In 1976 the fasted normal processor ran at around 5MHz (such as the RCA 1802).  Personal computers really hadn’t been thought of, and mainframes were massive.  It was then that Seymour Cray decided to build a Super Computer. A computer that would be better and faster then most anything that existed at the time.

The Cray-1 ran at a blistering 80MHz, and could work with a staggering 32MB of memory.  This performance was not achieved in personal computers until the 1990′s.  No single processor of 1976 could attain these speeds so Cray designed his own.  Only 4 different types of ICs were used in the Cray-1 (2 types of quad-NAND gates and 2 types of SRAM)  All of the logic was ECL (Emitter Coupled Logic) which was very fast, very power hungry, and produced a lot of heat.  In all the Cray-1 used some 200,000 gates, many of which were solely used to add timing delays to make sure signaling did not generate standing waves or switching noise.

Original Cray-1 Circuit Board

Recently a man by the name of Chris Fenton decided to make a 1/10th WORKING scale model of the Cray-1A. This is no small feat, there is not a lot of surviving documentation for the Cray, nor is there much of any software left (they were mostly retired from service by 1990).  Chris wished the Cray-1 to physically look like the Original (including the padded bench seat) as well as be binary code compatible.  His implementation runs at 33MHz on a Xilinx Spartan-3E 1600 CPLD.  Basically this is a dev board with a chip that has a complex array of programmable logic that you can program to do what you want.  In this case 1.6 million gates, about 1.2 Million of which are used in the design, significantly more the the original.

Cray-1A Model

The original Cray weighed in at 5.5 tons with the cooling system, and drew around 30kW of power. The 1/10th scale? will run on a few batteries.  Supercomputers are still an important part of computing, but as vector processing expands (what the Cray was orginally diesgned for)  such things as graphics cards can be used to perform much of the tasks of a supercomputer, and do so faster and cheaper.

Regardless, when people think of a Super Computer, they think of the Cray

The CPU Shack is pretty much on the trailing edge of technology, we are, after all, a museum.  However, we fancy the new technology as well, and like to crack it open for a look see.  The iPhone, in its 4th generation, is an oasis of CPU’s, sadly we have not been able to get one.  That has now changed….

Anthony, of the iPhone repair company Milliamp.com has graciously donated the logic boards from a iPhone 2G, 3G and 3GS. No 4G iPhones yet, but perhaps later.  Now there has been several teardowns of iPhones as they came out, notably by the good folks at iFixIt.  We are going to explore the many CPUs in each model of iPhone, the changes made as they evolved, and something new though not entirely unexpected.

CPUs by function and generation of iPhone:

Applications Processor vs Baseband Processor

On a device such as the iPhone it is common to have two separate CPUs that run the phone.  The Baseband Processor runs the underlying hardware of the phone (the radios, etc)  This is critical timing wise so it runs its own OS, a Real Time OS capable of dealing with all the complexities in making a phone call or sending data to a cell tower.

The Applications Processor runs just that, the applications, such as iTunes, and iOS itself, this way they are independent of the phone portion. This way if say the new game you installed crashes, it does not effect your phone talking to the tower.

In addition to the applications processor and baseband processor there are several others.  The GPS has its own processor, as does the Bluetooth, and the Wifi as well as the touchscreen. Some of these are pretty simple CPUs, but think back  a few years.  The CPU running JUST the wifi in an iPhone is faster then most desktop computers 15 years ago.

Apple iPhone Logic Boards

Apple iPhone 2G

The Original iPhone and the 3G used the same app. processor, an ARM11 based CPU made by Samsung. It initially ran at 400MHz but via a software update was bumped up to 412MHz.

The biggest change in the 2G to the 3G was the addition of GPS and a change in Baseband.  the 3Gs baseband ran at less then 200MHz, but the 3G runs at up to 312MHz, and included 2 actual ARM processors. add in the CPUs that runs the touch screen, GPS, wifi, and bluetooth and you scan see there is ALOT of processor power in the phone.  7 DIfferent CPUs just to make the phone work.

Apple iPhone 3GS

The 3GS iPhone boosted the speed of the applications processor considerably (and thus it runs iOS4 MUCH better then the 3G).  Again the app processor is made by Samsung, but now its clocked at 600MHz, and based on the ARM Cortex-A8, a faster core then the ARM11 design.  This processor will do 800+MHz but Apple underclocks it for the sake of battery life.  The baseband remains the same, but APple used an integrated chip to handle both the Bluetooth and the wifi.

Apple iPhone 4G

Previous models of iPhones carried something over from the previous model. Whether it was the app processor, baseband, or wifi, there was some reuse. Not so with the 4G, All the important bits are new.  The App processor is the same as in the iPad, the ARM Cortex-A8 based A4 (which really is a Samsung/Intrinsity design.  This design we know is capable of 1GHz (as it does such in the iPad, however, to preserve battery, its clocked at around 800MHz in the iPhone.  The Baseband processor is also all new, its now running a single ARM11 core at up to 416MHz.  The Baseband processor in the iPhone 4 is faster then the original CPU in the iPhone 3G. The Real Time OS that runs on the Baseband also changed, from Nucleos, to ThreadX. They are made by different companies (Mentor Graphics vs Express Logic) however the same designer wrote them both (William Lamie)

Apples mid-life CPU revisions

Its common for a design to evolve somewhat in the life of a product. This seems to have happened considerably within iPhone generations.

Apple used several revisions of what SHOULD be the same CPU. the iPhone and iPhone 3G use the same processor, but here we see no less then 3 different part numbers for it.  In the 3GS we see something similar, even for devices dated the same week, there is 2 different part numbers.  Its curious what Apple/Samsung saw fit to change.  If you know of other part numbers, lets us know

Its well known that manufacturers such as Intel and AMD will sell quad cores as dual cores, or 6-cores as quad-cores in order to meet demand, or to use dies that didn’t ‘make the cut.’ This process has been going on for over 30 years though. Back in the 70′s and 80′s it was very common for a device such as this:

Intel D2704 4k EPROM

Which is a 2704 4k EPROM, to actually be made from a 2708 die, just with not all the leads connected, or sometimes, with them connected but just labeled as the smaller part. In a production environment, it is cheaper to have a single production line making dies that can be used in more then one device, then having an entire seperate production line just to make a product that may not be the most popular.  Look at this die shot (its a bit blurry) but you can see its a 2708 die.

2704 with 2708 die

Once again, whats new, really isn’t we have just went from small EPROMs, to CPUs with billions of transistors

On February 20th of 1997 Cyrix announced the MediaGX processor, running at speeds of 120 and 133MHz. By June of that year they were up to 180MHz as production was ramped at National and IBM (see press release). These processors were based on the Cyrix M1 (5×86) architecture and integrated basic graphics, and audio functions. They were sold as a ‘PC on a chip’ for budget applications, with a bit of a budget performance.

Early MediaGX Marked Gx86 120MHz circa late '96

In October 1997 Cyrix announced plans for the Cayenne cored MXi, a follow on to the MediaGX. By 1999 National Semiconductor had made some samples of it, but thats as far as it got. This was also when National Semiconductor bought Cyrix, effectively ending Intel’s lawsuit against Cyrix over x86 licensing as National held an x86 license. The Media GX was bumped to 200 and 233MHz and MMX support was added.

National Semiconductor Geode 266MHz circa 2001 Sample

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Today while browsing the teardown section on Embedded.com I came across an article about a Kodak picture frame.  At its heart was a processor by a company called Amlogic.  They make among other things, processors for digital picture frames.  Their website doesnt have much more info about their products.  It appears many of their devices are based on a variety of ARM cores (as often is the case.

If anyone knows anything more about this company, or its interesting processors, let us know