SCSC 311 Information Systems: hardware and software

Chapter Objectives The history of computing Computer system capabilities and components Computer system classification Software Economics of System and Application Development Software Computer networks

Topic 1 History of Computing What is a computer?

Topic 1 History of Computing Originally, the term "computer" referred to a person who performed numerical calculations (a human computer ?!) often with the aid of a mechanical calculating device. Examples of early mechanical computing devices included the abacus, the slide rule, etc.

Topic 1 History of Computing However, none of those devices fit the modern definition of a computer. Why? What is the first computer by the modern definition? they could not be programmed

Mechanical Computers Jacquard loom Joseph Jacquard design punched paper cards as a template to allow his textile loom to weave intricate patterns automatically. (1801) the use of punched cards to define woven patterns can be viewed as an early form of programmability.

Difference Engine Charles Babbage saw high error rate of the people computing the tables, thus started his life’s work in trying to calculate the tables mechanically, removing all human error. He began in 1822 with what he called the difference engine, made to compute values of polynomial functions. around 25,000 parts, fifteen tons, eight feet high. Charles did not complete it. but difference engine was built using his plans in 1991.

Analytical Engine Babbage started designing a different, more complex machine called Analytical Engine would be able to perform all four arithmetical operations, plus comparisons and square roots. was to be powered by a steam engine, 30 m x 10 m The input (programs and data) was to be provided to the machine via punch cards, was to be a store capable of holding 1,000 numbers of 50 digits each. Unfortunately … Limitations of mechanical computers Complex design and construction Wear, breakdown, and maintenance of parts Low operating speed Because of financial, political, and legal issues, the analytical engine was never actually built. In its logical design the machine was essentially modern, anticipating the first completed general-purpose computers by about 100 years.

Electronic Computers (1) Two very important scientific Achievements in 20th century The use of digital electronics largely invented by Claude Shannon in 1937 A more flexible programmability model - von Neumann architecture uses a single storage structure to hold both instructions and data. The separation of storage from the processing unit is implicit in the von Neumann architecture. The term describes such a computer, which implements a Universal Turing machine.

Electronic Computers (2) Electronic Numerical Integrator and Computer ENIAC (1945—1955) the first large-scale, electronic, digital computer capable of being reprogrammed to solve a full range of computing problems weighed 30 tons, and consumed two hundred kilowatts of power.

Electronic Computers (3) Faster, more reliable electronic computers

Optical Computers Optical Computers: uses light, instead of electricity, to perform computations Represents data as pulses of light stored directly or indirectly by materials that reflect or don’t reflect light. Optical Computers are not realized yet Now optical technology is common in Optical fiber networks Optical storages – CD, DVD The future: optical computer, quantum computer (Technology Focus P25)

Index The history of computing Computer system capabilities and components Computer system classification Software Economics of System and Application Development Software Computer networks

Topic 2 Systems Architecture and Capabilities Systems Architecture describes structure, interaction, and technology of computer system components Capabilities of a computer Storage: accept numeric inputs Processing: perform computational functions Communication: communicate results the Von Neumann machine

Processor (will be covered in Ch 4) A processor is a device that performs data manipulation and transformation functions Computation and Comparison Control data movement among memory, mass storage, and input/output devices Terms (p27 – 29) Instruction, Program General-purpose processor vs. special-purpose processor Formulas, algorithms Comparisons, branching

Central Processing Unit (CPU) General-purpose processor Executes all instructions (computation and comparison functions) Directs all data movement

CPU Components Arithmetic logic unit (ALU) Contains electrical circuits that implement each instruction Registers Internal storage locations that can each hold a single instruction or data item Control unit Controls movement of data to and from CPU Accesses program instructions and issues appropriate commands to ALU

Storage (will be covered in Ch 5) Types of information to be stored Intermediate processing results Data Programs Characteristics of storage devices vary widely Cost Access speed Reliability

Storage Types

Primary and Secondary Storage Primary Storage holds program instructions and data for currently executing programs Implemented with random access memory (RAM) Provides access speed and allows CPU to read or write to specific memory locations Volatile; does not provide permanent storage Secondary Storage is composed of high-capacity nonvolatile storage devices that hold Programs not currently being executed Data not needed by currently executing programs Data needed by currently executing programs that does not fit within available primary storage

System Bus (will be covered in Ch 6) Internal communication channel that connects all other hardware devices Primary pathway for moving data and instructions among hardware components Capacity is critical to performance, secondary storage, and I/O device performance

Input/Output Computers must encompass many communication modes Sound, text, and graphics (for humans) Electronic or optical communication (for other computers) Input/Output Devices: implement external communication functions Human-oriented communication devices (e.g., keyboard, mouse, printer) Computer-oriented communication devices (e.g., modem, network interface unit)

Index The history of computing Computer system capabilities and components Computer system classification Software Economics of System and Application Development Software Computer networks

Topic 3 Computer System Classes Microcomputer Meets information processing needs of single user Examples: PCs, network computers Midrange computer Supports many programs and users simultaneously Mainframe Handles information processing needs of large number of users and applications Designed for large amounts of data storage and access Supercomputer Designed for rapid mathematical computation

Multicomputer Configurations Any organization of multiple computers to support a specific set of services or applications Common configurations Cluster Blade Grid What are the differences among them?

1. Cluster Cluster: a group of similar or identical computers that cooperate to provide services or execute a common application Advantages: scalability and fault tolerance Disadvantages: complex configuration and administration

2. Blade Blade: circuit board that contains most of a server computer; Is a specialized cluster Blade vs. Cluster Blade concentrates more computing power in less space Blade is simpler to modify

3. Grid Grid computing: a group of dissimilar computer systems, connected by high-speed network, that cooperate to provide services or execute a common application. Computers may be in separate rooms, buildings, or continents Computers work cooperatively at some times, independently at others Grid vs. cluster grids connect collections of computers which do not fully trust each other, and hence operate more like a computing utility than like a single computer grids typically support more heterogeneous collections

Grid Computing Grids use the resources of many separate computers connected by a network (usually the Internet) to solve large-scale computation problems. Grids provide the ability to perform computations on large data sets, by breaking them down into many smaller ones, or provide the ability to perform many more computations at once than would be possible on a single computer,

Bigger Isn’t Always Better Grosch's law is the observation about computer performance made by Herb Grosch in 1965: Computer performance increases as the square of the cost. can also be interpreted as meaning that computers present economies of scale: Bigger computers are more economical. The relevance of Grosch's law today is a debated subject. It has been rewritten due to: Multiple classes of computers Expanded abilities to configure computers for specific purposes Increased software costs relative to hardware costs Large computer databases Widespread adoption of graphical user interfaces Multicomputer configurations

Index The history of computing Computer system capabilities and components Computer system classification Software Economics of System and Application Development Software Computer networks

Topic 4 Software Software translates user requests into machine instructions Software performs complex translation process that bridges two gaps: Human language to machine language (binary) High-level abstraction to low-level detail

Software Types Application program Stored set of instructions for responding to a specific information-processing tasks Used directly by end users Utility program Contains instructions for performing general-purpose tasks Usually operates invisibly in the background System software Implements utility functions needed by many application programs Allocates computer resources to application programs Manages computer resources Does not interact with end users

The Interaction between the user, application software, system software, and hardware

System Software and Operating Systems OS is the most important system software component (will be covered in Ch 11) Main Functions of OS: Program storage, loading, and execution File manipulation and access Secondary storage management Network and interactive user interfaces

Application Development Software Application development software are programs used to develop other programs Types: Program editors Program translators Debugging tools System development tools Integrated Development Environment (IDE): is visual development tool, integrated with the compiler or application server, and may include tools for debugging, refactoring, version control, and so forth. Do you know Any IDE?

Index The history of computing Computer system capabilities and components Computer system classification Software Economics of System and Application Development Software Computer networks

Topic 5 Economics of System and Application Development Software System software consumes hardware resources Cost per unit of computing power has rapidly decreased Software is more cost-effective when reused many times

Topic 6 Computer Networks (will be covered in Ch 9) Computer networks: set of hardware and software components that enable multiple users and computer systems to share information, software, and hardware resources

Network Hardware Network communication devices Physical network Simpler than I/O devices; do not need to convert data represented electronically into another form Support communication at high speeds Physical network Complex combination of communication protocols, methods of data transmission, and network hardware devices

Network Software Finds requested resources on the network Negotiates resource access with distant resource allocation software Receives and delivers resources to requesting user or program May also listen for and validate resource requests, and deliver resources via the network

In Conclusion: Basic elements of computer system architecture Hardware Software Networks Importance of knowing how all components of a computer system interrelate as well as their internal workings