Architecture of Windows Phone 7-[WP development document translation series]

ArticleDirectory

• WP7 hardware components:
• WP7 software components:
• Memory Model and Management
• Kernel memory ing (kernel memory map)
• Process-Space Mapping)

I decided to focus more on the technical fields that I was interested in and do what I liked. I collected some books developed by WP, almost all of which are in English. I suddenly wanted to try to translate them, not only to train myself, but also to some extent to facilitate other people's Quick Start.

The first document selected architecture guide for Windows Phone OS 7.0, which is relatively simple and should be understood at the beginning of WP development.

This document mainly includes the following aspects:

• Introduction to Windows Phone 7 Architecture
• Windows Phone 7 Kernel
• BSP for widows Phone 7
• Graphics Rendering Technology for Windows Phone 7
• Windows Phone 7 network connection
• Windows Phone 7 File System
• Windows Phone 7 mobile phone upgrade
• Windows Phone 7 user-mode components
• Security of Windows Phone 7
• Enable and Disable Windows Phone 7

1. Introduction to Windows Phone 7 architecture:

This document provides some basic technical information about Windows Phone 7. To meet user experience requirements, WP7 integrates special hardware and software into a new platform on which users can propose different performance, quality requirements, and hardware differentiation.

This document describes the core architecture components of WP7 at a higher level, including:

• Hardware components;
• Software components, including in kernel mode and user mode (for example, kernel, main version support package ?, DriverProgram, OEM adaptation layer, and other system layers );
• Security: WP7 starts and disables processes.

The architecture of WP7 is based on the Windows Embedded ce 6.0 kernel !), Logically, there are three layers: Kernel Mode, user mode (software layer), and hardware. As shown in:

 
WP7 hardware components:

• Armv7 Processor
• Hardware acceleration (meets the needs of DirectX application programming interfaces)
• Capacitive touch screen
• Camera
• Connect Bluetooth to wifi
• FM radio
• A-GPS
• Accelerators, compass, flashlights, distance sensors, etc.

(Omitted a short section about hardware)

WP7 software components:

WP7 consists of kernel-mode and user-mode. For more information about the software and WP7 security and startup, and about how to disable processes, see the following section.

Ii. Windows Phone 7 kernel:

The kernel of WP7 provides some basic system services, such as memory management and process/thread scheduling. When 1 GB of virtual memory space is allocated, it can run 32,000 processes simultaneously in one second. The WP7 kernel must meet the following requirements:

• Improve system performance
• Improve Security
• Increase the robustness of the WP7 Platform

The figure below briefly illustrates the architecture of the WP7 kernel design:

WP7 is managed through a unified kernel, while other subsystems implement its functions by loading them as DLL. Because the functions implemented by these subsystems do not need to be implemented across processes, this unified kernel design can improve the functions of the entire system. The following table describes the functions of each component function in the kernel space:

 

Next, we will explain in detail some kernel concepts in WP7, such as memory model and management, processes/threads, and system calls.

Memory Model and Management

WP7 is a 32-bit operating system with a built-in 4 GB virtual address space ). From the design perspective, 2 GB space is allocated to the kernel, including the file system and the device driver manager in the kernel state. The other 2 GB is allocated to the processes in progress, such as processes.Code, User DLL files, memory ing files, etc. The following figure shows the memory architecture of WP7:

WP7 virtual storage management needs to achieve the following goals:

• Allocate as much virtual memory as possible to each process;
• No limit on the preset number of processes (not quite clear)
• Memory Allocation Policies between processes in user mode
• Minimum dependency on CPU resources for Running code
• More efficient allocation of virtual memory

Note: In this memory management mode, only one process maps to the memory at a time, and the active process completely controls 1 GB of memory space, other processes are not allowed to access this space. For more information about Memory sharing between processes, see the following content.

Kernel memory ing (kernel memory map)

The following chart describes the relationship between kernel memory allocation and ing:

Kernel space ing includes the following four aspects:

• System trap area
• Kernel VM-virtual memory shared by kernel, service, and driver
• Kernel xip DLLs-xip indicates execute in place.
• Direct physical address Mappings

Process-Space Mapping)

To be continued