1,Android system Architecture First layer:Linux kernel, second layer:C + + code base, third layer: Android SDK API, layer Fourth: applications.
2, the driver is the direct interaction with the hardware of a class of programs, device driver for the operation of the system and the use of hardware is critical.
3.Linux divides memory and peripherals into three main categories: Character devices, block devices, and network devices. the communication and character devices of the Linux kernel and network devices are very different from those of block devices, and the network devices are designed to receive and send packets. Character devices and block devices can be categorized as a class, they are all sequential / random reading and storage units, network equipment is a special device driver, it is responsible for receiving and sending frame data, may be physical frames, may also be IP packets , These features are determined by the network driver.
4,Android transplant can be divided into application transplantation and system transplantation.
5. Thelinux kernel version number is composed of major version number, minor version number, revision number, fine-tuning version number, and special tuning for specific Linux system.
6, The Linux kernel judgment method: see its kernel version number, example Linux2.4,Linux2.6{Concrete method: uname – a , Cat/proc/version} .
7,Linux driver is only related to the kernel, and system-independent.
8, the general Android driver has the corresponding HAL, but is not necessary.
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"Android Deep Exploration" Vol. 1 Chapter I notes