G4 Cube & Cinema Display by John Siracusa

Cube Ports and Core

All the ports are on the bottom rear surface of the Cube, and were discussed earlier in this section of the MacWorld Expo 2000 article. Briefly, the two ports you may not recognize are the 28V DC power connector and the Apple Display Connector (ADC) port. The MacWorld article included a table listing the pin-outs of the ADC. ADC is eerily similar to VESA's Plug and Display (P&D) standard. The connector shapes are different, so technically they're not "the same connector", but the pin-outs look very similar and both use Transition Minimized Differential Signaling (TDMS) to transfer video and "other stuff" (power, USB, etc.) on the same cable without the major interference problems inherent in this arrangement. The entire "core" of the Cube lifts out via the retractable handle on the bottom. What you'll find inside is a sort of metal exo-skeleton frame held together by torx screws. This is another complex, difficult-to-manufacture part, this time serving style indirectly by enabling the dense packaging job necessary to get all this stuff into an 8-inch cube. The Cube uses Apple's UMA-1 motherboard architecture. For those that don't know, UMA is Apple's Unified Motherboard Architecture. The UMA-1 initiative was started several years ago and is now used in every computer Apple ships.

That's not to say that every Apple computer has the same motherboard. UMA-1 is simply a set of motherboard components: sound chips, i/o controllers, the north bridge, etc. The actual board sizes and component layouts vary greatly between models. Nowhere is this flexibility more evident than in the Cube. The UMA-1 components have been divided among many small printed circuit boards, all connected by ribbon cables, riser cards, and T-junctions. There are several Cube-specific components and tiny extra PCBs for things like the touch-sensitive power switch, the digital audio output, and power distribution. There are also a handful of colored LEDs (mostly red and green) inside the case, many of which peek out through various vents and slits. (For more pictures of the insides of the Cube, check out this complete disassembly diary from an Italian web site.)

The various components and PCBs are arranged around a central chimney or tunnel which is itself formed by the gaping holes in the absolutely huge central heat sink. The photo on the right (courtesy of the Italian web site mentioned above) shows the central heat sink tunnel from the top. (The circle above the tunnel is the sensor for the power switch.) All this heat-conscious design may make you think the Cube produces a lot of heat. And as you might already know, there is no cooling fan inside the Cube. But there are other more important things missing, most notably the power supply and the audio amplifier. Those two components together seem to put out more heat than the Cube core in my informal "hand tests." So how much heat does the Cube put out? My answer after over a month of steady use: not much. The first thing you'll notice is that a hand on the top of a Cube that's been working hard for hours will simply not feel any significant heat. Only on rare occasions have I even felt the plastic case get detectably above the ambient temperature of the room. I suspected that the case itself may just be a very good insulator, so I removed the core to check the "internal" temperature. The insides were as hot as you'd expect, with the DVD drive and the Rage 128 heatsink being the hottest components. But the overall temperature was pretty cool—certainly no hotter than the equivalent components in my cavernous, fan-sporting G3/400. The huge central heat sink definitely seemed to be doing its job; the area around the CPU never got more than mildly warm. The final heat test was the "smell test." There is a clear smell of "electronics" coming from the top vent. What's an "electronic" smell? Go smell the top of your CRT monitor right now. That's the smell, only the Cube's smell is not nearly as pungent as what comes off the top of a typical CRT. The Cube also never gets nearly as hot as the top of a CRT. Nevertheless, that smell is my only concern about the Cube's temperature. I don't think it'll ever overheat or abruptly fail, but I suspect that the lifetime of the internal components may be shortened somewhat. But "shortened" by how much? I don't know, but I'm optimistic. My Mac 128k (the very first fan-less Mac) which was in regular use from 1984 to 1997 still works just fine, and that case has the motherboard, a floppy drive, the power supply, and a 9-inch CRT all inside the same case. Cube Complete Let's take a look at the complete package. Below is a picture of everything that comes in the Cube box:

There are a couple of items you might not recognize. First is the "VGA extension cable." As seen in the photo to the right, it's a stubby extension cable that attaches to the VGA port and extends it outward 6 inches at a right angle. This dongle may be necessary if you have an old Apple monitor that requires an Apple-video-to-VGA adapter that makes the entire connector assembly too large to fit under the Cube. Remember that there's only about 2.5 inches of clearance under there. I used the extension cable to hook up my Apple 17-inch Studio Display CRT (while I was waiting for the Cinema Display to arrive) despite the fact that the connector would have fit beneath the Cube. The extension cable simply makes it a more convenient connection and relieves stress near the connectors. I actually wish I had a similar extension for all my large cables; I hate seeing bulky connectors poking out of the back of the machine and bending downwards under the weight of their thick cables. (SCSI cables are the worst, in my experience.) The second curious item is the "Apple Hardware Test CD." Boot from this CD and you're presented with a simple tabbed dialog that includes a testing pane, an information pane, and an "about this software" pane. The testing pane couldn't be more simple. There are four buttons: Quick Test, Extended Test, Shut Down, and Restart. The Simple and Extended tests both examine the AirPort card (if present), the Logic Board, the memory, the modem, and the video RAM. (The extended test just takes a bit longer and does a more thorough job.) The information pane gives a brief overview of the hardware configuration (DIMMs installed, processor speed, cache size and speed, ethernet MAC address, etc.) It's not as extensive as the Apple System Profiler included in Mac OS, but it hits the highlights. It's good to see this type of thing included with the system. It's OS independent since you must boot from the test CD to use it, it provides information that will be very helpful during any sort of hardware support call, and it can help give users peace of mind when they suspect a hardware problem. One of the Macs in my office had a bad third party DIMM installed—bad enough to cause memory corruption from time to time, but not bad enough to keep the system from booting—and it took forever to track the problem down, eventually requiring a third party hardware test application. If the Mac had come with a hardware test CD, that likely would have been one of the first things tried. Next: Cinema Paradiso