[General Questions and Answers] xXx yYy:
To answer your questions:

1. Android Kernel

There are a few reasons why the Android kernel is spread across multiple repositories:

Modularization:

Different parts of the kernel are responsible for specific functionalities. Splitting them allows for independent development, maintenance, and easier contribution from various parties.

Hardware Diversity:

Android runs on a wide range of devices with varying hardware components. Separate repositories allow for customization of the kernel for specific hardware needs.

Security:

Isolating critical kernel parts in separate repositories enhances security by potentially limiting the attack surface.

2. Frameworks

Number:

There isn't a single official count, but there are dozens of Android frameworks available. Popular ones include React Native, Flutter, and Xamarin.

Number Needed:

Android can function with just the core Android framework (part of the Android Open Source Project - AOSP). However, additional frameworks can significantly speed up development and offer pre-built functionalities for features like user interface elements, networking, or sensor access.

3. Drivers

Qualcomm:

You can find Qualcomm's open-source drivers on their developer website or through the Linux kernel source code repository (https://www.kernel.org/).

Mediatek:

Mediatek's open-source driver approach can vary depending on the specific chipset. They might be available on their developer website or through community repositories. Searching for "Mediatek [Chipset name] Open Source Drivers" should help you locate them.

The common partitions found in most Android devices using eMMC storage include:

Boot: This partition holds the kernel, which is the core of the Android operating system. It's responsible for booting up the device and loading the system.

Recovery: This partition contains a recovery image that allows you to fix software problems or restore your device to factory settings.

System: This partition stores the core Android operating system files, including the framework, libraries, and apps that come pre-installed with the device.

Userdata: This partition stores your personal data, such as your photos, videos, music, contacts, and app data.

Cache: This partition stores temporary files that can be quickly accessed by the system.

Vendor:

This refers to the System-on-Chip (SoC) manufacturer.

The vendor partition on the eMMC stores files specific to the SoC, such as:

Board Support Package (BSP): Provides drivers and libraries for the specific hardware components of the SoC.

SoC-specific libraries: Code that interacts with the unique features and functionalities of the SoC.

ODM:

This refers to the Original Design Manufacturer.

ODMs design and manufacture the physical device itself, but often don't design the internal hardware (SoC).

The ODM partition on the eMMC stores files that customize the Android experience for the specific device, including:

Device-specific libraries: Code that interacts with the specific hardware components chosen by the ODM (e.g., camera sensors, fingerprint scanners).

Hardware Abstraction Layer (HAL): Allows the Android framework to interact with the device's hardware components regardless of the specific implementation.

Custom features: Code for functionalities unique to the device developed by the ODM.

Addendum:

There are two main resources for finding documentation about Android:

Android Open Source Project (AOSP) documentation (https://source.android.com/docs):

This website contains documentation for the Android operating system itself, which is open-source. It's more technical and for developers who want to contribute to the platform or learn about how Android works at a deeper level.

Android Developers (https://developer.android.com/develop):

This is the official website from Google for Android app development. It has everything you need to get started, including code samples, guides, and an API reference.