Operating SystemsSERVICES
BARNALI CHAKRABARTY
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 processes
Synchronization- Coordination of Events
Services by System ServersName Server - used to locate users, processes
or machines
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 ServicesWeb 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 system
Operating System Services that are helpful to usersUser InterfaceProgram ExecutionI/O OperationsFile System OperationsError Detection
User Interface
The means by which the user interacts with the system
Consists ofInputOutput
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 Information
Error Detection
OS needs to constantly monitor possible errors and
should take an appropriate action to rectify the error
Services for efficient operation of systemResource AllocationAccountingProtection and Security
Resource Allocation
Resource allocation must be properly done when multiple users or multiple jobs running concurrently.
Accounting
OS keeps track of what kind of resources used, how many users etc
Protection and Security
• Ensuring that all access to system resources is controlled
• Access to the system from outsiders requires user authentication
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] Approach 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[E.V.Hensbergen,08]
The paper deals with issues of scale by leveragingthe 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 user.
References[1]http://www.webopedia.com/TERM/o/operating_system.html[2]Wikipedia[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 Security,2006
[7] System support for many task computing, Van Hensberger, E.; Minnich, R.;Many-Task Computing on Grids and Supercomputers, 2008. MTAGS 2008. Workshop on 17-17 Nov. 2008 Page(s):1 - 8