Digital and Technological Solutions: Exploring the foundations of digitization (English Edition)

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Computer System Fundamentals

Introduction

Computer science is a field that deals with the study of computers and how they work. It involves learning how to create programs that can solve problems and make things easier. The field of computer science emerged during the mid-20th century with the development of the first electronic computers. Back then, computer science was closely linked to math, and people like Alan Turing, John von Neumann, and Grace Hopper made important contributions to both fields.

During the 1960s and 1970s, computer science experienced rapid expansion, leading to the development of fresh computer designs, programming languages, and innovative software creation methods. As time passed, computer science kept changing and improving. Personal computers, the internet, and mobile devices were created. Today, computer science is a diverse field and affects many parts of modern life, including science, business, entertainment, and social media.

Structure

In this chapter, we will cover the following topics:

• Understanding computers

• Computer architecture

• Software

• Operating system

• Algorithm

• Flow chart

Objectives

Upon completion of this chapter, students should be able to understand the generations of computers and their advancements from generation I to V. They will also be able to comprehend computer architecture, including hardware components like CPU, RAM, and storage devices. Further, students will recognize the significance of output units and their role in information display and distinguish between system software and application software, focusing on operating systems. Along with that, students will explore the fundamental aspects of algorithms, including their properties and representation, using flow charts.

Understanding computers

The computer is a machine that can handle and store information, and perform different tasks according to the commands it receives. It is made up of several parts that work together to make it function, such as CPU, memory, solid-state drive, or hard drive (storage), input devices like a keyboard and mouse, and output devices like a screen or speakers. The following figure illustrates parts of a computer system:

Figure 1.1: Components of a computer

Computers can perform a wide range of tasks, from simple operations like typing and calculating to complex ones like analyzing large sets of data or running simulations. They can be used for various purposes like creating documents, editing photos or videos, browsing the internet, playing games, and much more. Computers have become an essential part of our lives and are used in many industries and fields, including education, healthcare, finance, engineering, and entertainment. They have made many tasks faster, easier, and more efficient than they used to be, and have enabled us to accomplish things that were once impossible.

Generations of computers

It refers to the different stages of development in computer technology. Each generation represents a significant step forward in the design and functionality of computers. Typically, each new generation is marked by the introduction of new hardware and software technologies that enable faster processing, more efficient memory usage, and increased computing power. Each generation builds on the achievements of the previous generation, resulting in increasingly powerful and capable computers. Let us briefly understand each generation:

• Generation I: The first generation of computers was the vacuum tube era, which spanned from the late 1940s to the early 1950s. These computers used vacuum tubes to perform calculations. They were very large and expensive, but they were the first computers capable of performing complex calculations and were a huge leap forward for computer technology. Examples of first-generation computers are ENIAC, EDVAC, UNIVAC, IBM-701, and IBM-650.

• Generation II: Transistors replaced vacuum tubes during the late 1950s, marking the emergence of the second generation of computers. Transistors were more reliable, faster, and smaller than vacuum tubes, and they allowed for the creation of smaller and more powerful computers. Examples of second-generation computers are IBM 1620, IBM 7094, CDC 1604, CDC 3600, and UNIVAC 1108.

• Generation III: In the 1960s, the computer industry witnessed the emergence of the third generation of computers, which marked a significant milestone with the introduction of Integrated Circuits (ICs). These ICs revolutionized computer design by enabling the development of more compact and powerful machines. As a result, mainframe computers and minicomputers became possible, bringing about a new era of computing with enhanced capabilities and improved efficiency. Examples of third-generation computers are IBM 370, PDP-11, IBM System/360, UNIVAC 1108, Honeywell-6000, DEC series, and ICL 2900.

• Generation IV: The fourth generation of computers commenced in the late 1970s and extended throughout the 1980s saw the development of microprocessors. Microprocessors made it possible to create personal computers that were affordable and accessible to individuals and small businesses. Examples of fourth-generation computers are IBM 4341, DEC 10, STAR 1000, and PUP 11.

• Generation V: The fifth generation of computers initiated in the 1990s and has persisted to the present era, featuring significant advancements in technologies such as artificial intelligence and other cutting-edge innovations. These technologies have enabled the creation of machines that can learn, reason, and understand natural language, and they have revolutionized fields like healthcare, finance, and manufacturing. Examples of fifth-generation computers are Param 1000, Intel P4, IBM laptops, notebooks, and PCs of Pentium. The following figure illustrates the generations of computer:

Figure 1.2: Generations of computer

Computer architecture

Computer architecture is the design or blueprint that explains how different components of a computer system like hardware and software, work together to process information and execute programs. In short, computer architecture refers to how a computer system is designed and how it works.

Hardware

Hardware refers to the physical components of a computer system that can be touched and seen. Examples of hardware include the computer case, monitor, keyboard, mouse, motherboard, hard drive, and CPU.

Input unit

Input devices enable users to input data and commands into a computer system, allowing them to provide information in various forms, such as numbers, words, actions, and commands. Its primary role is to capture and direct these inputs into the computer. For instance, a keyboard serves as an input device for entering numbers and characters, while a mouse can be used to input directions and commands. Other examples of input devices include Magnetic Ink Character Recognition (MICR), barcode readers, Optical Character Recognition (OCR) devices, and touch screens.

Central Processing Unit

Central Processing Unit (CPU) is responsible for processing the data and commands received from users. It is an essential component of a computer system. There are three elements in the CPU: The control unit, the arithmetic and logic unit (ALU), and the memory unit. Let us briefly understand each element:

• Arithmetic and logic unit (ALU): It carries out arithmetic operations such as addition, subtraction, division, multiplication, and more.

• Control unit: This oversees the coordination of tasks among all components within a computer system. It gathers data from input units and directs it to the appropriate processing units based on its nature. Ultimately, it transmits processed data to output units for user accessibility.

• Memory unit: It stores the data entered by users via input devices. This data remains in memory until other CPU components process it. The memory unit utilizes a set of predetermined instructions to transmit this data to other sections of the CPU. Take a look at the following figure:

Figure 1.3: The basic three components

Primary memory

Commonly referred to as main memory, primary memory is the type of memory that the CPU can directly access. It is also volatile, which means that it requires power to retain its data. Primary memory is of two types, along with another form called cache memory. Let us briefly understand each type:

• Random access memory (RAM): It is the most common type of primary memory. RAM, which stands for random access memory, is a type of volatile memory that temporarily holds data and instructions required by the CPU for performing calculations. The data stored in RAM can be accessed in any order, which makes it faster than secondary memory. It is utilized to retain the data that the computer is currently processing. RAM chips are either static or dynamic and accordingly are categorized into following types:

o Static Random-Access Memory (SRAM) is a volatile semiconductor memory employed in computers and electronic devices for the rapid and frequent retrieval of data. In contrast to Dynamic RAM (DRAM), which necessitates periodic refreshing to preserve data, SRAM utilizes flip-flop circuits to store individual bits of information, enabling it to maintain data integrity as long as there is a power supply. This property imparts superior speed and energy efficiency to SRAM compared to DRAM. However, it comes at a higher cost and is typically used in smaller quantities, primarily in a computer’s memory hierarchy, notably in cache memory, where it ensures swift access to frequently utilized data.

o Dynamic Random-Access Memory (DRAM) is a volatile semiconductor memory frequently applied in computers and electronic devices to temporarily store data. In contrast to SRAM, where each data bit is held in a flip-flop circuit as long as power is present, DRAM employs capacitors to store bits as electrical charges. To prevent data loss, these charges require periodic refreshing. While DRAM is slower and consumes more power than SRAM, it is a cost-effective choice typically used in larger quantities as the primary system memory in computers.

o Double Data Rate Synchronous Dynamic Random-Access Memory (DDR SDRAM) is a variety of dynamic RAM utilized in computers and digital devices. It enhances performance over earlier SDRAM variations by transmitting data during both the ascending and descending edges of the clock signal, effectively doubling the data transfer speed. This technology is extensively employed in contemporary computer systems due to its heightened data throughput and effectiveness. Various iterations of DDR SDRAM, including DDR2, DDR3, DDR4, and DDR5, are available, each presenting incrementally faster data transfer rates and enhanced performance. Take a look at the following figure:

Figure 1.4: Primary memory

• Read-only memory (ROM): It is a permanent memory that stores crucial data necessary for the computer to function. ROM is programmed at the time of manufacturing and cannot be altered or deleted. The Basic Input/Output System (BIOS) is an example of ROM that is used to start the computer when it is turned on.

o Programmable Read-Only Memory (PROM) is a non-volatile form of digital memory employed in electronic devices and computers. Its unique characteristic is the ability to have data written to it just once, rendering it ideal for preserving permanent or essential data such as firmware. Despite the prevalence of more versatile memory solutions, PROMs continue to have their place in applications where data immutability is necessary.

o Erasable Programmable Read-Only Memory (EPROM) is a type of non-volatile semiconductor memory employed in electronics and computer systems. It shares similarities with PROM. It can have data written to it, but it possesses a unique characteristic – it can be erased and reprogrammed multiple times. EPROMs feature a distinct window that, when exposed to Ultraviolet (UV) light, enables the erasure of stored data, after which new information can be programmed. This flexibility renders EPROMs valuable for scenarios necessitating periodic updates or alterations to the stored content.

o Electrically Erasable Programmable Read-Only Memory (EEPROM) is a type of non-volatile memory technology commonly utilized in electronics and digital devices. This memory is writable, and it possesses the added benefit of being erasable and reprogrammable through electrical means, distinguishing it from traditional EPROMs that necessitate exposure to UV light for data erasure. EEPROMs offer the capability to electronically write, modify, and erase data, rendering them particularly suitable for applications demanding regular updates and alterations to stored information, including firmware and configuration data in a variety of electronic devices.

o Flash Read-Only Memory (Flash ROM) is a prevalent form of non-volatile memory employed in electronics and computer systems. Differing from traditional ROM, it is both writable and erasable using electrical processes. Flash ROM finds extensive use in storing firmware, software, and data across various devices such as smartphones, USB drives, Solid-State Drives (SSDs), and memory cards. It balances persistent data storage and the capability to make periodic adjustments and revisions to the stored information.

• Cache memory: A form of primary memory, the cache is positioned closer to the CPU compared to RAM. Its purpose is to store frequently accessed data and instructions, thereby reducing the CPU’s retrieval time for such information.

Secondary memory

Alternatively referred to as external memory, secondary memory is a type of non-volatile memory that permanently stores data. Its purpose is to retain information even when the computer is powered off, making it suitable for storing data that requires long-term preservation. Secondary memory is usually slower than primary memory. There are mainly four types of secondary memory, as follows:

• Hard disk drive (HDD): A non-volatile storage device that uses magnetic disks to store data. Data is accessed through read/write heads that move across the disk’s surface. HDDs are commonly utilized in desktops and laptops.

• Solid state drive (SSD): A non-volatile storage device that employs flash memory to store data. SSDs offer faster performance and higher reliability compared to HDDs, but at a higher cost. They are commonly employed in high-performance computers.

• External hard drives: Portable hard drives that can be connected to a computer via USB or other interfaces. They provide additional storage capacity for data backup and transfer purpose.

• Optical drives: Non-volatile storage devices that utilize laser technology to read and write data on optical discs, including CDs, DVDs, and Blu-ray discs. They are commonly used for data backup and distribution.

• Flash memory: A type of non-volatile memory that employs EEPROM technology to store data. Flash memory finds application in various electronic devices such as smartphones, cameras, and USB flash drives.

• Pen drives: Also known as USB flash drives or thumb drives, these small portable devices utilize flash memory for data storage. They can be connected to a computer’s USB port and are commonly used for data transfer and backup purposes. Take a look at the following figure:

Figure 1.5: An image describing the memory hierarchy

Output devices

Output devices are hardware elements or peripherals that display or present data to users or other devices. They transform electronic data from computers or digital devices into formats that can be comprehended by humans or machines. Some common examples of output devices encompass monitors/displays, printers, speakers, headphones, projectors, plotters, smart TVs, speakers/microphones, and so on.

Software

It is a collection of commands or instructions that guides a computer what to do. Alternatively, it can be referred to as a program which offers a series of instructions for carrying out user commands and directing the computer’s operations. Examples of software include applications like MS Excel, MSWord, Web browsers and Photoshop etc.

Software can be broadly categorized into two main types: application software and system software. Let us briefly understand each type:

• System software: System software is a type of software, that directly interacts with computer hardware and offers essential functionality for both users and other software to function effectively. It manages the internal operations of a computer and controls hardware devices like printers, storage devices and monitors. Acting as an intermediary between hardware and user applications, it facilitates communication between them. Some of the examples of system software are operating systems like macOS and Windows. Let us take a look at the characteristics of system software.

Characteristics of system software are as follows:

o System software is closely integrated with the computer system.

o Generally, low-level programming languages are used to develop system software.

o Designing and comprehending system software can be challenging.

o System software exhibits high operational speed.

o Compared to application software, system software typically offers less interactivity for users.

System software is further divided into several categories, including the Operating System, language processors, and device drivers. Let us understand each classification in detail:

o Operating system: The primary program of a computer system is the operating system, which is the initial software that loads into the computer’s memory upon power-up. Its main role is to manage system resources, including printers, memory, hard disks, CPU, and others. The operating system provides a user interface to facilitate interaction with the computer system. Moreover, it offers various services to other software, such as handling errors, managing resources, and executing programs. Apple macOS, Microsoft Windows and Linux are examples of widely used operating systems.

o Device driver: A device driver is a software program responsible for managing and overseeing the functions of a particular device. Its purpose is to ensure the proper operation and interaction between the device (for example, mouse, printer, modem) and the computer system. When a new device is connected to the computer, its corresponding driver needs to be installed. This enables the operating system to comprehend and efficiently handle the device’s capabilities and activities.

o Language processor: Language processors are a type of system software that converts programs written in high-level programming languages such as C++, Java, and C into machine-readable code, and vice versa. They enable the transformation of human-readable code to machine-readable code and vice versa. Code written in languages like C, Java, C++, Python, and so on, is commonly referred to as source code, while code written in machine language is known as object code or machine code. Examples of language processors include assemblers, compilers, and interpreters. Language processors can be classified into three primary categories as follows:

▪ Compiler: The compiler is a language processor that scans the complete source code and converts it into machine code, enabling the computer to understand and execute the program.

▪ Assembler: An assembler is a type of language processor specifically created to transform assembly language programs into machine code. Its purpose is to translate the source code into either object code or machine code, enabling the computer to understand and execute it.

▪ Interpreter: The interpreter is a type of language processor that sequentially processes the source code, line by line. It translates each line of code into machine code and executes it immediately before moving on to the next line of code.

• Application software: Application software, also referred to as application programs, are software programs that offer specific functions or perform tasks beyond the basic operations of a computer system. Their purpose is to meet the requirements and cater to the needs of end users. Examples of application software include popular programs like MS Office, PowerPoint, Excel, Word, and Outlook, which are designed to fulfill specific tasks and provide enhanced functionality to users.

Characteristics of application software are as follows:

o Designing and comprehending application software is typically straightforward.

o Application software is commonly written in high-level programming languages.

o Application software offers high interactivity for users, making it user-friendly and easy to use.

o Due to their functionality and features, application software tends to have larger file sizes, requiring more storage space.

Application software is utilized for performing specialized tasks such as word processing, photo editing, and more.

Primarily there are three categories of application software:

o General-purpose software: This is a form of application software that is designed to perform a diverse array of tasks and is not confined to a specific function. Instances of this software category include popular applications such as MS Excel, MSWord, MS PowerPoint, and similar programs.

o Customized software: This is a form of application software that is customized and created to fulfil specific tasks or functions, often tailored for specific organizations. Instances of such software include systems like invoice management systems, airline reservation systems, and railway reservation systems.

o Utility software: This is a form of application software that supports the computer infrastructure by providing tools for analysis, configuration, optimization, and maintenance of the system. It addresses the system’s requirements and may include antivirus software, disk fragmentation tools, memory testers, disk repair tools, registry cleaners, disk space analyzers, and more.

Software can also be classified into two main categories as follows:

• Open-source software: Open-source software refers to computer software that has its source code openly accessible on the internet. This allows programmers to make modifications to the code, introducing new features and capabilities without incurring any costs. These software projects are typically managed by a community of developers. Open-source software is often accessible for free, though it may or may not include a license. Users possess the freedom to study the software’s inner workings, enhance and modify it, and distribute it without any limitations. Ubuntu, Open Office, Firefox and Android are examples of open-source software.

• Proprietary software: Proprietary software refers to computer software that does not have its source code publicly accessible. Only the company or organization that developed it, possesses the ability to access and modify the source code. Users are required to pay for proprietary software, and commercial support is typically provided for maintenance purposes. The company grants users a valid and authenticated license to utilize the software. However, this license may impose certain limitations, such as restricting the number of installations, prohibiting illegal sharing of the software, setting a time limit on software usage, or limiting access to specific features. macOS, Windows, Google Earth, Microsoft Office, and Internet Explorer are examples of proprietary software.

Operating system

An Operating system (OS) is a program that serves as the ... serves as the interface between computer hardware and the user. It is a software that performs essential tasks like controlling peripheral devices like printers and disk drives, memory management, input and output handling, file management, and process management. Some well-known operating systems include Linux, and Windows.

Functions of an operating system

Operating systems are responsible for resource and service allocation, including memory, devices, and processors. These encompass a variety of programs responsible for managing system resources. These programs include schedulers, traffic controllers, I/O programs, memory management modules, and file systems. Let us take a look at each function one-by- one:

• Memory management: The OS manages primary memory, allocating memory to processes upon request and deallocating it when processes terminate.

• Processor management: The OS schedules processes, determining the order and duration of their execution. It tracks process status and assigns processors accordingly.

• Device management: The OS handles device communication through drivers, keeping track of connected devices, allocating access to devices, and releasing them when no longer needed.

• Disk management: The OS facilitates access to stored information on disks and utilizes disk scheduling algorithms to optimize performance.

• Security: Operating systems employ security measures such as password protection to safeguard user data, prevent unauthorized access, and protect programs and user data.

There are different types of operating systems, including Batch OS, real-time OS, and multiuser OS. Let us briefly discuss the three of them:

• Batch OS: The introduction to the Batch OS marked a significant milestone in the development of operating systems for second-generation computers, as it was the pioneering example in this domain. Rather than interacting directly with the computer, the operator organizes similar jobs into batches under the Batch OS. These batches are executed in sequential order, following the principle of first-come, first-serve. The Batch OS facilitates the efficient execution of similar jobs, enhances the management of large workloads, and enables multiple users to share batch systems. Nevertheless, troubleshooting batch systems can present significant challenges, leading to potential delays for other jobs in case of job failures.

• Real-time operating systems (RTOS): RTOS are used where numerous external events must be accepted and processed within strict time constraints. These systems are used in applications such as flight control, telephone switching equipment, industrial control, and real-time simulations. RTOS ensures that processing occurs within specified deadlines, and failure to meet these deadlines can result in system failure.

• Multiuser OS: In a multiuser operating system, numerous users have simultaneous access to different resources on a computer. This access is facilitated through a network comprising personal computers connected to a mainframe computer system. Each user can interact with the system independently and utilize shared resources. Multiuser OS enables efficient resource utilization and supports collaboration among users.

Advantages of operating system

The advantages of an operating system are as follows:

• Facilitates data and information sharing: A multi-user operating system allows for easy sharing of information and data among different users on the network.

• Resource sharing: Users can share hardware resources such as printers, reducing the need for individual devices for each user.

• System reliability: In the event of a computer failure, other computers on the network remain unaffected, ensuring continuity of