Chapter 1 - Introduction Flashcards
SR 1.1
What is hardware? What is software?
The hardware of a computer system consists of its physical components such as a circuit board, monitor, or keyboard. Computer software consists of the programs that are executed by the hardware and the data that those programs use. Hardware is tangible, whereas software is intangible. In order to be useful, hardware requires software and software requires hardware.
SR 1.2
What are the two primary functions of an operating system?
The operating system provides a user interface and efficiently coordinates the use of resources such as main memory and the CPU.
SR 1.3
The music on a CD is created using a sampling rate of 44,000 measurements per second Each measurement is stored as a number that represents a specific voltage level.
(1) How many such numbers are used to store a three-minute long song?
(2) How many such numbers does it take to represent one hour of music?
It takes 7,200,000 numbers for a 3-minute song (40,000 x 60 x 3) and 144,000,000 numbers for 1 hour of music (40,000 x 60 x 60).
SR 1.4
What happens to information when it is stored digitally?
The information is broken into pieces, and those pieces are represented as numbers.
SR 1.5 How many unique items can be represented with the following? a. 2 bits b. 4 bits c. 5 bits d. 7 bits
In general, N bits can represent 2^N unique items. Therefore:
a. 4
b. 16
c. 32
d. 128
SR 1.6
Suppose you want to represent each of the 50 states of the United States using a unique permutation of bits. How many bits would be needed to store each state representation? Why?
It would take 6 bits to represent each of the 50 states. Five bits is not enough because 2^5 = 32 but six bits would be enough because 2^6 = 64.
SR 1.7 How many bytes are in each of the following? a. 3 KB b. 2 MB c. 4 GB
A kilobyte (KB) is 2^10 = 1,024 bytes,
a megabyte (MB) is 2^20 = 1,048,576 bytes, and
a gigabyte (GB) is 2^30 = 1,073,741,824 bytes.
Therefore:
a. 3,072 bytes
b. 2,097,152 bytes
c. 4,294,967,296 bytes
SR 1.8 How many bits are there in each of the following? a. 8 bytes b. 2 KB c. 4 MB
There are eight bits in a byte. Therefore:
a. 64 bits
b. 16,384 bits
c. 33,554,432 bits
(a kilobyte (KB) is 2^10 = 1,024 bytes,
a megabyte (MB) is 2^20 = 1,048,576 bytes)
SR 1.9
The music on a CD is created using a sampling rate of 44,000 measurements per second. Each measurement is stored as a number that represents a specific voltage level. Suppose each of these numbers requires two bytes of storage space. How many MB does it take to represent one hour of music?
Unter the stated conditions, one hour of music would require 288,000,000 btes (40,000 x 60 x 60 x 2). Dividing this number by the number of bytes in a megabyte (1,048,576 bytes) gives approximately 275 MB.
Note that a typical audio CD has a capacity of about 650 MB and can store about 70 minutes of music. This coincides with an actual sampling rate of 41,000 measurements per second, two bytes of storage space per measurement, and the need to store two streams of music to produce a stereo effect.
SR 1.10
What are the two primary hardware components in a computer? How do they interact?
The two primary hardware components are main memory and the CPU. Main memory holds the currently active programs and data. The CPU retrieves individual program instructions from main memory, one at a time, and executes them.
SR 1.11
What is a memory address?
A memory address is a number that uniquely identifies a particular memory location in which a value is stored.
SR 1.12
What does volatile mean? Which memory devices are volatile and which are nonvolatile?
Main memory is volatile, which means the information that is stored in it will be lost if the power supply to the computer is turned off. Secondary memory devices are nonvolatile; therefore, the information that is stored on them is retained even if the power goes off.
SR 1.13
Select the word from the following list that best matches each of the following phrases:
controller, CPU, main, network card, peripheral, RAM, register, ROM, secondary
a. Almost all devices in a computer system, other than the CPU and the main memory, are categorized as this.
b. A device that coordinates the activities of a peripheral device.
c. Allows information to be sent and received.
d. This type of memory is usually volatile.
e. This type of memory is usually nonvolatile.
f. This term basically is interchangeable with the term “main memory”.
g. Where the fundamental processing of a computer takes place.
The word that best matches is
a. peripheral
b. controller
c. modem
d. main or RAM
e. secondary or ROM
f. RAM
g. CPU
SR 1.14
v
SR 1.15
v
