windows ce

Windows CE : 

Windows CE Windows Embedded Compact or Windows Embedded CE 1

Synopsis.. : 

Overview – Introduction Brief history of Windows CE Windows CE Memory Models New Features Compatibility 2 Synopsis..

Overview… : 

Company Microsoft Programmed in C++ OS family Windows CE Source model Closed source Initial release 16 November 1996; 13 years ago) Latest release 6.0 R3 / 22 September 2009; 11 months ago) Available language Multilingual Supported platforms x86, MIPS, ARM, (SuperH up to 6.0 R2) Kernel type Monolithic Official website Windows CE 3 Overview…

Brief History.. : 

4 Brief History.. SP1 2.11 SP2 2.12 Jameson 4.1 McKendric 4.2 Tomatin NMD FP

Windows CE Limits : 

From Windows CE 1 to Windows CE 5, Windows CE has always had limits.. 32 processes at any one time 32 MB Virtual Memory per process 5 Windows CE Limits

Windows CE 5.0 Memory Model : 

Virtual Memory Map 2 GB for Kernel Single 2 GB mapping for all processes Divided up into 32 MB “slots” 32 Process Limit Each process has one 32 MB slot 32 slots for processes Shared memory Upper half of user space is shared memory Read / Write by all processes 6 Windows CE 5.0 Memory Model

Windows CE Memory Model : 

7 Windows CE Memory Model 32 KProcess 2 GBperProcess 2 GBKernelSpace Process Code User VM KernelFilesystemGWESDrivers . . . . . .

Introducing the New Kernel : 

2 GB of Virtual Memory per process 32,000 processes Unified Kernel Critical OS components moved into kernel space Improved system performance Increased security and robustness High degree of backwards compatibility 8 Introducing the New Kernel

Kernel Virtual Memory Space : 

9 Kernel Virtual Memory Space 0x80000000 Kernel Space 2 Gigabytes Fixed mapping independent of user space 0xFFFFFFFF All XIP DLLs in kernel Cached access to physical memory Uncached access to physical memory Ram file system & ram registry Kernel Virtual Memory Shared by all kernel Servers and drivers System Trap Area CPU Specific VM Kernel VM256 / 512 MB Object Store (128MB) Kernel XIP DLLs (128 MB) Static Mapped Uncached 512 MB Static Mapped Cached512 MB

New OS Layout : 

Moving critical drivers, file system, and graphical window manager into the kernel Kernel version of Coredll.dll Same APIs without the thunks Benefit Greatly reduces the overhead of system calls between these components Reduces overhead of all calls from user space to kernel space Increase code sharing between base OS services 10 New OS Layout

Performance & Size : 

Improvements expected in process switching Same performance Thread Switching Memory Allocation System Calls Some slow down with interprocess calls Now involves data marshalling Size increase is less then 5% 11 Performance & Size

New Features : 

New Security Model “Trust / Run / No Load” model gone New: “Trust / No Load” Prepares operating system for ACL security Windows XP-like Access Control List security to be implemented in the future 12 New Features

New Features : 

New File Systems ExFAT Large file support Large volume support UDFS 2.5 read only support Large Memory Mapped File Support Support for mapping views into very large files Up to 64-bit files Big benefit for in car navigation and multimedia 13 New Features

New Features : 

New driver support USB On-the-go (OTG) New USB Function / Host class drivers Enhanced VoIP support VoIP support over wired and WLAN networks Full-featured phone application Updated SIP signaling and Media stack (RTC 1.5) 14 New Features

New Features : 

Wireless LAN enhancements Multiple radio support and faster AP-AP roaming Added 802.11i support for WPA2 compliance Added 802.11e support for QoS Bluetooth enhancements BT protocol stack performance optimizations Enhanced BT profiles: A2DP, AVRCP 15 New Features

Compatibility : 

Binary compatibility for applications is the key goal Well behaved applications will work w/ little/no changes Compatibility maintained through CoreDLL Minimize impact on Win32 APIs Changes hidden in API libraries Apps using undocumented techniques… Will likely have to be modified Such as passing handles or pointers between processes Main changes will be in drivers and services Some drivers will migrate with little work 16 Compatibility

Drivers : 

Two types of drivers will be supported Kernel Mode for performance User Mode for robustness The overall structure of the drivers remains Main changes are in how the drivers access client memory Drivers are still DLLs Same Stream interface 17 Drivers

Summary.. : 

Great new architecture Removes the old limits Performance expected as good as current Memory footprint similar OAL / Driver porting fairly straightforward 18 Summary..