This document provides information about operating systems and computer hardware concepts for a second year computer science course. It includes definitions of terms like 32-bit microprocessor, opcode, data bus, and cache memory. It also lists some common operating systems and describes concepts like multicore processors, virtualization, virtual memory, and the different states a process can be in.

1. Faculty of Computers andFaculty of Computers and
InformationInformation
Second Year (Second Semester)Second Year (Second Semester)
____________________________________________________________
Operating Systems IOperating Systems I
( )( )
____________________________________________________________
Dr. Ashraf ElsisiDr. Ashraf Elsisi
____________________________________________________

2. Computer Hardware Basics
• What are the meanings of the following terms?g g
1. 32-bit microprocessor, and 32-bit instructions.p ,
2. Opcode, immediate operand, and operand address.
3. Local data bus, and local address bus.3. Local data bus, and local address bus.
4. Machine cycle, processor cycle, and bus cycle.

3. It refers to the number of bits that can be processed
or transmitted in parallel, or the number of bits used
for single element in a data format.
Th titi th t ll difi d b thThe entities that are usually modified by these
numbers are:
•BusBus
•Microprocessor
•Software
•Operating system

5. Opcode operand and addressing modeOpcode, operand, and addressing mode
A hi i i i d f d d• A machine instruction is made up of an opcode and
one or more operands.
• The opcode tells the processor what action top p
perform over the following operands.
• The methods for specify the operand(s) for a machine
i t ti ll d dd i dinstruction are called addressing modes.

8. Bus
A bus is a collection of wires through which data
is transmitted from one part of a computer to
thanother.
According to the type of data transmitted through theg yp g
bus, we have:
b h b d l d• Data bus: The bus used to carry actual data.
•Address bus: The bus transferring information
about where the data should goabout where the data should go.
•Control bus: The physical connections that carry
control information between the CPU and other
devices within the computer.

9. According to the location of buses, or what kinds of
components they connect, we have:p y ,
Local bus:Local bus:
Another name of system bus, which connects the
microprocessor main memory and all kinds of I/Omicroprocessor, main memory, and all kinds of I/O
modules.
A local bus is also called frontside bus, memory bus, or, y ,
host bus.

10. Backside bus:
A microprocessor bus that connects the CPU to a Level 2
cache.
Typically, a backside bus runs at a faster clock speed than
the frontside
External bus:
A bus that connects a computer to peripheral devices.

14. S dSpeeds
• System clock
There are so many circuits inside a computerThere are so many circuits inside a computer.
To perform a specific action, it is necessary forp p y
some sort of synchronization to occur so that
different parts function and cooperate as expected.
The”conductor” of the PC is the system clock,
which brings synchronizationwhich brings synchronization.
A clock is just a signal that alternates between zeroj g
and one, back and forth.

15. The pulses generated by the clockThe pulses generated by the clock

16. Memory Access time:
also known as response time or latency refers to how
quickly the memory can respond to a read or write
trequest.
•Memory cycle:Memory cycle:
refers to the minimum period between two successive
requests.q
For various reasons the time separating two successive
i l 0 i i hrequests is not always 0, i.e a memory with a response
time of 80 ns cannot satisfy a request every 80 ns.

17. Machine cycle:Machine cycle:
also called instruction cycle, the four steps which the
CPU i t f h hi lCPU carries out for each machine language
instruction: fetch, decode, execute, and store.

18. CachesCaches
Level 1 (Primary) Cache:
•The fastest memory on the PC.y
•It is in fact, built directly into the processor itself.
•This cache is very small, generally from 8 KB to 64
KB, but it is extremely fast; it runs at the same speed as
the processor.
If the processor requests information and can find it in
the level 1 cache, that is the best case, because thethe level 1 cache, that is the best case, because the
information is there immediately and the system does
not have to wait.

19. Level 2 (Secondary) Cache:Level 2 (Secondary) Cache:
The level 2 cache is a secondary cache to the level 1
h d i l d li htl lcache, and is larger and slightly slower.

20. Name some OS’sName some OS s
• Linux • PalmOS
• Unix
• Windows
• TinyOS
• WinCEW dows
• Multics
• BSDUnix
W C
• Spring
• 2KBSDUnix
• Mac/Tiger
• Vista
2K
• ….
• Vista

21. MulticoreMulticore
• A multicore computer, also known as a chipA multicore computer, also known as a chip
multiprocessor , combines two or more
processors (called cores) on a single piece ofp ocesso s (ca ed co es) o a s g e p ece o
silicon (called a die).
• Typically, each core consists of all of the
t f i d d t hcomponents of an independent processor, such
as registers, ALU, pipeline hardware, and
control nit pl s L1 instr ction and data cachescontrol unit, plus L1 instruction and data caches.

22. • Virtualization
– enables a single PC or server to simultaneously run
l i l i l i l i fmultiple operating systems or multiple sessions of a
single OS
– a machine can host numerous applications, includinga machine can host numerous applications, including
those that run on different operating systems, on a single
platform
h t ti t t b– host operating system can support a number
of virtual machines (VM)
– each has the characteristics of a particular OSeach has the characteristics of a particular OS

23. VirtualVirtual
MemoryMemoryMemoryMemory
ConceptConcept

24. Process perspective:Process perspective:
• the machine on which it executes consists of the virtual memory space assigned to
the process
• the processor registers it may use
• the user-level machine instructions it may execute
• OS system calls it may invoke for I/O
• ABI defines the machine as seen by a process
Application perspective:Application perspective:
• machine characteristics are specified by high-level language capabilities and OS
system library calls
• API defines the machine for an application
Application perspective:Application perspective:
• processes share a file system and other I/O resources
OS perspective:OS perspective:
• system allocates real memory and I/O resources to the processes
• ISA provides the interface between the system and machine

25. Process and System Virtual MachinesProcess and System Virtual MachinesProcess and System Virtual MachinesProcess and System Virtual Machines

26. Process and System Virtual MachinesProcess and System Virtual MachinesProcess and System Virtual MachinesProcess and System Virtual Machines

28. •What is the meaning of installation?
(Installation program)(Installation program)
•Why we are using installation?
Wh t f i ll i ?•What are types of installations?
•What are Device drivers?
•List programs in system tools in Win7?•List programs in system tools in Win7?

29. Chapter 3
Process Concept and State

30. Major Requirements of an Operating
SSystem
• Interleave the execution of several jobs toInterleave the execution of several jobs to
maximize processor utilization while
providing reasonable response timep ov d g easonable espo se t e
All t t• Allocate resources to processes
• Support interjobs communication and user
creation of processes (jobs)

31. Process
• Textbook uses the terms job and process almost
interchangeablyinterchangeably
• Process a program in execution;• Process – a program in execution;
process execution must progress in sequential fashion
• A process includes:
– program counterprogram counter
– stack
– data section

32. It is program
switches theswitches the
processor from one
process to another

33. Traces of processes

34. Two-State Process ModelTwo State Process Model
• Process may be in one of two statesProcess may be in one of two states
– Running
– Not-runningNot running

35. Not-Running Process in a
QQueue

36. Process CreationProcess Creation
• When a new process, OS builds the data
structures that are used to manage the processstructures that are used to manage the process.
• Reasons for process creation
– Submission of a batch job
– User logs on
– Created to provide a service such as printingp p g
– Process creates another process (spawning)
[parent – child]

37. Process TerminationProcess Termination
• Any computer system must provide a meansAny computer system must provide a means
for a process to indicate its completion.
• Batch job issues Halt instruction (call for• Batch job issues Halt instruction (call for
termination)
U l ff• User logs off
• Quit an application
• Error and fault conditions

38. Reasons for Process TerminationReasons for Process Termination
• Normal completion
Ti li it d d• Time limit exceeded
• Memory unavailable
• Protection error• Protection error
– example write to read-only file
• Arithmetic errorArithmetic error
• When a process finishes, the operating system
will free the memory space it occupies andy p p
remove the data structures it allocated to
manage the process.

39. A fi t t d lA five-state model

40. • As a process executes, it changes statep , g
running: Instructions are being executed
new: The process is being created
waiting: The process is waiting for some event to
occur
ready: The process is waiting to be assigned to a
process
terminated: The process has finished executionterminated: The process has finished execution

41. • RunningRunning
• Ready
Bl k d
Not running
• Blocked
• New
• Exit

44. Using Two QueuesUsing Two Queues

46. Process swapping and Suspended
PProcesses
• Processor is faster than I/O so all processesProcessor is faster than I/O so all processes
could be waiting for I/O
• Swap these processes to disk to free up moreSwap these processes to disk to free up more
memory
• Blocked state becomes suspend state whenBlocked state becomes suspend state when
swapped to disk
• Two new statesTwo new states
– Blocked, suspend (in secondary memory)
– Ready, suspend in (secondary memory)y, p ( y y)

47. One Suspend StateOne Suspend State

48. Two Suspend StatesTwo Suspend States