1. نظام المحاضرات الالكترونينظام المحاضرات الالكتروني Computer Software

2. نظام المحاضرات الالكترونينظام المحاضرات الالكتروني

3. Application software Easy-to-use programs designed to perform specific tasks System software Programs that support the execution and development of other programs Two major types Operating systems Translation systems (compilers & linkers) Computer Software

4. نظام المحاضرات الالكترونينظام المحاضرات الالكتروني Computer Software

5. نظام المحاضرات الالكترونينظام المحاضرات الالكتروني Application Software Application software makes computer popular and easy to use Common application software: Microsoft Word. PowerPoint Internet Explorer Graphics. Spreadsheets. Groupware.

6. نظام المحاضرات الالكترونينظام المحاضرات الالكتروني Operating Systems Integrated system of programs that Integrated system of programs that Manages the operations of the CPU Manages the operations of the CPU Controls the input/output and storage resources and activities of the computer system Controls the input/output and storage resources and activities of the computer system Provides various support services as the computer executes application programs Provides various support services as the computer executes application programs

7. نظام المحاضرات الالكترونينظام المحاضرات الالكتروني Operating Systems (continued) Performs four basic functions Performs four basic functions 1: User interface: Provides a user interface 1: User interface: Provides a user interface Allows humans to communicate with the computer Allows humans to communicate with the computer 2: Resource management 2: Resource management Manages the hardware and networking resources of the system Manages the hardware and networking resources of the system Virtual memory capability Virtual memory capability

8. نظام المحاضرات الالكترونينظام المحاضرات الالكتروني Operating Systems (continued) 3: File management Controls the creation, deletion, and access of files of data and programs Keeps track of the physical location of files 4:Task management Manages the accomplishment of the computing tasks of end users Multitasking Multiprogramming Timesharing

9. نظام المحاضرات الالكترونينظام المحاضرات الالكتروني MULTIPROGRAMMING OPERATING SYSTEM UNUSED MEMORY PROGRAM 1 TRADITIONAL SINGLE- PROGRAM SYSTEM OPERATING SYSTEM UNUSED MEMORY PROGRAM 1 PROGRAM 2 PROGRAM 3 MULTIPROGRAMMING ENVIRONMENT The management of two or more tasks, programs, running on the computer system at the same time.

10. نظام المحاضرات الالكترونينظام المحاضرات الالكتروني MULTITASKING MULTIPROGRAMMING ON A SINGLE-USER SYSTEM SUCH AS A MICROCOMPUTER*

11. نظام المحاضرات الالكترونينظام المحاضرات الالكتروني TIME SHARING It is an extension of multiprogramming. In this mode, a number of users operate online with the same CPU, but each uses a different input/output terminal. In this mode, a number of users operate online with the same CPU, but each uses a different input/output terminal. The programs of these users are placed into partitions in primary storage. The programs of these users are placed into partitions in primary storage. Execution of these programs rotates among all users, occurring so rapidly that it appears to each user as though he or she were the only using the computer. Execution of these programs rotates among all users, occurring so rapidly that it appears to each user as though he or she were the only using the computer.

12. نظام المحاضرات الالكترونينظام المحاضرات الالكتروني Operating Systems (continued) Popular Operating Systems Popular Operating Systems Windows Windows 95, 98, ME 95, 98, ME NT NT 2000 2000 XP XP UNIX UNIX Linux Linux Mac OS X Mac OS X

13. نظام المحاضرات الالكترونينظام المحاضرات الالكتروني Computer Languages –Machine Language Uses binary code Machine-dependent Not portable Assembly Language Uses mnemonics Machine-dependent Not usually portable High-Level Language (HLL) Uses English-like language Machine independent Portable (but must be compiled for different platforms) Examples: Pascal, C, C++, Java, Fortran,...

14. نظام المحاضرات الالكترونينظام المحاضرات الالكتروني Machine Language The representation of a computer program which is actually read and understood by the computer. A program in machine code consists of a sequence of machine instructions. Instructions: Machine instructions are in binary code Instructions specify operations and memory cells involved in the operation Example: OperationAddress 00100000 0000 0100 01000000 0000 0101 00110000 0000 0110

15. نظام المحاضرات الالكترونينظام المحاضرات الالكتروني Assembly Language A symbolic representation of the machine language of a specific processor. Is converted to machine code by an assembler. Usually, each line of assembly code produces one machine instruction (One-to-one correspondence). Programming in assembly language is slow and error-prone but is more efficient in terms of hardware performance. Mnemonic representation of the instructions and data Example: Load Price AddTax StoreCost

16. نظام المحاضرات الالكترونينظام المحاضرات الالكتروني High-level language A programming language which use statements consisting of English-like keywords such as "FOR", "PRINT" or “IF“,... etc. Each statement corresponds to several machine language instructions (one-to-many correspondence). Much easier to program than in assembly language. Data are referenced using descriptive names Operations can be described using familiar symbols Example: Cost := Price + Tax

17. نظام المحاضرات الالكترونينظام المحاضرات الالكتروني Machine binary languageLow-level assemblyHigh-level An example:

18. نظام المحاضرات الالكترونينظام المحاضرات الالكتروني Translation System Set of programs used to develop software Types of translators: Compiler Linker Example Microsoft Visual C++.

19. نظام المحاضرات الالكترونينظام المحاضرات الالكتروني Software Development Major activities Editing (writing the program) Compiling (creates.obj file) Linking with compiled files (creates.exe file) Object files Library modules Loading and executing Testing the program