Distributed Component Object Model (DCOM)

1
Distributed Component Object Model (DCOM)

• By
• Deepak Goel Mukesh Punhani

2
Component Software Problem

• Interoperability
• Versioning
• Language Independence
• Transparency

3
Why Distributed Applications ?

• Inherently Distributed
• Flexibility
• Scalability

4
COM Architecture
COM Components in the same process
COM components in different processes
5
DCOM Architecture
DCOM COM components on different machines
6
Components Reusability

• Using Existing Components to Reduce Development
  Cost
• Future Reusability of Components being Developed

7
Language Neutrality

• Virtually all languages such as Java, Visual C,
  Visual Basic, Delphi, PowerBuilder, COBOL
  interact well with DCOM
• Enables Rapid Prototyping

8
Location Independence

• Components that interact more should be closer to
  each other
• Some components can only be run on specific
  machines
• Small Components Easy to Deploy - Increased
  Network Traffic
• Large Components Difficult to Deploy - Reduced
  Network Traffic

9
Scalability
Parallel Deployment
10
Scalability
Isolating Critical Components
11
Scalability
Pipelining
12
Security

• Provides Security at Component Level and Method
  Level
• Uses Access Control Lists (ACL) similar to
  Windows NT File System

13
Security
Per Interface Security using Registry Keys
14
Load Balancing

• Static Load Balancing
• Dynamic Load Balancing

15
Platforms

• UNIX/Mainframe
• Apple Macintosh
• Windows
• Java

16
Comparison with CORBA and RMI

• DCOM fits best with Microsoft Platform i.e.
  Windows 98 and Windows NT while CORBA is quite
  general.
• RMI works only with Java but is quite suitable
  when application wants to exploit features of
  Java

17
Performance

• Parameter Size 4 Bytes
  50
  Bytes
• In-Process
  0.00031
  0.00031
• Cross Process 0.42
  
  0.49
• Remote Call 2.7
  
  3.27