Chapter 1 Reed Answers

1. TRUE or FALSE? In order to be classified as a “computer,” a device must have a
keyboard and display screen.
FALSE

2. TRUE or FALSE? A bus is a collection of wires that carry information as electrical
signals between the hardware components of a computer.
TRUE

3. TRUE or FALSE? As computer programs can be complex and difficult to write, they
are known as “hardware.”
FALSE

4. TRUE or FALSE? A bit is a unit of data that correspond to one of two potential values
(commonly written as 0 and 1).
TRUE

5. TRUE or FALSE? A kilobyte of storage is 210 = 1,024 bytes, where a byte is a
collection of eight bits.
TRUE

6. TRUE or FALSE? A hard disk is classified as volatile memory, because it requires a
constant power supply in order to retain its information.
FALSE

7. TRUE or FALSE? Keyboards and mice are examples of computer input devices.
TRUE

8. TRUE or FALSE? A directory is a collection of files that are organized together and
labeled with a common name.
1.2
TRUE

9. TRUE or FALSE? The World Wide Web was developed in the early 1970’s, shortly
after the creation of the Internet.
FALSE

10. TRUE or FALSE? A Web browser is an example of applications software.
TRUE

11. Describe the difference between hardware and software and identify two examples of
each type.
The term hardware refers to the physical components of the computer, such as the
monitor, keyboard, hard drive, etc. Software refers to the programs that execute (i.e.,
run) on the computer, carrying out tasks such as word processing or accessing the Web.

12. Describe the three essential components of a computer that make up the von Neumann
architecture. How do these components work together to produce a machine that can be
programmed to complete different tasks?
Input/Output devices allow the user to communicate with the computer by entering
commands and then viewing the results. Memory stores information for the computer to
process, as well as programs, or instructions specifying the steps necessary to complete
specific tasks. Finally, the Central Processing Unit (CPU) is the component that carries
out programmatic steps in order to process data.

13. Modern computers integrate several different types of memory, such as cache, RAM,
hard disk, and floppy disk. Why are different types of memory used, as opposed to the
exclusive use of a particular technology? What would be the drawbacks, for example, of
using only cache memory, or only hard disk?
Different types of memory have different characteristics with respect to cost and
volatility. Main memory (cache and RAM) is fast, and so is used for data that is
currently being accessed. However, cache and RAM are too expensive for mass storage,
and they are volatile (requiring a constant flow of electricity to maintain stored values).
Secondary memory (hard disk, floppy disk, etc.) is much cheaper and permanent, but also
much slower than cache and RAM. However, it is sufficient for storing data that is not
currently needed.

14. Computer memory is usually grouped in bytes, which consist of 8 bits each. How many
different values can be represented using a byte? How many different values can be
represented using two bytes?
1.3
One byte (8 bits) can represent 28 = 256 different values. Two bytes (16 bits) can
represent 216 = 65,536 different values.

15. The Intel Core 2 Duo is an example of a processor, or CPU, as are the Celeron and
PowerPC. List the two main tasks that the CPU performs in controlling the computer’s
workings and provide a short explanation of each.
The CPU is responsible for two key tasks: (1) fetching program instructions from
memory, and (2) executing those instructions.

16. In what units are CPU speeds measured, and what does this measurement unit refer to?
If one computer has a 2 GHz Celeron D processor and another has a 2 GHz PowerPC
processor, does that imply they will be able to execute the same program in the same
amount of time? Explain.
CPU speed is generally measured in gigahertz (GHz), which indicates how many billions
of basic instructions a CPU can execute in a second. For example, a 2 GHz CPU can
execute approximately 2 billion instructions in a second. Since different families of
CPUs will provide different basic operations, performance comparisons based on CPU
speed are not always accurate.

17. Windows 7 is an example of an operating system, as are the Mac OS and Linux. List the
three main tasks that the operating system performs in controlling the computer’s
resources and behavior. Provide a short explanation of each.
The most fundamental task performed by the operating system is to schedule the
operation of the CPU, controlling how data and instructions are loaded from memory and
accessed by the CPU. The operating system also manages the memory of the computer,
organizing storage into files and directories (or folders). Finally, the operating system
connects the CPU and memory with the other hardware components of the computer,
allowing software applications to access memory and interact with the input/output
devices.

18. Describe three elements common to a Graphical User Interface (GUI)? How do these
elements make it easier for a user to interact with the computer.
A GUI utilizes intuitive, visual elements to simplify the process of viewing files and
executing programs. Programs, directories and files are represented as icons, or small
pictures that convey some aspect of the element they symbolize. Windows represent
separate workspaces that can be active at the same time, displaying files or executing
programs. Most GUIs also utilize pull-down menus of commands, which allow the user
to identify and select common commands easily.
1.4

19. Suppose you are shopping for a personal computer that you plan to use exclusively for
email and Web access. Which would be a better use of your limited funds – a faster
CPU or a larger hard drive? Why?
Since sending email and accessing the Web do not require extensive computation,
blazing speed is not necessary in a CPU. Most of the time, the CPU will be idle while
you are typing an email, or reading a message or Web page. On the other hand, if you are
going to be storing a large number of messages and downloading files off the Web, lots
of hard drive space might prove useful.

20. It has been said that the Internet could exist without the Web, but the Web couldn’t exist
without the Internet. Why is this true?
The Internet is a vast, international network of computers, which existed more than 20
years before the World Wide Web. Many networking applications are supported by the
Internet, such as email, instant messaging, ftp (file transfer), and the Web. The Web is a
collection of software that spans the Internet and enables the interlinking of documents
and resources.

21. What is a Web server, and what role does it play in the World Wide Web?
A Web server is an Internet-enabled computer that executes software for providing access
to Web documents. When the server receives a request for a particular page from a Web
browser, it locates the specified page in its directories and sends the page back to the
browser via the Internet.

22. Consider the following fictional URL: http://www.acme.com/products/info.html.
What does each part of this URL (separated by slashes) specify?
http://, specifies that the HyperText Transfer Protocol should be used in
communications between the browser and server. www.acme.com identifies the Web
server that stores the page. products is a directory on that server, and info.html is the
name of the file stored in that directory.