Frankencode

Help needed

There was some discussion this week on desktop-devel about turning ‘Assistive technologies’ on by default in Gnome. See Willie Walkers original e-mail.  Rob Taylor and I had discussed this previously, and at the time I didn’t have much of an opinion either way. After reading Willie’s e-mail though I was firmly in favor.

However Willie stumbled across a possible performance problem when accessibility is turned on. Using gtk-demo to test memory usage ‘top’ shows that accessibility can increase the ‘DATA’ memory section by 15mb, or over double the memory consumption. This was pretty shocking to me, so I tried to use massif to find the cause.

Thing is, massif reports that the memory allocation is not greatly increased by turning accessibility on.  The maximum stack size is not increased either. The ‘DATA’ field of ‘top’ apparently reports the DRS, or data resident set. The number of pages used by both the stack and heap. Rob suggested that fragmentation could be the problem, but in general I’m pretty stumped as to what is causing the discrepancy.

Help and suggestions greatly appreciated

Conduit conversations

We have John Carr in the office now. (Infact he’s been there more than Rob and I this week.) This means lots of conduit discussions. I was treated to a crash course on Conduit internals that left my brain feeling like a squeezed sponge, wrung cloth, and juiced orange all at once. This syncing thing is terribly hard and John has some difficult use cases that he wants to make work. (Tranferring contacts from his laptop go to GMail, and from GMail to the N810 and from that to his laptop. Whew.) Good luck to him. I think its the ‘Brain the size of texas’ award if he manages it.

The rest of the week…

Rob probably can’t blog to tell you this because he is gibbering somewhere in the corner muttering “Reference, Reference, where art thou?”. He’s been debugging lifecycle issues for a fortnight now. Its left us vowing never to touch ‘C’ again whenever humanly possible. (Which is not very often).

I have been working hard on the D-Bus version of pyatspi. Its going much slower than hoped, but i’ll get there in the end. I have a holiday coming this week, a trip to Finland for a friends wedding. I’m really looking forward to it. Were going to have a week of saunas in Lapland.

I had the pleasure of attending my first GUADEC last week. I doubt I’ll have a more enjoyable, tiring, embarrassing, or geek-filled time for the rest of the year.

I started the week locked up in my hotel room. Rob Taylor, John Carr and I were desperately trying to finish a demo that did not make it. Our trips out until Tuesday were mostly visiting restaurants, which would have been enough for me. Lamb Kebab and rice is just about my perfect meal, and during my entire stay in Istanbul I ate like a very happy king.

Once I got myself set up at the conference things got even better, there were some great talks. ‘UXD? WTF!‘ by Leisa Reichelt, ‘Introduction to the desktop data model‘ by Owen Taylor and ‘Syncronization and the GNOME deskop‘ by John Stowers all had me thinking.  It was a real shame that more people didn’t turn up to ‘Accessibility happenings in Novell‘, although it was the very last talk of the conference. Rob and I did a talk, ‘Wizbit a distributed revisioning file system‘, on Thursday morning. It was well attended, and I had a good time speaking.

The whole thing was smaller, and far friendlier, than I had expected. I was fortunate enough to meet Stormy just before, and soon after she had been announced as the GNOME executive director. She was just as lovely to me both times, so I assume power didn’t corrupt too much. Thanks to everyone I met for creating a thousand interesting conversations.

I can’t properly express my thanks to the people in Istanbul. They were incredibly helpful, patient and friendly. Even the ‘flexible prices’ that everyone seemed to experience only got bad when it came to taxis and drinks.  Thanks to Ali Sukru Goksu for his organization, and for showing us a great night out on Thursday. The conduit team and I went to an electronica festival on Friday night, which we never would have made it to without being looked after. Thanks Tuçe, Thanks Elvin.

The party prize and the most ‘flexible’ price prize go to John Stowers, for his 5-in-a-row 6am parties and for a certain vodka red bull.

I’ve come back really enthused about GNOME, about the people and the technology. Hopefully I’ll be able to put that enthusiasm to good use over the next year. See you all in Gran Canaria.

During work on client bindings for AT-SPI this week python managed to surprise me in a couple of ways.

1. Lambda doesn’t work as I think it should.

   lambda x: del(x) results in a syntax error. This is clearly stated in the python language reference: lambda_form ::= "lambda" [parameter_list]: expression The del statement is not an expression; unsurprisingly its a statement. Its still pretty non-intuitive.

2. You cant weak reference a weak reference.

   This must be an implementation issue. I’m sure a weak reference of a weak reference makes sense. It did to me at the time!

3. __slots__ is the most useful thing in the world.

   Just take a look at this graph. Its the results of a totally scientific, completely well researched, test into the size of different structures in python. They are all holding roughly the same amount of information.

   

   Structure Type	Memory use (kB)
   Slot Object	18988
   Tuple	19252
   List	19476
   Dict	42768
   Object	44320

Hopefully everyone already knows that Debian & Ubuntu have let us all down over the past two years by shipping a woefully insecure OpenSSL package. Personally its destroyed a-lot of faith that I had in the Ubuntu operating system.

Most of us, who arn’t deeply involved in our OS, have to simply trust in the processes and people putting it together. I’m no exception. Before this happened I had no real understanding of the packaging / development process for Ubuntu, and no great interest in it either. More fool me. This one security breach has left me scrambling to find out what went wrong.

 Fixing the cause

This one isn’t going to go away because the fix has been shipped. There is still a serious flaw in the Ubuntu and Debian development process that I’m hopeful the developers are working this out on the mailing lists / irc right now.

Erich Schubert had to say about the maintainer who made the mistake ” But you bet he’s going to be a lot more careful with any change in the future: he has learned his lesson”. I’m sure he has, but as Erich mentioned shortly after , lots of other maintainers won’t. Nor is there going to be a massive increase in the code quality of upstream software, even for security-sensitive things like OpenSSL. Badly commented software and miscommunications are facts of life, what Ubuntu needs is processes that catch these mistakes in a little less time than 2 years.

 Regaining my trust (and perhaps others too)

I’m fairly sure that things are taking place to make sure this doesn’t happen again. But, like so many institutions, Ubuntu can’t just do right on this one. It has to be seen to do right. The solutions that they come up with must be timely, and extremely public. There are a huge amount of people and companies that use Debian & Ubuntu. Not all of them have time to trawl mailing lists and blogs. Its a biggie, If Canonical don’t start talking loudly about this its a real incentive to move to a different distribution.

Work is starting on the port of the AT-SPI framework to D-Bus. Codethink are, graciously, being funded by Nokia to undertake the work. Mike Gorse is working on the project full time, as part of his work for Novell.

Mike has got alot done and there are some initial D-Bus specifications, as well as alot of code on the ATK to AT-SPI adapter side. For the moment we’ll both be working in a git repository on Codethink. Hopefully we will be able to move the code into a repository on freedesktop one day.

The AT-SPI D-Bus work is important as it is attempting to eliminate the last vestiges of CORBA from Gnome and at the same time help with cross desktop accessibility. I’m hopeful that despite the transition we will be able to create a flexible and performant D-Bus protocol for AT-SPI.

I’ve written before about our results on D-Bus vs CORBA performance, done in preparation for this project. The results were a bit shocking for the D-Bus team so there need to be some significant changes to the IPC for things to remain snappy.

history|awk ‘{a[$2]++ } END{for(i in a){print a[i] ” ” i}}’|sort -rn|head
118 ls
104 vim
72 cd
67 make
14 rm
12 ./test-directory
11 git
10 ./mjpass
9 gvfs-mount
9 cp

It seems that the posts by Mikkel and Daniel were April fools jokes. My sense of humor was broken by about midday so I missed the gag. Next year I will avoid the internet all together on the 1st of April.

A few years ago I had an unpleasant experience with the police over here in the UK. My mum was contacted about a car accident that had taken place in the car park of a fabric store. She had no idea what had taken place, apparently a car had been damaged while someone was maneuvering. My mother’s number plate had been taken and she was going to be charged. The whole thing was utterly overblown, and she was never convicted. (For anyone’s reference, you apparently can’t be charged for most motoring offenses if they take place on private property.)

My part in the affair was accompanying my Mum to the police station for questioning. When we got there she was fingerprinted, had her DNA taken, and was questioned somewhat aggressively by two police officers. (Remember this is for possibly scratching a car in a car park).

I was so mad at myself for a long time afterward. The police were taking advantage of us because it was new and unexpected. What happened to Mikkel and Daniel, who were contacted unannounced by legal representatives of Apple, sounded like something similarly abusive, and bought back some of the anger.

Its a mess

I’ve been worried recently about how secure I am online. There has been a huge amount of news coverage over here in the UK about personal digital security. As someone who works as a software engineer, I always feel slightly smug when such stories are reported.

I really shouldn’t have done. On spending time looking at where account were held:

31 separate logins.

3 passwords used.

4 sites I could no longer log in to.

Although I had tried to separate out junk and secure passwords, there were some relatively insecure sites using the same password as places that had access to financial details. All in all, very insecure and a complete mess.

What can be done

As time goes by I think this situation may just get worse unless websites wise up. I felt much better about the e-commerce sites I had been to that offered paypal payment methods, or simply payment without having to open up an account. OpenID certainly has a role to play, although seems pretty flawed without some improvements in the phishing situation.

Until then I’ll have to spend the time, dull time, organizing my digital identity. As will everyone else.

I’ve taken part in a couple of phone calls this week, a quick conversation with Michael Meeks and a conference call with the open a11y group. Both about AT-SPI D-bus. There was a week of silence after my initial e-mail to lots of accessibility lists, and after that something of a storm. It was good to actually hear everyones opinion, I think people care, and AT-SPI D-Bus will probably happen sooner rather than later.

Thats pretty good news as Rob and I have spent LOTS of time discussing this one, with some of it being rather heated. Its all about “standardising” the AT-SPI interface, what constitutes a “component” system, and whether accessibility really needs object lifecycle management. Could anyone really have raised voices in a conversation about that?

I’m going to put together our thoughts / proposals for everyone to go through. (With heavy input / modification from Rob Taylor) Hopefully it will be up to scratch.