CSC 101 - Introduction to Computer Science | Lecture Slides

CLU/COSC 101 INTRODUCTION TO COMPUTER SCIENCE BY Mrs. Hannah Akinwumi 3 Units  Course Outline History of Computer science and their generations Origin of computing machines Computer hardware; functional components Moder...

CLU/COSC 101 INTRODUCTION TO COMPUTER SCIENCE BY Mrs. Hannah Akinwumi 3 Units  Course Outline History of Computer science and their generations Origin of computing machines Computer hardware; functional components Modern I/O units. Diverse and growing computer/digital application Information processing and it's role in the society  Fundamentals of Computer System Definition of a Computer: A computer can be described as an electronic device that can receive data, process the data, and produce the result as the outcome. Conventionally, the received data is known as input while the result of the processing is known as output or information. A computer also has the capability of storing data and/or information in its memory for future use. This relationship is illustrated in Figure 1. Basically, a computer is divided into two major parts, namely, hardware and software. This configuration is like the division of human being into body and spirit/soul. That is, the body is the hardware while the software is the spirit or soul. While the hardware, the physical or most visible part is tangible, the software is intangible. Normally, the software resides and operates within the hardware. Essentially, hardware the physical part of the computer while the software is the code that runs on the computer  Fundamentals of Computer System  Computers are capable of processing numerical data in form of 0’s and 1’s or simply in binary digital format or shortened to bits from Binary digit.  Smallest unit of information computer can process  Can have one of two values: 0 or 1  This digital format is the basis of the machine language which differs from human-readable languages. They can solve repetitive computational jobs with high level of accuracy and timeliness depending on the software capability.  Fundamentals of Computer System  Byte Collection of 8 bits Can represent 256 different messages (256 = 28) Kilobyte, megabyte, gigabyte, and terabyte are terms that describe large units of data used in measuring data storage Example: 100 GB hard drive 8 bits = 1 Byte 1024 Bytes = 1 Kilobyte (KB) 1,048,576 Bytes = 1 Megabyte (MB) 1,043,741,824 Bytes = 1 Gigabyte (GB) 1,099,511,627,776 Bytes = 1 Terabyte (TB)  Fundamentals of Computer System Description of a Computer System A computer system involves a complete suite of hardware and software resources as well as the users that operate the computer system. While a computer system does the basic function of a computer device, different kinds of computer systems can handle certain specific additional functionalities. Ideally, a full-fledged computer system is made up of users, application software, systems software, operating system and hardware as shown in figure below.  What Computers Do Four basic operations:  Receive input: Accept information from outside world  Process information: Perform arithmetic or logical operations on information  Produce output: Communicate information to outside world  Store information: Store and retrieve information from memory and storage devices Architecture of a Computer system Components of a Computer system  Classifications and Types of computers Personal computers Personal computers, popularly shortened as PC, are common, cheaper, versatile, small and portable in sizes. They are single-user computer based on different kinds of microprocessors. Laptops are kinds of PCs that consume less power due to their miniaturized integrated internal components Workstations These computers are relatively more powerful than PCs in terms of computational capability. They are also single-user based. Although, a workstation is like a personal computer, however it has a higher specifications and better quality Minicomputers Minicomputers are multi-users-based computers. They support a large array of users concurrently and are usually able to handle larger complex or/and large computational jobs. PCs and workstations are usually connected to minicomputers in a network for the joint execution of tasks, processes, and programs. Minicomputers are not portable, they belong to large organizations such as the Nigerian National Space Research and Development Agency (NASRDA), National Identity Management Commission (NIMC), Central Bank of Nigeria (CBN), national astronautics and space administration (NASA), European Space Agency (ESA), among others. During your next industrial training, you may wish to visit such organization to see such computers  Classifications and Types of computers Mainframe Mainframe computers are larger, expensive and more powerful multi-user systems. They simultaneously support thousands of users than minicomputers. They have higher specifications in terms of processing speed and storage. They are quite huge and expensive. Mainframe computers are mostly found in large corporations, They are designed to perform large numbers of calculations for governments and large enterprises Supercomputer Although, these computers are similar to mainframe, they are extremely the fastest and can be used to perform hundreds of millions of instructions per second. They are designed to solve grand challenge problems that are often data- and computationally intensive, such as DNA sequencing/human genome, Space exploration, Mars mission, national population census, national electoral system, national database systems, banking applications and database, health informatics, etc. A  Historical Generations Advancements of Computers Computer history specifically dated back to 1833 when Charles Babbage, a mathematician, invented the first runner of digital programmable and general purpose computers. Barely, a century later, Electronic Numerical Integrator and Computer (ENIAC) was invented by John W. Mauchly and J. Presper Eckert, this computer was the first general-purpose electronic computer.  Historical Generations Advancements of Computers First Generation: 1940-1956 This generation showcased the use of vacuum tubes for logic circuitry through the flow of electrical current. Magnetic drums were used for data transfer and storage. During this period, machine language was developed for systematic programming. ENIAC was among the systems developed during this period. The drawbacks of the systems include slower speed, excessive heat, and high cost.  Historical Generations Advancements of Computers Second Generation: 1957-1963 In this generation, transistors were used as the major switching devices thus making computers smaller, faster and energy-efficient. The programming format was assembly languages. The figure shows a typical second generation computer.  Historical Generations Advancements of Computers Third Generation 1964-1971 Integrated circuits (IC) were developed and used as the switching devices for the flow of data. A single IC contains several numbers of transistors, capacitors, and resistors in the entire circuitry. computers became smaller in size, faster in processing and generally efficient. High level programming languages were also introduced during this period. Figure 7 shows a typical third generation computer. Prominent computers in the third generation were PDP (Personal Data Processor), IBM-168/360/370 series, Honeywell-6000 series  Historical Generations Advancements of Computers Fourth Generation Computers 1972-1990 The fourth-generation computers were based on the successful invention and development of microprocessors as the central processing units (CPU). Personal and portable computers were manufactured due to the production of miniatured computing components. As a result, the Very Large Scale Integrated (VLSI) circuits technology was implemented in the design of the microprocessors and other kinds of switching devices. Intel was the first company to design and develop microprocessors. Efficient high-level programming languages were also developed such as Java, C++, C#, VB.NET among others.  Historical Generations Advancements of Computers Fifth Generation Computers 1990 to date The computers of this generation are designed based on superconductors, VLSI, miniaturized components, multi-core technologies, and artificial intelligence. Future computers will advance more on machine learning, expert systems, natural language processing, neural networks, advanced parallel computation, robotics, and fuzzy logic designs. Virtual reality, fault-tolerance, and artificial intelligence will dominate the hardware and software designs of fifth- generation computer. Computer hardware; functional components System  Computer hardware; functional components System Computer devices in physical form it Comprises of 4 components: Input devices Central Processing Unit (CPU) Output devices Memory Modern Input/Output units Input device is any hardware component that allows users to enter data and instructions Input devices  Display devices are output device that visually conveys information Information on display device sometimes called soft copy Monitor houses display device as separate peripheral  Modern Processing units  CPU often called “processor”  Performs transformations of input into output  Interprets and executes instructions in programs  Performs arithmetic and logical data manipulations  Communicates with other parts of the computer system indirectly through memory Modern Microprocessor Complex collection of electronic circuits CPU housed with other chips on circuit board Circuit board containing computer’s CPU is called motherboard  The CPU – How it works  Typical CPU is divided into several functional units: Control unit Arithmetic logic unit (ALU) includes registers Decode unit Bus unit Prefetch unit  These units work together to complete the execution of program instructions. The CPU – How it works  Memory A memory is just like a human brain. It is used to store data and instructions. Computer memory is the storage space in the computer, where data is to be processed, results of processed data and instructions required for processing are stored. Memory is primarily of three types − (i) Cache Memory (ii) Primary Memory/Main Memory (iii) Secondary Memory  Memory Cache Memory is a special very high-speed memory. The cache is a smaller and faster memory that stores copies of the data from frequently used main memory locations. Cache used by the central processing unit of a computer to reduce the average time to access memory. The cache is a smaller, faster memory which stores copies of the data from the most frequently used main memory locations. When the processor needs to read from or write to a location in main memory, it first checks whether a copy of that data is in the cache. If so, the processor immediately reads from or writes to the cache, which is much faster than reading from or writing to main memory.  Primary Memory Primary storage or memory is also known as the main memory, which is the part of the computer that stores current data, programs, and instructions. Primary storage is stored in the motherboard which results in the data from and to primary storage can be read and written at a very good pace. Primary Memory examples are RAM, ROM, cache, PROM, EPROM, registers, etc. Classification of Primary Memory Primary memory can be broadly classified into two parts: Read-Only Memory (ROM) Random Access Memory (RAM) Read-Only Memory Any data which need not be altered are stored in ROM. ROM includes those programs which run on booting of the system (known as a bootstrap program that initializes OS) along with data like algorithm required by OS. Anything stored in ROM cannot be altered or changed Information is etched on chip when manufactured Stores start-up instructions and other critical information Random Access Memory Any process in the system which needs to be executed is loaded in RAM which is processed by the CPU as per Instructions in the program. Like if we click on applications like Browser, firstly browser code will be loaded by the Operating system into the RAM after which the CPU will execute and open up the Browser. Most common type of primary storage Stores program instructions and data temporarily Memory locations have unique addresses Volatile—disappears when power is turned off Called DIMMS. Rated by both size and speed.