HomeProjects & InfosCommodoreAtari STMacintosh 68kCP/M ComputerCP/M Software
CP/M Commander 
BASIC code examples 
C compiler 
Modula 2 
UCSD Pascal 
Power (Shell) 


Why not CP/M also for 6502 CPU's ?

DOS/65 - an interesting operating system with file system compatibility to CP/M-80 (and other similarities)

From the system description of DOS/65:
"What I (Richard A. Leary) have done is attack the software side of the problem in order to make any 6502 system a truly workable disk based system. In addition a degree of compatibility is now possible not only between 6502 systems but with large parts of the world of CP/M systems. The result of my efforts is a system of software which I have named DOS/65."

Richard's implementation is intially made for S-100 based systems, but he began to port it to the C64 also (see below).

DOS/65 has a lot of CP/M look-alike commands for the command line and also some applications like BASIC-E included.

Of course some differences between CP/M-80 and DOS/65 exist - the lowest memory areas (e.g. the "zero page") are not usable for the TPA, so the usable system memory area starts at a higher address (e.g. $0400).

Documentation files:

DOS/65 System description (PDF)
DOS/65 Sysgen manual (PDF)
DOS/65 System interface guide (PDF)
DOS/65 Bringing the system up (PDF) 

* NEW ! *
DOS/65 ASM Manual.pdf
DOS/65 BASIC-E Manual.pdf
DOS/65 EDIT Manual.pdf
DOS/65 DEBUG Manual.pdf

DOS/65 IEEE Standard 696 Manual.pdf 

Source code files (6502 Assembler):

BASIC-E compiler and runtime:  very useful !

Useful info for a port to C64  can be found at the C64 CP/M page, Richard converting PDFs to readable assembler files, thank you again, Richard !

 A working copy of a C64 port of DOS/65 !!

Richard has prepared two .D64 files (now updated):
DOS65-1C.D64 (Bootdisk with updated SIM C64S304.ASM)
DOS65A.D64 (Blank disk)

Load the bootdisk with: LOAD "DOS65",8,1:RUN

See for some advice using the assembler in the above PDF manual now.

The new source files are zipped now in one file:

He has written a sample BASIC/E program FILESTAT.BAS also.

Some screenshots:
Before boot but disk already inserted...

...after boot:

New ! Screenshot of running DOS/65 on a SX-64 with 1541 Ultimate.

Richard can be contacted at  richardaleary AT .

Important ! Please note this from the author:
"DOS/65 software and documentation are provided as shareware for non-profit, educational, or private use. Any other use is prohibited without approval of Richard A. Leary."


HomeProjects & InfosCommodoreAtari STMacintosh 68kCP/M ComputerCP/M Software

Copyright (c) 2005-2011 Peter Dassow. All rights reserved.