[Xiaomi Mi A1 Questions & Answers] Lupin The Third:
A thread for everyone from everyone! Noob friendly and a home for every newcomer!​

Thread rules:

1. Respect xda rules regarding conduct. (Rule no. 2 here)

2. All questions allowed by xda rules are welcomed.

3. Your questions must show that you want to learn. No one will criticize you because you are trying to learn.

4. Ask politely no matter how desperate you might be.

5. Do not post or request warez. XDA rule 6 here.

6. There are no bad questions, but only bad intentions and bad answers.

7. Don't use this thread as an excuse to ask all kinds of questions everywhere in the forums, especially in development threads. This is why this thread is for.

8. For all who want to help, do that kindly according to the rule 2.3 of xda

Work In Progress

Android related questions

Q: What is a smartphone?

A: ... just kidding, you are way past that!

Q: What is an android ROM?

A: Android Read-Only Memory. A file containing the Android operating system and its apps. The "stock ROM" comes preinstalled on the phone.

Q: What is a custom ROM?

A: A custom ROM replaces your device's preinstalled Android operating system (or Stock ROM), normally stored in read-only memory, with a new version of the Android operating system.

Q: What is a kernel in android?

A: A kernel is the component that helps the applications communicate with the hardware. It manages the system resources, communicates with external devices when needed, and so on. Android uses a variation of the Linux kernel. The kernel is the bridge between the ROM and hardware.

Q: Rooting-What is it?

A: Rooting is the process of allowing users to attain privileged control (root access) over various Android subsystems. As Android uses the Linux kernel, rooting an Android device gives similar access to administrative (superuser) permissions as on Linux. Rooting gives the ability (or permission) to alter or replace system applications and settings, run specialized applications that require administrator-level permissions, or perform other operations that are otherwise inaccessible to a normal Android user.

Q: What is a recovery in android?

A: In Android, recovery refers to the dedicated, bootable partition that has the recovery console installed. It is accessible with a combination of key presses, or instructions from a command line.

Q: What is Stock Recovery?

A: The Recovery that comes with your Android Device from the manufacturer is called Stock Recovery. Stock recovery can be used to flash updates from an update.zip file, OTA Updates, for factory reset etc.

Q: What is a Custom Recovery?

A: From stock recovery, we cannot flash Custom ROMs, Modules etc. For this, you need to flash custom recoveries like TWRP. Flashing a custom recovery overwrites the system recovery. Custom Recoveries have been coded to allow for backup and restore functions, selective deletion of data so you don't have to wipe everything, and modified to allow update packages that have not been digitally signed by official sources.

Q: What does TWRP stand for?

A: Team Win Recovery Project.

Q: What does OTA stand for?

A: Over The Air Update. An OTA Update is a software update that is distributed via Wi-Fi or broadband network, making use of functions built into the operating system itself.
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Note:

Noobs and newcomers: If someone answers you and the answer is helpful to you, press the "thanks" button for that person. It's a polite thing to do in the forums and saves you from creating a post just to say "thanks".

And remember: there are those that are noobs and those that were noobs!

Credit: Google.com for helping me to search, select, format and prepare some of the answers for easy reading.