Seeing what looks like a full iPhone attached to it (I know it's just the screen, but the inclusion of a taped-over home button is interesting) gives me kind of a "Thinking quickly, Dave constructed an iPhone using a circuit board, some tape, and an iPhone" vibe.
That's likely a ex post facto hack, as a production iPhone's front piece was likely attached to make this prototyping board more complete.
The engineers back then certainly wouldn't have seen the iPhone-shaped screen assembly, they would either use the video out to a regular monitor (sufficient for most hardware testing and kernel development) while the developers responsible for making the touch screen work might have gotten a screen unit that wasn't iPhone-shaped.
(This particular board might have been assigned to someone who was only ever expected to use the video output ports.)
These dev boards were modular, so that engineers without a need-to-know for e.g. the screen or radio didn’t get one. But this is not a retrofit; if you needed a display or touch then this is what you got.
The video out ports were only used for the 30-pin video out, the main display never ran on them (could not run on them).
iPhoneOS kernel developers could hardly care less about the display; everything was done with the serial port and JTAG (I don’t recall whether Ethernet debug was ever supported).
There are a bunch of other errors / misconceptions in the article sadly. These boards were pretty cool & highly functional and it’s sad not to see justice done to them.
I'm not saying you're wrong—I'm just some random person on the internet. But I find it surprising that they'd even have that many pieces of iPhone shaped glass attached to working touchscreens early on in the process.
Of course people working on developing the UX would want to see and touch a contextualised screen so I suppose the configuration we see here would make sense for them.
This board’s not from “early on in the process”. Making touch work well was once of the major undertakings, and there had been various iterations of display around for literally years at this point. By the time this board was made, the display / touch was largely a done deal and they were being built in respectable volume.
Likewise the UX development started years before, some of the earliest hardware was just a handheld display & touch tethered to an old G3 PowerPC Mac (to get the performance constraints about right). The purpose here was to get representative displays into the hands of relatively large numbers of engineers.
I was also curious about that. In other stories I've read, I've heard it referred to as a big ugly box with a touch screen embedded on top of it, which is what I imagined most people worked on. But this just looks like a normal iPhone with a large breadboard connected.
Since the iPad display is much larger than the phone display, sitting it on the board like this wasn’t practical. There was an iPad dev board that looked a lot like this, but there were also ‘acrylics’ - chassis made from cnc’d Acrylic sheeting - that supported the screen connected to the board by a flex.
Most engineers wanted nothing to do with the display units; they were bulky and relatively fragile and desk space is always at a premium.
I always imagined that the iPad came about because some engineer had a Retina iPhone prototype on a standard 72dpi screen and figured it might work to replace a laptop.
I believe “iPad” was actually being developed prior to iPhone and was put on pause while multitouch and other technology was lifted from the project to support iPhone.
If anything a big board like this is one way to ensure it's not easy to steal.
The on-board (pun intended) documentation - "Do not connect battery without removing J49", etc - is pretty neat too. Is this something that's fairly standard in the industry?
I love when the info makes it to the shipped version. My bass amp has a miniature schematic drawing etched into itself, it's been incredibly useful. Here's my favorite PCB etching though: http://i.imgur.com/28cYobo.jpg
The "M68" name is interesting, given that Apple has a long history with the M68K processor, which isn't involved here. I wonder if it's a nod to the first Mac or the Lisa.
That's really interesting. Whose job is it to actually design and develop the prototype board? It seems like that team would have to know quite a bit, if not nearly everything, about the device.
Usually the design engineer that handles the production board goes through the EVT boards.
Basically the purpose of EVT to a) ensure all the components identified in the initial survey/design review actually work together b) enable software development early in the process c) iron out any showstoppers and kinks that could jeopardize the project later on.
The next few design stages usually get rid of all the super-debug stuff (such as the ethernet port on the iphone; also maybe get the form factor down) while still retaining the regular debug stuff (JTAG etc). This usually when mechanical can jump in and preliminary compliance stuff can take place (EMC etc)
Why the anonymous source? 10 year old secrets in a rapid-development technology seem like non-secrets, so who's willing to "leak" but not be identifiable at this point?
Maybe Apple has strict secrecy rules that are only partially enforced? I don't quite get it.
Thanks for the helpful clarification. Clearly someone has this dev board or has access to it in such a way that they were able to share it. My point was simply that they might have something they shouldn't, and that fact helps explain some quirks of the article that seemed confusing to the GP.
Is it me or does it look like the top layer has reaaaaally thick copper? Look at how it differs between areas with those squares contra area without. Looks like it's very very thick. Perhaps the solder mask.
Nothing out of the ordinary for prototypes. Much easier to solder fixes to without accidentally stripping a trace and better RF properties, which will help with an oversized board like this one.
