Computer application software plays a pivotal role in enabling computer science professionals to solve complex tasks efficiently. Understanding how software operates within computer systems is essential for designing, implementing, and managing solutions in diverse Kenyan sectors such as finance, education, and public administration. This chapter explores the foundations of computer software operation, focusing on system software and operating systems, which form the backbone of all computer-based applications. Mastery of these concepts equips learners with the ability to optimize software use and troubleshoot related issues in practical environments.

1.1 Computer software

A computer without software is only a collection of electronic parts that cannot do anything useful. Software is the set of instructions that tells the hardware what to do, and it is what turns a machine into a tool for banking, teaching, record keeping or communication. Understanding what software is and how it is grouped is the starting point for understanding how a computer is configured and managed. Example: when a clerk at Kenya Commercial Bank branch prints a customer statement, several kinds of software work together, from the code that drives the printer to the banking program that prepares the statement.

1.1.1 Definition

Computer software is a set of programs, data and related documentation that instructs the hardware how to carry out tasks. Hardware refers to the physical parts that can be touched, while software exists as coded instructions stored on a disk, memory chip or other storage medium. Software is written by programmers in a programming language and is then translated into machine code, which is the only form the processor can execute directly. Example: at Nyeri County Hospital, the patient registration program is software, while the computer, keyboard and screen on the reception desk are hardware.

Characteristics of software

• Intangible: Software cannot be touched. It exists as electronic patterns on storage media, and it is only visible through what it makes the hardware do.
• Instruction based: Software is made of ordered instructions that the processor fetches and executes one after another, so a program is only as good as the logic written into it.
• Does not wear out: Unlike a printer or a hard disk, software does not deteriorate physically. It becomes outdated or faulty because of errors, changing needs or new hardware, and it is fixed through updates.
• Easy to copy and distribute: A program can be copied at almost no cost and sent over the internet. This is why licensing and piracy control matter to software vendors.
• Needs hardware to run: Software is useless without a processor, memory and storage to execute it, and it often has minimum hardware requirements such as RAM size and disk space.
• Can be changed and updated: Developers release patches and new versions to correct faults, close security gaps and add features, without replacing any physical part.

Software, hardware and firmware compared

1.1.2 Classification

Software is grouped according to the job it performs. The main groups are system software, application software, utility software and firmware. System software runs and controls the computer, application software helps users perform their own tasks, utility software maintains and protects the system, and firmware is permanent software built into hardware devices. Example: a sacco in Meru uses an accounting package (application software), an antivirus (utility software), the Windows platform it runs on (system software) and the firmware in its Wi-Fi router, all on the same day.

System software

System software manages the hardware and provides the platform on which other software runs. It starts when the computer is switched on and remains active until shutdown, and the user seldom interacts with it directly. Example: at Strathmore University computer laboratory, the machines can only run learning programs after the system software has started and prepared the hardware.

• Operating systems: Control the hardware and supply services to other programs. Windows, Linux, macOS and Android are common examples.
• Device drivers: Small programs that let the system communicate with a particular device such as a printer, scanner or graphics card. Without the correct driver the device may not work at all.
• Language translators: Compilers, interpreters and assemblers convert programs written by humans into machine code that the processor can execute.
• Linkers and loaders: A linker combines separate pieces of compiled code into one executable program, and a loader places that program into memory so that it can run.
• Bootstrap programs: The small startup routine that runs when power is applied, tests the hardware and begins loading the operating system.

Application software

Application software performs tasks that the user wants done, such as writing a report, keeping accounts or browsing the internet. It depends on system software to reach the hardware. It is either general purpose, used across many professions, or specialised, built for one particular job. Example: a Kisumu shop owner records daily sales in a spreadsheet, which is general purpose software, while a school bursar uses a fee management program built only for schools.

• Word processors: Create and format text documents such as letters, reports and examination papers. Microsoft Word and LibreOffice Writer are examples.
• Spreadsheets: Organise figures in rows and columns and calculate with formulas. They suit budgets, payrolls and stock lists.
• Database management programs: Store, search and report on large amounts of related data. A county revenue office uses them to track rates paid by each plot owner.
• Presentation software: Prepares slides for training and meetings, for example Microsoft PowerPoint.
• Web browsers and email clients: Let users view websites and send messages, for example Chrome, Firefox and Outlook.
• Specialised packages: Built for a profession, such as hospital management systems, point of sale systems for supermarkets, and computer aided design programs used by building contractors.

Utility software

Utility software performs maintenance and protection tasks that keep the computer healthy and efficient. Some utilities come with the operating system and others are installed separately. They do not produce the user's work themselves, but they protect and prepare the environment in which that work is done. Example: the ICT officer at a Nakuru secondary school schedules a weekly virus scan and a nightly backup on the school's administration computer.

• Antivirus programs: Detect, block and remove viruses, ransomware and other malicious software, and need regular updates of their threat definitions.
• Backup tools: Copy files to another disk or to cloud storage so that data can be restored after loss, theft or failure.
• Disk cleanup and defragmentation tools: Remove temporary files and reorganise scattered data so that storage is used well and files open faster.
• File compression tools: Reduce file size so that files take less space or send faster by email, for example WinRAR and 7-Zip.
• Disk partitioning and formatting tools: Divide a disk into sections and prepare them to hold files.
• Task and resource monitors: Show which programs use the processor, memory and disk, helping the technician find a slow or stuck program.

Firmware

Firmware is permanent software stored in non-volatile memory inside a hardware device, such as ROM or flash memory. It holds the basic instructions the device needs in order to start and operate, and it keeps its contents even when the power is off. It sits between hardware and software, and it can be updated only through a special process called flashing. Example: a Mombasa hotel's guest Wi-Fi router stops working properly until the technician flashes a newer firmware version supplied by the manufacturer.

• BIOS or UEFI: Firmware on the motherboard that tests the hardware at power on and hands control to the operating system.
• Router and modem firmware: Controls traffic routing, security settings and the web page used to configure the device.
• Printer firmware: Controls paper feeding, print quality and communication with the computer.
• Mobile phone and tablet firmware: The low level code that controls the radio, camera and screen before the operating system loads.
• Embedded device firmware: Runs inside machines such as digital door locks, electronic scales, ATMs and smart meters, each doing a single fixed job.

Chapter Summary

This chapter explored the fundamental concepts of computer software operation by first defining systems and their classification. It then provided a clear definition of an operating system and examined key concepts that underpin its operation. The chapter identified the primary functions of an operating system, highlighting its role in managing hardware and software resources. Different operating system structures were discussed, including monolithic, layered, virtual, and the client-server model, explaining how each architecture organizes system components. Various types of operating systems were reviewed, emphasizing their diverse applications and characteristics. Finally, the chapter outlined the essential requirements for installing the Windows operating system, ensuring proper setup and functionality. Together, these topics establish a comprehensive understanding of operating systems and their critical role in computer applications.