Android Deep Explore--hal and Driver Development----Chapter One reading notes

1, Android system architecture has four layers, its development is now more mature, popular in the current market. Its architecture consists of four tiers (Linux kernel, C + + code base, Android SDK API, application).

2, the driver is the direct and hardware interaction of a class of programs, device driver for the operation of the system, the use of hardware is a key part.

3, Android system migration can be divided into two parts: application porting and system porting. The main work of Android porting is as follows: Porting Linux driver, porting HAL.

Application porting: Is porting the application to a particular hardware platform, in order to compensate for the differences between the hardware, we need to modify the source code. System migration: Refers to the Android operating system on a specific hardware platform to run, system porting in addition to porting the CPU architecture, the most important thing is to migrate Linux drivers.

4. Linux divides memory and peripherals into 3 categories: Character devices, block devices, and network devices. The communication between the Linux kernel and the network device is completely different from that of the character device and the block device, and the network device is designed for packet reception and transmission. Character devices and block devices can be categorized as a unit that can be read and stored sequentially/randomly, the network device is the driver of the special device, it is responsible for receiving and sending frame data, either physical or IP packets, these features are network-driven decisions.

5, Linux driver is only related to the kernel, and system-independent, the Linux kernel is judged by its kernel version number, such as linux2.4,linux2.6 and linux3.x{method: Uname–a or Cat/proc/version}.

6, the general Android driver will have the corresponding HAL, but not necessary.

7. Hal is located in the code base of the. os file and can only access the Linux driver directly through the HAL.

http://www.cnblogs.com/caoyutao/

Android Deep Explore--hal and Driver Development----Chapter One reading notes