Android Partitions Explained: boot, system, recovery, data, cache & misc
Unless you have been using your Android phone just for calls, SMS, browsing and basic apps, you should know that Android uses several partitions to organize files and folders on the device. Each of these partitions has a distinct role in the functionality of the device, but not many Android users know the significance of each partition and its contents. In this guide, we will take you on a tour of Android partitions, what they contain and what can be the possible consequences of modifying their content.
Let’s start with a list of standard internal memory partitions on Android phones and tablets. These are:
In addition, there are the SD card partitions.
Note that only /sdcard is found in all Android devices and the rest are present only in select devices. Let’s now take a look at the purpose and contents of each of these partitions.
This is the partition that enables the phone to boot, as the name suggests. It includes the kernel and the ramdisk. Without this partition, the device will simply not be able to boot. Wiping this partition from recovery should only be done if absolutely required and once done, the device must NOT be rebooted before installing a new one, which can be done by installing a ROM that includes a /boot partition.
This partition basically contains the entire operating system, other than the kernel and the ramdisk. This includes the Android user interface as well as all the system applications that come pre-installed on the device. Wiping this partition will remove Android from the device without rendering it unbootable, and you will still be able to put the phone into recovery or bootloader mode to install a new ROM.
The recovery partition can be considered as an alternative boot partition that lets you boot the device into a recovery console for performing advanced recovery and maintenance operations on it. To learn more about this partition and its contents, see the ‘About Android Recovery’ section of our guide to ClockworkMod recovery.
Also called userdata, the data partition contains the user’s data – this is where your contacts, messages, settings and apps that you have installed go. Wiping this partition essentially performs a factory reset on your device, restoring it to the way it was when you first booted it, or the way it was after the last official or custom ROM installation. When you perform a wipe data/factory reset from recovery, it is this partition that you are wiping.
This is the partition where Android stores frequently accessed data and app components. Wiping the cache doesn’t effect your personal data but simply gets rid of the existing data there, which gets automatically rebuilt as you continue using the device.
This partition contains miscellaneous system settings in form of on/off switches. These settings may include CID (Carrier or Region ID), USB configuration and certain hardware settings etc. This is an important partition and if it is corrupt or missing, several of the device’s features will will not function normally.
This is not a partition on the internal memory of the device but rather the SD card. In terms of usage, this is your storage space to use as you see fit, to store your media, documents, ROMs etc. on it. Wiping it is perfectly safe as long as you backup all the data you require from it, to your computer first. Though several user-installed apps save their data and settings on the SD card and wiping this partition will make you lose all that data.
On devices with both an internal and an external SD card – devices like the Samsung Galaxy S and several tablets – the /sdcard partition is always used to refer to the internal SD card. For the external SD card – if present – an alternative partition is used, which differs from device to device. In case of Samsung Galaxy S series devices, it is /sdcard/sd while in many other devices, it is /sdcard2. Unlike /sdcard, no system or app data whatsoever is stored automatically on this external SD card and everything present on it has been added there by the user. You can safely wipe it after backing up any data from it that you need to save.
This is not a standard Android partition, but has become popular in the custom ROM scene. It is basically an additional partition on your SD card that acts as the /data partition when used with certain ROMs that have special features called APP2SD+ or data2ext enabled. It is especially useful on devices with little internal memory allotted to the /data partition. Thus, users who want to install more programs than the internal memory allows can make this partition and use it with a custom ROM that supports this feature, to get additional storage for installing their apps. Wiping this partition is essentially the same as wiping the /data partition – you lose your contacts, SMS, market apps and settings.
With this, we conclude our tour of Android partitions. Now whenever you install a ROM or mod that requires you to wipe certain partitions before the installation, you should be in a better position to know what you’re losing and what not and thus, you’ll know what to backup and what not.
- Android 系统镜像: boot.img kernel.img ramdisk.img system.img userdata.img cache.img recovery.img
boot.img(kernel.img+ramdisk.img) ramdisk.img(/) system.img(/system) userdata.img(/data) cache.img(/c ...
- How To Backup Your Android Phone’s Boot, Recovery And System Partition Images -- RomDump
One can’t stress enough on the importance of backups and when it comes to tinkering with your Androi ...
- Linux下 解包/打包 Android 映像文件 system.img, boot.img, ramdisk.img， userdata.img.
Linux下 解包/打包 Android 映像文件 system.img, boot.img, ramdisk.img, userdata.img. 2014年10月20日 ⁄ 计算机视觉 ⁄ 共 1 ...
- Bootloader - main system - Recovery的三角关系【转】
本文转载自:http://blog.csdn.net/u012719256/article/details/52304273 一.MTD分区: BOOT: boot.img,Linux ...
- Bootloader - Main system - Recovery的三角关系
原文地址:http://blog.csdn.net/myarrow/article/details/8115610 一.MTD分区:BOOT: boot.img,Linux kernel ...
- recovery 升级&#39;@/cache/recovery/block.map&#39; failed错误问题
随着android版本升级,升级包越来越大,当升级包无法存储在cache分区的时候,会把升级包下载到data分区,然后从data分区升级,最近从data分区加载升级包升级的时候,遇到了如下错误: [ ...
- Global UNIX file system cylinder group cache
A global cylinder group (CG) cache is stored in file server memory and shared by a plurality of file ...
- System.Web.Caching.Cache类 缓存 各种缓存依赖
原文:System.Web.Caching.Cache类 缓存 各种缓存依赖 Cache类,是一个用于缓存常用信息的类.HttpRuntime.Cache以及HttpContext.Current.C ...
- Android 程序drawable资源保存到data目录
我讲到过利用rsync实现数据的镜像和备份,但是要实现数据的实时备份,单独靠rsync还不能实现,本文就讲述下如何实现数据的实时备份. 一.rsync的优点与不足 与传统的cp.tar备份方式相比,r ...
CSS3的filter属性 (版权归原作者所有) http://www.jianshu.com/p/ca7a2bdcc1e7/comments/4956985 filter: blur(5px); f ...
一般情况下,MySQL安装以后是自动运行的,不知道我这台机器是什么原因,MySQL不能自动运行,每次开机后都要手动运行mysqld.exe,比较麻烦,于是用以下方法将MySQL自动启动: 1. 运行c ...
最近在搞whenever时看到可以用cron语法设置定时任务.所以研究了下cron 语法. every '0 0 27-31 * *' do command "echo 'you can u ...
DOM级别 文档类型: 节点类型: 判断节点类型(注意Node对象): <div id="container">这是一个元素节点</div> <scr ...
- HDU4893--Wow! Such Sequence! （线段树 延迟标记）
Wow! Such Sequence! Time Limit: 10000/5000 MS (Java/Others) Memory Limit: 65536/65536 K (Java/Oth ...
- A Bit Fun
A Bit Fun Time Limit : 5000/2500ms (Java/Other) Memory Limit : 32768/32768K (Java/Other) Total Sub ...
- 【Django】 rest-framework和RestfulAPI的设计
[rest-framework] 这是一个基于django才能发挥作用的组件,专门用于构造API的. 说到API,之前在其他项目中我也做过一些小API,不过那些都是玩票性质,结构十分简单而且要求的设计 ...
1.Cookie和Session都是会话技术,Cookie是运行在客户端,Session是运行在服务器端. 2.Cookie有大小限制以及浏览器在存cookie的个数也有限制,Session ...