Apple A4

The Apple A4 is a system developed by Apple and manufactured by Samsung System-on -a- chip ( SoC). The A4 was developed by Apple's internal chip design department of the acquired company PA Semi arose. It combines an ARM CPU with a PowerVR graphics processor and also takes over the functions of a conventional PC chipset. Often called Apple A4 is used alone for the ARM processor, but this is not strictly correct. The internal name Samsung S5L89xx the previous SoCs was maintained at A4, the name Apple A4 is the marketing. The actual name of the A4 is S5L8930, the A4 thus remains one of the S5L SoCs. Predecessor of the A4 was the S5L8922, successor to the Apple A5.

The A4 was introduced together with the first-generation iPad on January 27, 2010. In addition, he was in the iPhone 4, used in the iPod Touch 4th Generation and the Apple TV 2nd generation.

Description

The system -on -a-chip connects CPU integrated GPU and other parts. There is little information on the components used. The main processor is an ARM Cortex- A8 core comes with up to 1 GHz ( the iPad ) are used. The default clock frequency is 800MHz in the iPhone 4, the iPod touch 4G 776MHz. The graphics processor PowerVR SGX is a 535, which is supported by a PowerVR VXD audio and video playback. The latter was licensed from Imagination Technologies, as in an annual report must be read on 18 December 2009. The A4 supports OpenGL ES 2.0, OpenGL 2.0 and OpenVG 1.0.1 and 1.1.

Competing architectures of similar products are Qualcomm's Snapdragon, Texas Instruments ' OMAP 4, Nvidia's Tegra 2 and Samsung Exynos.

The site iFixit has the built- in iPad Apple A4 can be investigated by the Canadian company Chipworks early April 2010. For this, the chip was cut layer by layer, treated with acid and examined under an electron microscope. The study yielded the following results:

• The chip comprises a plurality of superimposed layers of three in this multi-chip module design.
• Two layers are each a DDR SDRAM from Samsung with 1 Gbit (128 MB) of memory ( 256 megabytes); the iPhone 4, the storage capacity has been doubled to 512MB.
• The third layer is the actual ARM Cortex- A8 processor core.

The A4 thus greatly resembles its predecessor, the S5L8922. The only difference is the slight increase clock speed of bus, processor, memory and GPU.

Design errors

A design flaw of the older iPhone S5L89xx master processors was acquired in A4 Chip: It can be carried out by the so-called Limera1n exploit arbitrary code, which was mainly used by the jailbreak. This is not patchable through software updates bug allows among others the passcode lock the iPhone by executing a brute force program to read within a few minutes without much effort. This error has been fixed with the successor, the Apple A5.

Trivia

The appearance of the propagated by Apple A4 chip was only introduced with the finished iPads, while the A4 SoC in the prototypes of the iPad in their labeling the previous by PA Semi -designed S5L SoCs were similar.