. Second, there is simply NO

character which is in the 4023 set which will produce what

chr$(198) prints on a graphics screen. I can usurp your one and

only programmable character to patch around it, but only by

killing any chance you have of using the programmable character

reliably in a program. To me it is too high a price to pay just to

straighten out a line displaced the height of one dot on your

printer by Commodore.

PRINT# WITH the CBM PRINTERS by Tony Goceliak

Question: When I am addressing the printer with print#, it

always advances the printer a line. Is there any way to resolve

this situation ?

Answer: When you are addressing the printer in immediate

mode, the printer is on line and listening. Basic sees the CR at

the end of the line and automatically sends a CR and LF to the

printer just as it would to the screen.

If you place a semi-colon at the end of the print# line you

will suppress the linefeed and transmit the desired command.

(Contused 4023 Characters continued from Page 1)

cial characters or codes to the printer that normally would not

be accessible using Superscript. For example, if we want to

print the character whose CBM ASCII code is 91, we would

pick a format (represented by a digit from 0 to 9) to store the

code. This is done with:

*1=91

Other commands can precede or follow this command by

using a colon to separate them, as usual. Please note, that as

explained above, the underline represents which characters will

be in reverse when displayed in Superscript.

The above would be done somewhere near the top of the

document. At the point where the character (code 91 in our

example) is desired in the document, we would press ESCape

1, which will show as a reversed 1 (1) in Superscript. When

printed, Superscript will output the 91 code when it encounters

the 1. It will assume that the code caused the printer to print a

character, that is, to use a column on the output.

Superscript uses the last encountered definition for a format

(if there is more than one) when it finds the reversed digit in the

text.

Armed with this knowledge, whenever you want to make a

document intended for either Commodore dot matrix printers

or other printers, put these lines at the top of your file:

*cm l= !b, 2=bs, 3 = rb, 4=ua, 5=Ia

*l=219:2=220:3=221:4=222:5=223:cm CBM dot ma

trix

*l=91:2 = 92:3 = 93:4= 94:5 = 95:cm AH other printers.

The first line is just a reminder comment line. Replace the

lb with the left bracket symbol, the bs with the British pound

symbol (representing back slash), the rb with the right bracket,

the ua with the up arrow, and the la with the left arrow.

Now, whenever you need a left bracket in your text, don’t

put a left bracket, put in an ESCape 1 (l)instead. Similarly, use

an ESCape 3 (3) in place of a right bracket, and so on.

Now, when you print to a Commodore printer with the

infamous bug, insert a cm just before the first 1 in the third line

above, as in:

*cm l=91:2 = 92:3 = 93:4= 94:5 = 95:cm All other print

ers.

which will cause Superscript to ignore the entire line. So,

Superscript will use the first set of definitions when it sees the

1, 2, etc. And, when you print to any other printer without the

bug, just make sure you don’t have the cm at the beginning of

the third line. That will cause it to redefine each of the format

codes and use the later set when it encounters a 1, 2, etc.

Please note that in the *1 = ... command the digits should

not be in reverse. But when the codes are put in the text, they

must be (eg. 1). Make sure you get this straight right away to

save yourself some confusion down the road.

The format code command may be used to access other

printer characters, such as the degree symbol, or whatever the

print wheel has.

THE REAL PROBLEM:

You can ignore this section if you don’t care why the above

contortions are necessary.

June 1993

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