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[OSHUG / OSSG] Machines and systems of past, present, future - 17/01/19

Happy new year folks,
To start off the year, we have a series of talks around the theme of
Acorn computers, RISC OS, RISC-V toolchain (preview of talks upcoming at
FOSDEM [1] [2]).

Meeting is on the 17th of January (18:30 to 21:00) at BCS London, 1st
Floor, The Davidson Building, 5 Southampton Street, London, WC2E 7HA.

Registration link:

1) Brief history of Unix-like operating systems on Acorn hardware

Stephen Borrill first encountered Unix while working for a PhD in
Psychoacoustics and as a long-term Acorn user, his Acorn RiscPC was his
hardware of choice to run it on.

While finishing his PhD, Stephen started a part-time job at Acorn
Computers working in technical support. This led to full-time employment
at Acorn and Xemplar (an Acorn and Apple joint venture focussed on UK
education) during which he developed products based on BSD Unix on Acorn
hardware which were sold nationally.

In 1999 he founded Precedence Technologies who took over support and
development of the products he worked on at Acorn and Xemplar. He
continues to with the products 20 years later.

2) RISC OS : What's Next
As of 2018, RISC OS is an open source operating system. This talk will
cover the heritage of RISC OS, direction it would like to go, the
response since it was open sourced as well as a demo of the latest
computers that run RISC OS.

Richard is a co-founder and director of RISC OS Developments Ltd. Since
its inception in April 2017, Richard has been a driving force in making
RISC OS truly open source; this was achieved with significant funding
and community support in November 2018.

Richard is also the sole director of GeneSys Developments Ltd, an IT
company, which additionally incorporates Orpheus Internet, an ISP company.

Despite not having a 'techie' background, Richard would end up assisting
or implementing IT solutions for the companies he worked for. Taking the
opportunity to further his technical knowledge and experience, Richard
went on to work in the IT industry and set up his own business in 1995.

In the early 80's, Richard spent some time in Canada. Here, he worked in
the camera industry where he acquired advanced skills in photography, a
love of which had been instilled in Richard as a young person by his
father and continues to be a key skill in his career to date.

3) Embedded FreeBSD on a five-core RISC-V processor using LLVM

We were tasked with bringing up and testing embedded FreeBSD on a custom
five-core 32/64-bit RISC-V processor using LLVM. Given FreeBSD has
already been ported to RISC-V and LLVM is the standard BSD C/C++
compiler surely this should be easy.

But it wasn't. LLVM for RISC-V is still relatively immature,
particularly for 64-bit. FreeBSD runs on symmetric multi-core 64-bit
QEMU RISC-V, but not on embedded systems and not on heterogeneous
multicore systems.

In this talk we'll go through the steps needed to bring up a functioning
embedded FreeBSD system on multi-core heterogeneous RISC-V system. Our
target hardware was not available at the start of the project, so we
used the generally available HiFive Freedom Unleashed board.  The result
is a reference embedded FreeBSD implementation for RISC-V, freely
available to the community.

This is not a talk about the deep internals of FreeBSD, but about the
practical engineering steps needed to bring up an embedded operating
system where many of the key components are not yet fully mature.

Jeremy Bennett is Chief Executive of Embecosm (, a
company developing open source compiler tool chains and porting embedded
operating systems for new architectures. He is author of the standard
text book "Introduction to Compiling Techniques" (McGraw-Hill 1990,
1995, 2003) and is an active member of the RISC-V Compliance Task Group.

4) Buildroot for RISC-V (Using Buildroot to create embedded Linux
systems for 64-bit RISC-V)

Buildroot is an embedded Linux build system that generates complete
system images from source for a wide range of boards and processors. I
have recently added support for 64-bit RISC-V to the official Buildroot
distribution which make it a viable alternative to other build systems
for RISC-V such as Yocto.

During this presentation I will give a brief overview of Buildroot and
how it compares to Yocto for those in the audience who are unfamiliar
with these systems. In the main part of the talk I will look at the
issues relating to the implementation of RISC-V support, based on my
experiences. This will include a look at the status of the RISC-V
software ecosystem with regard to the selection of a suitable toolchain,
C library, kernel and bootloader. I will then run through how to
configure and build a minimal system for booting under QEMU. Finally I
will consider any further work required to improve Buildroot for RISC-V
including the status of 32-bit support.

Mark Corbin is Embedded Operating Systems Lead at Embecosm
( He has an extensive background in embedded systems
development and has worked with Linux since 1996. He specialises in
building embedded Linux distributions and is currently the RISC-V
maintainer for the Buildroot project.



Sevan Janiyan

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