RomWBW/ReadMe.md

**RomWBW Introduction** \
Version 3.6 \
Wayne Warthen  ([wwarthen@gmail.com](mailto:wwarthen@gmail.com)) \
30 Jan 2026

# Overview

RomWBW software provides a complete, commercial quality implementation
of CP/M (and work-alike) operating systems and applications for modern
Z80/180/280 retro-computing hardware systems.

A wide variety of platforms are supported including those produced by
these developer communities:

- [RetroBrew Computers](https://www.retrobrewcomputers.org)
  (<https://www.retrobrewcomputers.org>)
- [RC2014](https://rc2014.co.uk) (<https://rc2014.co.uk>),  
  [RC2014-Z80](https://groups.google.com/g/rc2014-z80)
  (<https://groups.google.com/g/rc2014-z80>)
- [Retro Computing](https://groups.google.com/g/retro-comp)
  (<https://groups.google.com/g/retro-comp>)
- [Small Computer Central](https://smallcomputercentral.com/)
  (<https://smallcomputercentral.com/>)

A complete list of the currently supported platforms is found in [RomWBW
Hardware](https://github.com/wwarthen/RomWBW/raw/master/Doc/RomWBW%20Hardware.pdf)
.

# Description

## Primary Features

By design, RomWBW isolates all of the hardware specific functions in the
ROM chip itself. The ROM provides a hardware abstraction layer such that
all of the operating systems and applications on a disk will run on any
RomWBW-based system. To put it simply, you can take a disk (or CF/SD/USB
Card) and move it between systems transparently.

Supported hardware features of RomWBW include:

- Z80 Family CPUs including Z80, Z180, and Z280
- Banked memory services for several banking designs
- Disk drivers for RAM, ROM, Floppy, IDE ATA/ATAPI, CF, SD, USB, Zip,
  Iomega
- Serial drivers including UART (16550-like), ASCI, ACIA, SIO
- Video drivers including TMS9918, SY6545, MOS8563, HD6445, Xosera
- Keyboard (PS/2) drivers via VT8242 or PPI interfaces
- Real time clock drivers including DS1302, BQ4845
- Support for CP/NET networking using Wiznet, MT011 or Serial
- Built-in VT-100 terminal emulation support

A dynamic disk drive letter assignment mechanism allows mapping
operating system drive letters to any available disk media.
Additionally, mass storage devices (IDE Disk, CF Card, SD Card, etc.)
support the use of multiple slices (up to 256 per device). Each slice
contains a complete CP/M filesystem and can be mapped independently to
any drive letter. This overcomes the inherent size limitations in legacy
OSes and allows up to 2GB of addressable storage on a single device,
with up to 128MB accessible at any one time.

## Included Software

Multiple disk images are provided in the distribution. Most disk images
contain a complete, bootable, ready-to-run implementation of a specific
operating system. A “combo” disk image contains multiple slices, each
with a full operating system implementation. If you use this disk image,
you can easily pick whichever operating system you want to boot without
changing media.

Some of the included software:

- Operating Systems (CP/M 2.2, ZSDOS, NZ-COM, CP/M 3, ZPM3, Z3PLUS, QPM
  )
- Support for other operating systems, p-System, FreeRTOS, and FUZIX.
- Programming Tools (Z80ASM, Turbo Pascal, Forth, Cowgol)
- C Compiler’s including Aztec-C, and HI-TECH C
- Microsoft Basic Compiler, Microsoft Fortran, and Microsoft COBOL
- Some games such as Colossal Cave, Zork, etc
- Wordstar Word processing software

Some of the provided software can be launched directly from the ROM
firmware itself:

- System Monitor
- Operating Systems (CP/M 2.2, ZSDOS)
- ROM BASIC (Nascom BASIC and Tasty BASIC)
- ROM Forth

A tool is provided that allows you to access a FAT-12/16/32 filesystem.
The FAT filesystem may be coresident on the same disk media as RomWBW
slices or on stand-alone media. This makes exchanging files with modern
OSes such as Windows, MacOS, and Linux very easy.

## ROM Distribution

The [RomWBW Repository](https://github.com/wwarthen/RomWBW)
(<https://github.com/wwarthen/RomWBW>) on GitHub is the official
distribution location for all project source and documentation.

RomWBW is distributed as both source code and pre-built ROM and disk
images.

The pre-built ROM images distributed with RomWBW are based on the
default system configurations as determined by the hardware
provider/designer. The pre-built ROM firmware images are generally
suitable for most users.

The fully-built distribution releases are available on the [RomWBW
Releases Page](https://github.com/wwarthen/RomWBW/releases)
(<https://github.com/wwarthen/RomWBW/releases>) of the repository.

On this page, you will normally see a Development Snapshot as well as
recent stable releases. Unless you have a specific reason, I suggest you
stick to the most recent stable release.

The asset named RomWBW-vX.X.X-Package.zip includes all pre-built ROM and
Disk images as well as full source code. The other assets contain only
source code and do not have the pre-built ROM or disk images.

#### Distribution Directory Layout

The RomWBW distribution is a compressed zip archive file organized in a
set of directories. Each of these directories has its own ReadMe.txt
file describing the contents in detail. In summary, these directories
are:

| **Directory** | **Description** |
|----|----|
| **Binary** | The final output files of the build process are placed here. Most importantly, the ROM images with the file names ending in “.rom” and disk images ending in .img. |
| **Doc** | Contains various detailed documentation, both RomWBW specifically as well as the operating systems and applications. |
| **Source** | Contains the source code files used to build the software and ROM images. |
| **Tools** | Contains the programs that are used by the build process or that may be useful in setting up your system. |

#### Building from Source

It is also very easy to modify and build custom ROM images that fully
tailor the firmware to your specific preferences. All tools required to
build custom ROM firmware under Windows are included – no need to
install assemblers, etc. The firmware can also be built using Linux or
MacOS after confirming a few standard tools have been installed.

## Installation & Operation

In general, installation of RomWBW on your platform is very simple. You
just need to program your ROM with the correct ROM image from the RomWBW
distribution. Subsequently, you can write disk images on your disk
drives (IDE disk, CF Card, SD Card, etc.) which then provides even more
functionality.

Complete instructions for installation and operation of RomWBW are found
in the [RomWBW User
Guide](https://github.com/wwarthen/RomWBW/raw/master/Doc/RomWBW%20User%20Guide.pdf).
It is also a good idea to review the [Release
Notes](https://github.com/wwarthen/RomWBW/blob/master/RELEASE_NOTES.md)
for helpful release-specific information.

## Documentation

There are several documents that form the core of the RomWBW
documentation:

- [RomWBW User
  Guide](https://github.com/wwarthen/RomWBW/raw/master/Doc/RomWBW%20User%20Guide.pdf)
  is the main user guide for RomWBW, it covers the major topics of how
  to install, manage and use RomWBW, and includes additional guidance to
  the use of some of the operating systems supported by RomWBW

- [RomWBW
  Hardware](https://github.com/wwarthen/RomWBW/raw/master/Doc/RomWBW%20Hardware.pdf)
  contains a description of all the hardware platforms, and devices
  supported by RomWBW.

- [RomWBW
  Applications](https://github.com/wwarthen/RomWBW/raw/master/Doc/RomWBW%20Applications.pdf)
  is a reference for the ROM-hosted and OS-hosted applications created
  or customized to enhance the operation of RomWBW.

- [RomWBW Disk
  Catalog](https://github.com/wwarthen/RomWBW/raw/master/Doc/RomWBW%20Disk%20Catalog.pdf)
  is a reference for the contents of the disk images provided with
  RomWBW, with a description of many of the files on each image

- [RomWBW System
  Guide](https://github.com/wwarthen/RomWBW/raw/master/Doc/RomWBW%20System%20Guide.pdf)
  discusses much of the internal design and construction of RomWBW. It
  includes a reference for the RomWBW HBIOS API functions.

An online HTML version of this documentation is hosted at
<https://wwarthen.github.io/RomWBW>.

Each of the operating systems and ROM applications included with RomWBW
are sophisticated tools in their own right. It is not reasonable to
fully document their usage. However, you will find complete manuals in
PDF format in the Doc directory of the distribution. The intention of
this documentation is to describe the operation of RomWBW and the ways
in which it enhances the operation of the included applications and
operating systems.

Since RomWBW is purely a software product for many different platforms,
the documentation does **not** cover hardware construction,
configuration, or troubleshooting – please see your hardware provider
for this information.

# Support

## Getting Assistance

The best way to get assistance with RomWBW or any aspect of the
RetroBrew Computers projects is via one of the community forums:

- [RetroBrew Computers Forum](https://www.retrobrewcomputers.org/forum/)
- [RC2014 Google
  Group](https://groups.google.com/forum/#!forum/rc2014-z80)
- [retro-comp Google
  Group](https://groups.google.com/forum/#!forum/retro-comp)

Submission of issues and bugs are welcome at the [RomWBW GitHub
Repository](https://github.com/wwarthen/RomWBW).

Also feel free to email Wayne Warthen at <wwarthen@gmail.com>. I am
happy to provide support adapting RomWBW to new or modified systems

# Contributions

All source code and distributions are maintained on GitHub.
Contributions of all kinds to RomWBW are very welcome.

## Acknowledgments

I want to acknowledge that a great deal of the code and inspiration for
RomWBW has been provided by or derived from the work of others in the
RetroBrew Computers Community. I sincerely appreciate all of their
contributions. The list below is probably missing many names – please
let me know if I missed you!

- Andrew Lynch started it all when he created the N8VEM Z80 SBC which
  became the first platform RomWBW supported. Some of his original code
  can still be found in RomWBW.

- Dan Werner wrote much of the code from which RomWBW was originally
  derived and he has always been a great source of knowledge and advice.

- Douglas Goodall contributed code, time, testing, and advice in “the
  early days”. He created an entire suite of application programs to
  enhance the use of RomWBW. Unfortunately, they have become unusable
  due to internal changes within RomWBW. As of RomWBW 2.6, these
  applications are no longer provided.

- Sergey Kiselev created several hardware platforms for RomWBW including
  the very popular Zeta.

- David Giles created support for the Z180 CSIO which is now included SD
  Card driver.

- Phil Summers contributed the Forth and BASIC adaptations in ROM, the
  AY-3-8910 sound driver, DMA support, and a long list of general code
  and documentation enhancements.

- Ed Brindley contributed some of the code that supports the RCBus
  platform.

- Spencer Owen created the RC2014 series of hobbyist kit computers which
  has exponentially increased RomWBW usage. Some of his kits include
  RomWBW.

- Stephen Cousins has likewise created a series of hobbyist kit
  computers at Small Computer Central and is distributing RomWBW with
  many of them.

- Alan Cox has contributed some driver code and has provided a great
  deal of advice.

- The CP/NET client files were developed by Douglas Miller.

- Phillip Stevens contributed support for FreeRTOS.

- Curt Mayer contributed the original Linux / MacOS build process.

- UNA BIOS and FDISK80 are the products of John Coffman.

- FLASH4 is a product of Will Sowerbutts.

- CLRDIR is a product of Max Scane.

- Tasty Basic is a product of Dimitri Theulings.

- Dean Netherton contributed multiple components:

  - eZ80 CPU support
  - Sound driver infrastructure
  - SN76489 sound driver
  - Native USB driver (keyboard, floppy, mass storage)

- The RomWBW Disk Catalog document was produced by Mykl Orders.

- Rob Prouse has created many of the supplemental disk images including
  Aztec C, HiTech C, SLR Z80ASM, Turbo Pascal, Microsoft BASIC Compiler,
  Microsoft Fortran Compiler, and a Games compendium.

- Martin R has provided substantial help reviewing and improving the
  User Guide and Applications documents.

- Mark Pruden has made a wide variety of contributions including:

  - significant content in the Disk Catalog and User Guide
  - creation of the Introduction and Hardware documents
  - Z3PLUS operating system disk image
  - Infocom text adventure game disk image
  - COPYSL, and SLABEL utilities
  - Display of bootable slices via “S” command during startup
  - Optimisations of HBIOS and CBIOS to reduce overall code size
  - a feature for RomWBW configuration by NVRAM
  - the /B bulk mode of disk assignment to the ASSIGN utility

- Jacques Pelletier has contributed the DS1501 RTC driver code.

- Jose Collado has contributed enhancements to the TMS driver including
  compatibility with standard TMS register configuration.

- Kevin Boone has contributed a generic HBIOS date/time utility (WDATE).

- Matt Carroll has contributed a fix to XM.COM that corrects the port
  specification when doing a send.

- Dean Jenkins enhanced the build process to accommodate the Raspberry
  Pi 4.

- Tom Plano has contributed a new utility (HTALK) to allow talking
  directly to HBIOS COM ports.

- Lars Nelson has contributed several generic utilities such as a
  universal (OS agnostic) UNARC application.

- Dylan Hall added support for specifying a secondary console.

- Bill Shen has contributed boot loaders for several of his systems.

- Laszlo Szolnoki has contributed an EF9345 video display controller
  driver.

- Ladislau Szilagyi has contributed an enhanced version of CP/M Cowgol
  that leverages RomWBW memory banking.

- Les Bird has contributed support for the NABU w/ Option Board

- Rob Gowin created an online documentation site via MkDocs, and
  contributed a driver for the Xosera FPGA-based video controller.

- Jörg Linder has contributed disassembled and nicely commented source
  for ZSDOS2 and the BPBIOS utilities.

- Marshall Gates has contriubed sample program source files for all of
  the language disk images.

- Randy Merkel provided the ZSDOS Programmer’s Manual as translated by
  Wayne Hortensius.

- Henk Berends added support for the MSX platform.

- Jay Cotton provided the SCSI transport code upon which the SCSI driver
  is based.

## Related Projects

Outside of the hardware platforms adapted to RomWBW, there are a variety
of projects that either target RomWBW specifically or provide a
RomWBW-specific variation. These efforts are greatly appreciated and are
listed below. Please contact the author if there are any other such
projects that are not listed.

#### Z88DK

Z88DK is a software powerful development kit for Z80 computers
supporting both C and assembly language. This kit now provides specific
library support for RomWBW HBIOS. The Z88DK project is hosted at
<https://github.com/z88dk/z88dk>.

#### Paleo Editor

Steve Garcia has created a Windows-hosted IDE that is tailored to
development of RomWBW. The project can be found at
<https://github.com/alloidian/PaleoEditor>.

#### Z80 fig-FORTH

Dimitri Theulings’ implementation of fig-FORTH for the Z80 has a
RomWBW-specific variant. The project is hosted at
<https://github.com/dimitrit/figforth>.

#### Assembly Language Programming for the RC2014 Zed

Bruce Hall has written a very nice document that describes how to
develop assembly language applications on RomWBW. It begins with the
setup and configuration of a new RC2014 Zed system running RomWBW. It
describes not only generic CP/M application development, but also RomWBW
HBIOS programming and bare metal programming. The latest copy of this
document is hosted at [http://w8bh.net/Assembly for
RC2014Z.pdf](http://w8bh.net/Assembly%20for%20RC2014Z.pdf).

# Licensing

## License Terms

RomWBW is free software: you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free
Software Foundation, either version 3 of the License, or (at your
option) any later version.

RomWBW is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
more details.

You should have received a copy of the GNU General Public License along
with RomWBW. If not, see <https://www.gnu.org/licenses/>.

Portions of RomWBW were created by, contributed by, or derived from the
work of others. It is believed that these works are being used in
accordance with the intentions and/or licensing of their creators.

If anyone feels their work is being used outside of its intended
licensing, please notify:

> Wayne Warthen  
> <wwarthen@gmail.com>

RomWBW is an aggregate work. It is composed of many individual,
standalone programs that are distributed as a whole to function as a
cohesive system. Each program may have its own licensing which may be
different from other programs within the aggregate.

In some cases, a single program (e.g., CP/M Operating System) is
composed of multiple components with different licenses. It is believed
that in all such cases the licenses are compatible with GPL version 3.

RomWBW encourages code contributions from others. Contributors may
assert their own copyright in their contributions by annotating the
contributed source code appropriately. Contributors are further
encouraged to submit their contributions via the RomWBW source code
control system to ensure their contributions are clearly documented.

All contributions to RomWBW are subject to this license.