Bloomberg Businessweek has published an interesting profile of Johny Srouji, Apple’s silicon chief (official title: Senior Vice President of Hardware Technologies), who joined the company back in 2008 to lead development of the A4, the first Apple-designed system-on-a-chip that made its debut in the iPhone 4 and the original iPad.
Apple is now widely praised by critics and fans alike for taking its chip destiny in its own hands. The article tells an in-depth story of how then CEO Steve Jobs had the foresight and courage to take Apple on a risky path to make it a fabless silicon designer.
Apple-designed mobile chips went on to differentiate iPhones and iPads on the hardware level from competing devices using off-the-shelf parts. The story also gives us our very first peek at chip-durability testing at an unmarked Apple lab in Cupertino.
Custom silicon as important differentiator
As mentioned, Apple started designing its own mobile chips starting with the A4 processor which in 2010 made its way into the iPhone 4 and the original iPad. Prior iPhones used Samsung’s chip designs and other silicon parts from a bunch of suppliers, including “elements from a Samsung chip used in DVD players.”
That in turn frustrated Jobs because relying on third parties for crucial components like the engine than runs the iPhone meant the Apple handset lacked the oomph Jobs thought it deserved to have.
“Steve came to the conclusion that the only way for Apple to really differentiate and deliver something truly unique and truly great, you have to own your own silicon,” Srouji says. “You have to control and own it.”
How iPad Pro almost ended up having iPad Air 2’s A8X chip
The article reveals that Apple originally planned to put the iPad Air 2’s A8X processor in the iPad Pro. But given the iPad Pro would launch in fall alongside the iPhone 6s, it would run a slower processor and look feeble next to the iPhone 6s. So Srouji put his engineers “on a crash program” to move up the rollout of the A9X chip (which powers the iPad Pro) by half a year.
Secret chip-testing lab in Cupertino
Hidden behind several locked doors at an unmarked lab is a room where Apple tests future-generation chip designs. The image below gives us our very first peek at that secret room, filled with what appear to be custom blades in the racks.
“All the equipment is operated remotely. The boxes are running software that scans for possible flaws in the chip architecture. Testing proceeds for several days on one element of the chip, then moves on to the next, and then the next, until the process is done, which can take months,” explains the article.
“We beat the silicon as much as we can,” Srouji says. “If you’re lucky and rigorous, you find the mistakes before you ship.” And in an adjacent room, circuit boards are wired together in milk carton-size stacks to simulate the capabilities of a future iPhone or iPad.
“Apple’s software programmers, sitting anywhere in the world, can remotely test how their code holds up against a future chip design,” reads the article.
Another unmarked building a few miles away holds rows of customized Mac minis, tasked with testing prototype chips under various temperature and pressure conditions.
“Standing in an aisle, surrounded by exposed circuit boards and digital innards, is like being inside the Matrix. ‘No one has seen this before,’” Srouji says.
Custom silicon design can be unforgiving
I especially liked this bit about “unforgiving” silicon design:
If there’s a bug in software, you simply release a corrected version. It’s different with hardware. “You get one transistor wrong, it’s done, game over,” Srouji says.
“Each one of those transistors has to work. Silicon is very unforgiving.” Among computer and smartphone makers, industry practice is to leave the processors to specialists such as Intel, Qualcomm, or Samsung, which sink billions into getting the chips right and making them inexpensively.
I suggest reading the whole piece, it’s a very interesting read.
Source: Bloomberg Businessweek