--- DiscoBSD 2.1 RELEASED ---

DiscoBSD 2.1 Released

August 31, 2023

DiscoBSD 2.1 is released.

This is the second official release of DiscoBSD, the multi-platform 2.11BSD-based operating system for microcontrollers.

DiscoBSD 2.1 offers ports to two different microcontroller platforms: * DiscoBSD/stm32 - STM32F4 family of 32-bit Arm Cortex-M4 microcontrollers from STMicroelectronics * DiscoBSD/pic32 - PIC32MX7 family of 32-bit MIPS32 M4K microcontrollers from Microchip

DiscoBSD/stm32, unique only to DiscoBSD, offers a familiar BSD environment on the many available STM32F4 development boards.

DiscoBSD/pic32, inherited from RetroBSD, offers a familiar BSD environment on the many available PIC32MX7 development boards, as well as full use with the included VirtualMIPS PIC32 simulator.

A nearly-complete development environment is included in DiscoBSD.

There are: various text editors and compilers, a MIPS assembler and MIPS linker, as well as many more programming languages in addition to C and asm, such as Scheme, BASIC, Forth, RetroForth, yacc, and TCL. Examples are provided in the file system at /usr/share/examples.

As a descendant of 2.11BSD, DiscoBSD inherits its strong BSD heritage. The userland is powerful, full-featured, and comfortable to competent UNIX users, as it is derived from the rich 4.3BSD-Tahoe userland and steady improvements along the way.

Install, build, and debug instructions can be found in the README files.

Significant Changes and Improvements

New Features

• libtcl 6.7 available through build system, mainly for tclsh(1).

Filesystem

Major overhaul of DiscoBSD's root filesystem. The root filesystem is now more in line with a 4.4BSD system than the 2.9BSD-style system inherited from RetroBSD.

Notable changes are: * The return of the /usr directory. * Separation of executables into /bin, /sbin, /usr/bin, /usr/sbin, /usr/libexec, and /usr/games, based on single user mode needs. * The creation of a user /home directory, on its own filesystem. * Both the root filesystem and user filesystem are 200 MB each.

Build System

Major overhaul of DiscoBSD's source tree and build system. * Both BSD make and GNU make are fully supported. * Non-portable features of GNU make and BSD make are replaced with portable alternatives. * The source tree follows a more 4.4BSD layout, with each executable having its own directory in the right hierarchy. * Build objects are now universally installed into ${DESTDIR}, default location is /distrib/obj/destdir.${MACHINE}. * /etc/Makefile target distrib-dirs builds the skeleton filesystem hierarchy in ${DESTDIR}. * Build tools install into ${TOOLBINDIR}, default location is the persistent /tools/bin directory. * Build outputs in ${DESTDIR} from different architectures can co-exist simultaneously. * Added ${HOST_CC} make variable for host compiler. * tools/aoututils for building a.out system libraries. * Kernels are now called unix, not unix.elf. * Consistent CFLAGS, AFLAGS, ASFLAGS, LIBS, LDLIBS. * Build system with -fcommon in ${CFLAGS}. * FreeBSD is now a host development environment.

DiscoBSD/stm32 Specific Improvements

• Implemented ARMv7-M fault trap handling.
• Dumps fault stack frame upon fault.
• Add MCU and revision IDs for STM32F407xx.
• Portable Makefiles for kernel builds.

DiscoBSD/pic32 Specific Improvements

• Portable Makefiles for kernel builds.

Bugfixes and Corrections

• Numerous K&R -> ANSI fixes.
• Newer compilers exposed many unsafe structures, and they were promptly remedied.
• Many updates concerning the hierarchy changes.
• Perform ranlib -t to touch libraries after installation.
• Steady improvements and corrections in games.
• Steady improvements and corrections in libraries.
• Manual page fixes and improvements.

Host Development Environment

While DiscoBSD is primarily developed and tested on OpenBSD, Linux and FreeBSD are also supported as host environments.

These host development environments have been tested:

OpenBSD 7.3

• Host compiler Clang 13.0.0
• BSD make and GNU make
• DiscoBSD/stm32
• arm-none-eabi-gcc 7.4.1
• DiscoBSD/pic32
• Custom port of mips-elf-gcc 4.8.1

OpenBSD 6.8

• Host compiler GCC 4.2.1
• Host compiler GCC 8.4.0
• Host compiler Clang 10.0.1
• BSD make and GNU make
• DiscoBSD/stm32
• arm-none-eabi-gcc 7.4.1
• DiscoBSD/pic32
• Custom port of mips-elf-gcc 4.8.1

Ubuntu 23.04

• Host compiler GCC 12.3.0
• Host compiler Clang 15.0.7
• BSD make and GNU make
• DiscoBSD/stm32
• arm-none-eabi-gcc 12.2.1
• arm-none-eabi-gcc 10.3
• DiscoBSD/pic32
• Untested

Ubuntu 18.04

• Host compiler GCC 9.2.1
• BSD make and GNU make
• DiscoBSD/stm32
• arm-none-eabi-gcc 7.3.1
• DiscoBSD/pic32
• Custom compilation of mips-elf-gcc 4.8.1

FreeBSD 13.2

• Host compiler Clang 14.0.5
• DiscoBSD/stm32
• arm-none-eabi-gcc 10.3.1
• DiscoBSD/pic32
• Untested

Developers and Contributors

• @chettrick
• @lhondareyte
• @saper
• @omarandlorraine
• @amarkee