CPM-65 Junior Computer II Port
===========
Dietrich Lausberg 
https://github.com/dietrich-l
This repository contains the Junior Computer II Port of CPM-65, 
a CP/M-80 analogue operating system for 6502 based microcomputers



System Requirements

Junior Computer II
Expansion Card
Special thanks for support and testing goes to 
Joerg Walke, Developer of the Junior Computer II system, Norbert J. and Edzard

  System Structure

CPM-65 consists of 3 layers:

BIOS Basic I/O system - Drives can be A-D non consecutive.
BDOS Basic disc operating system - this is the CPM-65 kernal. Size 2 kB
CCP Console command program - a simple console which only allows to invoke CPM-65 programs. 
      No resident commands. Size 1 kB

On the JC ][ CPM-65 resides on 1 MB images on a SD card. Upon Boot the JC ][ first executes a 
program in BOOT.SYS in the root directory of the SD. BOOT.SYS offers all bootable images found 
in the Root directory for booting. The images must have the CPM-65 system in sectors 1 to 11.
The program then loads CPM-65 to memory, mounts the selected image as Drive A: via a BIOS call
and starts the CCP. Up to 4 images can be mounted with the utility SD-UTIL. 
A more detailed description how to prepare a bootable SD card can be found 
under docs/CPM-65 JC-II BOOT preparations.txt



  File & Disc Format

Filenames are CP/M-style d:filename.ext with d <Drive A-D>
Programs must have .COM as extension and are loaded to $2000 and started there.
The directory structure is nearly CP/M-compatible. Disk images can be read with appropriate  tools 
like CPMTOOLS, CIFE (CPM Image File Explorer) or CpmtoolsGUI. A disdefs file is in the IMAGES section.
The Disc format is 128 tracks/ 32 sectors/ 256 byte/sector. 
It is defined in the BIOS. The BDOS operates on sector numbers.

Software List

Program	Version	Description
ALLOC	2.9	shows disc allocation map
ASM	2.8	native 6502 Assembler
BASIC	1.6	Microsoft Basic interpreter
BDOS	2.4	CPM-65 BDOS
BIOS	1.1	JC II CPM-65 BIOS
BOOT	1.3	JC II CPM-65 BOOT program in track 0, sector 0
BOOTSYS	1.8	JC II CPM-65 BOOT program on SD, main directory
BROWSE	1.2	text file browser
CCP	1.5	CPM-65 CCP
COPY	1.4	multi file copy utility
D	2.3	show directory alphabetically sorted
DEBUG	1.9	Debugger, 8 breakpoints, stepping, disassembler,...
DUTIL	1.5	disc sector editor
EDIT	1.1	Simple editor for text files & FORTH screens
ERASE	1.5	erase files
FDISK	1.0	Disk initializer
FORTH	1.6	FIG FORTH including module for standalone applications
RENAME	1.1	rename files
SD-UTIL	1.5	SD utility for image handling and sector inspection
SYS	1.6	puts code for BOOT, BIOS, BDOS, CCP into the system tracks
SYSGEN	1.0	copy operating system to another disc
TYPE	1.7	prints text file to screen
XMODEM	2.3	File transfer XMODEM protocol, via serial I/O 19200 Baud

 
All software is supplied as assembler files to be assembled with the CPM-65 assembler.

In case you wish to use a different assembler, the syntax has to be adapted accordingly.

Documentation

--------------------

Currently the documentation of CPM-65 is sparse and only for my personal needs.

I plan to write appropriate docs over time. If there are any whishes, please open a DISCUSSION

Errors

--------------------

The Junior Computer II port of CPM-65 is now in V1.0 and reasonably stable. Please report errors and crashes in the ISSUE section

The CPM-65 system itself has now seen more than 30 years of service. Currently there are no known errors.

However, since an error free software does not exist, please report any errors in the ISSUE section

Other related systems

---------------------

When I started the development of cpm-65, I was blissfully unaware of any other aproaches.

However there are some, most notably:

- DOS/65 by Richard Leary. There is a limited compatibility

- OUP/M by Jiang - Xiong Shao. Published 1983, no further development

- CPM65 by David Given, published 2022

Redistribution

--------------

Source code, and all documents, are freely redistributable in any form.

Please see the the COPYRIGHT file included in this Repository.