4.1 What Controls Your Computer?
The first instructions your computer uses when you turn on the power are stored in a ROM BIOS chip located on the motherboard (the circuit board that holds the vari- ous elements of your computer). These instructions are called firmware. Firmware in a computer system contains code that is used to start the computer and load system software.
System Software
System software includes your operating system and several types of utility software.
The operating system (OS) provides you with an interface to work with your computer hardware and applications, while the utility software, or utilities, optimizes and main- tains your computer. The OS and utilities are typically combined in an operating system package such as Windows, Linux, UNIX, macOS, Android, or Chrome OS. Portable devices such as tablets and smartphones typically use a mobile operating system that pro- vides similar functionality to the OS on your desktop or laptop computer.
The OS part of the system software allows you to organize and control your com- puter hardware and software. It’s in charge of loading files, deciding which applica- tions get to do what and when as you work, and shutting down your computer. The OS is essential for you to interact with your computer because software and hardware simply can’t run without an OS in place. Your OS translates your commands and per- forms appropriate actions.
The utilities included in an operating system package such as Windows aren’t essential to the functioning of the OS but are useful to the OS and to the user. Disk Cleanup in Windows, for example, helps the OS function by maintaining your com- puter and getting rid of unused or unusable files.
Figure 4.1 shows some of the devices and components that are managed by the OS.
Starting Your Computer
The process of starting your computer, called booting, is handled by instructions that reside on the BIOS (basic input/output system) chip slotted onto the motherboard.
These instructions load the OS, which then loads the remaining system and software files into RAM (memory). If you start a computer when the power is turned off, you’re performing a cold boot; if you restart the computer (shut it down and then turn it on again without turning the power off), you’re performing a warm boot.
A new specification for booting your computer, called UEFI (Unified Extensible Firmware Interface) is meant to eventually replace the aging BIOS firmware and
System software performs basic computing functions, including starting your computer and loading the operating system, which provides the interface between you and the machine.
It also provides tools for configuring and main- taining your computer system and managing programs and files.
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makes booting computers a much speedier process. UEFI provides a layer of security called Secure Boot that prevents unauthorized code from being installed on your com- puter. UEFI can stop malware from loading before your operating system and its secu- rity features are running.
FIGURE 4.1 Examples of Devices and Components Run by the OS
Though outsold by Windows, macOS has a loyal and growing following. This is the macOS desktop.
Figure 4.2 shows the steps in booting a computer. During this procedure, the fol- lowing components are involved:
• The motherboard, which holds the central processing unit (CPU) and other chips.
• The CPU, or microprocessor chip, which is the brains of your computer.
• The BIOS or UEFI chip on the motherboard with the embedded code (firm- ware) that your computer uses to load the operating system and communicate with hardware devices.
• System files, which run when you start up your computer and provide the instructions that the operating system needs to run.
• System configuration, a definition or means of defining your entire comput- ing system, including the identity of your computer, the devices connected to it, and some essential processes that your computer runs.
The Operating System Package
An operating system package such as Windows or Linux includes system software that runs and manages your computer’s hardware and software resources; organizes files and folders containing your documents, images, and other kinds of content;
and helps you perform maintenance and repairs when your computer has problems.
Operating system packages also offer security features such as password protection to keep others from using your computer and a firewall to prevent someone from remotely accessing your computer.
Operating system packages also include basic applications you can use to get your work done or be entertained, such as simple word processing programs like WordPad;
“
Rebooting is a wonder drug—it fixes almost everything.”
—Garrett Hazel, “Help Desk Blues”
FIGURE 4.2 Steps in Booting a Computer
The process of booting your computer is actually a series of steps that load system software and configurations for your system.
games like Spider Solitaire; media players such as Windows Media Player to play music or videos; and tools such as a calculator, a calendar or address book, and an internet browser.
A (Brief!) History of Operating Systems
There was a time when computers had no operating system. In this pre-OS time, every program had to have all the required drivers (software that allows an oper- ating system to interface with hardware) and specifications needed to connect to hardware such as printers. In the early days of computing, functions in software were simple enough that this system worked. As programs became more sophisticated and hardware grew more complex, something was needed to orchestrate the interaction between software and hardware.
Mainframe computers—the pre-consumer computers that were often the size of a large desk or van—typically used an operating system created for them by their manufacturer. UNIVAC I, the first
commercial computer produced in the US, is an example. In the pre-personal computer period, names of the operating systems were not significant because the hardware drove the purchase decision.
UNIX, an OS written with the C programming language, was devel- oped by AT&T Bell Laboratories in the 1970s and became popular with corporations for running their work- stations. It was usable across a variety of hardware and could be customized by the companies who licensed it.
Operating systems make your computer work, but they also offer access to applications and games to entertain you. For example, the Windows Store app is where you can download apps and games. App stores offer new content often.
In 1951, the Remington Rand Corporation introduced the first commercial computer produced in the US, the UNIVAC I.
UNIX continues to be widely used by larger organizations today, and there are several ver- sions of this OS.
With the development of microprocessors, small personal computers began to catch on, and by the 1980s it was clear a more stan- dardized OS was needed. In 1980, Microsoft produced its first OS, MS-DOS, which even- tually became known simply as DOS (an acro- nym for disk operating system). This and other early operating systems were command-line interfaces, meaning that you typed com- mands as text, but they were not in plain English—and they weren’t very intuitive.
A huge breakthrough in operating system development came in the 1980s and 1990s when the graphical user interface (GUI) was introduced to the public first by Apple and subsequently used by Microsoft. A graphical user interface was a much more user-friendly way to work with a computer, because you could click icons and choose options from menus and dialog boxes, rather than typing commands.
All subsequent versions of Windows incorporated a graphical user interface. With Windows 8 and Windows 8.1 Microsoft expanded and improved touchscreen function- ality in its operating system, representing a significant shift in how users provide input to their computing devices. With the release of Windows 8 in 2012, the design of Windows was modeled after mobile device operating systems. Windows 10 improved and expanded the design to provide a consistent interface across all types of
Windows 10 devices.
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DOS sported white, amber, or green letters on a black background and required that the user memorize commands to use it.
