DTrace: My first bug…

Well I’ve not blogged that much recently. However, I’ve been pretty busy and I’ve got quite a lot to blog about. So, I suppose the best place to start would be the middle of last week…

On Wednesday or Thursday last week (I forget exactly) Kim Austin who runs the Campus Ambassador program for Sun informed me that she would (officially now) be taking me on as the Aberystwyth University Campus Ambassador when Chris Talbot leaves at the end of this academic year. I had for some time been a shoe in for the job, however it is now official which is excellent.

At the same time as this Kim also introduced the other interns and myself to the SAI (Sun Academic Initiative) website. This is a excellent website that offers pretty much all of Sun’s courses (except it seems Solaris Internals) for free to students. If you’re a student, specifically a Computer Science (or perhaps Physics/Maths) student, I really recommend you get yourself over to http://www.sun.com/solutions/landing/industry/education/sai/index.xml and register. If your university isn’t already registered they can do, for free! All you need to do is get a professor to register here.

So, what else has happened. Well on Friday we took down our x86 Sunray server, eagain (all our Sunray servers are named after Unix error codes), to replace it with a Huron. ‘Huron’ is the internal code name for the new T5120/T5220 systems Sun sell based on the Niagara 2 chip. These machines are truly amazing - in a 2U rack you get 32 Thread engines (64 total threads) and 64GBs of RAM… This makes the Gnome system monitor a sight to behold…

The funny thing is the way it sort of gives up choosing colours after 4 CPUs…

As most of you will know I’ve recently been given the opportunity to do some work on DTrace, initially just fixing a few bugs and doing some RFEs (Request for Enhancements). Well a number of things have happened since I had my first meeting.

First, Robin (my house mate who thinks that this whole blog is centered round him) has decided to port MouthOS to SPARC. This has proven to be most interesting for both him and myself. Whilst we’ve still not even managed to get characters on the screen we’ve both learned an awful lot about the way that OBP works and how SPARC boots and functions. I have to admit that I’ve been truly amazed at what OBP provides you out of the box compared to x86. OBP defines a number of amazingly useful functions (such as putchar() and printf() etc) so that your boot loader/OS can just call them directly. It also has great debugging utilities built in to the point where you can literally set break points in your OS and then print CPU registers and all sorts of things. All this and it will even give you a nice tree structure with all the hardware devices in the system.

Apart from getting slightly side tracked you may be wondering what this has got to do with DTrace. The simple answer is not much other than this has now meant that Robin will also be doing some Solaris Kernel work - specifically with ‘newboot’ which is designed to allow Solaris (SPARC) to boot ZFS file systems. I’ve no idea when it’s planed to be released or what state the project is at - but I would like to wish Robin good luck with his future Solaris development work, and I also think that another thank you to Paul and also Tim Graves is in order, not to mention Chris Beal who has agreed to be Robins’ mentor.

Anyway, moving on a bit… In regards to my work on DTrace. Apart from endless hours of reading the source code (which I have to admit is the most well commented code I’ve ever seen) yesterday I finally chose my first bug - http://bugs.opensolaris.org/view_bug.do?bug_id=6287021.

It doesn’t look to be a particularly complex or important bug - but it’s a great place to get started with the development as it will require quite a bit of investigation first in order to produce a test case. With a test case I can then start to identify where the error is happening in the code and I can then implement the fix.

I think that pretty much sums up what I’ve been up to recently. This weekend I’m off home again for Mothers Day and my sisters birthday. I’ve booked a couple of days off work (Monday to Wednesday) to have a look around for a new car also, so with any luck I shall hopefully be returning to Farnborough with a car! I’ve seen a couple of Mondeos and a Vectra at a place called Robert Car Sales (about an hour drive from home) - I can’t wait as it’s been so long since I had a car now.

Talking of cars, Matt (another intern at Sun, and friend) had quite a nasty crash the other day on the M1. Some truck driver basically pulled out of the slow lane into the middle lane - into him. His car rolled all the way onto the hard shoulder. Fortunately (bar a cut on his arm) he’s alright - though his car is a write off I have given him some advice from when I had my crash so at the very least he’ll know what to expect from the Police, insurance etc. The only problem is the truck driver just drove off and no one seems to have got his number plate!! From the sounds of it he’s going to get off scott free as the CCTV was also down due to road works!

I think that’s everything for now, so until my next exciting installment!

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