Operating Systems

Question 1

Operating system is an intermediary between

Answer 1

user of a computer and the computer hardware

Question 2

Functions of Operating Systems

Answer 2

-Oversee (seyretmek) operation of computer
-Store and retrieve (okumak) files
-Schedule programs for execution
-Coordinate the execution of programs
++Uses the computer hardware in an efficient manner

Question 3

OS works 2 basic way

Answer 3

OS an extended machine (resource allocator)
-Hides messy details which must be performed
-Presents user with a virtual machine, easier to use
-Manages all resources
-Decides between conflicting reuests for efficient and fair resource use
OS a resource manager (control program)
-Each program gets time with the resource
-Each program gets space on the resource
-Controls execution of programs to prevent errors and improper use of computer

Question 4

Four components of computer system

Answer 4

computer hardware<operating system<system and application programs<users

Question 5

Hardware

Answer 5

provides basic computing resources
-CPU, memory, I/O devices

Question 6

Operating System

Answer 6

Controls use of hardware among various applications and users

Question 7

Application programs

Answer 7

Defines the ways in which the system resources are used to solve the computing problems of the users

Question 8

Users

Answer 8

People, machines, other computers

Question 9

Software tree

Answer 9

Software
Application and System
System is utility and Operating system
Operating system is kernel and user interface

Question 10

Operating system components

Answer 10

Kernel and User interface

Question 11

Kernel

Answer 11

performs basic required functions
-file manager
-device drivers
-memory manager
-schedular and dispatcher

Question 12

difference between schedular and dispatcher

Answer 12

schedular: işlemleri seçer sürece ekler veya süreçten kaldırır
dispatcher: zaman aralıklarının dağılımını ayarlar.seçilen işlemler alıp çalıştırır. bir zaman aralığına son vermek için bölücü sinyal yollar

Question 13

user interface

Answer 13

communicates with users
-Text based (shell)
-Graphical user interface GUI

Question 14

Componenets of kernel

Answer 14

**File manager
-Directory (folder) a user created a bundle of files and subfiles
-Directory path a sequence of directories within directories
**Memory manager
-Allocates space in memory
-May create a illusion and look like it has more memory than it actually does (virtual memory)by playing a shell game

Question 15

Getting is started (…)

Answer 15

(bootstrapping)

Question 16

Bootloader

Answer 16

Bilgisayar açılınca çalışır, hafızaya operating sistemi alır
Program in ROM (examole of firmware)
-Run by the CPU when power is turned on
-Transfers operating system from mass storage to main memory
-Executes jump to operating system

Question 17

Process and process state

Answer 17

Process süreç
Process state Mevcut durum
-Program counter
-General purpose registers
-Related portion of main memory

Question 18

Semaphore

Answer 18

A control flag

Question 19

Critical region

Answer 19

Tek bir süreçle çalıştırılması gereken bir grup komut

Question 20

Mutual exclusion

Answer 20

requirement for proper implementation of a critical region

Question 21

Deadlock

Answer 21

Processes block each other from continuing
Conditions required for deadlock
1-Competition for non-sharable resources
2-Resources requested on a partial basis
3-An allocated resource can not be forcibly retrieved

Question 22

Filozofların akşam yemeği problemi

Answer 22

-Tamamen rastgele davranışlarla çözüm beklenir, garantisi yoktur (Random solution)
-Bir garson sırasıyla biri alacak biri almayacak biçimde dağıtır ve deadlock/starvation sorunları çözülür (Conductor solution)
-Bir kişi alcak bir kişi almaycak şeklinde davranırlar. (Monitor solution)
-Bir garson 5. filozof hariç diğerlerinin isteklerini yerine getirecektir.
-4 değerinde bir semaforla herhangi 4 filozofun yemek yemesi durdurulup diğer filozofun kesin olarak yemek yemesi sağlanır. Yemek bitince smafor değeri 1 azaltılır
-Her filozofa ilk olarak düşük numaralı chopstick aldırılıp deadlock önlenir.
-Her chopsticke semaphore konur. Müsaitlik durumuna göre chopstickleri alan filozoflardan yalnızca bir chopstick alması durumunda elindekini bırakıp sırasını tekrar beklemesi sağlanır.

Question 23

Evolution of shared computing

Answer 23

Batch processing
Interactive processing
-requires real-timeprocessing
Timesharing/Multitasking
-Implemented by multiprogramming
Multiprocessor machines