Interrupt Time Line For a Single Process Doing Output

Interrupt Time Line For a Single Process Doing Output

Interrupt Handling

*    The operating system preserves the state of the CPU by storing registers and the program counter.

*    Determines which type of interrupt has occurred:

* polling

* vectored interrupt system

*    Separate segments of code determine what action should be taken for each type of interrupt

Common Functions of Interrupts

     * Interrupt transfers control to the interrupt service routine generally, through the interrupt vector, which contains the addresses of all the service routines.

    * Interrupt architecture must save the address of the interrupted instruction.

    * Incoming interrupts are disabled while another interrupt is being processed to prevent a lost interrupt.

    * A trap is a software-generated interrupt caused either by an error or a user request.

    * An operating system is interrupt driven.

Computer-System Architecture

Computer-System Architecture

Real-Time Systems

Real-Time Systems

Often used as a control device in a dedicated application such as controlling scientific experiments, medical imaging systems, industrial control systems, and some display systems.

 Well-defined fixed-time constraints.

 Real-Time systems may be either hard or soft real-time.

 

Hard real-time:

Secondary storage limited or absent, data stored in short term memory, or read-only memory (ROM)

Conflicts with time-sharing systems, not supported by general-purpose operating systems.

Soft real-time

Limited utility in industrial control of robotics

Useful in applications (multimedia, virtual reality) requiring advanced operating-system features.

 

Clustered Systems

Clustering allows two or more systems to share storage.

 

Provides high reliability.

 

Asymmetric clustering: one server runs the application while other servers standby.

 

Symmetric clustering: all N hosts are running the application.

Distributed Systems

Distributed Systems

Distribute the computation among several physical processors.

Loosely coupled system – each processor has its own local memory; processors communicate with one another through various communications lines, such as high-speed buses or telephone lines.

Advantages of distributed systems.

Resources Sharing

Computation speed up – load sharing

Reliability

Communications

 

Requires networking infrastructure.

Local area networks (LAN) or Wide area networks (WAN)

May be either client-server or peer-to-peer systems.

 

 

Parallel Systems

Parallel Systems

Multiprocessor systems with more than on CPU in close communication.

Tightly coupled system – processors share memory and a clock; communication usually takes place through the shared memory.

Advantages of parallel system:

Increased throughput

Economical

Increased reliability

graceful degradation

fail-soft systems

 

Symmetric multiprocessing (SMP)

Each processor runs and identical copy of the operating system.

Many processes can run at once without performance deterioration.

Most modern operating systems support SMP

Asymmetric multiprocessing

Each processor is assigned a specific task; master processor schedules and allocated work to slave processors.

More common in extremely large systems

 

Time-Sharing Systems–Interactive Computing

Time-Sharing Systems–Interactive Computing 

The CPU is multiplexed among several jobs that are kept in memory and on disk (the CPU is allocated to a job only if the job is in memory).

A job swapped in and out of memory to the disk.

On-line communication between the user and the system is provided; when the operating system finishes the execution of one command, it seeks the next “control statement” from the user’s keyboard.

On-line system must be available for users to access data and code.

 

Mainframe Systems

Reduce setup time by batching similar jobs

Automatic job sequencing – automatically transfers control from one job to another.  First rudimentary operating system.

Resident monitor

initial control in monitor

control transfers to job

when job completes control transfers pack to monitor

Resource allocator – manages and allocates resources.

 

Control program – controls the execution of user programs and operations of I/O devices .

 

Kernel – the one program running at all times (all else being application programs).

Abstract View of System Components

computer system components

 Computer System Components

1.  Hardware – provides basic computing resources (CPU, memory, I/O devices).

2.  Operating system – controls and coordinates the use of the hardware among the various application programs for the various users.

3.  Applications programs – define the ways in which the system resources are used to solve the computing problems of the users (compilers, database systems, video games, business programs).

4.  Users (people, machines, other computers).

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What is an Operating System?

A program that acts as an intermediary between a user of a computer and the computer hardware.

Operating system 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.

http://sateeshbagadhi.blogspot.in

 

Program using OLE Container control:

1.      Select OLE control in Toolbox.

2.      Place the control on the form with the required size.

3.      As soon as OLE control is placed on the form, Insert Object Dialog is displayed to allow you to either embed or link an object into OLE Container.

4.      The available options in insert dialog are - Create New, where you select an Object Type and create an object using the appropriate application, or Create from File, where you can create an object by selecting a file from file system.

To embed a word document into OLE Container control:

1.      In Insert Object Dialog box select Create from File radio button.

2.      Click on Browse button and select a document file. Click on Ok

3.      An object is embedded into OLE Container control and a part of document is displayed.

4.      Run the project using F5.

5.      Double click on OLE Container control. This action will invoke MS-Word and run it in OLE Container control. When OLE Server runs in OLE Client, it is called as In-Place Activation.

6.      Make necessary changes using MS-Word.

7.      Press ESC key to come out of In-Place activation.

 

Application for OLE drag and drop manually:

1.      Start a new project using File-> New Project and select Standard EXE as the type of the project.

2.      Place two textboxes along with labels and a command button.

3.      Arrange the controls on the form in a neat format.

4.      Change the following properties.

Object	Property	Value
Label1	Caption	Source
Text1	Name	txtsource
	Text	""
	OLEDragMode	0-Manual
	OLEDropMode	2-Automatic.
Text2	Name	txtTarget
	Text	""
	OLEDragMode	1-Automatic
	OLEDropMode	1-Manual
Form	Caption	OLE Drag and Drop
Command1	Name	Cmdend
	Caption	&END

DESIGN VIEW:

 

CODING:

Private Sub cmdend_Click()

End

End Sub

Private Sub txtsource_MouseDown(Button As Integer, Shift As Integer, X As Single, Y As Single)

' start OLE dragging

 txtsource.OLEDrag

End Sub

Private Sub txtsource_OLECompleteDrag(Effect As Long)

  If (Effect And vbDropEffectMove) <> 0 Then ' bitwise Anding

          txtsource.Text = ""

  End If

End Sub

Private Sub txtsource_OLEStartDrag(Data As DataObject, AllowedEffects As Long)

  ' set allowed effects

  AllowedEffects = vbDropEffectMove Or vbDropEffectCopy

  Data.SetData UCase(txtsource.Text)

End Sub

Private Sub txttarget_OLEDragDrop(Data As DataObject, Effect As Long, Button As Integer, Shift As Integer, X As Single, Y As Single)

 Txttarget.Text = Data.GetData(vbCFText)

  Effect = vbDropEffectMove

  End Sub

VB program for CALCULATOR:

1. Design the form.

2. Create a command Button named as a Command1 and copy that and paste it 10 times. This will create a control array.

3. Create a cmdoperator control array using another Command Button named as Command2.

4. Place Command Button named as Command3 and set its caption to ‘clear’.

5. Place Command Button named as Command4 and set its caption to ‘=’.

6. place a Textbox for the Display.

DESIGN VIEW:

 

CODING:

Private lastoperator As String

Private firstpart As String

Private Sub Form_Load()

TxtResult.Enabled = False

Me.KeyPreview = True

End Sub

Private Sub Form_KeyDown(KeyCode As Integer, Shift As Integer)

'number in main keyboard

If (KeyCode >= 48 And KeyCode <= 57) Then

addDigits (Chr(KeyCode))

End If

'numbers in numpad

If (KeyCode >= 96 And KeyCode <= 105) Then

addDigits (Chr(KeyCode - 48))

End If

'if backspace

If (KeyCode = 8) Then

If (TxtResult.Text <> "") Then

TxtResult.Text = Left(TxtResult.Text, Len(TxtResult.Text) - 1)

End If

End If

'for various operators

If (KeyCode = 111) Then registerOperator ("/")

If (KeyCode = 106) Then registerOperator ("*")

If (KeyCode = 109) Then registerOperator ("-")

If (KeyCode = 107) Then registerOperator ("+")

End Sub

Private Sub cmdoperator_Click(Index As Integer)

registerOperator (cmdoperator(Index).Caption)

End Sub

Private Sub cmdclear_Click()

firstpart = ""

lastoperator = ""

TxtResult.Text = ""

End Sub

 

Private Sub Cmdequals_Click()

Select Case lastoperator

Case Is = "+"

TxtResult.Text = firstpart - TxtResult.Text + TxtResult.Text + TxtResult.Text

Case Is = "-"

TxtResult.Text = firstpart - TxtResult.Text

Case Is = "/"

TxtResult.Text = firstpart / TxtResult.Text

Case Is = "*"

TxtResult.Text = firstpart * TxtResult.Text

End Select

firstpart = ""

lastoperator = ""

End Sub

Private Sub Command1_Click(Index As Integer)

addDigits (Command1(Index).Caption)

End Sub

Private Sub addDigits(Digit As String)

TxtResult.Text = TxtResult.Text & Digit

End Sub

Private Sub registerOperator(Operatortext As String)

lastoperator = Operatortext

firstpart = TxtResult.Text

TxtResult.Text = ""

End Sub

Program to Handle Horizontal Scrollbar & Vertical Scrollbar:

Control	Property	Value
Vscroll 1	Min	1
Vscroll 1	max	100
Vscroll 1	Large change	10
Vscroll 1	Small change	1
Vscroll 1	value	50
Hscroll 1	Min	1
Hscroll 1	Max	100
Hscroll 1	Large change	10
Hscroll 1	Small change	1
Hscroll 1	value	50
Text 1	Font	MS Sans Serif, 12
Command 1	Caption	End

 

CODING:

Private Sub Command1_Click()

End

End Sub

Private Sub Form_Load()

VScroll1.Min = 1

VScroll1.Max = 100

VScroll1.LargeChange = 10

VScroll1.SmallChange = 1

VScroll1.Value = 50

HScroll1.Min = 1

HScroll1.Max = 100

HScroll1.LargeChange = 10

HScroll1.SmallChange = 1

HScroll1.Value = 50

End Sub

Private Sub HScroll1_Change()

Text1.Text = "horizontalsetting:" & Str(HScroll1.Value)

End Sub

Private Sub VScroll1_Change()

Text1.Text = "verticalsetting:" & Str(VScroll1.Value)

End Sub

OUTPUT: