System Software and Operating Systems

Overview of System Software

  • Software is categorized into two primary types:

    • Application Software: Software used for everyday tasks at home and work.
    • System Software: Necessary software that must be running before any application software can be used. It helps run the computer and coordinates instructions between application software and the computer’s hardware devices.

  • System software consists of two primary programs:

    • Operating System (OS): A group of programs that controls how the computer system functions.
    • Utility Programs: Small applications that perform special functions on the computer.

Classifications and Types of Operating Systems

  • Modern operating systems allow for multitasking and provide networking capabilities (specifically Microsoft Windows and macOS).

  • OS for Personal Use:

    • Personal Computer OS: Windows, macOS, Linux.
    • Mobile Device OS: Android, iOS, iPadOS, watchOS.
    • Cloud-based OS: OneDrive (Windows), iCloud (Apple).
    • Web-based OS: Chrome OS.

  • Linux Highlights:

    • It is an open-source OS used for personal computers and web servers.
    • Known for being a stable OS that can be quickly modified or updated.
    • Available for download in various packages known as distributions (distros). Information on distros is available at distrowatch.com.

  • OS for Machinery, Networks, and Business:

    • Real-Time OS (RTOS): Used for machines performing repetitive series of specific tasks in precise time; also referred to as embedded systems.
    • Multiuser Operating System (Network OS): Allows multiple users to access the computer at the same time.
    • UNIX: A multiuser, multitask operating system primarily used with mainframes. Its source code is proprietary and belongs to The Open Group. Any vendor meeting requirements can use the UNIX name and modify the code for their hardware.

Essential Operating System Functions

  • The OS coordinates and directs the flow of data and information through the computer system across six essential areas:
1. User Interface
  • Provides the means for users to interact with the computer. Three types exist:
    • Command-driven interface: Requires typing specific commands.
    • Menu-driven interface: Users choose from a list of options.
    • Graphical User Interface (GUI): Used by modern OS like Windows and macOS. Linux users can choose between many interfaces, such as GNOME and KDE, to change the look and feel.
2. Processor Management
  • The OS manages the CPU by arranging the execution of activities and assigning a slice of time to each, switching millions of times per second to create the appearance of simultaneous action.
  • Preemptive Multitasking: The mechanism where the OS processes tasks with higher priority before lower-priority tasks.
  • Interrupts: Unique signals generated by devices (e.g., a printer) indicating a need for immediate attention.
  • Interrupt Handler: Prioritizes these requests.
  • Stack: When an interrupt is received, the OS suspends the current activity and creates a memo in a stack to remember where it left off.
  • Spooler: A program that coordinates print jobs. If a printer is busy, the OS puts the request in a buffer until the spooler can process it.
3. Memory and Storage Management
  • The OS uses RAM as temporary storage for instructions and data needed by the processor.
  • Virtual Memory: If RAM capacity is full, the OS borrows space from the hard drive.
    • Swap File: The temporary storage area on the hard drive used for virtual memory.
    • Paging: The process of swapping data between RAM and the swap file.
    • Thrashing: The condition of excessive paging that slows the system down. Increasing RAM is the solution to avoid virtual memory usage.
4. Hardware and Peripheral Management
  • Device Drivers: Facilitate communication between the device and the OS by translating device commands into OS-understandable commands.
  • Plug and Play (PnP): A hardware and software standard that facilitates the installation of new hardware.
5. Software Application Coordination
  • Application Programming Interface (API): Code that the CPU recognizes, allowing software applications to interact consistently with the CPU.
6. File Management
  • Provides an organizational structure using a hierarchical directory structure including:
    • Drives: Such as drive C:.
    • Libraries.
    • Folders: Collections of files.
    • Subfolders.
    • Files: Collections of program instructions or data treated as a single unit.
    • Root Directory: The top-level filing structure (e.g., C:).

Detailed File Management and Naming

  • Tools and Paths:

    • File Explorer: The primary tool for finding and managing content in Windows.
    • File Path: Starts with the drive, followed by folders, subfolders, file name, and extension.

  • Naming Conventions:

    • User-assigned file names can be up to 255255 characters long and must be unique.
    • Extensions: Follow the file name and a period (.) in Windows. They identify the application needed to read the file. Mac and Linux do not require extensions.

  • Common File Extensions:

    • .docx: Microsoft Word 20072007 and later (Word processing).
    • .xlsx: Microsoft Excel 20072007 and later (Workbook).
    • .accdb: Microsoft Access 20072007 and later (Database).
    • .pptx: Microsoft PowerPoint 20072007 and later (Presentation).
    • .pdf: Adobe Acrobat/Reader (Portable Document Format).
    • .rtf: Rich Text Format (General text).
    • .txt: Plain text.
    • .htm / .html: Hypertext Markup Language (Web page).
    • .jpg: Joint Photographic Experts Group (Image).
    • .zip: Various compression programs (Compressed file).

  • Maintenance and Recovery:

    • Actions include Open, Copy, Move, Rename, and Delete.
    • File History: A Windows utility that automatically creates duplicates of libraries, desktops, and favorites to an external storage device.
    • File Retrieval Programs: Such as Disk Drill Data Recovery.
    • File Compression: Makes large files compact by removing redundancies and repeated patterns, making them easier to send.

The Boot Process (Start-up)

  • The boot process loads the OS into RAM through four basic steps:
  1. Activating BIOS: The CPU activates the Basic Input/Output System (stored on ROM). BIOS manages data exchange between the OS and devices and is responsible for loading the OS from the hard drive into RAM.
  2. Performing the POST: BIOS performs a Power-on Self-test to ensure essential peripherals are operational. It compares results against configurations in the CMOS (which contains info on memory, disks, and components).
  3. Loading the OS: BIOS loads system files and the Kernel into RAM. The Kernel manages the processor and essential components. Once loaded, the OS takes control.
  4. Checking Configurations: The OS checks the Registry for system component configurations and verifies authentication/user account settings.

Handling Boot Errors

  • Methods for troubleshooting:
    • Powering the computer off and back on.
    • Uninstalling recently installed software via the Control Panel.
    • Last Known Good Configuration: Accessed via the Windows Advanced Options Menu (pressing F8F8 during boot) if Windows detects an error.
    • Reset this PC: A utility for diagnosing and fixing Windows system files.
    • System Recovery: Reverting to a previous configuration.

Utility Programs and System Maintenance

  • Utility programs are categorized by source: included with the OS, sold as stand-alone, or offered as freeware (e.g., Ad-Aware by Lavasoft).

  • Specific Utilities:

    • Disk Cleanup: Removes unnecessary files like temporary internet files, offline web pages, and the Recycle Bin contents.
    • Storage Sense: Automatically deletes temporary items and long-ago downloads.
    • Task Manager: Used to check performance or exit non-responsive programs.
    • Disk Defragmenter: Rearranges fragmented data so related file pieces are unified for faster access.
    • System Restore: Rolls system settings back to a specific date when the system was stable.

  • Accessibility Utilities (Ease of Access):

    • Magnifier: Magnifies a portion of the screen.
    • Narrator: Reads screen contents, menus, and typed text.
    • Speech Recognition: Voice control and dictation.
    • On-Screen Keyboard: Text entry via pointing device.
    • High Contrast: Inverts screen colors for limited vision.

Questions & Discussion

  • Q: What are the two primary programs of system software?
    • A: Operating system and utility programs.
  • Q: What is the ability to perform more than one task at once called?
    • A: Multitasking.
  • Q: What OS is for machinery with precise timing?
    • A: Real-Time OS (RTOS).
  • Q: Which interface requires typing specific commands?
    • A: Command-driven interface.
  • Q: What is a unique signal from a device like a printer?
    • A: An interrupt.
  • Q: How does the OS prioritize higher-priority tasks over lower-priority ones?
    • A: Preemptive multitasking.
  • Q: What happens if RAM required exceeds installed RAM?
    • A: The computer uses virtual memory (borrowing hard drive space).
  • Q: What software facilitates device-to-OS communication?
    • A: Device driver.
  • Q: What is the primary goal of file compression?
    • A: To make large files more compact for easier and faster sending.
  • Q: What is the first step of the boot process?
    • A: Activating the BIOS.
  • Q: What is the purpose of the POST?
    • A: To ensure essential peripheral devices are attached and operational.
  • Q: What are the three sources of utility programs?
    • A: Included with OS, Stand-alone programs, and Freeware.
  • Q: Which utility removes temporary internet files?
    • A: Disk Cleanup.
  • Q: Which utility helps exit non-responsive programs?
    • A: Task Manager.
  • Q: What is the function of disk defragmentation?
    • A: It rearranges fragmented data so related file pieces are unified for faster access.
  • Q: Which Windows utility duplicates libraries to an external drive?
    • A: File History.