Solipsism Gradient

Rainer Brockerhoff’s blog

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Here’s some wild speculation about the supposedly-soon-to-be-announced Apple Tablet. Rumors are flying fast and furious but all agree that the device will be based on a 9.7″ (or 10″) screen.

A week ago I saw compelling arguments that the Rumored Apple Tablet Is a Train Wreck. The article is quite logical: if Apple builds a touch tablet based on a 10″ screen, it will probably fail. It would be too large to use like an iPhone, holding it in one hand and touching with the other, and too large to carry in a pocket. It would also have to be relatively thick (and therefore, heavy) to protect the screen. Lying flat on a desk, the screen would be at a disadvantageous angle. In other words, it would be a keyboardless netbook; not Apple’s style at all. See the Amtek for an example of this.

Note that the word “tablet” is already too connected, in people’s minds, with certain features. I’m not sure what this new Apple device should be called; in fact, I hope that Apple avoids this designation entirely. I do think that it will, at least for its first generation, be primarily an entertainment device. More built for travel or leisure than for work, in other words.

Let’s look first at the constraints that Apple probably sees in such a device. First of all, they will want to avoid overlapping features with the existing product lines (or, at least, with where they’ll be taking these lines in the near future). So, the new device won’t have any direct phone functionality. It will of course play from a music library, as all Apple products do, but it’ll be too large to work as an iPod does. On the other side, it can’t compete with the low end of Apple’s laptops; this rules out running Mac OS X and/or having an arbitrary number of applications running simultaneously.

I see four basic applications for the new device: ebook reading, game playing, single-foreground apps like web browsing, and, perhaps, data entry. Current AppStore applications can do all of that to some extent, but are limited by the iPhone/iPod Touch’s small screen and puny input resources. So the new device needs a larger screen with full touch capabilities; 1280×720 pixels is necessary for HD movies, would be excellent for games, and reasonable for other applications. The screen would have to be thin, fast, brightly colored, and low-power. OLEDs seem to be the only technology available today that fits these requirements.

A 10″ OLED screen would have a pixel density of about 145 ppi. For comparison, a MacBook Air’s screen is 100 ppi, while the iPhone’s screen is 160 ppi. However, a serious issue with such dense screens is fabrication yield – the percentage of built screens that pass factory testing without too many defective pixels. Another problem with a single 10″ screen would be that a sizable portion of it will be taken up by a virtual keyboard or some other input control. A physical keyboard would make the device a small laptop and therefore is out of the question. Finally, the applications I listed above demand differing orientations of the device: horizontal for movies and games, vertical for ebooks.

One way of solving these problems is to use a clamshell-like design, but with two screens – more like a Nintendo DS than a netbook (this is also suggested by the “train wreck” author). Won’t two screens make it more expensive? Not at all, because of the yield problem, two smaller screens will probably cost 50% to 70% of a large screen. Making a 1280×720 screen at 200 ppi should be possible, giving a screen size 6.4″ by 3.6″ – about 163x92mm (roughly 7″ diagonal). With the same dimensions at 160 ppi, the screen would be 1024×576 pixels, keeping the 16:9 aspect ratio but sacrificing full HD capability.

So what’s near these dimensions? Well… I have here the paperback edition of “Cyberbooks” by Ben Bova (Jan.1990). It’s a quite funny story, but sadly out of print; the cyberbook’s inventor struggles against resistance by the entrenched publishing industry (hah!). This book is 178mm high, 101mm wide, and 20mm thick; easy to carry and to read.

And by a coincidence, these measures are only a few mm larger than the screen size I calculated above. So, for now, let’s assume a paperback-size device. I guess I should say mass-market-paperback-sized, as now there are these pesky “trade paperbacks”, which are not too well standardized, more expensive, and make me build my bookshelves larger than I want to – but I digress.

OK, let’s postulate a small book-sized device that opens in the middle. Each half measures 178x101x10mm, and the hinge is constructed to lock at certain angles. By the way, these are rectangular slabs with black glass on the screen side and Apple’s aluminum unibody elsewhere; the edges have to be rounded, but not much. The 10mm thickness is constrained mostly by battery capacity. Assuming the unibody back-wall to be 1mm, and the touchscreen to use up 2mm, we’ll have 6 to 7mm inside for a battery in one of the halves (the other half will contain the electronics). Apple’s new Li-polymer technology should allow for a 20 Watt-hour battery with these dimensions, by my rough calculations.

OLED screens have very variable power consumption; almost zero for black, maximum for white. Let’s estimate an average of 2W for each panel, and 3W for the electronics. This gives us a battery life of 3 hours when using both screens. If you play a movie on only one screen, this would go up to 4 hours; not too bad for a first-generation device. How would our applications work on this form factor?

Ebook reading: there are two options here, holding the “book” vertically as usual. Either we open the device 180 degrees, showing two pages, or we fold the right-hand screen completely behind the device. The second option is more likely, as only one screen would be active (reducing power consumption). Only the book application would be in the foreground.

Game playing: hold the device horizontally in both hands, with the bottom screen folded behind the device. Gameplay would be controlled with all 10 fingers (note that Apple has a patent for a touchscreen in the back of such a device). The back screen would be turned off to conserve power. Only the game application would be in the foreground.

Movie watching: this too is horizontal. The lower screen could be folded behind, as in the previous scenarios, or with the hinge locked at 110° as in a laptop, for sitting on a table. This would be stable as the bottom screen would be the one with the battery, which would be 2/3 of the device’s weight. Only the movieplayer application would be in the foreground.

Web browsing, or similar apps: two options. Horizontally, locked at 110°, the upright screen would show that foreground application, while the bottom screen would show the virtual keyboard, controls, and some status indicators. Vertically, with the device locked at 180 degrees, and joining the two screens into one – basically turning it into a classic tablet/netbook.

The 180 degree netbook mode is the one that has serious drawbacks. The hinge should bring the two screen halves together with a very small seam; tricky to implement, and making the screen edges sharper and more fragile. It also means that both screens would work at full brightness, raising power consumption. If the two screens are always separate, the lower/right one would be used only for virtual input – some bright pixels but a mostly black background, and then it could also have lower resolution – perhaps only half that of the main screen, lowering both costs and power needs.

Also notice that in all cases, there’ll be a single foreground app using the entire screen, and perhaps small widgets or background app icons on the “keyboard” screens. This also means that the device will run a version of OS X – no Mac-style interface, since that is very much tied to a mouse-type input device.

Further hardware refinements are possible. Apple has a patent on interleaving a camera with screen pixels. Doing that on both screens might be too expensive, but doing it on the screen that folds to the back might be just the thing for “augmented reality” applications. Haptic feedback? I don’t think there’s anything like that on the market yet. Voice input and stylus/handwriting input should be easy to do. An iPhone-style connector would be the minimum external interface (plus the usual audio connectors). Accelerometers, compass, GPS etc. will be built-in; an SD slot probably too.

Other details. The device will have any or all of the usual wireless connections – WiFi, WiMax, Bluetooth, 3G – but no direct phone capability. 32GB SSD storage would be a minimum. This will probably be the cue to roll out a CPU based on a P. A. Semi design; should it run the ARM instruction set, we’ll probably see current AppStore apps running in a compatibility box. In any event, Apple’s new Clang compiler technology means that supporting a new CPU architecture should be a piece of cake.

With all that, my tip would be a price in the $899-$999 range; rumors hint at a September 15th introduction, with availability sometime around the end of November. Will we see all of this in the first-generation device? Time will tell.

Re: WWDC 2009

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The conference will be over tomorrow and I’m quite satisfied with the outcome. Now for some comments about the announcements and (NDA permitting) about what I learned.

I had some vague idea of going to some iPhone sessions and letting presenters (or friends developing for the iPhone) convince me that I should start developing for it. No such thing happened; session overlap was so severe, and there were so many labs to go to, and people to talk to, that I skipped any non-Mac session or discussion. What little I heard in the corridors confirmed my notion that the current state of iPhone development and the AppStore deviates too far from my preferred position as a utility developer – a niche Apple still keeps closed on the iPhone. Maybe when the tablet comes out… icon_neutral.gif

Speaking of tablets, while everybody agrees that one is in the works, it seems to be a year or so away from announcement. (Ditto for the new CPUs I hinted at, in my last post.)

Snow Leopard is the small new thing. Small for the user in a sense; it’s just refinements and greater speed. For developers, though, it’s the BIG new thing. And, as variously described as early as a year ago (can’t find URLs right now), much of the new stuff is driven behind the scenes by open-source projects Apple is driving: the Clang compiler, the LLVM back end, and the technologies made possible by Grand Central Dispatch, blocks and OpenCL. So, most of the sessions either expanded on this directly or offhandedly mentioned “there’s an API for that now – and it’s fully XYZ-enabled” (insert one of the technologies above).

These things have become possible because CPU chips had run into a clock frequency “sound barrier”; 3GHz is about the maximum current silicon can do without extensive and expensive cooling or exotic technology. So multicore has become the solution du jour: all Apple computers now have at least 2 core, and the top machine has 8 (16 virtual). Expect that number to double every 2 years, at least.

But for years multi-processor machines were hard to program. About 14 years ago, at another WWDC I bought a Genesis MP 528: this Mac clone had 4 PowerPC 604 processors running at a blistering 132MHz. It didn’t have much caching on those chips, and only Photoshop and a few other specialized apps could see more than one CPU, and that only for image filters. In two years the first PowerPC G3 CPU card, with a single processor but caching, running at 300MHz, had about the same Photoshop performance – and that performance was then available to all apps. So why didn’t more apps take advantage of the 4 CPUs? The classic Mac System 7 (to 9) had no easy way to allow for this; there was a very primitive multiprocessing API but the system was pretty much locked out of it.

As said in the keynote, Snow Leopard will support only Intel Macs; PowerPC Macs are, therefore, stuck in the Leopard era, and only some few bug fixes will appear on 10.5, then it’s over. I couldn’t find hard figures comparing the installed base; I’ve seen percentages quoted of between 10 and 35% of Macs Macs still in use being PowerPCs. I personally didn’t think this would dip below 25% before 2011; then again, as a stockholder, I’m glad Apple sold so many new Macs recently… icon_wink.gif

Some people question why PowerPC users will be left out of the Snow Leopard advantages, and I think I know why. While the top 4-CPU PowerPC machines still can hold their own with more modern machines under certain circumstances, the vast majority of PowerPC Macs have only 1 CPU; only a few big desktops have 2, and even fewer have 4. Most advantages of Snow Leopard come into play when you have at least 2 CPU cores, and there’s serious testing and bug fixing to be done for supporting an entire architecture. Apple probably just weighed those factors (with better numbers than I have available) and decided it wouldn’t work out.

Positives of the new Clang/LLVM combo: better compiler speed, better code optimization – both still starting out but they’ve more power in reserve, while the current gcc compiler and backends are pretty much maxed out; way better error messages, the Clang static analyzer is just awesome (a word I usually hesitate to use, but this really is!); lots of goodies to come from tighter integration with Xcode. Negatives: may still generate wrong/inefficient code in some circumstances; no C++ support yet (I don’t care myself about this one).

A sleeper advantage is, also, that the intermediate (LLVM) bytecode generated by Clang could possibly be stored as such inside executables, and be just-in-time compiled for execution on any target CPU. In other words, the same executable could run on a new machine Apple puts out, even if it has a new CPU chip/architecture, as long as the JIT compiler is in place for that; application developers wouldn’t have know (or care).

Regarding blocks (or “closures”, as they’re known in other places), they’re a syntactic convenience for programmers to pass executable code as data. As such, they make programs more readable. What makes them inordinately powerful in Snow Leopard is that they’re also the basic executable units for all of the cool new multiprocessing stuff in Grand Central Dispatch. Therefore, with a little discipline, it becomes easy for developers to chop up tasks into little slices than can be executed in parallel by however many CPU cores (or, with OpenCL, GPU units) are available to do them; and for the first time anywhere I know of, this facility is available throughout the system, even at a quite low level.

So, am I running off to convert all of my code to the new technologies? Well, yes and no. Many things still have to be done in a serial manner, and the system will do others in parallel behind my back. Also, it seems that writing a generic application that runs on both 10.5 and 10.6 (using the new stuff) is tricky; I’m still investigating how to best do it. Stay tuned for developments…


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Well, the nice folks at MacMagazine (thanks Rafael!) have republished a slightly updated version of an interview I gave a few years ago. It’s mostly about the 1985 Unitron Mac512, the very first Mac clone.

It’s in Portuguese, so here’s a translated-by-Google sort-of-English version. Rafael has hunted down some good pictures of an early prototype; I regret not having taken any myself.

Re: More tradeoffs

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While most of yesterday’s Macworld keynote was uninteresting to me personally – I rarely use any of the updated software, and don’t have iTunes store access – the new 17″ MacBook Pro was mostly as I expected: the additional space was used for a larger battery, and more USB ports.

It was gratifying to see Apple’s battery page practically repeat my reasoning about the infrastructure (and wasted space) needed to accommodate removable batteries. (See also Chuq Von Rospach‘s discussion of the issue.) Not that the 15″ model’s infrastructure is quite as large as they show in the video, of course… but it makes the point well.

Judging from the pictures, the hard drive is inside a space that’s almost exactly square. In theory, they could have rotated the drive 90 degrees and made the battery 30mm wider, for maybe 10% more capacity. So why didn’t they do that? It would have meant extra weight, a beefed-up charging circuit, more heat dissipation, and either a larger power supply (which already is at 85W) or a longer charging time.

I don’t doubt that we’ll see incremental upgrades for iMacs and Mac minis rolled out without much fanfare over the next two months. My tip for the iMacs is that they’ll use the exact same front and back bezels as the corresponding-sized displays, with only a 10mm shim module inserted to accommodate the CPU and drives. The advantage, of course, would be that you could add a second display to your iMac with the exact same styling, screen parameters, and height; a good selling point. It would be a no-brainer for the 24″ model. I’m not sure that a 20″ display from Apple would sell well by itself, but if it used bezels and nearly all components from the 20″ iMac, it might be price competitive, and the styling advantage would be worth paying a few bucks extra. A 28″ iMac has been rumored; would that, then, mean that the current high-end 30″ display would be shrunk to 28″ too? I hope we’ll have the answer soon.

Re: More tradeoffs

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Thanks to John Gruber for mentioning my recent analysis of the new MacBooks (and MB Pros).

From there, several other sites picked it up. The emphasis and comments on some were… interesting. Let’s go into that a little.

The article at Wired has a somewhat sensationalistic headline (which was copied by others): “Killing FireWire on MacBooks Was Necessary”. Well, a careful reading will reveal I didn’t say so outright. I said that under the design conditions that were chosen there was no good way to include a FireWire port on the MacBook. Also, most of my arguments didn’t touch on the FireWire port at all, and there were almost no comments about those; so I’ll mostly confine myself to FireWire in my answers here.

By the way, the lack of the FireWire port on the MacBook doesn’t necessarily mean that Apple is “killing” FireWire at all. Yes, Apple killed the floppy drive, ADB, serial ports and so forth; because no shipping Macs include these. Contrast to FireWire: two shipping laptops don’t have the ports, all others have them.

The Wired article also features some feedback from iFixIt, whose pictures of the laptop’s disassembly I’d linked to:

IFixit’s Luke Soules, who performed the disassembly of the MacBook cited by Brockerhoff, agreed with the engineer’s assessment that there isn’t room for a FireWire port given the new unibody design and motherboard layout. Soules added that it’s also important to keep in mind that the new MacBooks are substantially thinner than their predecessors (.95″ vs 1.08″).

I spent some time reading all comments posted to the various sites. Some people, as expected, hadn’t read my post at all, or not carefullly. After filtering out the noise, here’s a list of points of view expressed in decreasing order: (percentages sum to more than 100% since some people scored in more than one category)

35% say Apple/Steve Jobs are idiots and/or just want your money and/or don’t care as long as idiot Mac users pay. I don’t know how to respond rationally to that, so I’ll leave it to the specialists.

31% agree with my arguments, at least for the most part. Thanks.

25% say that Apple can do anything they want to, so they obviously didn’t want to in this case. These were about equally divided between people disagreeing with the particular trade-off chosen (which is reasonable) and people of the “bah just jam an extra port in there, make it so” variety (who overlap a lot with the first crowd, above).

(Most of the following arguments suggest inserting a FireWire port. To make things shorter, I’d like to recall my previous comments about any such port needing extra board space in form of a PHY (transceiver) chip and filters, several watts extra power supply requirements, extra battery capacity, all implying in either much shorter battery life or increasing the size of the machine. Yes, Apple could use Sony’s 4-pin connector, or leave the 6-pin connector unpowered, getting around part of the problem… but imagine the complaints!)

18% say Apple should have put an extra FireWire port elsewhere; on the other side, in front or on the back. Of course it’s not possible to put anything on the back – the hinge precludes that – or on the front, as that would have meant cutting down a little on the battery (refer to these photos). Putting one or more ports on the side, near the optical drive, means moving or shrinking the speaker (see also my comment below on the security lock). Some people objected to my describing this as an expensive solution, no doubt thinking of the cheap ribbon cables used inside desktop PCs. Well, inside a laptop such cables have to be thin and shielded against interference, especially at FireWire speeds. Think of your normal FireWire cable… with the thinner body, there’s little or no space to route that behind other components. In older laptops, Apple got partially around that problem by using very thin (and therefore, flimsy and expensive) flat cables.

15% say that Apple should have left off one USB port and put a FireWire port in its place. At first glance this sounds reasonable; port sizes are about the same, the functions are supposed to be about the same, and the existence of adapters like the USB->Ethernet adapter for the MacBook Air reinforce this opinion. (Many people also asked why Apple doesn’t bundle or make USB->FireWire or Ethernet->FireWire adapters; see more on that below.) Then again, some were complaining about having only two USB ports…

12% say that Pro users should buy the Pro models. However, much of the controversy is either about Apple’s definition of what “Pro” means, or about people wanting “Pro” features at “Con” price. It’s easy to forget that these are just temporary marketing names for price points.

11% complain that Apple is putting form over function, and letting the designers run free. Of course that’s Apple’s shtick, so to speak (ahem), and a big part of their appeal. (And yes, it doesn’t always work out fine.) But in my humble opinion that’s not the case with the MacBooks.

8% want even more things: more(!) USB ports, two FireWire ports for chaining devices (perhaps the “consumer pros”?), an ExpressCard slot, or one or more “media card” slots. Unsurprisingly, most of these also belong into the “make it so” group; they want it all, but in a small cheap package.

7% say that Apple should have moved the security lock to the other side (where it indeed is, in the MacBook Pros), and put a FireWire port where the notch in the motherboard is. But moving the lock would also mean flipping the battery latch mechanism to the other side, which would mean having the lock just above the hard drive, moving the optical drive upwards, and leaving no space for the speaker.

5% would opt for leaving out the Ethernet port and inserting a FireWire port there (nearly all of these were immediately contradicted by people who do need Ethernet). The Air’s USB->Ethernet adapter is a makeshift, since it can’t attain gigabit speeds. All Macs (except the Air) do have gigabit Ethernet, so… (Yikes! Apple would be killing Ethernet!!!)

5% say that Apple should have made the MacBook thicker or longer, or made the battery smaller. Can you imagine Steve Jobs signing off on that?

The rest are miscellaneous ideas: using stacked ports, leaving out the optical drive, crowding the connectors closer together, combining two ports, and so forth; and fall under similar arguments.

A common thread in many suggestions is a misunderstanding, or perhaps just ignorance, of the technical details of USB and FireWire. While their areas of application overlap, the solutions they offer are different, and so are the protocols they use. USB is master/slave, FireWire is peer-to-peer. Converting one to the other isn’t simply a matter of rearranging pins, or reencoding signals, as happens inside most video adapters; you’d need a fast processor and RAM to do that, and even so you can’t replicate special functions like target mode or streaming on the USB side. You’ll find very few such converters on the market, and they’ll all have some limitations.

Finally, a frequent question is “why doesn’t Apple just implement target mode on USB”? It’s not that simple. On FireWire, target mode is just a software matter – since the interface is peer-to-peer, no chip change is necessary. On the USB side, target mode would imply switching the originating Mac from master to slave and using a hard-to-find A-to-A plug. Current USB chips don’t support that, and connecting such a cable without the port being pre-switched would probably fry one end or both. The upcoming USB On-The-Go supplementary standard supports this over two new protocols and a new connector type; neither work over hubs, and it needs different PHY chips too.

Re: More tradeoffs

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Farewell Firewire, Nice Knowin’ Ya

The Mac community seems to be quite enraged about Apple’s decision the slowly get rid of Firewire on the new MacBooks. The newly-introduced smaller MacBook (13-inch) has no Firewire port whatsoever and the larger MacBook Pro (15-inch) only has a …

Re: More tradeoffs

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Psystar Still At it – Now With Notebooks

Six months ago, Psystar entered the Desktop arena with a PC for $600 that could get your choice of Windows, Linux or Mac OSX. Of course Apple responded with a Lawsuit and Psystar countered. Every time we speculated Psystar is…

More tradeoffs

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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.

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