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- 1I/O InterruptsGenerated by an I/O controller, to signal normal completion of an operation or to signal a variety of error conditions
- 2Timer InterruptsGenerated by a timer within the processor. This allows the operating system to perform certain functions on a regular basis, like scheduling
- 3Hardware Failure InterruptsGenerated by a failure (e.g. power failure or memory parity error).
- 4Traps (Software Interrupts)Generated by some condition that occurs as a result of an instruction execution
- 5Components in Operating System-Process/Thread Management
-Memory Management
-File Management - 6Time Sharing Systems-Multiple interactive users.
-CPU is allocated to jobs in Round-Robin.
-Response time for each user should be short. - 7Multiprogrammed SystemsRun several jobs “concurrently”
Take turns to use CPU and I/O devices - 8Operating system (OS) goals-Execute user programs and make solving user problems easier
-Make the computer system convenient to use
-Use the computer hardware in an efficient manner - 9Parallel High-Performance SystemsGoals:
Increased performance/throughput
Increased reliability: fault tolerance
Multiprocessor systems: more than one CPUs
Tightly coupled system – processors share memory, bus, IO, and a clock; communication usually takes place through the shared memory
Symmetric multiprocessing (SMP) vs. asymmetric
SMP: each processor runs an identical copy of the operating system; all processors are peers
Asymmetric: master-slave - 10OS User ViewUser interface, ease of use vs. performance (windows vs. command line; terminal vs. minicomputer; networked workstations; handheld; embedded )
- 11OS System ViewOS is a resource allocator:
Manages all resources (CPU, memory, file-storage, I/O devices etc.)
Decides between conflicting requests for efficient and fair resource use
OS is a control program:
Controls execution of programs to prevent errors and improper use of the computer - 12KernelThe one program running at all times on the computer” is the kernel. The kernel runs at all times and acts as an intermediary between the user/programs and hardware.
- 13CPU-load instructions from main memory,
-load/store data from/to memory system
-controls I/O devices to perform certain tasks - 14System callsprovide the interface between a running program and the operating system
- 15Types of System CallsProcess control
File management
I/O management
Communications
Accounting
Protection - 16Examples of System Calls (name 4)fork
close
read
waitpid
sleep
lseek
exit
write
pipe
chmod
etc... - 17Two key mechanisms to interact with the Operating System kernelInterrupts
System Calls - 18How to Handle an Interrupt (8 STEPS)1.) Interrupt is issued
2.) Processor finishes its current instruction
3.) Processor acknowledges the interrupt
4.) The processor pushes the PSW and PC to the control stack
5.) The new PC is loaded by the interrupt vector
6.) ISR saves the rest of the process state info
7.) ISR executes
8.) ISR restores process state info and the old PSW and PC are restored from the control stack. - 19How System Calls Work• User application calls a user-level library routine (gettimeofday(), read(), exec(), etc.)
• This generally causes a software interrupt, ntrapping to kernel
• Invokes system call through stub, which
specifies the system call number.
• Kernel looks up system call number in
syscall table, calls appropriate function
• Function executes and returns to interrupt handler, which returns the result to the user space process - 20Process
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- Fichas sobre Sin título, creado por Jacob de los Santos el 05/03/2020.
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- Jacob de los Santos
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