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Who wrote this stuff?
This trivia was originally written by Jim Brain as part of the now long defunct C= Hacking Magazine, but happily Jim has kindly agreed to let me reproduce it in HTML-ized format for retro computing fans everywhere.

If you are interested in seeing the Commodore Trivia digests in their original form, take a look at this website.

For those who are interested, these pages were generated from the original text files using Perl and Velocity (and a nice template originally found here)


	How many general purpose central processing units does a C128

	The "3 computers in one" machine only contains 2 CPUs.  The
        Z80 handles CP/M mode, while the 8502 handles both 64 and 128
        mode.  The "3" in the C128 motto threw a bunch of folks.

	The Commodore 128 contains a MMU IC.  What does MMU stand for?

	MMU = Memory Management Unit.  Technically, the 64 contains one
        as well, but it was always referred to as the PAL or PLA in the
        64.  The 128 MMU does more than the 64 version, though.

	What Commodore produced cartridge is specifically mentioned in
        the 128 PRG as being incompatible with the 128?

	The Commodore 64 CP/M 2.2 cartridge.  

	The C128 introduces the concepts of "banks"  How many such banks
        are recognized by the C128 BASIC?

	16. Bank 0 through Bank 15.

	What version is the BASIC included in the C128 in native mode?

	BASIC 7.0.  

	Can any of the BASIC graphics commands be used on the 80 column

	It depends on how you define "graphics commands".  When writing the
        question, I was thinking of commands like BOX and CIRCLE that are
        written solely for use with the 40 column screen.  However, commands
        like SCRNCLR, CHAR, and COLOR commands are considered part of the
        graphics set.  Graphics commands that draw pixels on the bitmapped
        screen will NOT work on the 80 column screen, but those that merely
        set attributes or put characters at certain locations will work.
        However, don't let this fool you into thinking the 80 column screen
        can't support graphics.  It can.

	How many high-level graphics commands are available on the C128
        in C128 mode?

	14 high level graphics commands are included on the 128.

	In C128 mode, at what location does screen memory start?

	It resides in the same location as on the 64: 1024-2023 
        ($0400 - $07e7).

	The 80 column IC in the 128 can display how many full character
        sets of 256 characters each at one time?

	2.  While the VIC-IIe can only display 1, the VDC IC can handle
        display opf both sets simultaneously.  That means a person can
        print upper/lowercase and graphics/uppercase characters on the 
        same screen.

	Many have scorned the C128's 80 column video IC.  What about this
        IC makes it so hard to use?

	The VIC-IIe 40 column IC maps its configuration registers and
        screen memory into the C64/C128 memory map.  The 8563 VDC IC
        does neither.  All of its registers, screen memory, and color
        memory are hidden behind two registers.  These two registers
        control access to the entire IC.  In effect, these two registers
        are the "portal" to the VDC memory map.  To modify or read a 
        VDC internal register, the programmer must place the register
        number in one lcoation and wait for the result to appear in the
        other register.

	What number is the 80 column IC referenced by?


	What machine language addressing modes cannot be used with the
        80 column chip?

	The manual warns against using "indirect" addressing opcodes by
        claiming their use could generate "false" bus states that confuse
        the IC.  In reality, howevr, only the indirect mode of the STA
        opcode will cause any harm.  To understand why, one must note that
        the STA ($00),y instruction executes a read of memory before doing
        its write.             	   				    

	The C128 contains keyboard keys not present on the C64.  What IC
        is used to read these keys? (besides the CIA, as on the 64)

	There are two answers. Aside from the ROM, the CPU, and the above 
        mentioned CIA, the VIC-IIe IC provides the extra 3 lines used to 
        scan the keyboard.  The C128 MMU IC provides the capability of 
        reading the status of the 40/80 key. (Thanks for Marko Makela
        for this info)

	Following the introduction of the C128, a new version of was
        developed.  Name it.

	It is alternately called CP/M Plus or CP/M 3.0

	Many people refer to C128s as 16k or 64k units.  To what does this

	In question $209, we noted that the 8563 80 column IC in the C128
        has an internal memory map.  As such, the 8563 can have varying
        amounts of RAM attached to it.  Earlier C128 contained 16kB of
        this "VDC" RAM, while later variations and some third party
        products increased this to 64 kB VDC RAM.

	According to the C128 literature, the C128 can be expanded to use
        how much memory?

	640 kB.
The information in this between the lines marked by (BEGIN) and (END)
is copyright 1996 by Jim Brain.  Provided that the information
between the (BEGIN) and (END) lines is not changed except to correct
typographical errors, the so marked copyrighted information may be
reproduced in its entirety on other networks or in other mediums.  For 
more information about using this file, please contact the address 
shown below.
Jim Brain
10710 Bruhn Avenue
Bennington, NE  68007
(402) 431-7754
--------Commodore Trivia Edition #33 Questions and Answers (END)---------


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