1. Chapter 2 Introduction to Systems Architecture

2. Chapter goals Discuss the development of automated computing Describe the general capabilities of a computer Describe computer system components and their functions List computer system classes and their distinguishing characteristics Define the role and function of application and system software Describe the economic role of system and application development software

3. Why invent a computer? What kinds of problems were people trying to solve?

4. Primary characteristics of a computer General-purpose processor capable of performing computation, data movement, comparison, and branching functions Storage capacity sufficient to hold large numbers of program instructions and data Flexible communication capability through the use of multiple media and devices

5. Computer hardware

6. CPU Architecture

7. Storage Categories

8. Input/output capacity PC is a varied collection of devices connected through internal communication (system bus) Readings from White on evolution of the system bus

9. System bus How does capacity of system bus compare to CPU? Why is “backwards compatibility” an important issue for the bus?

10. Computer System Classes Microcomputer/Network Computer (PC) Minicomputer (up to 100 simultaneous users) Mainframe (1000s of simultaneous users) Supercomputer (computationally intense applications – weather forecasting, computer animation)

11. Computer System Classes

12. The Role of Software

13. Complexity of software creation Software performs a complex translation: Identified need or task Human language description of how to complete the task (algorithm, recipe, construction plan, blueprint) Algorithm to programming language (code) Programming language to machine language Machine language to CPU instructions (all binary, 0s and 1s)

14. Software types Application software System software

15. Systems software Invisible to user (ideal) IS professional – needs to understand/configure/install/maintain/ update systems software

16. Software layers

17. Software/hardware layers

18. System software layers System management – utilities called by user/system administrator System services – functions common to many applications carried out by system software (print) Resource allocation – manage multiple requests for same resource Hardware interface – carries out instructions that operate directly on devices (device drivers)

19. Machine independence Layers “hide” specific details about hardware Standard service requests (print) are translated at lowest possible level to specific hardware instructions Example: adding a new printer changes your OS, not every application installed on your machine

20. Machine independence (cont.) Placing all hardware interface functions within a single system software layer Concept of virtual machine (used by Java,.NET) Same applet is downloaded Each individual machine (unix, mac, windows) has own systems level to carry out instructions from applet

21. Operating systems functions Program storage, loading and execution File manipulation and access Secondary storage management Network and interactive user interfaces

22. Application development Toolkit or suite to assist in development of software Referred to as Integrated Development Environment (IDE) Programs that helps create other programs

23. Application development (cont.) IDE consists of Program translator (compiler) Program editors Debugging tools System development & modeling tools (CASE computer aided software engineering)

24. Computer networks Set of hardware and software components that allows information, software and hardware resources to be shared among multiple users and computer systems

25. Network components External Resources Network Software Network Communication and the Physical Network

26. Chapter summary This chapter introduces the primary topics of the text: Hardware Processor Software Operating systems Networks