Computer and Number Systems

1. (10 pt) You have been hired to develop a website-based sales system for a large international retail firm. List and describe at least fourfeatures that are specific to the Web design of your system and customer service important to consider if your system is to be successful at attracting and keeping customers living outside of the US. Include not only characteristics of the user interface, but those issues that must be uniquely addressed to successfully service your non-US customers.

 

 

 

2. (2.5 pt each) In order to receive credit for these problems, you must show all of the steps you took to arrive at your answers.

(c) Convert the following decimal number to binary:
        21842 = 101010101010010

 

 

 

 

 

 

 

 

(d) Convert the following binary number to decimal:
        11000111011.101 = 1595.62500000000000000000

 

 

 

 

 

(c)Convert the following hexadecimal number to decimal:
        CA97 = 51863

 

 

 

 

(d) Convert the following binary number to hexadecimal:
        1110011111011010100 = 73ED4

 

 

 

 

 

 

CPU and Memory

3.  (10 pt) ASCII, Unicode, and EBCDIC are, of course, not the only numeric / character codes. The Sophomites from the planet Collegium use the rather strange code shown in the Figure below. There are only thirteen characters in the Sophomite alphabet, and each character uses a 5-bit code. In addition, there are four numeric digits, since the Sophomites use base 4 for their arithmetic. Given the following Sophomitesequence, what is the corresponding binary message being sent by the Sophomites?

 

(HINT: Decode the sequence reading from left to right then write the corresponding binary sequence, leaving a space between each binary sequence.)

 

 

 

 

 

 

 

 

 

 

 

 

4. (10 pt) Define memory cache write-through and write-back techniques and describe the advantages and disadvantages of each.

 

The tradeoffs between write-through and write-back caching when writes hit in a cache are considered. A mixture of these two alternatives, called write caching is proposed. Write caching places a small fully-associative cache behind a write-through cache. A write cache can eliminate almost as much write traffic as a write-back cache. They are outcome from the fact that writes to cache are intended for physical memory. Therefore, writes to cache will be transferred to physical memory. A memory writes is a requisite for every cache write, which slows down performance.

The advantage of cache memory is that the CPU does not have to use themotherboard’s system bus for data transfer. Its size is small so we cannot store too much data on it.  Thedisadvantage is that we cannot store data permanently in cache memory. Itstores data as long as power supply is provided.

 

 

Input / Output

5. Answer the follow questions about interrupts.

a. (5pt) Describe in detail the steps that occur when a system receives an interrupt.

 

 

In general, there are hardware interrupts and software interrupts. A hardware interrupt occurs, for example, when an I/O operation is completed such as reading some data into the computer from a tape drive. A software interrupt occurs when an application program terminates or requests certain services from the operating system. In a personal computer, a hardware interrupt request  has a value associated with it that associates it with a particular device.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

b. (5pt) Describe how these steps differ in the case when a system receives multiple interrupts

 

 

 

 

 

 

 

 

 

 

Computer Systems

6. Answer the following questions about clusters.

a.(5pt) Describe how you might use a cluster to provide fault-tolerant computing

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

b.(5pt) Describe how you might use a cluster architecture to provide rapid scalability for a Web-based company experiencing rapid growth.

 

 

 

Networks

7. Answer the following questions about communication protocols.

a.(5pt) Using the operations of UDP (User Datagram Protocol) and TCP (Transmission Control Protocol) as a basis, carefully explain the difference between connectionless and connection-oriented communication.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

b.(5pt) If you were ordering a number of items from an online seller, such as amazon.com, which Protocol (TCP or UDP) would you recommend and explain why.

 

 

 

 

 

 

8. In the context of network security,

a.(3pt) explain the purpose of non-repudiation.

 

 

 

 

 

 

 

 

 

 

 

 

 

b.(3pt) How does non-repudiation differ from authentication?

 

 

 

 

 

 

 

 

 

 

 

 

c.(4pt) Create a business scenario that illustrates the importance of each.

 

 

 

 

Data Communications

 

9.(2 pt each)Circle or highlight the correct answer to the following questions / statements about data communications:

 

(a)What characteristic of an analog signal is measured in Hertz, or cycles per second?

a.            Amplitude           c.             Phase

 

b.            Frequency          d.            Skew

 

 

 

(b)What measurement unit describes the speed and capacity of a communication channel?

a.            Throughput        c.             Response Time

 

b.            Access Time       d.            Data Transfer Rate

 

 

 

(c)____ can be produced by a variety of sources, including electric motors, radio equipment, and nearby power transmission or communication lines.

a.            EMI                        c.             Distortion

 

b.            Attenuation       d.            Signal/noise (S/N) ratio

 

 

 

(d)A(n) ____ can extend the range of an electrical signal by boosting signal power to overcome attenuation.

a.            repeater              c.             amplifier

 

b.            return wire         d.            signal wire

 

 

 

(e)Which of the following does not allow multiple messages to be carried on a single channel?

a.            time division multiplexing                    c.               packet switching

 

b.            frequency division multiplexing         d.              half-duplex

 

 

 

 

 

Operating Systems

 

10. Answer the following questions about user interfaces:

(a) (5pt) List and explain at least two of the definite advantages to the use of a command line interface (CLI) over other types of interfaces.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

(b)(5pt) There are some capabilities that are easy to achieve with a GUI (graphical user interface), but much more difficult with a CLI. Describe at least  two of these capabilities.

 

 

 

File Management

 

11. Answer the following:

a.(5 pt) Use the following four processes that have arrived in the ready queue in the sequence shown below and answer the following about process scheduling:

• Process 1 has a total run time of 25 seconds and a priority of 2, but it will require 15 seconds of I/O after 10 seconds of execution
• Process 2 has a total run time of 30 seconds, a priority of 1, but it will require 10 seconds of I/O after 20 seconds of execution
• Process 3 has a total run time of 15 seconds and a priority of 3
• Process 4 has a total run time of 20 seconds, a priority of 2, but it will require 15 seconds of I/O after 5 seconds of execution

 

(i)Both shortest job first and non-preemptive priority queue scheduling algorithms will complete all four processes at the same time, but not in the same order. In which algorithm will Process 1 finish first? Provide the time Process 1 finishes and explain your answer.

 

 

 

 

 

(ii)If the round robinscheduling algorithm is used, which process will finish first? At what time will it complete?

 

 

 

 

 

 

b.(5 pt) Using a variable-partitioned multiprogramming memory, which of the four holes shown below will be used to satisfy a 40 KB program requirement under the conditions of:

0-15 KB	15-40 KB	40-125 KB	125-155 KB	155-275 KB	275-330 KB	330-420 KB	420-470 KB	470-505 KB
occupied	Hole A	occupied	Hole B	occupied	Hole C	occupied	Hole D	occupied

 

___ Best-fit
___ Worst-fit

 

 

Internet

12. (10pt)Show the bit pattern in an asynchronous transmission with evenparity if the data to be sent is the character string “EXAMS“. Use 7-bit ASCII code found in Englander’s Figure 4.3 (page 102) and be sure to include start and stop bits.

 

 

 

Computer and Number Systems

1. (10 pt) You have been hired to develop a website-based sales system for a large international retail firm. List and describe at least fourfeatures that are specific to the Web design of your system and customer service important to consider if your system is to be successful at attracting and keeping customers living outside of the US. Include not only characteristics of the user interface, but those issues that must be uniquely addressed to successfully service your non-US customers.

 

 

 

2. (2.5 pt each) In order to receive credit for these problems, you must show all of the steps you took to arrive at your answers.

(c) Convert the following decimal number to binary:
        21842 = 101010101010010

 

 

 

 

 

 

 

 

(d) Convert the following binary number to decimal:
        11000111011.101 = 1595.62500000000000000000

 

 

 

 

 

(c)Convert the following hexadecimal number to decimal:
        CA97 = 51863

 

 

 

 

(d) Convert the following binary number to hexadecimal:
        1110011111011010100 = 73ED4

 

 

 

 

 

 

CPU and Memory

3.  (10 pt) ASCII, Unicode, and EBCDIC are, of course, not the only numeric / character codes. The Sophomites from the planet Collegium use the rather strange code shown in the Figure below. There are only thirteen characters in the Sophomite alphabet, and each character uses a 5-bit code. In addition, there are four numeric digits, since the Sophomites use base 4 for their arithmetic. Given the following Sophomitesequence, what is the corresponding binary message being sent by the Sophomites?

 

(HINT: Decode the sequence reading from left to right then write the corresponding binary sequence, leaving a space between each binary sequence.)

 

 

 

 

 

 

 

 

 

 

 

 

4. (10 pt) Define memory cache write-through and write-back techniques and describe the advantages and disadvantages of each.

 

The tradeoffs between write-through and write-back caching when writes hit in a cache are considered. A mixture of these two alternatives, called write caching is proposed. Write caching places a small fully-associative cache behind a write-through cache. A write cache can eliminate almost as much write traffic as a write-back cache. They are outcome from the fact that writes to cache are intended for physical memory. Therefore, writes to cache will be transferred to physical memory. A memory writes is a requisite for every cache write, which slows down performance.

The advantage of cache memory is that the CPU does not have to use themotherboard’s system bus for data transfer. Its size is small so we cannot store too much data on it.  Thedisadvantage is that we cannot store data permanently in cache memory. Itstores data as long as power supply is provided.

 

 

Input / Output

5. Answer the follow questions about interrupts.

a. (5pt) Describe in detail the steps that occur when a system receives an interrupt.

 

 

In general, there are hardware interrupts and software interrupts. A hardware interrupt occurs, for example, when an I/O operation is completed such as reading some data into the computer from a tape drive. A software interrupt occurs when an application program terminates or requests certain services from the operating system. In a personal computer, a hardware interrupt request  has a value associated with it that associates it with a particular device.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

b. (5pt) Describe how these steps differ in the case when a system receives multiple interrupts

 

 

 

 

 

 

 

 

 

 

Computer Systems

6. Answer the following questions about clusters.

a.(5pt) Describe how you might use a cluster to provide fault-tolerant computing

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

b.(5pt) Describe how you might use a cluster architecture to provide rapid scalability for a Web-based company experiencing rapid growth.

 

 

 

Networks

7. Answer the following questions about communication protocols.

a.(5pt) Using the operations of UDP (User Datagram Protocol) and TCP (Transmission Control Protocol) as a basis, carefully explain the difference between connectionless and connection-oriented communication.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

b.(5pt) If you were ordering a number of items from an online seller, such as amazon.com, which Protocol (TCP or UDP) would you recommend and explain why.

 

 

 

 

 

 

8. In the context of network security,

a.(3pt) explain the purpose of non-repudiation.

 

 

 

 

 

 

 

 

 

 

 

 

 

b.(3pt) How does non-repudiation differ from authentication?

 

 

 

 

 

 

 

 

 

 

 

 

c.(4pt) Create a business scenario that illustrates the importance of each.

 

 

 

 

Data Communications

 

9.(2 pt each)Circle or highlight the correct answer to the following questions / statements about data communications:

 

(a)What characteristic of an analog signal is measured in Hertz, or cycles per second?

a.            Amplitude           c.             Phase

 

b.            Frequency          d.            Skew

 

 

 

(b)What measurement unit describes the speed and capacity of a communication channel?

a.            Throughput        c.             Response Time

 

b.            Access Time       d.            Data Transfer Rate

 

 

 

(c)____ can be produced by a variety of sources, including electric motors, radio equipment, and nearby power transmission or communication lines.

a.            EMI                        c.             Distortion

 

b.            Attenuation       d.            Signal/noise (S/N) ratio

 

 

 

(d)A(n) ____ can extend the range of an electrical signal by boosting signal power to overcome attenuation.

a.            repeater              c.             amplifier

 

b.            return wire         d.            signal wire

 

 

 

(e)Which of the following does not allow multiple messages to be carried on a single channel?

a.            time division multiplexing                    c.               packet switching

 

b.            frequency division multiplexing         d.              half-duplex

 

 

 

 

 

Operating Systems

 

10. Answer the following questions about user interfaces:

(a) (5pt) List and explain at least two of the definite advantages to the use of a command line interface (CLI) over other types of interfaces.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

(b)(5pt) There are some capabilities that are easy to achieve with a GUI (graphical user interface), but much more difficult with a CLI. Describe at least  two of these capabilities.

 

 

 

File Management

 

11. Answer the following:

a.(5 pt) Use the following four processes that have arrived in the ready queue in the sequence shown below and answer the following about process scheduling:

• Process 1 has a total run time of 25 seconds and a priority of 2, but it will require 15 seconds of I/O after 10 seconds of execution
• Process 2 has a total run time of 30 seconds, a priority of 1, but it will require 10 seconds of I/O after 20 seconds of execution
• Process 3 has a total run time of 15 seconds and a priority of 3
• Process 4 has a total run time of 20 seconds, a priority of 2, but it will require 15 seconds of I/O after 5 seconds of execution

 

(i)Both shortest job first and non-preemptive priority queue scheduling algorithms will complete all four processes at the same time, but not in the same order. In which algorithm will Process 1 finish first? Provide the time Process 1 finishes and explain your answer.

 

 

 

 

 

(ii)If the round robinscheduling algorithm is used, which process will finish first? At what time will it complete?

 

 

 

 

 

 

b.(5 pt) Using a variable-partitioned multiprogramming memory, which of the four holes shown below will be used to satisfy a 40 KB program requirement under the conditions of:

0-15 KB	15-40 KB	40-125 KB	125-155 KB	155-275 KB	275-330 KB	330-420 KB	420-470 KB	470-505 KB
occupied	Hole A	occupied	Hole B	occupied	Hole C	occupied	Hole D	occupied

 

___ Best-fit
___ Worst-fit

 

 

Internet

12. (10pt)Show the bit pattern in an asynchronous transmission with evenparity if the data to be sent is the character string “EXAMS“. Use 7-bit ASCII code found in Englander’s Figure 4.3 (page 102) and be sure to include start and stop bits.