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2	Introduction to the Microsoft .NET Framework Andrew Scott Computing Department Lancaster University, UK
3	Overview Microsoft .NET Framework .NET Compact Framework Framework Namespace Common Language Runtime .NET Type System Metadata Just In Time Compilation Assemblies Evidence Based Security Multi-Generational Garbage Collection
4	Microsoft .NET Framework Inbuilt object-based type system Multi-language Language neutral platform Cross language inheritance Zero impact install Side by side execution Multiple versions of components can co-exist Even in same application
5	Microsoft .NET Make distributed applications as easy to develop as desktop applications Client-Server systems Web based applications Mobile applications Adopt many research ideas from last few years Commercial realisation Rationalise Microsoft’s development tools Develop once, run anywhere…
6	.NET Compact Framework Reduced footprint implementation Few assumptions about device Screen size, colour depth, etc. Touch screen, Keypad, … RAM, Flash, ROM Floating point File system Threading etc.
7	Concept Realisation
8	Microsoft .NET Framework
9	.NET Framework Namespace
10	Common Language Runtime Provides common type system Consumer languages Extender languages Robust and secure execution environment Verifies type safety Code access security Exception handling Provides access to host resources
11	.NET Primitive Types
12	.NET Primitive Types
13	.NET Primitive Types
14	.NET Primitive Types All languages adopt framework types So… a string is a string whatever the language Unified type system Everything is an object
15	.NET Type System Reference types Classes Interfaces Arrays Delegates Value types Primitives Enumerators Structures
16	Metadata All .NET objects carry metadata Object name Method names and parameters Variables names and types Reflection Object construction Method invocation Access to public data in object
17	Just In Time Compilation
18	Just In Time Compilation
19	Just In Time Compilation
20	Just In Time Compilation
21	Assemblies Each assembly contains All IL code, Metadata and Attributes Manifest List of files Public and private resources Dependencies (other assemblies) Security permissions and requirements Public key
22	Evidence Based Security Source of code and invoking user Works with chains of components
23	Evidence Based Security Source of code and invoking user Works with chains of components
24	Evidence Where did the assembly come from? Site URL Directory Zone (My Computer, Intranet, Internet, …) What is the name of the assembly? Who signed and published assembly? Public Key based digital signatures
25	Garbage Collection Ensures no memory leaks Multi-generational, mark and compact Fundamental to .NET Framework …and not individual languages Self tuning Sweep typically takes ~1ms
26	Multi-Generational Garbage Collection
27	Multi-Generational Garbage Collection
28	Multi-Generational Garbage Collection
29	Multi-Generational Garbage Collection
30	Multi-Generational Garbage Collection
31	Multi-Generational Garbage Collection
32	Multi-Generational Garbage Collection
33	Multi-Generational Garbage Collection
34	Garbage Collector Special provision for Servers v Workstations Multi-processor systems Multi-threaded applications Can be influenced by applications But not generally recommended