Kevin Boone's website

This is a landing page for my various articles on building a period-appropriate CP/M system using the RC2014 bus.

Using an RC2014-based retrocomputer with genuine RS232 peripherals requires support for voltage level conversion.

The Pronto offers a salutary lesson in how an excellent product can die, leaving a gaping hole in the market that nobody wants to fill.

The Cowon D2 DAB was a media player ahead of its time.

A landing page for my various CP/M articles and utilities.

Shared subscriptions are a 'new' feature in JMS, that seems to be poorly understood, particularly in a clustered environment.

No 80s computer is complete without the chucka-chucka-chucka sound of a floppy disk drive doing its thing.

The Pi Pico is an impressive microcontroller for its size and cost, but it lacks specific non-volatile memory.

An 80's-style 8-bit computer has to be cable of making 80's 8-bit sound.

A step-by-step guide to building and installing a modified version of the RomWBW firmware on a CP/M Z80 board.

This article describes a couple of methods for sharing data and code between a CP/M system with RomWBW BIOS and a Linux system.

Constructing and programming a real-time clock board for my Z80 CP/M system

Because -- why not?

CP/M only recognized four serial devices.

CP/M has no timing or delay functions, because CP/M never stipulated that compatible hardware have any kind of clock.

Is it really possible to design an operating system for a computer built from scavenged parts after civilization has failed?

Using the 1989 HI-TECH C compiler on CP/M, and some general observations about CP/M programming with real hardware.

This article continues my explanation of using Keycloak as an authentication provider for Apache Artemis, by showing how to use a bearer token to authenticate a JMS client.

This article describes how to create a self-contained CP/M-based microcomputer using a Z80 single-board computer, a Raspberry Pi Zero, and some assorted electrical parts.

The Raspberry Pi is widely used as part of a more complex electronic project or construction.

This article is the second on my series on using the Oracle database as the message data store for the Apache Artemis message broker.

This article describes the fundamentals of setting up the Apache Artemis message broker to use an Oracle database as the message data store.

AMQP is not a trivially-straightforward protocol to understand, but it's necessary to get to grips with it to write effective software that uses the Qpid Proton AMQP library.

Most image editing applications provide a 'saturation' adjustment; some provide adjustments of 'brilliance', 'chroma', and other things.

Darktable isn't supposed to be an alternative to Adobe Lightroom, but many people hope to use it as one.

Mapping keyboard keys to key codes on Linux is well-documented for the graphical desktop.

This article continues my original framebuffer "just the essentials" article, by describing how to handle less straightforward framebuffer configurations.

The absolute minimum information needed to start using the Linux framebuffer as a graphical display in C/C++ applications.

This article describes how to construct a desktop photo clock using a Raspberry Pi Pico and some solder-free peripherals.

The Maxim DS3231 I2C real-time clock is a reasonably accurate, inexpensive device, that is easy to interface to the Raspberry Pi Pico.

This article describes how to generate and use compressed, anti-aliased font data, for use in a microcontroller application.

I've been using the Raspberry Pi Pico for embedded projects for the last two years or so.

This is a versatile touchscreen display module with a strikingly low cost.

An oddity of the GCC C compiler that can lead to strange results, particularly in an embedded application

This is the second of (at least) two articles on loading and running arbitrary executable code into RAM on the Pico, and running it.

The Pi Pico has USB host support, and can work with a USB keyboard.

This article provides a brief overview of the rdkafka library, illustrated by a simple test application in C.

Administrators of middleware message brokers often struggle to get adequate throughput.

A mains inverter is a very useful device, but inexpensive models create significant electrical safety hazards.

Using a Camel application based on Quarkus to provide a way to route messages to and from a message broker using HTTP requests

Implementing a webservice in C and Java, to see which performs better in terms of throughput and resource usage.

The use of dithering when mastering a CD is well-established, and its effectiveness is rarely challenged.

The Raspberry Pi doesn't offer much in the way of analog outputs, or even hardware controlled PWM.

In this article I explain how to construct, and program in C, an I2C interface to the popular HD44780 LCD display for the Raspberry Pi.

Many battery-backed power supplies for the Raspberry Pi, and similar systems, use the INA219 current/voltage monitor IC.

The HC-SR04 proximity sensor is an inexpensive and widely-used ultrasonic device.

A simple and inexpensive shift register can be used to increase the digital output provision of a Raspberry Pi or microcontroller.

Misrepresentations of scale are common in the literature of organizations that seek to deceive.

It's common for hifi amplifiers and speakers to have a power rating expressed in terms of "RMS watts".

The calculus of variations is a branch of mathematics that deals with finding functions that optimize systems.