•Operating Systems are of different types
4.Personal Computer OS
5.Real Time OS
7.Smart Card OS
•Room sized Computers still found today also in major corporate data centers.
•I/O Capacity is large (1000 disks and thousands of gigabytes of data)
•High-end web servers, Large Scale E-comm sites, Servers for business-to-business transactions
•Mainframe Os’s are heavily oriented towards processing many Jobs at once, needs prodigious amount of I/O.
•Typically offers 3 kinds of services:
•Batch processing (No user Interaction)
–Routine Jobs like claims processing in LICs or Sales reporting for a chain of Jobs.
•Transaction Processing (small requests, but system must handle thousands per second)
–Check Processing or Airline Reservation or any Reservation System.
•Time-Sharing (multiple users)
–Querying a big databases.
•Mainframe OS is OS/390 a descendant of OS/360.
•They Typically run on Servers (Large PCs, Workstations, Mainframes)
•Serves multiple users over a network
•Allows users to share H/W and S/W resources
•Servers provide print service, file service or web services.
•Internet providers use servers to support customers & web sites to store web pages & handle incoming requests.
•Email, Groupware & messaging
•Caching (usually Internet by storing previous files)
•Typical server OSs are Novell Server, Win NT, UNIX, Win 2000, Linux.
•To get major computer power is to connect multiple CPUs in single system.
•Depending on connection and what is shared, these are Parallel Computers, Multicomputers or multiprocessors.
•Special OS, Variation of Serve OS with connectivity & communication features.
•When number of users increases the response time has to be kept more.
•When the volume of data to be processed like
•Just one processor did not suffice the purpose.
•Speed of computer has to be enhanced by adding more processors.
•Two major multiprocessor and Parallel systems
1.To increase Throughput
•By increasing number of processors, major work can be done in shorter period of time.
2.Can save money compare to multiple single systems.
•By sharing peripherals, cabinets, Power Supplies etc.
•If several programs are to operate on the same set of data then cheaper to store on one disk instead of diff disks and diff processors share them.
3.They increases reliability
•Failure of one processor will not halt the system, instead work of failed processor can be distributed among other processors.
•SUN OS version 4 & version 5.