Apple’s new MacBooks (and MacBook Pros) are out, and there’s the usual breathless enthusiasm from some people and angry disdain from some others. As always, it’s about design tradeoffs – what I called the snowball effect in my discussion of the MacBook Air, several months ago.

Sidenote: it’s been over six months since I bought my Air; I took it on our 70-day trip and I’m mostly well satisfied with it. The 80GB hard drive is a little tight, mostly because I insisted on carrying my full iPhoto library around; otherwise it wouldn’t be an issue. One positive surprise was the glossy screen, which didn’t bother me at all, even under wildly varying lighting conditions. Having only a single USB port (which I used mostly with the Ethernet adapter or an SD card reader) was no problem either; I’m glad circumstances conspired to not let me buy an extra USB hub, it wouldn’t have seen any use.

Apple’s new laptops embody significant trends. The styling and keyboard are based on the first MacBook Air, combined with the April ’08 iMac’s glass screen. While the “unibody” construction is also derived from the Air’s, it’s an evolution. Being a little thicker at the borders, the new laptops are in themselves very rigid, not depending at all on the battery for bracing, as the Air does. It will be interesting to see if the third version of the Air gets a removable battery – though that probably will imply incorporating the battery into the bottom cover, instead of having a panel over it.

Structurally the new laptops are great. Access to the hard drive is very convenient – this mitigates, in the MacBook’s case, the unavailability of Firewire target mode, at least for a technician. The major components are also easier to access; previous laptops were a nightmare of special adhesives, tricky assemblies, and easy-to-break snaps. That said, some things are now much more expensive to replace, being either single parts (the enclosure) or considered as such (display or keyboard).

There’s a surprising overlap of structural design and marketing. The fossil remains of the previous lines are the low-end white MacBook, the 17″ MacBook Pro, and to an extent the MacBook Air; all of which have received superficial updates but are structurally unchanged, and hit the same markets. No doubt all three will, in their next incarnation, be adapted to the new marketing distinctions… but which distinctions are these, then?

As always, differentiating the “Pro” from the “consumer” line is tricky both for Apple and for users. With the new unibody, for the first time, both lines use the same materials and design. This means that Apple must distinguish the lines by feature sets alone. In this case, it seems that the major distinction is screen size: the normal MacBook has a 13″ screen, while the MacBook Pros have larger screens. Of course there are the usual somewhat faster CPUs and larger hard drives, but these are more of an expected consequence of the size difference. All this also makes for a natural spread in prices among the lines.

Now, of course, there’s a sizable contingent of users who want Pro features at consumer prices, and want Apple’s designers to produce such a miracle every time. These “prosumers” are also prone to think that the “real” Macs are the high-end ones, but that Apple then maliciously cuts features from them to produce the low-end machines; call it the conspiracy theory of hardware design.

While I can’t say with certainty that this never happened in the past (remember the Performa days?), it’s very unlikely in this specific case; the MacBook is not a crippled MacBook Pro. Indeed, indications are that, surprise, the MacBook Pro is really an expanded MacBook. Let’s look at design considerations for the new MacBook.

First of all, Apple is usually limited to standard sizes built by its suppliers, at least for such a high-volume item, and of course to the width of a standard keyboard; reusing parts from other successful product lines is also a win. This means a 13.3″ screen; sharing the display with the MacBook Air pretty much fixes the front/top dimensions and makes the keyboard also shareable. So, we have our width/depth dimensions; the LED backlight and display determine most of the lid thickness; the body thickness is determined by the thickest connector and internal peripheral.

A full-size Ethernet plug needs at least 10mm, not counting any PC board it rests on, while current DVD drives are 9.5mm thick. (Notice the MacBook Air excluded both items.) From pictures, I estimate that the MacBook display measures 8mm, the body is about 16mm thick, the side where the port connectors are measures barely 11mm; and indeed the Ethernet connector opening uses up nearly all of the latter. The extra 5mm of the rounded bottom were probably necessary to ensure a minimum battery volume.

Turning the MacBook over, the decision to make the hard drive accessible under the battery cover (and the need of using 2.5″ drives which are both inexpensive and of reasonable capacity) makes the rest of the layout fall into place. At this point, you may want to refer to one of the many disassembly photos available on the web; I liked the ones from ifixit. Check out the photo in step 11; notice how there’s no component overlap (except, unavoidably, for the keyboard). The left top rectangle is the optical drive and the black rectangle north of it is the speaker/subwoofer. The right part is the motherboard with a cutout for the fan and another one for the RAM modules. On the bottom, the hard drive uses the left portion, so the battery has to use up the remaining rectangle on the right.

Again, I want to emphasize that this very rational layout is a serious design win. It’s made possible by the unibody’s rigidity and space-saving, but once you take those into account, it’s almost forced; you can’t have a smaller laptop using those particular components.

But there are consequences. In older models, the motherboard either spanned the entire width of the machine to accomodate ports on both sides, or there was a secondary module on the opposite side, with fragile/expensive ribbon cables connecting that to the main board; not a good solution. Remember that making a unibody is an expensive process and that cost must be shaved off elsewhere; even so, the MacBook is $100 more expensive than its predecessor.

So we pretty much have to accomodate all ports on one side of the MacBook. Check out this page, especially the logic board photo in step 17. This is where some more tradeoffs come in. Apple has decided to adopt the new DisplayPort standard, apparently in all Macs from here on. While at first glance HDMI might have been a better choice, DisplayPort is license- and royalty-free. Remember Jobs giving licensing issues as a reason to avoid Blu-ray for now. Without going into further details, note that Apple has taken a dislike to the standard DisplayPort connector; I couldn’t find the standard dimensions, but it seems to be at least 17mm wide. Of course this means yet another proprietary mini-version of the connector; hopefully Apple is coming into the market early enough, so that other manufacturers may adopt it.

Even with the mini-display connector, space is limited. Audio in and out are necessary, so there’s space for only 3 normal-sized ports. Apple has decided in favor of Ethernet and two USB ports. I’ve seen arguments favoring 3 USB ports (meaning the Air’s USB/Ethernet dongle would be necessary); 1 Ethernet, 1 USB and 1 Firewire port; 1 USB port and 2 Firewire ports; eSATA in the mix; and so on. Stacking USB ports, while not unknown in laptops, tend to go over the allowed 10mm height; mini-USB ports are fragile and would need special dongles or cables. No doubt an argument could be made for some sort of combined port expansion box, or a combination hub, or…

Omission of a Firewire port has raised the most objections; this happened too when the Air came out, remember? No Firewire also means no target disk mode. Target mode for migration, while convenient, is not really necessary if you have gigabit Ethernet. With the hard drive so easily accessible, a technician no longer needs target mode for debugging; it’s easy to yank the drive out and plug it into a SATA-USB converter.

Now, there’s a crowd of prosumers using Firewire for audio and video, and complaining. I’ve no idea how large this crowd is; apparently Apple thinks that it’s insignificant compared to the number of people needing two USB ports. Whatever the rationale, I’ll repeat here what I said in a previous post about the missing Firewire in the MacBook Air:

To put in a FireWire connector means reserving resources for a 7W additional power drain…

while an additional USB port uses only 0.5W; only the first USB port on recent Macs seems to get the full 2.5W allotment.

I don’t think that this means the end of Firewire as such. The FW800 connector will also support the upcoming FW1600 and FW3200 standards, and works with FW400 peripherals if you have a converter cable or inexpensive adapter. It’s just being squeezed into larger (which now means higher-end) equipment.

This post is already too long, and it’s late, so I’ll talk about the MacBook Pro design tomorrow.