peteg's blog

/noise/beach/2009-2010 | Link

Making a habit of these morning snorkels, I headed down to Gordons Bay around 9am. The surf was a bit rough so I went westwards into the bay where I found loads of immature blue gropers. There were also some quite long things that looked like garfish but were swimming at depth, and heaps of the usual species. The water remains comfortable, the day is sunny and the wind mild. Visibility was only fair between the whitewater and plant litter. Getting out was more work than I wanted it to be.

We have real time.

/hacking/nixie_clock | Link

Finally I have managed to get a real-time Linux kernel running on the ts7250, resulting in a flicker-free display. Score one to patience.

Briefly, the Linux RT blokes skipped 2.6.32.x as the kernel's concurrency foundations got a reworking. They released an RT patch against, and as ynezz has forward-ported the ts72xx patches it was a cinch to move to the bleeding edge. YAFFS (a flash filesystem) broke as it uses some old-school mutexery. Grossly updating it all to the struct mutex way of doing things is straightforward and seems to work.

Hacking the clock driver code is trickier now though, as the process runs at the maximum real-time priority. If it loops without making syscalls, the system dies.