On 06/24/2015 11:26 AM, Piotr Kubaj wrote:
Hi all,
I'm mainly a FreeBSD user but want to learn OpenBSD. I'm also interested
in basic electronics, like programming own thermometer. That's why I
want to install OpenBSD on my BeagleBone Black and write some simple
programs using I/O pins. Are there any tutorials on this? I have found
some books about FreeBSD kernel programming, but none for OpenBSD.
Thanks for your help.
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For programming I/O pins there is probably a driver already
written. User processes could do what you want.
If you want to write a parallel pin driver, a general familiarity with
kernel concepts is probably enough. Then copy something like the
lpt driver.
The McKusick books are a reasonable introduction to the kernel
as it was some decades ago. The concepts haven't changed.
The System V book also.
General familiarity with concepts like address spaces, interrupts,
process contexts, memory management, etc. helps a lot.
Once you have that basis reading the man pages and the code
is a lot easier.
FreeBSD and OpenBSD have diverged but not so far as to make
the conceptual bases incompatible.
Linux went its own way from the beginning and it isn't close to BSD.
Geoff Steckel
