Arnt Gulbrandsen
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2012-01-23

Regarding recent developments at Trolltech

Nokia's rampage makes me want to post the picture below.

It's from a very rainy Friday in September 2000. I had a meeting around noon that day. Directly afterwards, I went for a weekend in the mountains with two friends, and I felt just like that.

About an hour after the picture was taken, over dinner, I explained my mood. Unless things change, I expect I'll leave in a few months. My forecast was good, I gave notice four months later, ten minutes after another depressing meeting.

A minor security bug in Ubuntu

This has two parts.

First, sudo, which ubuntu encourages using rather than su. Sudo can be set up to allow users to do just some things as root rather than everything, by editing the file /etc/sudoers.

Second, various Ubuntu programs that run as root. Some expect that the user's $PATH starts with /sbin and /usr/sbin, and run programs without specifying the complete file name.

If a user has limited sudoers privileges, then various Ubuntu-supplied programs can often be tricked into granting the user complete root access.

For example, sudo apt-get install firefox will run either ldconfig or start-stop-daemon (I forget). Not every package has this problem, but many enough to make it a FAQ.

I feel sure that whoever reports this will be told by the sudoers maintainers that the problem is with e.g. apt-get, and by the apt-get people that the problem is with sudoers. Both are reasonable responses, but I'd rather write code than argue. So all I'll do is publish this.

2012-01-10

No mail today

I am reminded of the Inmos Transputer.

That, as my older readers may still vaguely remember, was a freak processor in the eighties. It was designed for parallelism: Its fundamental design was for a computer with many transputers, not one with a single humongous blob. Each CPU was small, simple (the wikipedia page includes the complete instruction set) and linked to four other CPUs using bidirectional message-passing connections, and the design allowed vast CPU meshes with message routing and forwarding.

The thing that reminds me of the transputer is the way those links worked. When a Transputer received a message that had to be forwarded, it would prioritise communication over its own computation.

I am reminded of this because my mail is down. A great big failure happened during Christmas vacation. Then a routing mishap left me unable to take part in a video conference this morning. I am forced to prioritise my own programming over message passing, and it feels so good. Yesterday was great.

Tomorrow I shall apologise to borud about my unresponsiveness. But today, I plan to wallow in solitary hacking.

Actually I'll wait a few hours with publishing this. There's a chance someone might see it.

2012-01-09

Marcato Atlas 150 manual

The Marcato 150 is a fine pasta maker whose manual is small enough that we lost it within five minutes of it entering our kitchen for the first time. Oops. We found it later, nestling within the pages of a cookbook, but not before discovering that where can I download a Marcato 150/180/Atlas manual? is a bit of a FAQ.

Below are the most important paragraphs. If you'd prefer to have the complete manual (containing more text, a dough recipe, lots of pictures, etc), have a look at the Marcato FAQ. (more…)