Operating Systems

Operating Systems Overview

  • Operating System (OS): A collection of programs that control interactions with hardware and interpret user commands. An application is user software like a word processor or database.

Computer Hardware Basics

  • Computer: A device that calculates.
  • Microcomputer: A small computer used by one person with a microprocessor CPU.
  • Integrated Circuit (IC): A small electronic component consisting of transistors.
  • Input/Output (I/O):
    • Input Hardware: Keyboard, touch screen, microphone (information in).
    • Output Hardware: Display screen, speakers, printer (information out).
  • RAM: Main memory for active programs and data.
  • Motherboard: Circuit board for internal components.
  • Storage: Hard drive, Solid-State Drive, DVD, CD, USB drive.
  • Firmware: Integrated circuits with small programs for basic communication between OS and hardware.
  • Server: Provides services to other computers over a network (file, print, messaging, email, web services).
    • Server OSs: Windows, Apple macOS, Linux, and UNIX.
  • Client: Computer/software receiving services.
  • Desktops and Laptops: Personal computers (PCs) designed for stationary (desktop) or portable (laptop) use, running OSs like Microsoft Windows, macOS, Linux, or ChromeOS.
  • Mobile Devices:
    • Mobile device: small handheld device
    • System-on-a-chip: A microchip containing all (or most) of a device’s circuitry
    • Embedded OS: An OS stored in firmware
    • Smartphone: Cell phone with many hardware features and apps
    • Tablet: Larger than a cell phone, may not have cell capabilities
    • BYOD: Bring your own device
  • Internet of Things (IoT): Network-connected devices like kitchen appliances, thermostats, and industrial controls.

Functions of Microcomputer Operating Systems

  • Booting: Operating system starts up.
  • OS Kernel: Manages low-level tasks.
  • User Interface (UI): Allows user interaction with the OS.
    • Command-Line Interface (CLI): Text-based.
    • Graphical User Interface (GUI): Graphic elements, menus, icons, pointer.
  • Job Management: Controls the order and time programs run (process scheduler).
  • Task Management: Runs two or more tasks simultaneously (multitasking), manages Processes.
  • File Management: Allows OS to read, write, and modify data; uses file systems, partitions, and directories.
  • Device Management: Controls hardware devices using device drivers and Plug-and-Play (PNP).
  • Memory Management: Placement of programs/data in memory.
  • Security: Built-in features like password protection and access restrictions.

Evolution of Operating Systems

  • UNIX: Operating system for various platforms, evolved from Bell Labs; variants include BSD, FreeBSD, and AIX.
  • Early Computing (1950s-1960s): Managed tape data storage; disk systems emerged in mid-1960s.
  • 1970s:
    • MITS Altair 8800 sparked computer enthusiast communities.
  • Early Apple Computers:
    • Apple II (1977) gained popularity; VisiCalc was a "killer app."
    • Lisa (1982) was the first commercially available computer with a GUI and mouse.
    • Macintosh (1984) had a GUI and mouse but lacked memory management and full multitasking.
  • IBM PC (1981):
    • Filled a market void and exceeded sales forecasts.
    • PC DOS (based on MS-DOS) had a text-mode CLI and was single-tasking.
    • Lotus 1-2-3 was a "killer app" for DOS.
  • OS/2: Developed by Microsoft & IBM as a DOS replacement. IBM discontinued the OS/2 support.
  • Microsoft Windows:
    • Windows 1-3.1 were GUI shells on top of MS-DOS.
    • Windows for Workgroups 3.1 included client & server networking software.
    • Windows NT was a new secure OS.
    • Windows 95/98 had improved GUIs but lacked security.
    • Windows Me (Millennium Edition) was for the home market.
    • Windows 2000 was an upgrade of NT with a Windows 98 GUI.
    • Windows XP was popular for consumers, available in 32-bit and 64-bit editions.
    • Windows Vista had improvements but was slow and had high hardware requirements.
    • Windows 7 was faster and better at device recognition.
    • Windows 8/8.1 featured a controversial GUI with a Start screen.

Today’s Desktop Operating Systems

  • Windows 10:
    • New Start menu, Windows Hello, Cortana, Microsoft Edge.
    • Universal apps, improved Xbox app, multiple desktops. Support ends October 2025.
  • Windows 11:
    • Hardware-assisted security, upgraded Microsoft Store, Android app support.
    • Features a redesigned GUI with Snap Layouts and Widgets.
  • Apple macOS:
    • Based on NextStep UNIX kernel, GUI and CLI options, upgraded annually.
  • Linux:
    • Open-source OS developed by Linus Torvalds, written in C.
    • Uses CLI natively but has GUI shells available.
  • Chrome OS:
    • Google creation optimized for cloud-based apps, based on the Linux kernel.

Today’s Mobile Operating Systems

  • Cloud Computing:
    • Cloud: Image to hide complexity of an internetwork.
    • Cloud computing: Use of cloud services.
    • Cloud storage: Data storage service.
  • Mobile Devices:
    • Include wireless network radios, high-quality touch screens, digital cameras, and SSDs.
  • Connectivity:
    • Smartphones use cellular standards.
    • Tablets may have optional cellular.
    • Both use Wi-Fi, Bluetooth, and NFC.
  • Features:
    • Touch screen and virtual keyboard support with multiple screen gestures.
    • Screen rotation between portrait and landscape orientations.
    • Updateable OS for usability and security.
    • Availability of apps through app stores.