Will a MacBook Air have enough horsepower for occasional development in Ruby? Objective C? Cocoa?
Are there any other major limitations with doing this?
Notes:
Yes, it is. Although I don't use one I know a few Ruby developers that do.
Also...
"I know a MacBook or Pro would be more appropriate but they are simply not as cool."
omg... lol.
Only if you're going to use it to code at Starbucks.
I'm kidding. Most kinds of development don't require all that much horsepower. Just about any consumer grade, or even budget level, laptop should be more than sufficient for Ruby and Objective C development, especially "occasional development". The Air falls into this category.
The MacBook Air has one annoying habit: While it has a Dual-Core CPU, it turns one of them off once the machine gets too hot. Which happens often once you're using XCode. Which makes you end with with a single-CPU machine, effectively.
XCode is a resource-hungry beast, often scanning your sources for its code completion awareness, etc. And two cores let you effectively build twice as fast. (One trick is to use a hidden setting that tells Xcode how many processes to launch for compiles - default is set to the number of cores, which doesn't lead to full CPU utilization, though. But when setting it to a higher value, e.g. 3 on a dual-core Mac, it'll make much better use of the CPUs. To get to this setting, install the "Secrets" prefpane.)
I'd recommend a full-size MacBook or even a Pro version instead. Or look into a lighter PC Laptop which can run OS X. I haven't tried it myself but read reports that some PCs can be configured in a way that you can then install OS X out of the box, and also let OS X update itself without problems.
Note: I am building bigger projects with Xcode, though, where a complete rebuild can take a minute or more. YMMV.
make sure that you get the most recent revision with the nvidia chipset as it will be more capable of driving an external display than the previous generation.
Also, the new unibody macbooks are very much similar in look and feel to the air and are a bit cheaper and higher spec.
Apple generally sets its machines up with very little RAM. This is true even for the Mac Pro (mine came with a measly 1GB even though I had four Xeons). Mac OS X Leopard is also very hungry.
Therefore, if you intend to use an intensive IDE like Eclipse, I would recommend avoiding the air.
Also, and this may appear silly at first, but most IDEs use a white backgrounds. You can actually save a lot of battery by having most of your screen be black with the font in lighter colors. You can toggle this sort of negative in the universal access panel. If you use the air for development away from an AC, this may help.
You're in good company: Wil Shipley (creator of Delicious Monster and other famous Mac software) uses his MacBook Air for dev (cite). His first-gen with SSD was faster than the MacBook Pro he was using previously.
Control-alt-cmd-8 will get you a "more black" screen for battery-saving :)
I have a 17" MBP that has 4GB Ram. It was fine when I was doing perl/LAMP/Cocoa. Now that I'm doing quite a bit of C#/.Net in VM's, I've mostly migrated to a Mac Pro. The 4GB on the laptop wasn't enough.
I'd think if Shipley is fine coding Cocoa on his MBAir, then you will be too.
Yes. I use my Air full time, not just for occasional development work. I do miss having a larger screen, but to be honest, not that much. I code in Rails using TextMate, and XCode.
The thing about the Air that I love love love is how light it is. I can use it for hours on the couch without problems or a power connection. It's remarkable.
As for being an ignorant Windows developer, that's my background as well. I not only found the transition to be mostly painless, but I also found that I now understand why Mac people say "it just works." It isn't that it just works, it's that there are myriad little things that just feel so nice that the overall experience is highly pleasant.
My only wish: I had the second-gen Air, not the first-gen. Nevertheless, still very happy.