These lines are dedicated to C128, later were updated
Commodore 128 has unlike other Commodore computers 2 video subsystems - VIC-IIe and VDC, which allow to use 2 desktops. Features also with 2 CPUs - MOS 8502 and Zilog Z80, what allows to use software for 2 architectures: X65 and X80. Z80 CPU was used mainlyfor compatibility with CP/M, in my eyes most versatile operating system. Z80 performs more effective code with less memory coststhan X65 CPUs, so I added it as feature of The Ace. But X80 architecture is missing or better to say both architectures are replaced when using SuperCPU - WDC 65816 CPU in 65K architecture. So, if is anybody interest in programming Z80 and owns SuperCPU must to turn off SuperCPU for accessing Z80.For Commodore 64 were designed 2 expansion cards with Z80 CPU:
CP/M 2.2 Commodore cartridge - allows to use CP/M 2.2 by C64, so there's accessible Z80
Z-80 Videopak - 80 column card and Z80 all in one
CP/M was never so popular for C64 users 'cause slow 1541 disk drive speed. In case of C128 is CP/M also slow for downclocking Z80 to 2 MHz for VIC-IIe sync, but disk access is fast. But fact is that CP/M cartridge contains Z80 CPU and works with Commodore 64 and Commodore 128 (in both modes) and even with SuperCPU turned on!Even if is SuperCPU missing or turned off, Commodore 128 has available 3 CPUs: 8502, Z80 inside C128 and Z80 inside cartridge! This is new door to make both architectures open!
Z-80 Videopak... Z80 CPU and 80 Column card together...
80 Columns for Commodore 64 or 2nd desktop? In case of Commodore 128 both UI in 80 Columns or 3rd desktop?
Anybody can say - why to have 2 desktops, also C64 can use standard cLIVE UI...
Working withmore than one desktop is easier, more effective and comprendious - personally I'm using 3 desktop PC and always use both desktops with working C128.I was searching for 80 column cards manufactured for Commodore 64. These allows to display by C64 80×25 screen instead 40×25. It's not easy to use 'cause they can at power on switch C128 native mode to C64 mode, if not, they're accessible, but support must to be rewritten for C128. Most of them using text mode only, but there is also one which allows all what VDC has. Here's list:
BI-80 uses MOS6545 chip
CBM64 uses MOS8563 chip, allows all what VDC - has same chip and output
EX80 uses MC6845 chip, textmode
Protecto 80 uses MC6845 chip
Z-80 Videopak incl. Z80 CPU, monochrome text mode
Videopak 80 - monochrome text mode
Zero 80 uses MC6845 chip, has RTC, text and graphic mode, allows picture mix which is anything like Genlock
ZK-80 Plus has Pass-Thru expansion port
CBM64 - the same chip like C128's VDC, same output and possibilities. Problem can be conflict with VDC registers 'cause programming can be same like VDC, so it can mean that can be only mirror of VDC desktop, if not it's fully independednt 3rd desktop. Main problem is that was never released but schematics were published so enhusiasts can to create own and use card by way like wants
ROOS Zero 80 - uses MC6845 chip, features RTC and colors (background has own color, text and border have same color), also graphic mode and feature like no one: possible to picture mix! This function seems Genlock like.
Z-80 Videopak - features monochrome 80×25 text mode with Z80 CPU - both solutions in one!