II. Programming Technologies

II.1 The machine code programCode of algorithm steps + memory addresses:

MOV AX,1234h ;0B8h 34h 12h - number (1234h) to AX registerMUL WORD PTR [5678h] ;0F7h 26h 78h 56h - multiply AX with the data of the given address (extra segment)MOV [5678h],AX ;0A3h 78h 56h - write back the result in AX to the address

II.2 Program making programsSource code program >> Compiler/Interpreter >> Executable program

Generation of Languages1GL: machine code2GL: assembly (mnemonics)

3GL: high-level procedural:• FORTRAN, PASCAL, C

4GL: problem oriented:–Functional: LISP (LISt Processing),–Logical: PROLOG (PROgraming LOGics),–Database management: SQL,

–Object-oriented: C++, JAVA. C#, –Component based development languages.

5GL: natural languages???

Timeline of programming languages

Some interesting dates:• 1st: Eniac coding system (von Neumann and others - 1943)

• BASIC (Kemeny/Kurtz- 1964), Altair BASIC (Bill Gates, Paul Allen – 1975), Commodore BASIC (1975), IBM BASIC (made by Microsoft – 1981)

• Pascal (Niklaus Wirth /Kathleen Jensen – 1970)

• C (Dennis Ritchie - 1972), C++ (Bjarne Stroustrup - 1983), C# (Anders Hejlsberg – 2000, Java (James Gosling –Sun Microsystem – 1995)

II.3. Data and Programs

[const| readonly] type_name variable_name [,…][= starting_value]

Integers:byte / sbyte 0..255 / -128..127 1 byte ushort/ short 0..65 535 / -32 768..32 767 2 byteuint, int 0.. 4 294 967 295 / -2 147 483 648..2 147 483 648 .. 4 byte

Logical typeBool false..true 1 byte

Floating point (real number) typeFloat -3.4×1038.. 3.4×1038 4 byteDouble ±5.0×10−324.. ±1.7×10308 1.3, 2.1e6, 3.4F, 4.2L 8 byteDecimal (-7.9 x 1028.. 7.9 x 1028) / (100..28) 28, 29 digits

Letters:Char ’A’, ‘\n’, ’\t’(!!!) 2 byteString ”Apple” n*2byte

Enumerated lists:Enum enum number {one, two, three} // 0,1,2

enum thislist {a=6,b=11} // 0..15number.two

II.3.2 Basic algorithm elements

II.3.2.1 Concatenation

int i = 3; int j = 4; int k = i + j;

II.3.2.2 Alternation (selection)

if (i > j) { k = i - j; } else { k = j - i;}

II.3.2.3 Iteration (cycling)

i = 0;k = 0;while (i < 10) { k += i++;}

II.4. Subprograms, Functions

type_name name ([parameters]) { // function body

p

f

it

f/t

t/f

p

fv

call fv

[local definitions, declarations][statemens][return [value]; // if exists] }

Usage modes:

function_name([param1, param2,…]);

i = name([param1, param2,…]);

int main () {}

II.5 Object, class (to be discussed in details in seminars)

ObjectData

Program

II.6. Windows is an event-driven program

}}

}Console.Beep();

{e)EventArgssender, objectbutton1_Click(private void

}InitializeComponent();

{Form1()public{Form1 : Formpublic partial class

{WindowsFormsApplication1namespace Case

Message Loop

DefWindowProc

Windows

Message queue

CallBack

WinMain

Maximum CPU utilization ? Multiprogramming.

• Several processes are kept in memory at one time.

• Any process can take over the CPU.

• Process Scheduler is the component of the OS.

• Scheduling of the CPU is fundamental to OS design.

Scheduling Objectives:

• Share time fairly among processes• Prevent starvation of a process• Use the processor efficiently• Have low overhead• Prioritise processes when necessary

Windows NT-based operating systems (including Windows 8.x and 10.x) use a multilevel feedback queue. 32 priority levels are predefined. General rules:

◦ Give preference to short jobs.

◦ Give preference to I/O bound processes.

◦ Quickly establish the nature of a process and schedule the process accordingly.

All processes receive a priority boost after a wait event, but processes that have experienced a keyboard I/O wait get a larger boost than those that have experienced a disk I/O wait.

II.7. Windows pre-emptive multiprogramming

System and application waiting queues

Timeslice distribution with variable priorities

42

distribTimeslice

Primary scheduler

pr=12pr=20pr=16

pr=20

pr=4

thread5

thread4thread

3

thread2

thread1

MS-DOS VMMS-DOSS VMSystem VM

16 Bit appsapps

32 Bit apps

Messages

primarywaiting queue

16 bit appwaiting queue

32 bit threadwaiting

queue

bit thread

32waiting queue

bit thread

32

System Applications

Waiting line

Messages

DevicesMouseKeyboardDisks Printer

II.8. Rapid Application Development Environment Component based development:

}}

}BackColor = System.Drawing.Color.Red;button1.Text = "alma";

{private void button1_Click(object sender, EventArgs e)

}InitializeComponent();

{public Form1()

{public partial class Form1 : Form

{namespace WindowsFormsApplication1

using System.Windows.Forms;using System.Text;using System.Linq;using System.Drawing;using System.Data;using System.ComponentModel;using System.Collections.Generic;using System;

II.9. Microsoft.Net

Aim: Safe development

trudctureSypeTommonCCTS

nfrastructureIanguageLommonC

CLI Network solutions•

independency-Platform•

compilerime Tn Iust J

JIT

anguageLntermediateI

ommonCCILetc.Managed C++ J#JScriptVB.NetC#

New, CLR functions (garbage collection)

servicesWeb

)anguageLarkup Mtensible Xe-(XML Data with multilevel type checking

Basic Classes

Operating System

machineCode runs on virtual amchines virtuális

(untimeRanguageLommonC–CLR

Web/Windows user layer

Existing functions (file open)