Saturday, October 07, 2006
I love Free Software. Like many free software developers, I'm rather concerned about the recent debates regarding the role of trademarks and free software. Just five years ago, the idea that trademarks would be a problem with free software was almost laughable. With high profile projects like Firefox developing questionable trademarking policies, the question of how trademarks affect free software is becoming very important. As I write this, there's a heated debate within the Xen community over XenSource's new trademark terms specifically regarding the Xen trademark. Suffice to say, that the terms concern RedHat enough that they've announced that they're considering renaming Xen to CNH, or Common Neutral Hypervisor. They appear to be concerned that they can not live up to the trademarking terms. Personally, I'm not in a position to comment about the new trademark policy. I try to keep my nose clean of this sort of thing. However, it's times like this that I realize how important the GPL is in defining what free software is and how lost we would be without it (or at least, how much arguing there would be). I wonder if there's enough room in the GPLv3 process to introduce trademark terms...
Tuesday, October 03, 2006
Optimizing VNC for localhost
I've got some free time now and have been thinking recently about revisiting QEMU GUI support. Previously, I had a set of patches that implemented a shared memory transport for QEMU's graphic interface. The first change I wanted to make to my old patches, was to use a TCP transport instead of QEMU's char device interface. I quickly realized though that there would be a lot of shared code between this new transport and the VNC transport. At this point, I started thinking about what it would take to add a shared memory transport to VNC. Conceptionally, all this would require is a new encoding type that can send back a shared memory ID. The client would have to send a little more than just a SetPixelFormat though since the bytes-per-line is also needed. What this would allow though, is for the server to allocate a shared memory segment, hand that info over to the client, and the client could then hand that over to the X server. This would have fantastic performance on the localhost case. Reusing the VNC protocol means a much simpler client. I sent off a note to the VNC folks asking to reserve a pseudo-encoding range. Once I get a response, I should be able to hack something up fairly soon.