ARC doesn't work just as well. At least theoretically, ARC retains a lot more garbage because the compiler has to be much more conservative about reachability than the garbage collector. ARC has theoretical failure modes that can cause huge amounts of retained garbage, and that's less well-understood than the failure modes of GC. Doing reference count updates is also generally slower in terms of CPU cycles than doing garbage collections. Oh, and ARC doesn't handle cycles.
That said, I think reference counting warrants more attention than it has gotten in memory management research. If you're willing to punt on the leaking cycles issue, you can get a lot of mileage out of using a reference counting collector as a tenured generation with a copying nursery.
Killed ethernet? Thats a somewhat ill-informed statement to make. The latest iMac still has an ethernet port.
They did remove it from their line of portables as most people use wireless with their laptops (and they scored some valuable real-estate on the main board!) but you can get a Thunderbolt network card if you really want to be tethered to your desk.
Ah, the iMac that you still can't buy (end of the year is a really strange time to have no inventory of your new flagship desktop)... But that's another rant.
Apple's computers (desktops included, save for the Mac Pro which is essentially EOL) no longer have an optical drive, maybe I should have used that instead. I saw a coworker hunting for his MacBook's ethernet port today, so it was was fresh in my mind.
If you have an always on, reasonably fast and unmetered broadband connection perhaps. I understand it on the laptops, but desktops have plenty of available space so they're removing them simply for the sake of removing them.
I don't use the optical drive on my iMac much, but the times I have had to were not times I would have been able to avoid. I don't want yet another accessory/dongle or one less USB port. There's tons of room, just include the drive.
This came up recently with trying to install Windows inside Parallels on my girlfriend's laptop. Their IT people had a DVD and of course her laptop has no DVD drive, so I looked up how to use Remote Disc and found out that it works great except explicitly not for installing an OS and oddly almost all the other common uses of an optical disc.
These types of discs are not supported by DVD or CD sharing: These types of discs are not supported by DVD or CD sharing: DVD movies, Audio CDs, Copy protected discs such as game discs, Install discs for an operating system such as Microsoft Windows (for use with Boot Camp), or Mac OS X.
It's easy to get into a world of hurt even when Apple does its best to make their frameworks well-behaved with GC.
Retrofitting a conservative GC onto C is really hard, and they were never able to fully make it work. If you look at the Boehm collector's page, you see a lot of potential issues that can and do arise. Having these issues in an optional add-on that you adopt (or not) after weighing the issues is one thing, having them in a system-component that is declared to (a) be the future and (b) "Just Work™" is another.
I think he meant more generally. ARC, as a general algorithm, has killed the need for garbage collection, as a general algorithm [I]anywhere[/I]. As supposed to what you're saying: ARC, Apple's implementation of ARC, has persuaded Apple to abandon their GC implementation. These are two very different meanings (but yes, in Apple's case ARC has killed GC because of particular characteristics and needs of Apple's developer toolchain and environment).
It doesn't work nearly as well. ARC doesn't handle cycles at all, which makes it substantially more painful to use than a garbage collector. Don't get me wrong. ARC is great compared to the previous situation, but it's simply not a substitute for a real GC.
Automatic reference counting dates back to probably the 1950s. If it "works just as well" as garbage collection, don't you think it would have won by now?
One day a student came to Moon and said, "I understand how to make a better garbage collector. We must keep a reference count of the pointers to each cons." Moon patiently told the student the following story - "One day a student came to Moon and said, "I understand how to make a better garbage collector...