$0C0) The early 1541 drives used a mechanism developed by ______. Name
the company.
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$0C1) On later models, Commodore subsequently changed manufacturers
for the 1541 drive mechanism. Name the new manufacturer.
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$0C2) What is the most obvious difference(s). (Only one difference is
necessary)
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Alps: push-type latch, round LED.
Newtronics: lever-type latch, rectangular LED.
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$0C3) On Commodore BASIC V2.0, what answer does the following give:
PRINT (SQR(9)=3)
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0. According to Commodore BASIC, the answer should be -1, which
is the BASIC value of TRUE. However, the above equation is NOT
true. Doing PRINT SQR(9) yields 3, but doing PRINT (SQR(9)-3)
yields 9.31322575E-10 (C64). This anomaly can be attributed to
roundoff errors in the floating point math routines in Commodore BASIC.
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$0C4) In Commodore BASIC (Any version) what does B equal after the following
runs: C=0:B=C=0
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B = -1. The second statement is the one to look at. The second
equals sign is treated as a comparison, while the first is treated
as a assignment. B gets set to the outcome of the comparison, which
is TRUE (-1).
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$0C5) The first PET cassette decks were actually _______ brand cassette
players, modified for the PET computers. Name the comapny.
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Sanyo. Specifically, Model M1540A. What a model number!
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$0C6) In Commodore BASIC (Any version), what happens if the following
program is run:
10 J=0
20 IF J=0 GO TO 40
30 PRINT "J<>0"
40 PRINT "J=0"
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On BASIC 2.0 or greater:
?SYNTAX ERROR IN 20
READY.
On BASIC 1.0: (found on the PET 2001 series)
J=0
READY.
BASIC 1.0 totally ignored spaces, so line 20 became "IFJ=0GOTO40".
That statement would be correctly parsed, since it contains the "GOTO"
keyword.
However, on BASIC 2.0 or greater, spaces weren't ignored so completely,
and the "TO" in "GO TO" would be tokenized separately, so some code was
added to BASIC to check to "GO". As the code that accepts GOTO as a special
case for THEN after an IF statement wasn't patched this way, the above fails,
because GO is not a valid keyword after IF. The statement SHOULD
work correctly, but does not because of this failure to fix the IF
command parsing.
On BASIC 2.0 or greater, substituting the following line for line
20 will cause the program to work:
20 IF J=0 THEN GO TO 40
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$0C7) In question $068, we learned how Jack Tramiel first happened upon the
name "COMMODORE". According to the story, though, in what country
was he in when he first saw it?
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$0C8) On the Commodore user port connector, how many edge contacts are
there?
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24. Two rows of 12 contacts each.
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$0C9) On most Commodore computers, a logical BASIC screen line can contain
up to 80 characters. On what Commodore computer(s) is this not true?
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According to Commodore documentation, a _physical_ screen line is
defined as one screen line of characters. A _logical_ screen line is
defined as how many _physical_ lines can be chained together to
create a valid BASIC program line.
With that in mind, most Commodore computers chose a _logical_
screen line that was a multiple of the screen width. This works fine
for 40 and 80 column screens, but what do we do with the VIC-20, with
its 22 column screen. Solution: make the _logical_ line length equal
to 4 _physical_ lines, or 88 columns.
When the Commdore 128 was introduced, the number rose to 160
characters, which is 4 _physical_ lines in 40 column mode, or
2 _physical_ lines in 80 column mode. However, you can only take
advantage of this in 128 mode. 64 mode is limited to 80 characters.
To add to all this confusion, a valid BASIC program line (in memory)
can actually be 255 (tokenized) characters long, but creating such
a long line cannot be done from the built-in editor in direct mode.
The AmigaBASIC, available on the Amiga, also does not have the 80
column line limit. However, that BASIC is SOOO much different that
I am not surprised. The older CBM BASICs, on the other hand, were
all derivatives of the original Level 1 BASIC for the PET.
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$0CA) If a file is saved to a Commodore Disk Drive with the following
characters: chr$(65);chr$(160);chr$(66), what will the directory
entry look like?
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The filename will show up as "A"B, with the 'B' showing up to the
right of the '"' mark. This could be used to make program loading
easier. A file that showed up as "filename",8,1 could be loaded
by simply hitting shift-run/stop on that line.
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$0CB) What is the maximum length (in characters) of a CBM datasette
filename?
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References I have on hand say 128 characters. However, the actual
code on the 8032 and the C64 acts as though 187 characters can
actually be sent (tape buffer-5 control bytes = 192-5=187). The
references that claim 128 characters are Nick Hampshire's
_The VIC Revealed_ and _The PET Revealed_. ANyone care to lay
this one to rest?
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$0CC) How many keys are on a stock Commodore 64 keyboard?
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66 keys. This is the same number as found on the VIC-20 and the
Commodore 16.
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$0CD) Commodore BASIC uses keyword "tokens" to save program space. Token
129 becomes "FOR". What two tokens expand to include a left
parenthesis as well as a BASIC keyword?
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TAB( (163) and SPC( (166).
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$0CE) There are 6 wires in the Commodore serial bus. Name the 6 wires.
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1) Serial /SRQIN
2) GND
3) Serial ATN IN/OUT
4) Serial CLK IN/OUT
5) Serial DATA IN/OUT
6) /RESET
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$0CF) On the Commodore datasette connector, how many logical connections are
there?
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6. Opposing pins on the connector are hooked together electrically.
Jim Brain
j.brain@ieee.org
10710 Bruhn Avenue
Bennington, NE 68007
(402) 431-7754
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