1. 1 California State University, Fullerton Chapter 5 Information System Software

2. 2 California State University, Fullerton Software Concepts A program is a set of instructions that tells the computer what to do. Software can be a single program or a group of programs needed to perform several functions. Simple programs may have a few hundred instructions (lines of code) though most have many more (several million).

3. 3 California State University, Fullerton Individual Application Software Word processing Spreadsheet Graphics Database Browser

4. 4 California State University, Fullerton Workgroup Application Software Groupware E-Mail software Electronic conferencing software

5. 5 California State University, Fullerton Other Application Software Organizational application software Generally organization specific Examples include payroll, account payable. Interorganizational application software Generally common to the participating organizations Electronic Data Interchange (EDI) Electronic Funds Transfer (EFT)

6. 6 California State University, Fullerton Operating System Concepts An operating system is a group of programs that manages the operation of the computer. Three functions of an operating system Operation (Process) management Resource management Data management

7. 7 California State University, Fullerton Operating System Concepts (cont’d.) Organization of an operating system Most operating system programs are stored in secondary storage. One operating system program is stored in a section of primary storage. It goes by various names – kernel, nucleus, core, … – but generically called the “supervisor”.

8. 8 California State University, Fullerton Using an Operating System Starting the computer is called booting which transfers the “supervisor” from secondary storage to primary storage. Connecting to a network or other multi- user environment is called logging in. Detaching from a network is called logging out.

9. 9 California State University, Fullerton Elements of an Operating System’s User Interface User interface is the visual link between the user and the software. Icons are the small pictures on the screen. Graphical User Interface (GUI) uses Buttons (radio buttons, check boxes) Icons Menus Dialog boxes

10. 10 California State University, Fullerton Capabilities of Operating Systems Multitasking is appearing to execute more than one program at a time, though the CPU can execute instructions from only one program at a time.

11. 11 California State University, Fullerton Capabilities of Operating Systems (cont’d.) Multi-user or Multiple-user systems permit more than one person to use the system at a time. The technique that is used with multiple-user operating systems is time sharing. With this technique, the users are each allocated a small amount of time by the operating system.

12. 12 California State University, Fullerton Capabilities of Operating Systems (cont’d.) Two types of operating systems Batch operating systems where all the transactions belong to a program are processed at the same. Interactive operating systems allow user interaction as the program executes. In this method of processing one transaction is performed at the time, so the user can correct the errors.

13. 13 California State University, Fullerton Capabilities of Operating Systems (cont’d.) Virtual memory is supplemental primary storage (RAM) or “real” memory where the programs are too big for primary storage. It is created on a secondary storage device.

14. 14 California State University, Fullerton Capabilities of Operating Systems (cont’d.) Virtual memory operating systems execute large programs by dividing the program into parts and transferring the necessary parts of the program from secondary storage to primary storage as needed. The transfer process does not require any action by the user.

15. 15 California State University, Fullerton Other System Software Utility programs Sort utility – rearranges data in a specified order Merge utility – merges two files into one Print utility – prints the contents of a file Copy utility – copies data from one device to another

16. 16 California State University, Fullerton Other System Software (cont’d.) Communications software – used for communications between computers. Database management software – used for managing databases. Software development software – software used to develop software.

17. 17 California State University, Fullerton What is a Programming Language English is a natural language. It has words, symbols and grammatical rules. A programming language also has words, symbols and rules of grammar. The grammatical rules are called syntax. Each programming language has a different set of syntax rules.

18. 18 California State University, Fullerton Why Are There So Many Programming Languages Programming languages have evolved over time as better ways have been developed to design them. Different programming languages are designed for different types of programs. First programs were developed in the 1950s.

19. 19 California State University, Fullerton What Are the Types of Programming Languages First Generation Languages Second Generation Languages Higher Generation Languages

20. 20 California State University, Fullerton First Generation Languages Machine language Operation code – such as addition or subtraction. Operands – that identify the data to be processed. Machine language is machine dependent as it is the only language the computer can understand. Very efficient code but very difficult to write.

21. 21 California State University, Fullerton Second Generation Languages Assembly languages Symbolic operation codes replaced binary operation codes. Assembly language programs needed to be “assembled” for execution by the computer. Each assembly language instruction is translated into one machine language instruction. Very efficient code and easier to write.

22. 22 California State University, Fullerton Higher Generation Languages Closer to English. Less Efficient. Because Programs written in source code which must be translated into machine language programs called object code.