Android system. IMG: yaffs or ext4?

Source: Internet
Author: User

As the mobile phone's internal storage has changed from NAND to emmc, now system. IMG is increasingly using ext4 as a file system, rather than the previous yaffs2.

Run the file command to view system. IMG. If the output is: VMS Alpha exectutable, this is yaffs.

If the output is data, it is probably ext4. However, this image is a spare image and contains some spare data. Therefore, you must first process the image with simg2img and then mount it directly.

As to why emmc is used instead of NAND, an excerpt from Baidu encyclopedia is as follows:

Currently, emmc is the most popular local storage solution for mobile devices. It aims to simplify the design of mobile phone memory. Different brands of NAND Flash chips include Samsung, kingmax, and Toshiba) or Hynix and Micron must be redesigned based on the product and technical features of each company, in the past, no technology was available to use all the factory-branded NAND Flash chips. Every time the NAND flash process technology is upgraded, from 70 nanometers to 50 nanometers, and then to 40 nanometers or 30 nanometers, mobile phone customers need to design again, however, the process technology of semiconductor products will be updated every one year, and the memory problem will also drag down the speed at which new types of mobile phones will be launched, therefore, the concept that all the memory and control chips for managing NAND Flash are packaged on one MCP, such as emmc, is becoming increasingly popular.

The design concept of emmc is to simplify the use of memory in the mobile phone. The NAND flash chip and the control chip are designed as one MCP chip. Mobile phone customers only need to purchase the emmc chip and put it into the new mobile phone, there is no need to deal with other complex problems of NAND Flash compatibility and management. The biggest advantage is to shorten the time-to-market cycle and R & D costs of new products and accelerate the pace of product innovation. 

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