Note: The following premise is that the system has been rooted.

/systemIt is the Android system directory, which stores Android system applications and lib. Sometimes we need to write files into this directory. For example, we build our own apk into the system and start it as a system apk, but this directory has only read permission by default. no write permission will appear after the execution write Read-only file systemwrong tips.
The following describes how to get the write permission:

  • Execute adb shell su. Enter adb shell as root user;
  • Execution mount|grep /system, you can see the following information, different devices, see different information.
/dev/block/platform/15740000.dwmmc0/by-name/system /system ext4 ro,relatime,data=ordered 0 0

image copied from google

Android Champ is developed to get depth knowledge about the android internals. It is designed by developers and experts. Our goal is to create a space for handpicked blog posts and proof-read all of them. Our editors are developers, and we know what is valuable for engineering knowledge. We are happy to support your blog post promotion in the community and provide you with the necessary guidelines.

Below are some best practices we kindly ask to follow for every submission:

  1. Every story/post will be reviewed by industry experts so please don’t submit spam or entertainment related posts.
  2. Any Technology-driven story…

screen image is taken from google

We often need SSH or telnet to remotely log in to the Linux server, and often run some tasks that take a long time to complete. During this period, we cannot close the window or disconnect, otherwise, the task will be killed and everything will be aborted or, the network will suddenly be interrupted and the task is not completed. At this time, we can open the screen session to solve it.

The screen command can separate the current window from the task. Even if we are offline, the server is still running tasks in the background. …

Battery status

if you want to know the battery status or hardware status of the android device, here you can see all the details using the ADB.

You can dump the battery status with the following command:

adb shell dumpsys battery

When I run the command, I get the following output:

unique is identify by using it’s ID

Android assigns each application a UID( userID) at the install time. Unlike PID (Process ID) which is transient and keeps changing all the time, UID stays constant as long as the application is not reinstalled.

The UID should be unique to each application, except when the application explicitly requests to share a userID with another application, i.e. there are security restrictions around this, the two applications must be signed with the same private key.

Android uses the UID to set up a kernel-level Application Sandbox. The kernel enforces security between apps and the system at the process level through standard…

Usually after the new version of AOSP is released by Google, the SoC vendor needs to upgrade the HAL, and the OEM can upgrade the HAL and Framework before the user can receive the push of the OTA upgrade package on the device.

VTS itself means the compliance test suite of Android Vendor Interface (VINTF).

VINTF is a versioned, stable interface for Android vendor implementation. This concept is introduced from Android version 8.0 (Oreo) in order to improve the engineering productivity, launch velocity, security, and reliability of Android device ecosystem.

VTS consists of a set of testing frameworks and test…

Linux Fstab

What Is Fstab?

Fstab is your operating system’s file system table. In the old days, it was the primary way that the system mounted files automatically. Nowadays, you can plug in a USB drive of any kind and it’ll just pop up in Nautilus as it does in Windows and Mac OS, but once upon a time, you had to manually mount those disks to a specific folder using the “mount” command. This held true for DVDs, CDs, and even floppies.

Back then, your only alternative was the tell the computer that anytime a specific device was plugged in, it…

In this article, I am covering the basic understanding of android beginner framework development. I have written some other articles about the android framework concepts. To know about these articles, please go through the below profile link:

First, briefly introduce the architecture of Android

The interviewer in interviews asked these questions with top-tier Internet companies. Familiarity with the knowledge points listed in this article will greatly increase the chance of passing the first two rounds of technical interviews.

Mainly divided into the following parts:

(1) Java interview questions

(2) Android interview questions

(3) Advanced development technology interview questions

(4) Cross-platform Hybrid development

Java interview questions

Mastering java is very important. Large companies not only require you to use a few APIs, but also require you to be familiar with the principles of source code implementation, and even require you to know what are the deficiencies, how to…

This technological era is driven by globalization that is revving up the job market. Working with one or two organizations during one’s career lifetime is thing of the past. In this fast-paced world, diverse and stimulating career options are easily accessible, across borders.

Let’s list down a few of the most common reasons that may drive one to quit.

  • Bad appraisals
  • Incompetent manager/supervisor
  • Company Policies
  • Lucrative job offers
  • Fat pay packages/hikes
  • Travel opportunities
  • Change in career option
  • Working in a different country

The above are stimulants that compel us to explore the job marketplace.

This is widely evident in a…

Budhdi Sharma

A developer is responsible for developing a framework and system applications for devices powered by the Android operating system.

Get the Medium app

A button that says 'Download on the App Store', and if clicked it will lead you to the iOS App store
A button that says 'Get it on, Google Play', and if clicked it will lead you to the Google Play store