Wednesday, 16 March 2011

9.4

Code for 9.4 task - There is 2 parts to this task, they will be seperated by a space:


Public Class Form1

    Private Sub btnNewName_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnNewName.Click
        Dim Name, NewName As String
        Name = txtname.Text
        NewName = UpperCaseFirstLetter(Name)
        lblNewName.Text = NewName
    End Sub
End Class


TASK 2
Module Module1
    Function UpperCaseFirstLetter(ByVal OldString As String) As String
        Dim FirstLetter As Char
        Dim NewString As String
        FirstLetter = Char.ToUpper(OldString.Substring(0, 1))
        Mid(OldString, 1, 1) = FirstLetter
        NewString = OldString
        Return NewString
    End Function
End Module

9.3

Code for 9.3 task below:


Public Class Form1

    Private Sub btnCalcInterest_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnCalcInterest.Click
        Dim Interest, AmountInvested As Decimal
        Dim RateOfInterest As Single
        Dim Years As Short
        AmountInvested = txtamountinvested.text
        RateOfInterest = txtInterestRate.Text
        Years = txtYears.Text
        Interest = CalculateInterest(AmountInvested, RateOfInterest, Years)
        lblinterestrate.Text = Format(Interest, "Currency")

    End Sub
    Function CalculateInterest(ByVal Principal As Decimal, ByVal InterestRate As Single, ByVal numberYears As Short) As Decimal
        Dim Interest As Decimal
        Dim Year As Short
        Interest = 0
        For Year = 1 To numberYears
            Interest = Interest + ((Principal + Interest) * InterestRate / 100)
        Next Year
        Return Interest
        CalculateInterest = Interest
    End Function


End Class

9.2

Code below for the 9.2 task:

Option Strict On
Public Class Form1
    Dim Total As Integer
    Dim NumberOfMarks As Integer

    Private Sub btnOK_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnOK.Click
        Dim Number As Integer
        Number = CInt(txtMark.Text)
        lstMarks.Items.Add(Number)
        Call ProcessOneNumber(Number, Total, NumberOfMarks)
        btnShowMean.Enabled = True
        txtMark.Text = ""
        txtMark.Focus()

    End Sub

    Private Sub btnShowMean_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnShowMean.Click
        Dim Mean As Double
        Call Calcmean(Total, NumberOfMarks, CSng(Mean))
        txtMean.Text = CStr(Mean)
        txtMean.Visible = True
        lblMean.Visible = True
        txtMark.Enabled = False
        btnOK.Enabled = False

    End Sub

    Private Sub btnQuit_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnQuit.Click
        Me.Close()
    End Sub

    Private Sub txtMark_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles txtMark.TextChanged
        btnOK.Enabled = True

    End Sub
    Sub ProcessOneNumber(ByVal ExamMark As Integer, ByRef MarksTotal As Integer, ByRef CountOfMarks As Integer)
        MarksTotal = MarksTotal + ExamMark
        CountOfMarks = CountOfMarks + 1
    End Sub
    Sub Calcmean(ByVal MarksTotal As Integer, ByVal CountOfMarks As Integer, ByRef Average As Single)
        Average = CSng(MarksTotal / CountOfMarks)

    End Sub
End Class

9.1

This is the VB code used to complete the task below:

Private Sub hsbRed_Scroll (...) Handles hsbRed.Scroll
    Me.BackColor = ColorTranslator.FromO1e(RGB(hsbRed.Value, hsbGreen.Value, hsbBlue.Value.))
End Sub

Private Sub hsbGreen_Scroll (...) Handles hsbGreen.Scroll
    Me.BackColor = ColorTranslator.FromO1e(RGB(hsbRed.Value, hsbGreen.Value, hsbBlue.Value.))
End Sub

Private Sub hsbBlue_Scroll (...) Handles hsbBlue.Scroll
    Me.BackColor = ColorTranslator.FromO1e(RGB(hsbRed.Value, hsbGreen.Value, hsbBlue.Value.))
End Sub

---

Private Sub hsbBlue_scroll (ByVal sender As System. Object, ByVal e As System.Windows.For (...)
    Call ShowFormColour( )
End Sub

Sub ShowFormColour( )

End Sub

End Class

---

Me.BackColor = ColorTranslator.FromO1e(RGB(hsbRed.Value, hsbGreen.Value, hsbBlue.Value))

---

Private Sub hsbRed_Scroll (...) Handles hsbRed.Scroll
    Call ShowFormColour( )
End Sub

Private Sub hsbRed_Scroll (...) Handles hsbRed.Scroll
    Call ShowFormColour( )
End Sub

Private Sub hsbRed_Scroll (...) Handles hsbRed.Scroll
    Call ShowFormColour( )
End Sub

Sunday, 6 March 2011

System Software

Characteristics of different types of operating systems and their uses: batch, real-time, single-user, multi-user, multi-tasking and network systems.

  • Batch: grouping data together and processing them at the same time. for example: printing bills, data is sent to the printer and when a certain number or a certain time is reached they are all processed together

  • Real-time: there is continual input, processing and  output as data is sent to be processed. For example, withdrawing money from your bank account and the money is deducted from your account balance straight away

  • Single-user: It is an Operating System that is developed and intended for use on a  machine that can only have a single user at anyone time. for example these can be found on home computers or other work environments.

  • Multi-user: This is an OS that allows multiple users on different computers to access a single system with the same OS on it at the same time. This means it can receive multiple instructions at the same time and manage and process all of them. For example, a mainframe or a server is an example of multi-user OS. A server where or example multiple personal accounts send print jobs to a printer at the same time and then can manage and print all of the tasks told too.

Thursday, 3 March 2011

Purpose of Operating Systems

 Operating System Purposes:
 
An operating system is the framework that allows you to communicate with computer hardware in an interactive way. Without this, you would not be able to tell the computer to do anything and it would have any instructions to follow. This is why it is important for a computer to have an operating system. In early days without OS so much problems where faced like accessing or getting output it takes two days. To make it much more efficient OS is used.
 
 
Operating System Summary and Overview:

operating system

The most important program that runs on a computer. Every general-purpose computer must have an operating system to run other programs. Operating systems perform basic tasks, such as recognizing input from the keyboard, sending output to the display screen, keeping track of files and directories on the disk, and controlling peripheral devices such as disk drives and printers.
For large systems, the operating system has even greater responsibilities and powers. It is like a traffic cop -- it makes sure that different programs and users running at the same time do not interfere with each other. The operating system is also responsible for security, ensuring that unauthorized users do not access the system.
Operating systems can be classified as follows:

  • multi-user : Allows two or more users to run programs at the same time. Some operating systems permit hundreds or even thousands of concurrent users.

  • multiprocessing : Supports running a program on more than one CPU.

  • multitasking : Allows more than one program to run concurrently.

  • multithreading : Allows different parts of a single program to run concurrently.

  • real time: Responds to input instantly. General-purpose operating systems, such as DOS and UNIX, are not real-time.

  • Operating systems provide a software platform on top of which other programs, called application programs, can run. The application programs must be written to run on top of a particular operating system. Your choice of operating system, therefore, determines to a great extent the applications you can run. For PCs, the most popular operating systems are DOS, OS/2, and Windows, but others are available, such as Linux.
    As a user, you normally interact with the operating system through a set of commands. For example, the DOS operating system contains commands such as COPY and RENAME for copying files and changing the names of files, respectively. The commands are accepted and executed by a part of the operating system called the command processor or command line interpreter. Graphical user interfaces allow you to enter commands by pointing and clicking at objects that appear on the screen.

    Wednesday, 2 March 2011

    Theory 1

     Hardware:

    INPUT ---> RAM <---> PROCESSOR ---> OUTPUT
                         ^
                         |
                         v
                  STORAGE

    Software:

    Sets of instructions which tell the system how to do things.  These sets of instructions are collected together in workable groups known as programs.

    Operating system provides translating software to translate high level language into machine code that can be processed almost as 'true's and falses'