Lecture for Chapter 2.3 (Fall 09)

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Transcript Lecture for Chapter 2.3 (Fall 09)

What is an Operating System ?
Features of Operating System
 Multi user
 Multiprocessing
 Multitasking
 Multithreading
 Real time
Classification of Services[Chow07]
 Primitive Services –fundamental functions that the
kernel must provide
 Services by System Servers- services that need not
reside in the kernel but are still essential
 Value Added Servers –services that are not essential in
implementation but are useful in supporting
distributed applications
Primitive Services
 Communication- Exchange of Information between
 Synchronization- Coordination of Events
Services by System Servers
 Name Server - used to locate users, processes or
 Network Server –used to translate addresses and
locations obtained from Name server
 Time Server-synchronization of processes to
maintain a total order of event occurrences
 File Server- managing shared file system resources
Value Added Services
 Web Server – accepts requests from the clients ,
processes it and returns a response
 Group Server –manages creation and termination of
groups of interacting processes
Classification of Services [Galvin05]
 Services that are helpful to users
 Services for efficient operation of
Operating System Services that
are helpful to users
 User Interface
 Program Execution
 I/O Operations
 File System Operations
 Error Detection
User Interface
The means by which the user interacts with the system
Consists of
 Input
 Output
Program Execution
• Loading
• Running
• Execution
I/O Operations
The communications between the computer
and the outside world
File System Manipulation
Programs need to read and write files and directories,
create and delete them, search them, list file
Error Detection
OS needs to constantly monitor possible errors and
should take an appropriate action to rectify the error
Services for efficient operation of
 Resource Allocation
 Accounting
 Protection and Security
Resource Allocation
Resource allocation must be properly done when
multiple users or multiple jobs running concurrently.
OS keeps track of what kind of resources used, how
many users etc
Protection and Security
• Ensuring that all access to system resources is
• Access to the system from outsiders requires user
WebOS: A Framework of OS services for
wide area Applications[A.Vahdat97]
 Global Naming
 Wide-Area File System
 Security and Authentication
 Process Control
Privacy as an Operating System
Service [S.Iosannidis06]
1.Transparent, privacy-providing storage and network
2. Privacy-enhanced system calls
3. Privacy Libraries
4. Privacy-policy Management
System Support for Many Task Computing
The paper deals with issues of scale by leveraging
the large number of nodes to spread operating systems
services and components across the machine, tightly coupling the
operating system. The authors plan on provisioning nodes to provide
workload execution, aggregation, and system services, and dynamically
re-provisioning nodes as necessary to accommodate changes, failure,
and redundancy.
Future Work
Implementation and Development of Liquid Operating
system, which is spontaneous and adaptive to
dynamically meet the changing requirements of the
[3]Distributed Operating Systems and Algorithm Analysis, Andy Chow &
Theodore Johnson,1997
[4] Operating System Concepts , Silberschatz, Galvin and Gagne ,2005
[5] WebOS: Operating System Services for Wide Area Applications,Amin Vahdat
et al,1997
[6] Privacy as an operating system service ,Ioannidis ,S; Sidiroglou ,S; D.
Keromytis,A;Proceedings of the 1st USENIX Workshop on Hot Topics in
[7] System support for many task computing, Van Hensberger, E.; Minnich,
R.;Many-Task Computing on Grids and Supercomputers, 2008. MTAGS 2008.
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