Think the Apple TV lacks functionality? Think again
Specifically, some people were bothered that Apple TV could only play few video formats or that it didn't have enough features for advanced users; others thought that the device's 40GB hard drive was too small. Those criticisms continued, even as Apple TV began shipping to customers.
But then something happened: People started receiving their Apple TVs, and some of those people--including myself--started taking them apart. In fact, within days of the first Apple TV being delivered, new sites sprung up focused on hacking the set-top box. It turns out the Apple TV isn't so "limited" after all--at least not when it comes to the hardware inside.
When I took my own Apple TV apart last Friday, I discovered that the hard drive inside is actually a standard 2.5-inch ATA drive, just like the ones used in older Mac laptops; this bodes well for inexpensive upgrades (see below). On the other hand, this stock drive is a 4,200-rpm drive with a 2MB cache, specs that aren't all that impressive given that all currently-shipping Macs, even the laptops, use SATA drives with a minimum speed of 5,400-rpm and an 8MB cache. (To be fair, the slower speed and smaller cache of the Apple TV's stock drive is unlikely to result in reduced performance--it should be able to easily keep up with network transfers and media playback. The bigger issue is the size of the drive; I'll get to that shortly.)
The fine folks over at AnandTech went above and beyond my basic disassembly by completely dismantling their Apple TV to find some interesting stuff inside. For example, after a bit of sleuthing, they deduced that the Intel chip in the Apple TV is an "Ultra Low Voltage Pentium M based on the Dothan core, running at 1GHz (max frequency), 400MHz FSB and a 2MB L2 cache." The Apple TV also includes 256MB of RAM and an NVIDIA GeForce Go 7300 with 64MB of dedicated video RAM; the latter, a laptop-focused GPU, isn't exactly a barn-burner, but it's more than capable of handling HD video.
More interestingly, the audio chip in the Apple TV is a Realtek ALC885, which the manufacturer describes as a "7.1+2 Channel High-Performance High Definition Audio Codec." The specs on this chip are quite impressive, and seem to indicate that the Apple TV's reported audio-output limitation--Dolby Pro Logic II--is due to software, not hardware. In fact, Roughly Drafted reports that if you play a sample DTS audio file through your Apple TV, the Apple TV's optical digital-audio output jack does indeed put out 5.1 audio. On the other hand, the ALC885 also supports "advanced lossless content protection technology," so perhaps we have hardware DRM in our video-playing future.
On a software note, Apple TV runs a version of Mac OS X; version 10.4.7 Build 8N5107, to be exact.
Surprisingly, Apple hasn't made it difficult to get inside the Apple TV. The rubber "foot" on the bottom is attached using adhesive but peels back easily. Lift the corners, loosen a few Torx screws, and the bottom of the case lifts right off. The first thing you'll see after doing so is the unit's hard drive, which helps explain why the first Apple TV surgery we saw performed around the Web was a hard-drive upgrade. (My replacement hard drive hasn't yet arrived; when it does, I'll be performing just such a warranty-voiding transplant and writing up the procedure here on Macworld.)
Although the process isn't as simple as cloning the stock drive to a new one using a utility such as SuperDuper and then swapping, it's not terribly complex--given the small capacity of the included hard drive, I suspect that more than a few Apple TV owners will be upgrading to a significantly larger drive. (If you don't feel comfortable doing this yourself, at least two companies have already announced for-fee drive-swapping services.)
Like the iPod, the Apple TV--specifically, its included Apple Remote--has special button combinations for accessing various "hidden" features. For example, pressing Menu and Up (+) simultaneously, for approximately six seconds, will cycle through possible display resolutions. Even more interesting, pressing Menu and Down (-) will bring up the Apple TV Recovery screen, which gives you options to Restart, Run Diagnostics, or perform a Factory Restore. (The latter tells me that one of the Apple TV's hard drive partitions--the drive has several--contains a copy of OS X and the Apple TV software; restoring the unit restores the Apple TV, from this partition, to an out-of-the-box configuration.)
It also turns out that, Apple's statement notwithstanding, connecting a keyboard to the Apple TV's USB port does do something. Specifically, you can boot the Apple TV into single-user mode by holding down Command+S at startup--you can't do much from there, but it's still interesting--and you can enable Verbose startup mode by holding down Command+V at startup.
Related to the previous two items, one other neat trick that's been discovered is the ability to boot the Apple TV off a USB drive. In the video below, a clever Apple TV fan uses Recovery mode to reboot his Apple TV from a USB hard drive containing a copy of the Apple TV's own hard-drive contents.