计算机导论期末复习资料

四川大学计算机导论期末复习资料总结。

1． Numbers Convertion

In this section, you will convert numbers among binary, decimal and hexadecimal representations.

a. Complete the following chart by converting the numbers given in one of the notations to the

other two. Show calculations.

b. What is the minimum number of bits that can be used to represent the

decimal number 1013? (Hint: convert 1013 to binary.)

10

c. What is a purpose of using hexadecimal notation?

Answer:

Using hexadecimal notation is to express binary values more concisely.

Because when we express a value, it will take more digits in binary

notation than in decimal notation.

d. What is ASCII code?

Answer:

ASCII code is American Standard Code for Information Interchange. It

is the built-in binary code for representing characters in all computers

except IBM mainframes and realizes data transmission standardization

in vary computer systems. In modern time most mainframe and all PC

use it . ASCII code includes two set : Standard ASCII code with 128

characters and Extended ASCII code with 128 characters appended.

2. Computer Speed

a. One Hz is one _____ per _____.

四川大学计算机导论期末复习资料总结。

One Hz is one cycle per second.

b. Define IPS.

IPS is instructions per second which is a rating of how many instructions can be executed by

a processor in a given second.

c. Answer the following questions on the relationship of Hz to IPS.

i. Which is a better determiner of speed: MHz or IPS?

IPS is a better determiner of computer performance.

ii. Does a high Hz equal a high IPS, and can they be inversely proportional? Explain.

A high Hz can indicate that the IPS is high, but they are not directly proportional, but can

never be inversely proportional

iii. How is it possible for a machine with a lower clock speed (Hz) to have a higher

IPS than a machine with a higher clock speed?

An instruction can take a variable amount of cycles or partial cycles. Thus, a computer can

execute instructions more quickly than another computer because of this.

d. What is the relationship between the system clock and Hz?

The system clock sends out pulses at regular intervals to set up the timings for all timed

system activities, such as determining the Hz of a processor.

3. BIOS and CMOS

a. Explain the function of the BIOS ROM in the boot process.

The BIOS ROM is a permanent storage device that contains the startup instructions

for the computer.

b. Define flashing, with respect to BIOS ROM.

Flashing is the process of rewriting an EEPROM. This process allows the BIOS to be

updated without changing ROM chips.

c. Explain the function of the CMOS in the boot process.

The CMOS contains the configurable system information that the BIOS reads during

startup.

d. What is the advantage of having an unchangeable ROM and a changeable CMOS

during the boot process?

By having an unchangeable BIOS, a default startup configuration is always possible.

Since, however, startup configurations may differ from machine to machine, the

changeable CMOS allows users to specify exactly how the boot will occur on their

machines, possibly changing the startup from the default.

四川大学计算机导论期末复习资料总结。

4. Layers e. Consider that the CMOS has lost power. i. What happens to the data that was stored in the CMOS? The CMOS is volatile and will lose all data contained in it if it loses power ii. How does the CMOS losing power affect the boot process? When CMOS power fails it no longer contains configuration data, and therefore when a machine is booted, it will use the default settings contained in the BIOS. f. List two ways to change the information in the CMOS. Windows Plug-N-Play, as an example. BIOS setup and configuration utility, as an example.

a. The layers of software have already been list down. Fill the correct number of

layers in table from lowest to highest.

(1) User Interface

(2) Run-Time Libraries

(3) User-Written Scripts or Macros

(4) Application Programming Interface

(5) Kernel

(6) BIOS

(7) Application

(8) Operating System

(9) Device Drivers

b. Describe encapsulation with respect to the layers of software.

四川大学计算机导论期末复习资料总结。

Encapsulation means that a layer is closed off from other layers, achieving only it

owns ends without knowing much about the other layers.

c. Describe abstraction with respect to the layers of software.

Abstraction is the means of sharing data and communicating that is established

between various layers of software.

d. What advantage do encapsulation and abstraction give to software developers?

Encapsulation and abstraction allow developers to provide limited means of

accessing data to their layer, and that they only must support limited influx of data

from other layers' abstraction. The layer can be comprised of code that other layers

need not be involved in.

5. Networks

a. What is a LAN?

Local Area Network. A network smaller than a WAN; typically a computer network

covering a local area, like a home, office, or group of buildings.

b. What is a WAN?

Wide Area Network. A computer network larger than a LAN; typically a network that spans

buildings, cities, or countries. The internet is a WAN.

c. What is a thin client?

A network application in which the client does very little processing and the network server

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