QUESTION 1: (a) If you have 16 coins, and flip them, how many different possible
ID: 3600975 • Letter: Q
Question
QUESTION 1:
(a) If you have 16 coins, and flip them, how many different possible ways can they come up heads or
tails? Why?
(b) If you have 8 bits, how many possible combinations (patterns) of 0s and 1s are there? Why?
(c) If you need 60 possible values – represented of course by 60 possible combinations (patterns) of 0s
and 1s - what is the smallest number of bits you need to do this? Why?
(d) If you need to represent 256 possible values – represented of course by 256 possible combinations
(patterns) of 0s and 1s - what is the smallest number of bits you need to do this? Why?
(e) How many bits are in a single byte?
QUESTION 2:
You are asked to design a scheme to digitally represent the 12 Months of the Year. Design a scheme to
do this.
(a) Determine the smallest number of bits you will need to be able to represent your patterns,
(b) Draw your complete combination table to account for ALL the bits and possible combinations,
(c) Then assign your month values to their corresponding combinations as needed. Remember you may
end up with un-used combinations (just mark these as "not used" if applicable), but you need enough
combinations to create the correct number of unique patterns. Also, draw your combination table the
EASY way!
QUESTION 3:
Below is part of a table of contents on a hard disk, and some of the data on the hard disk itself. Assume
that our disk is broken up into 4-byte "chunks." In this problem we will be working with the file called
TextFile.txt. This is an ASCII text file where each byte represents a character, as per your ASCII chart. For
this example, assume the 00 byte when using text files just means "unused byte."
Partial table of contents:
File Name Start Address End Address
MyBootlegMovie.mpg 501 73421
Paper.doc 73424 74000
ShortFile.ppt 75000 75123
TextFile.txt 73422 73423
Etc... ... ...
What is on the disk (partial):
Address Disk Contents
.. ...
73421 FF FF FE EC
73422 49 20 6C 6F
73423 76 65 00 00
73424 AC E2 34 E5
... ...
74000 48 5A 61 00
... ...
75000 E2 FF 6C 22
... ...
The file TextFile.txt currently reads as "I love" (verify this against your ASCII chart!). I want to edit and
save the file so it instead reads "I love to learn!" NOTE: The quotation marks are for illustration and are
not part of the file.
(a) Write out the bytes (in base-16) from the ASCII file necessary to complete the file below. Make sure
you do not forget the space character in the beginning of your new bytes needed! You will need 10 new
bytes.
(b) Update the disk contents (in base 16) to reflect the edited and saved file, including your new disk
addresses (just regular base-10 numbers) you will need to store the file in. To point you in the right
direction I made it quite obvious where some free space will be located for it! Remember this disk
scheme uses 4 bytes per address!
(c) Also update the table of contents accordingly.
QUESTION 4:
You are functioning as the microprocessor. An instruction comes in that says (in plain English):
Step 1: Read the number at memory address 143 and copy it into register R1.
Step 2: Read the number at memory address 145 and copy it into register R2.
Step 3: Move the numbers contained in registers R1 and R2 into the ALU, and ADD them.
Step 4: Put the result into Register R3.
Step 5: Move the number in register 3 to memory location 147.
IMPORTANT: Remember the values stored in the memory addresses referenced by this instruction
represent actual quantities (numbers)! Like our other examples, they are also represented in base 16. But
again, the patterns in this context represent quantities, not ASCII characters! ALL work for this problem
must be done in Base-16!
Memory Address Contents
... ...
142 0
143 8C2
144 682D
145 B71
146 DF33
147
... ...
(a) What is inside registers R1 and R2 after Step 2 completes? R1: ____________ R2: _______________
(b) What is inside register R3 after step 4 completes? Show your work below! R3: _______________
(c) Update the memory contents table above to show what the memory will look like after Step 5
completes.
QUESTION 5:
You are functioning as the microprocessor. An instruction comes in that says (in plain English):
Step 1: Read the logical value in address 245 and copy it into register R1.
Step 2: Read the logical value at memory address 249 and copy it into register R2.
Step 3: Move the logical values contained in registers R1 and R2 into the ALU, and perform a Boolean OR
operation against them.
Step 4: Put the result into Register R3.
Step 5: Move the logical value in register 3 to memory location 248.
IMPORTANT: Remember the values stored in the memory addresses referenced by this instruction
represent Boolean logical values! The result will likewise represent a logical (Boolean) value. Again, the
context of the problem determines what the patterns of 0 and 1 stored in memory actually "mean."
Memory Address Contents
... ...
245 1
246 6C3
247 FFFF
248
249 0
250 6B
... ...
(a) What is inside registers R1 and R2 after Step 2 completes? R1: ____________ R2: _______________
(b) What is inside register R3 after step 4 completes? Show your work below! R3: _______________
(c) Update the memory contents table above to show what the memory will look like after Step 5
completes.
QUESTION 6:
(a) You are asked by a high-tech aeronautical company to design a very critical software program for use
in a flight navigation system. The system must be capable of complex calculations, including detecting
altitude, speed, and other various flight conditions, very quickly. This software will only be run on a very
specialized computer that was designed for this application only.
Would you choose to design a compiled system, or an interpreted system? Why? Explain.
(b) You are asked by a college to design a software program that will allow students to enroll in classes
from home or anywhere else they may be at any given time. This college does not issue personal
machines to each student, so there is no telling what type of computer a student may be using.
Obviously the college wants the maximum number of students to be able to use the system, to increase
student satisfaction and retention.
Would you choose to design a compiled system, or an interpreted system? Why? Explain.
QUESTION 7:
A computer user wants to load and watch a 10GB movie file.
The operating system is monitoring the 8GB of RAM available in the machine. The operating system
determines that there are only 2 GB of free RAM available, and that all the rest of it is currently being
used by other applications/data files/etc.
(a) What will the operating system need to do? Explain.
(b) What effect will this have on the performance of the computer? Why?
QUESTION 8:
The following are packets. The packets contain pieces of an ASCII text file. Our packets for this example
are using 10-Byte data "chunks." Data is represented using two base-16 digits for each byte. You are
now functioning as the receiver machine (Machine_007).
File ID My_unique_file_ID_001
From Machine_4572
To Machine_007
Total packets: 3
Packet # 2
Data 69 73 20 6E 6F 74 20 76 65 72
File ID My_unique_file_ID_001
From Machine_4572
To Machine_007
Total packets: 3
Packet # 1
Data 54 68 69 73 20 74 65 73 74 20
File ID My_unique_file_ID_001
From Machine_4572
To Machine_007
Total packets: 3
Packet # 3
Data 79 20 68 61 72 64 21
(a) Re-assemble the data contained in the packets (keep in base 16) and show below:
(b) Translate the file into human-readable characters using your ASCII chart and show below:
QUESTION 9:
The following are packets. The packets contain pieces of an ASCII text file. Our packets for this example
are using 10-Byte data "chunks." Data is represented using two base-16 digits for each byte. You are still
functioning as the receiver machine (Machine_007). You are receiving another file from Machine_4572.
Look at these packets carefully.
File ID My_unique_file_ID_002
From Machine_4572
To Machine_007
Total packets: 4
Packet # 2
Data 69 73 20 6E 6F 74 20 61 74 20
File ID My_unique_file_ID_002
From Machine_4572
To Machine_007
Total packets: 4
Packet # 1
Data 54 68 69 73 20 74 65 73 74 20
File ID My_unique_file_ID_002
From Machine_4572
To Machine_007
Total packets: 4
Packet # 4
Data 61 6C 6C 21
(a) Will you be able to reassemble the file successfully? Yes or No? ______________
(b) If not, please explain what the problem is, and – importantly - what you would need to do at this
point. Be specific – Explain what you are doing as if you are speaking directly to me – assume that I
know nothing about these packets or where they came from.
QUESTION 10:
Given:
File Size is 52 MB
Upload Bandwidth is 750 Kbps
Download bandwidth is 13 Mbps
Assume that the throughput is equal to bandwidth (i.e. there is nothing preventing the communication
channel from working at its maximum efficiency).
(a) How long will it take - in minutes - to upload the file?
(b) How long will it take - in minutes - to download the file?
Explanation / Answer
Answer 1
(a) Each coin can have 2 outcomes (head/tail). So 16 coins can generate a total of 216 combinations or 262144 combinations
(b) Each bit can be set or unset. So with 8 bits, we can have 28 or 256 combinations
(c) n bits can represent 2n combinations. So, to represent 60 values, we need atleast 6 bits, so that 26 wil be 64
(d) n bits can represent 2n combinations. So, to represent 256 values, we need atleast 8 bits, so that 28 wil be 256
(e) There are 8 bits in 1 byte