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Commodore Trivia 05
Here are the answers to Commodore Trivia Edition #5 for April, 1994.
Q $040) The company that produces The Big Blue Reader, a program that allows
reading and writing of IBM formatted disk in 1571s and 1581s, is
called SOGWAP. What does SOGWAP stand for?
A $040) Son Of God With All Power. They also market the Bible on diskettes.
Q $041) What version of DOS does the Commodore 8280 8 inch dual drive have?
A $041) The 8280 has version 3.0. Many have not ever seen this IEEE-488
compatible drive used on some PETs. It has the same DOS version
that is in the D90XX hard drives, and could read 250kB and 500kB
IBM formatted disks, as well as some CP/M formats. Note that although
this version number is used on the 1570/71 disk drives, the code is
different.
Q $042) What was the color of the original Commodore 64 case?
A $042) Some early versions of the Commodore 64 were housed in VIC-20 color
cases, so off-white is the correct answer.
Q $043) On an unexpanded Commodore 64, how does one read the RAM
locations $00 and $01?
A $043) Well, you cannot do so with the CPU directly, since it resolves these
locations into internal addresses. However, the VIC II can see these
addresses as external memory. So, just make one spritexs with the
first bit in the sprite set, and move it over the first two bytes,
pretending they are part of a bitmap. By checking the sprite-to-
background collision register, you can tell if the bit in the byte is
set. Email me for a more complete description.
Sven Goldt and Marko Makela get credit for this answer and the next.
Q $044) On an unexpanded Commodore 64, how does one write the same locations?
A $044) It seems the 6510 generates a valid R/W signal any time it does an
internal read or write. This is to be expected, since the 6510
internal registers were grafted onto a 6502 core processor.
Howevere, the address lines are also valid during any internal read
or write, since failure to do so may write the data on the data bus
to some invalid address. The data on the bus, however, comes not from
the CPU, but from residual effects of the data last read of written by
the VIC chip. Thus, by programming the VIC chip to read data from
some known location, and by placing relevant data in that location, a
write to location $00 or $01 will place the data from that last read
VIC location into $00 or $01. This is usually accomplished by placing
the data to be written out into location $3fff, which the VIC fetches
during the time the border is being displayed. By triggering a
routine when the raster hits the bottom border, you can copy location
$3fff to $00 or $01.
Q $045) What is 'CB2 Sound', and on what computers was it popular?
A $045) This is the sound made by sending square out of the 6522 IC on some
Commodore computers. It is called 'CB2', since that is the name of
the pin on the 6522 that outputs the waveform. I won't go into a
complete description, except to say that most models of the PET
had the capability, and most PET owners used it as the ONLY sound
source, since the PETs did not have a sound chip. Although the VIC
did have some sound capabilities, by that time Commodore had
realized its widespread use and included some information on it in
the Commodore VIC-20 Programmer's Reference Guide. For more info,
reach for your nearest VIC PRG and look at page 232.
Q $046) in question $021, the Batteries Included logo description was asked
for. Now, what is the name of the man in the logo?
A $046) "Herbie" Jim Butterfield supplied me with this one.
Q $047) Why was the Commodore VIC-20 produced with so many 1K chips in it?
(Hint: it had little to do with the cost of SRAM at the time)
A $047) Jack (Tramiel) decreed that Commodore had a surplus of 1K chips,
so he didn't care how much memory it had, as long as the designers
used 1K SRAMs.
Q $048) What does ADSR stand for?
A $048) ADSR = Attack, Decay, Sustain, Release. These are the four values
specified to define a SID waveform.
Q $049) In question $035, it was learned that the Commodore 64 kernal
revision number is stored at $ff80 (65408). Now, what is the number
stored there for:
a) The first revision?
b) The PET64 (4064)?
A $049) a) 170. (Yep, this was prior to 0!)
b) 100. (The PET 64 uses this value to adjust the startup logo
accordingly.)
Q $04A) Who was the mastermind behind the original Commodore Kernal?
A $04A) John Feagan. He had intended it to provide upward compatibility
for future computer systems. Unfortunately, the kernal was
modified enough with each new computer system, that the idea of
compatibility never really surfaced. Still, it was a nice try.
Q $04B) Who designed the first VIC prototype?
A $04B) There are two answers to this question. At the time, the VIC had no
name and was called the MicroPET or No Name Computer. Jack Tramiel
wanted to show some prototypes of the VIC at the 1980 Comsumer
Electronics Show (CES). The funny thing is, he got not one
prototype, but TWO. Bob Yannes, working against time, had hacked
together a minimal working prototype using spare PET/CBM parts.
Another prototype, brought to the show by Bill Seiler and John
Feagans, had been put together after some preliminary discussions
with Yannes.
Q $04C) How many pins does a Commodore 1525 printhead have in it?
A $04C) Trick Question. The two 1525 printers I have show that the 1525
printhead has but one pin. The seven dots are created by a revolving
7 sided star-wheel for the platen, which presses the paper against the
printhead in the seven different dot locations.
Q $04D) Why does mentioning a PET computer in France make people chuckle?
A $04D) PET means "FART" there.
Q $04E) What interface IC is used to drive the IEEE-488 bus in a PET computer?
A $04E) A 6520. It is appropriately called a PIA (Peripheral Interface
Adapter).
Q $04F) What was the primary reason Commodore went to a serial bus with the
introduction of the VIC-20?
A $04F) Jim Butterfield supplied me with this one:
As you know, the first Commodore computers used the IEEE bus to
connect to peripherals such as disk and printer. I understand that
these were available only from one source: Belden cables. A
couple of years into Commodore's computer career, Belden went out
of stock on such cables (military contract? who knows?). In any
case, Commodore were in quite a fix: they made computers and disk
drives, but couldn't hook 'em together! So Tramiel issued the
order: "On our next computer, get off that bus. Make it a cable
anyone can manufacture". And so, starting with the VIC-20 the
serial bus was born. It was intended to be just as fast as the
IEEE-488 it replaced.
And it would have been, except dor one small glitch. But that is
another trivia question.
End of Commodore Trivia Edition #5!
Jim Brain
brain@mail.msen.com
2306 B Hartland Road
Hartland, MI 48353
(810) 737-7300 x8528
--
Jim Brain, Embedded Systems Designer, Brain Innovations.
brain@msen.com
Dabbling in VR, Old Commodore Computers, and Good Times!
"The above views DO reflect my employer, since I am my employer" - Jim Brain
