Rentzsch on Core Audio: The API of Rock Stars

It was the second and final day of the NSConference 2010 Mac Developer Conference and most delegates were tired and a little hungover. But there was another great line up of speakers for the day, and it was another day of socialising and fun, as well as all that other learning stuff.

Perhaps the biggest things I took away from the Mac conference was taking a pragmatic approach to anything which became a recurring theme in a lot of the talks – like yesterday’s conference, extremes were presented such as Dave on not using singletons, but at the end of the day it’s a judgement call and you shouldn’t do or not do something ‘because Dave said it’, but rather because it’s either right or not right for what you want to do. There was also some recurring memes, such as The Matrix and kitties, which snuck their way into certain presenters’ talks, but most of all, I learnt that people can be (fairly) civil when discussing version control, and also that the GPL sucks.

Jeff LaMarche – Writing Super Superclasses

Jeff was still jetlagged and tired, and made several comments as such throughout his talk. However, despite this, his talk on the Objective-C runtime was very interesting and informative to listen to. He started the talk off with a cliché – ‘you can’t see the forest through the trees’ – and likened this to software development. As developers we are often too pedantic and only focus on the little things, but we also need to be able to step back and look at our projects as a whole on a larger scale.

He then went into the guts of his talk, talking about such things as dynamic method resolution and introspection at a lower level. He introduced Objective-C as different from other languages in terms of the patterns used and also touched on a criticism by others that it is missing things, however this is by design and not simply an oversight.

He then started talking about his SQLitePersistentObjects project which leverages the Objective-C runtime in several ways, and then demonstrated some of these features such as dynamic method resolution using IMPs and was well explained with the associated pros and cons of using certain runtime features. Like many of the other talks, he explained the limitations of using the runtime, for example Apple may not approve apps for the App store that use it, and also to be pragmatic about its use and not simply use it because you can.

Andy Finnell – Brushing up on OpenCL

I’ll be honest, after listening to Andy’s talk, I felt stupid. And I think there were other attendees around the room who were in a similar boat. He opened up with a demo, which was a great start to his talk, a demo which simulated the effect of watercolours on a canvas, and leveraged OpenCL to provide the graphics and calculate the drawing of the pigment and the interaction with the surface.

Although the maths and physics was way above me (and wasn’t helped by lack of sleep) it was still an informative and interesting talk, and I liked the structure of the presentation – cool demo at the beginning which made you interested then the rest of the time spent explaining how it all worked.

Andy also opened with a short intro on OpenCL and how it operated which was nice for those who hadn’t been at Drew’s Concurrency workshop on Sunday, however it would have been nice for this section to be expanded a bit, with less of a focus on the mechanics of the demo.

The presentation was also entertaining with accommodation for British spellings (“watercolo(u)r”) which is always a nice touch and other comical remarks and slides which helped a bit when it came to digesting the hardcore code samples. The coding side was also a nice contrast from the higher-level talks that were presented over both days of the Mac conference which also made it a useful and informative talk.

Dave Dribin – Version Control System Shoot Out

[Apologies for not having an accompanying photo]

Dave’s talk was all about version control and mostly a history or comparison of the different VCS’s out there. There was a feeling before the talk that it could go horribly wrong but Dave kept it pretty objective and didn’t particularly favour any of the VCS’s.

He presented the history of version control systems first, with SCCS, RCS, CVS, SVN and other systems that use similar acronyms, before moving onto distributed version control with Git, Mercurial and Bazaar, quoting Linus’s talk where he explained the naming for Git: ‘I’m an egotistical bastard and I name all my products after myself, first Linux and now Git’. With all the version control systems he presented the pros and cons, and only discredited Git slightly. Overall a pretty well rounded talk for the allotted time of about 35 mins.

Graham Lee – Code Signing

Graham had been given the opportunity to present at very short notice, and it was very well executed. It was astounding the quality and detail of his talk despite the little preparation time that he had, and he had a great presentation style which was very entertaining. He also included lots of puns and other fun comments, such as a reference to a hypothetical harmful piece of injected code which he called Malicious Monster and also referenced as Malicious Library. For those who didn’t attend, the reference to the Matrix had become kind of a meme by this point and even though Graham had prepared his presentation in about 24 hours he still managed to fit it in.

He also did a live demo which was very useful and demonstrated some of the code signing in action; he also anticipated our needs well by cutting a few minutes short in aid of food. Overall a brilliant, informative presentation.

Aaron Hillegass – The Many Faces of Data Persistence

Aaron’s talk was – as you probably guessed – focused on data persistence and the what the options are on Mac OS X. He started off by stating ‘The file is dead’ and explaining how his HDD is essentially a cache for data that is stored in the Cloud, which prompted him to comment ‘Long live the cache!’. He used the example of iWork on the iPad in that it uses a “Library” to store files which is essentially an abstraction for the filesystem and that this is the way forward.

He then went on to talk about archiving in Cocoa and Cocoa Touch, discussing Keyed vs Unkeyed archiving and the associated pros and cons. He also presented a timeline of events in terms of data persistence, from the early 90’s with NeXT right up until Core Data in 2005. He presented some nicely formatted object graphs of some of the Core Data things which was also useful.

He spent most of the second half of the presentation talking about his new data persistence project, BNRPersistence, which provides classes that wrap Tokyo Cabinet which is used to store the data, which received much applause from everyone when he announced that it was open-source, available on GitHub, and not licensed under the GPL. It was certainly an interesting project and he had some numbers for certain cases compared to Core Data and it performed much faster. But he was dealing with object graphs that had 1K and 1M objects and for “everyday” use with smaller objects it was unclear whether BNRPersistence would be better than Core Data because he didn’t have any figures on it.

What I liked about Aaron’s talk which I don’t think any of the other speakers did was that he was more engaging with everyone whilst he was talking – his style was like a lecture, but he periodically checked that we were all following everything, something which I guess comes from the teaching which he does, and was a nice touch.

Cocoa Rumble

The rest of the allotted time had been reserved for something different, in the form of a “Cocoa Rumble”. Earlier in the day, Scotty had announced that people could put their names in a hat to be chosen for this mystery event. Names were picked out of this hat and each person chosen was assigned a speaker from the conference.

The combined speakers and delegates were then split up into three groups and had to pick from the hat which now contained another set of slips of paper, which had written on them different “Core–” frameworks. The three chosen were Core Text, Core Audio and Core Image, and the teams had some time to prepare a presentation for why their framework was the “Core of the Year”. All presentations were very entertaining, with talks from Mike, Wolf and Graham and at the end, Core Image (presented by Graham) won for the compelling reasons that he had put into a table.

Whilst the teams were preparing, there was also a chance for the speakers and some of the delegates to provide tips, and there were some great tips from such people as Uli who provided a load of cool Xcode tips, Aaron on having the old Xcode documentation browsing behaviour, and Jeff on conditional build settings.

A nice fun end to the day, with something different and all in the community and social spirit.

Final thoughts

It was my last day of NSConference and what a brilliant conference it had been, with Matt Gemmell’s workshop on Sunday and the Mac developer conference too. It was great to socialise with loads of Mac developers who were all really friendly and I entered into some interesting discussions, and I took a great deal away from the conference which was something that Scotty laid out as one of the goals at the beginning.

I would like to thank Scotty, Tim, Dave, Rob, Simon and all the other people who made NSConference possible, because it was a great experience indeed, and to all the great people that I met there. Thanks also to Uli for setting up the NSConference Reflector.

It was the first day of the NSConference 2010 Mac developer conference and a great lineup was ahead.

In terms of the day generally, it was a brilliant experience. It was well organised and many thanks go to Scotty, Tim, Dave and all the other NSConference staff. The WiFi (although irritating that you had to keep filling out the signup form) worked quite well and you could get some pretty good speeds, which was good considering that the room was filled with over 100 developers, almost all of which I imagine had a Mac or iPhone for most of the day.

It was also a great social event, and the breaks were a nice chance to go around and talk to someone you’d never met before and have some interesting discussions. It was also nice to be in this tight community, separated from all the “normal” people who were also around at the venue.

In terms of the talks generally, I felt that they were all very well done and it was clear that they had put a lot of work into them. The presentations were very well laid out and simple, and not wordy and the speakers all obviously knew what they were talking about and had lots of interesting things to say. However one big thing that I felt could be improved on was the interaction with the audience – that is, many of the slides were in more of a lecture-style and although a couple made up for this with a Q&A at the end I thought this could be improved upon.

The Speakers

Scotty

Scotty kicked off the morning with a nice introduction to the conference, welcoming everyone and thanking us all for being here. He presented his recent case of being rushed into hospital for a “routine” operation as a metaphor for what we’re doing here, and he explained how even though he has little knowledge of the detailed ins and outs of the medical profession, he had a respect for them due to the reputation that the collective members have earned over the years. This was related to Mac development and our collective ‘responsibility to the platform’ and what we do, and the expectations of the Mac or iPhone platforms which is ultimately our responsibility. He also talked about how there is pioneering but also sharing of ideas in the medical profession and again linked this to our role in the Mac/iPhone/iPad community.

He also went on to talk about the community spirit, and emphasised that all the speakers had given up their own time (and money) to be here which because of this, and was a nice to start the day.

Mike Lee – Conference Keynote: Engineering Life

Mike’s presentation was evidently something slightly different and original to start the day but was a nice sideline to our ability to crank code, and was more thinking at a higher level about what we do, and perhaps being a bit more philosophical about it. He was relating what we do and our profession to life in general, and how we can ‘engineer life’. He defined problems as ‘reality we do not like’ which was a topical tie-in with software development since problem solving is one of the key aspects to what we do.

Mike also used several anecodes during his presentation which brought in a realistic sense rather than something purely theoretical, reality which is often missed when talking about software and software development, with purely theoretical statements. He also likened the Universe to a computer in that both are simply entities which are constantly changing state.

The next part of the talk became perhaps a little morbid with discussion on ‘Death 101′ with the conclusion that ‘death sucks’ but you can’t really do anything about it and you’ll be dead in the ground so won’t care about it anyway. However he also likened this to fear and how you can engineer your way around fear and tackle it head-on rather than let it get the better of you. He also talked about having a legacy and a part of you that lives on when you die by accomplishing something that you are remembered for, which can perhaps give you a kind of immortality.

He finished on the note of ‘be the hero’, and overall the talk was an interesting and somewhat unusual. I heard later on that there was about a 50/50 split on people who liked/disliked the presentation but I thought it was an interesting, though-provoking topic and good to be a part of.

Wolf Rentzsch – Spelunking OS X

Wolf started with the statement that he had ‘90 slides in 60 minutes’ and it was pretty fast-paced, although for the most part fine to follow. He dug into Mac OS X under the hood and ways you can access this information and interact with it, introducing such tools as otx, otool and class-dump.

The low-level nature of his talk was a great contrast to Mike’s previous talk which was a demonstration of the breadth of talks within NSConference and was more of a code and tool-based talk. He introduced hexadecimal editors such as HexFiend, which ‘are your friend’, then went on to deal with different sections with prying into OS X internals such as static analysis with strings and files, and code injection.

The great part of presenting these tools was the accompanying screenshots of a terminal and the associated output, and also examples of useful commands and how they could be used, which was probably the killer feature of the presentation for me. He also had a clear presentation style and after talking to him later at the bar was a nice, bubbly person to talk to and obviously knows his stuff.

As a suggestion for improvement it would have been nice to see a live demo of some of the tools in action – he had some screenshots of probing applications such as TextEdit, but a live demo of the tools live would have been a nice addition.

Dave Dribin – Clean Code

I think that Dave’s presentation was perhaps my favourite of the day and talked about different ways of writing clean code and bad ways that can introduce “code smell” and ways to get around this and I agree that it is an important part of being a programmer.

He used the analogy of the iPhone as a way into the presentation; with the divide between internal and external quality – the external beauty is the interface that is seen by the user but the internals are the code that we write and sits behind the scenes. With an application it’s the difference between a beautiful interface and the underlying implementation of that in code.

The presentation was filled with quite a lot of tips, such as guidelines on naming classes and common principles such as DRY (Don’t Repeat Yourself) and OAOO (Once and Only Once) with the example of using enumerations or constants for dictionary keys instead of repeating strings throughout your code.

The Q&A was also useful and for most of the other talks there wasn’t time so it was a nice feature to be able to ask questions about the content discussed.

Drew McCormack – Data Presentation in Mac Apps

Drew lead into the presentation by talking about his scientific background and explaining how different data can be displayed and visualised in different ways. His presentation was also nice because it was one of the ones that wasn’t directly related to churning code and was more about the UI and talking about the various controls – standard or custom – and where they are best used.

I liked the format of looking at these different controls – he presented images of each and then talked about the advantages and disadvantages of each. This was particularly useful when comparing controls, such as the NSTableView and the NSCollectionView, and his slides were perhaps the best of the day and contained very little text on them, just visual cues such as images and the likes.

To this end I learnt a lot about how different views are implemented – he explained using Tweetie (Mac) as an example that it uses an NSTableView to display its list of data, and also Versions implements some of its custom controls using HTML, CSS and Javascript with WebKit.

Near the end he did talk about non-standard controls and focused on drawing graphs with CorePlot. However he spent quite a long time talking about this, which although interesting it would have been nicer if he’d demonstrated a few more, different controls.

Marcus Zarra – Core Animation

Marcus started his talk by explaining how Core Animation wasn’t just for designers, and used himself as an example of a non-designer, but that it could still be used to enhance or help create sleek interfaces. However he also warned that Core Animation can easily be overused and turn a simple, clean UI into something horrible and even very unintuitive. He also explained how Core Animation, although its interface is quite simple, it is also very powerful.

He gave a few examples of using Core Animation, and then gave a live demo of an application that was doing lots of complex animations using Core Animation and how smooth and seamless they all were. It was evident that he had spent a lot of time on the project and he explained how the rotating gears displayed were constructed as paths which was a nice touch to the talk, to get a real demo application.

However even though he had an hour slot, he only used about 35 minutes talking and left the rest of the time for questions, which was quite a nice idea since it was more engaging with everyone rather than simply a lecture. However, it would have been nice for him to use more of his allotted time to show some more Core Animation examples.

The first day of NSConference 2010 kicked off with two workshops – Concurrency Programming on Snow Leopard by Drew McCormack, and The World According to Gemmell, by the Legend himself, of which I was an attendee.

The session started with a discussion about a certain recently released Apple product which was very interesting and allowed us to present our thoughts on the device. We covered such areas as the human psychology behind it, the display of “real” objects as the interface and the much more emphasised touch interaction including two-handed UI, as well as getting “wanky” about the emotional connection with the device.

Andy had also created a great model of the device, that was the exact dimensions (although the back didn’t slope like the real thing) and half the weight of an actual iPad. This was really useful in the talk from Matt, when he was explaining such things as how people would hold the device.

We also discussed the changing seeds of user interfaces and the switch away from clutter-based interfaces, such as inspector panels which ‘can edit anything that has ever lived’.

Our workshop

A few weeks ago Matt sent an email round to all the workshop attendees asking whether we had any UX topics that we wanted to discuss that could form the basis of the workshop. This was a great structure and in the session we got through 7 or 8 discrete topics, from such topics as the evolution of your app and removing features to when the best time to release your 1.0 is.

Although Gemmell said that he had put the slides together quickly and a bit haphazardly (and Scotty had been fiddling around with the slide animations*), the slides were well arranged, and contained only a few – although thought-provoking – bullet points for each topic, and allowed us to really discuss the ins and outs and how one would go about dealing with these problems. The workshop dynamic really helped this section and the group discussion bit was great as we could all have our opinions heard and commented on, with Matt being the suspiciously-bearded ringleader of the event.

Workshop dynamic

Matt’s talk was arranged as a workshop and consisted of around 30 people. The tables had also been arranged into groups of about 5 or 6 and all of this combined made a great, much more personal dynamic for the session, because as Matt himself put it, we were all participants and it was our workshop, not just his.

It was a great social occasion to this end, and allowed for group collaboration which was a real strength of the workshop and made it a really enjoyable event.

Final thoughts

A brilliant first day to NSConference and a great thought experiment with lots of things to take away and think about. As I mentioned when speaking to Matt in one of the breaks, the Mac/iPhone/iPad platforms are so brilliant partially due to the fusion and interwoven nature of code and design, the latter of which is given a lot of thought in most instances, which made the workshop a very topical and interesting one indeed.

The Mac conference (Monday 1st Jan – Tuesday 2nd Jan) has a lot to live up to but a great start to what I’m sure will be a great conference.