This
is text written by Simeon Cran which describes MYZ80 and
its use
WELCOME to MYZ80
by Simeon Cran!
MYZ80 by Simeon Cran is a Z80 emulation package which allows you to run CP/M operating systems on your IBM AT compatible (or better) computer. It features the MicroFast Z80 Emulation Engine which gives MYZ80 the highest performance of any comparable emulator. MYZ80 emulates more than just the Z80 and 64180 CPU chips; it emulates a complete banked memory Z80 based computer system, ready to run CP/M 2.x, CP/M 3.0, ZPM3, ZCPR or any other compatible CP/M system.
MYZ80 by Simeon Cran automatically senses what kind of hardware your computer has and uses 32 bit code if possible for even higher performance. MYZ80 is also multitasker friendly and has been tested and shown to run very well under DOS versions from 3.3 on, OS/2 version 2, Desqview, and even Windows. MYZ80 truly is the Z80 emulator for the '90s and beyond!
MYZ80 provides complete emulation of the Z80 instruction set in an environment which simulates a typical Z80 based personal computer. The BDOS, CCP and BIOS are written in Z80 code, just as they are on a real Z80 based computer, and this means you can replace any of these components to make the system work the way you want it to. MYZ80 can run CP/M 2.2, CP/M 3.0 and ZCPR... virtually ANY CP/M 80 style operating system. CP/M disk drives are "virtualised" on your MS-DOS hard disk. A fast RAM disk is available at all times. Terminal emulation is switchable between a number of popular terminal emulations. MYZ80 is written entirely in assembly language.
CPM.EXE is the main program file containing all the 80x86 code that makes MYZ80 work. It is provided in a compressed form which automatically uncompresses when run. That's why CPM.EXE is so small! In fact it is over 160k when uncompressed.
"DISK FILES" are files that are created on your MS-DOS disk by MYZ80. On a real CP/M system, all your data is held on floppy or hard disks. On the MYZ80 system, all your data is held in DISK FILES. The disk files MYZ80 uses are called A.DSK, B.DSK and C.DSK and refer to the virtual A:, B: and C: CP/M disks respectively.
"BOOT FILES" are similar to the system tracks on real CP/M disks: they hold the Z80 system (the BDOS, BIOS and CCP). When CPM.EXE starts, it loads the contents of a BOOT FILE into memory, switches to Z80 emulation mode, and starts running the Z80 code it has just loaded. Normally that means starting up a CP/M system of some sort, but BOOT FILES can contain any Z80 code.
CP/M files are not visible from MS-DOS because they are contained in the disk files. MYZ80 comes with a number of CP/M files; you will no doubt add many more of your own.
Only a minimum of CP/M files has been provided for you, and you won't be able to do very much useful work with just what you've got. But you will certainly be able to add more files thanks to the program IMPORT.COM. IMPORT.COM allows you to import files from the MS-DOS environment into the MYZ80 CP/M environment. It is simple to use. For example, to import the program file ZFILER.COM from the directory that you were in when you started CPM.EXE, enter the command "IMPORT ZFILER.COM" at the prompt (pressing return at the end of the line of course!). IMPORT.COM will do its job and a DIR will show that ZFILER.COM is now in the MYZ80 environment on your current DU:.
iMPORT.COM accepts wildcards too. So you could import all the files required for WordStar with the command "IMPORT WS*.*".
IMPORT.COM is the most important utility to get you started, but there are other utilities provided with MYZ80. Here's the list:
IMPORT.COM - Imports files FROM MS-DOS to the MYZ80 environment.
EXPORT.COM - Exports files FROM MYZ80 to the MS-DOS environment.
COLOUR.COM - Changes the colour scheme for your screen.
TERMINAL.COM - Changes the terminal emulation.
KEY.COM - Loads and saves keyboard definitions.
COLDBOOT.COM - Coldboots MYZ80 (optionally with a different system).
SHRINK.COM - Shrinks disk files to their minimum size.
DOSDIR.COM - Shows a directory of the MS-DOS disks.
QUIT.COM - Exits MYZ80 (optionally with an error level).
SLOWDISP.COM - Slows down the MYZ80 display.
The MYZ80 utilities will display some helpful information about themselves if you run them with the argument "//".
E.G. DOSDIR "//". Remember, everything enclosed in [ ] is optional. In addition you will find the following files on your MYZ80 A: disk:
HELLO.TXT - The file you are reading now.
MYZ80GO.COM - The program which is run on startup.
And look for further interesting and useful files in user area 1 (type USER 1 at the CP/M prompt).
Good Luck!
The MYZ80GO.COM program is a simple program which displays HELLO.TXT to you. Unless you want to see HELLO.TXT every time you start up MYZ80 you should erase MYZ80GO.COM (with the CP/M command "ERA MYZ80GO.COM"). But because the system will still attempt to run MYZ80GO.COM at every start you can rename another program to MYZ80GO.COM and have it run instead. At any time you can use the command "TYPE HELLO.TXT" to see this document again.
One final thing... there are two online menus called up by pressing the control+break keys and the control+shift+break keys. Try them now!
Enjoy MYZ80! And don't forget to register!
Simeon.