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ECS 15: Introduction to Computers
Midterm
Notes:
The midterm is open book, open notes.
No wandering eyes or unauthorized leaving of the exam room.
Please write your name at the top right of each page you turn in!
Please, check your work! If possible, show your work when multiple steps are involved.
How many bytes are there in one Megabyte (MB)? 2pts
1,000,000
1,000,024
1,048,576
1,024,000
Which of the following is NOT a valid HTML tag: 2pts
An operating system is: 2pts
a maintenance program should the computer crash
the firmware stored on ROM to boot the system
the software that manages the sharing of the resources of a computer
another name for the manual that explains how to use the computer
Which binary number comes right after the binary number 101111 2pts
101112
110000
111000
111111
Assume you are preparing a term paper and want to use the Web as a source of information. Which of the following statements is TRUE? 2pts
You are free to copy information you find on the Web and include it in your paper
You do not have to cite the Web sources you use for your paper
You should never consult the Web when you are working on a paper
Just like print sources, Web sources must be cited in your paper. You are not free to plagiarize information you find on the Web.
If we go from 8 bits to 9 bits of quantization the number of distinct levels that can be recorded: 2pts
Stays the same
Increases by one
Doubles
Quadruples
If we go from 8 bits to 10 bits of quantization the number of distinct levels that can be recorded: 2pts
Increases by two
Doubles
Triples
Quadruples
To run several programs apparently simultaneously on a computer, you need: 2pts
As many CPU or computing cores as programs that you want to run simultaneously
An operating system that allows multi-threading
An operating system that allows multi-tasking
A super-computer; no personal computers or laptops can run several programs apparently simultaneously.
If a computer fails the POST, it is likely that: 2pts
The operating system has crashed,
One application is using more memory than it has asked for,
The Master Boot Record is empty,
One piece of hardware attached to the computer has failed.
Which of the following retains its information when the computer is turned off?
ROM 2pts
CPU
RAM
GPU
1024 bits correspond to N bytes, where N is: 3pts
8192
128
1024
10
A computers BIOS does not: 3pts
Shutdown the computer
Identify component hardware
Prepare the computer so that other programs can load and execute
Be loaded first when the computer is turned on
The base 10 equivalent of the hexadecimal 1AD is 5pts
Recall A=10 and D=13 in hexadecimal
1AD = (1*162) + (10*16) + (14*1) = (1*256) + (10*16) + (13) = 256 + 160 + 13
= 429
What is the maximum number that can be stored in a half of a byte? 5pts
A byte is 8 bits. Half a byte is 4 bits. The biggest number that can be stored in a bit:
1111 = 23 + 22 + 2 + 1 = 8 + 4 + 2 + 1 = 15
(Note this is also equal to 24-1)
What is the maximum number that can be stored in N bits? 5pts
Max number in N bits is equal to 2N-1.
Assume the human heart beats at 60 beats per second. To get the right measurement of the heart dynamics, at what rate do you sample? (Express the answer in Hz.) 5pts
Via Nyquist theorem, sample at twice the highest frequency, so 120 Hz.
If each data point is stored in 16 bits, how many BYTES of data would you need to store 10 minutes of human heart beat data? 5pts
(120 samples/sec)*(16 bits/sample)*(1 byte/8 bits)*(60 sec/min)*(10min) = 144,000 bytes
Part III. For the next portion, examine the statement, indication if it is or is not a proposition. If it is a proposition, indicate its truth value (otherwise indicate N/A). 2pts each line
StatementProposition
(Y or N)T or F or N/AThe cute catNN/AX = Y + 2NN/AStudy hardNN/AIs the cat cute?NN/AThe moon is made of green cheeseYFThis statement is falseNN/AThis is a statementYT
Part IV Logical implications
Consider the following propositions:
P = You learn the basics of computers
Q = You get a good job
Assume the implication P -> Q is True. Assess whether the following statement is logically correct or logically flawed.
You did not learn the basics of computers so you do not have a good job. 2pts
Logically correct
Logically flawed (Claims not(P) -> not(Q), but there can exist good jobs that dont use computers.)
You have a good job, so you learned the basics of computers. 2pts
Logically correct
Logically flawed (Claims Q -> P, but again there can exist good jobs that dont use computers.)
You do not have a good job so you did not learn the basics of computers. 2pts
Logically correct (Claims not(Q) -> not(P).)
Logically flawed
Part V
Look carefully at the logical circuit below, and complete the table. Remember: an input of 0 means switch off/open/no current flows, while an input of one means switch on and current flows.
1pt each 2pts each
Input AInput BIntermediate outputOutput1101100101100011
This may not be a simple AND or OR gate, but can you write an expression using AND, OR, and NOT for the operation on inputs A and B that the gate implements?
NOT (Not(A) AND B) = (NOT(A) NAND B) = A OR NOT(B) 2pts
________________________________________
Part VI. The table below lists on the left devices that can be found inside a computer. For each of these devices, give their purpose (center column), and list in the right column what could happen if they would stop working
5 pts in total each row.
ComponentWhat it doesPossible problemMotherboardBackbone of the computer, houses many hardware devices (CPU, RAM, Hard drive, buses) and many interfaces for additional hardware (keyboards, mice, internet interface, power supply connector)Many problems, from the computer not booting, to certain devices (hard drive, keyboard, etc) not working properly.BIOS EPROM chipThe Erasable Programmable Memory Chip that stores the firmware to initiate and run the Basic Input/Output system installed by the computer manufacturer.The BIOS wont run and the computer will not boot. Bus between the CPU and RAMTransports electronic signals, and hence data, between the Central Processing Unit and the Random Access Memory.No data, or erroneous data, will be loaded into the CPU.
Extra credit: Fill out the table below.
Input AInput BInput COutput11101101101010010110010100110001
Extra credit: Convert 233 from base 10 to base 2
Number Number % 2 Remainder
233 116 1
116 58 0
58 29 0
29 14 1
14 7 0
7 3 1
3 1 1
1 0 1
Answer: 11101001
Name:__________________________________
ID: ___________________________________
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