COSC2473 - Computer Systems and Platform Technologies - RMIT 2018

This document presents the solutions to a homework assignment focusing on computer systems and platform technologies. It includes detailed answers to questions related to binary number conversions, logic gate design and truth tables, error detection using parity checking, understanding of CSMA/CD and CSMA/CA protocols, and floating-point number representation. The assignment also involves comparing different circuit designs and discussing the importance of floating-point representation for data comparison and arithmetic operations. The solutions are well-structured and provide clear explanations, referencing relevant academic sources. Desklib offers a platform for students to access similar solved assignments and study resources.

Running head: COMPUTER SYSTEMS AND PLATFORM TECHNOLOGIES
Computer Systems and Platform Technologies
Name of the Student:
Name of the University:
Author Note

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COMPUTER SYSTEMS AND PLATFORM TECHNOLOGIES
Answer to question number 3
Given,
Let A = xxxx xxxx2, where each x is a unique bit (0 or 1).
a)
Byte A – 01000001
Decimal value of the number is 65
b)
Byte A – 01111101
Decimal value of the number is 125
Answer to question number 4
a)
The Output and expressions of the logic design is:
O = A.B. (A’+B.C)’ = A.B. (A’’. (B.C)’) = A.B. (A’’. (B’+C’)) = AB. (AB’ + AC’) = ABC’
Truth Table
A B C AB A’ BC A’+BC (A’+BC)’ A.B.
(A’+B.C)’
0 0 0 0 1 0 1 0 0
0 0 1 0 1 0 1 0 0
0 1 0 0 1 0 1 0 0

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COMPUTER SYSTEMS AND PLATFORM TECHNOLOGIES
0 1 1 0 1 1 1 0 0
1 0 0 0 0 0 0 1 0
1 0 1 0 0 0 0 1 0
1 1 0 1 0 0 0 1 1
1 1 1 1 0 1 1 0 0
b)
The Output and expressions of the logic design is:
O = ABC’
Truth Table
A B C C’ ABC’
0 0 0 1 0
0 0 1 0 0
0 1 0 1 0
0 1 1 0 0
1 0 0 1 0
1 0 1 0 0
1 1 0 1 1
1 1 1 0 0
c)

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COMPUTER SYSTEMS AND PLATFORM TECHNOLOGIES
By comparison, we can easily say that the both the truth tables provides the same result
and hence, it can be said that both the circuits are same.
Answer to question number 5
a)
There was an error in the transmission of the data. The data provided is 01000110 which gives an
error in the even parity checking method.
b)
The given data is 01000110
Length of Data Sequence Number of Parity
Bits
Length of Code Word
8 5 13
Parity Scheme
P0 = D0 + D1 + D3 + D4 + D6
P1 = D0 + D2 + D3 + D5 + D6
P2 = D1 + D2 + D3 + D7
P3 = D4 + D5 + D6 + D7
P4 = D0 + D1 + D2 + D3 + D4 + D5 + D6 + D7 + P0 + P1 + P2 + P3
Syndrome Matrix
D7 D6 D5 D4 D3 D2 D1 D0 P4 P3 P2 P1 P0
1 1 1 1 1 1 1 1 1 1 1 1 1
1 1 1 1 0 0 0 0 0 1 0 0 0

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COMPUTER SYSTEMS AND PLATFORM TECHNOLOGIES
1 0 0 0 1 1 1 0 0 0 1 0 0
0 1 1 0 1 1 0 1 0 0 0 1 0
0 1 0 1 1 0 1 1 0 0 0 0 1
The check matrix shows that the modified code word contains no errors.
The modified data is 0100011001000
Answer to question number 6
a)
CSMA/CD works by detecting a collision in the medium and backing off (after transmitting a
jam signal) as necessary
b)
For the calculation of the back of time an interval is selected. And the timer is set to zero.
If the channel is being used and the station is ready for sending a data packet. The amount time
the station has to wait is known as the back-off time.
c)
CSMA/CA operates by sensing the state of the medium in order to prevent or recover
from a collision. The major difference in between CSMA/CA and CSMA/CD is that the CSMA
CA does not deal with the recovery after a collision.
Answer to question number 7
a)

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COMPUTER SYSTEMS AND PLATFORM TECHNOLOGIES
For the 16-bit representation of a number the first bit or the MSB is used for the sign
representation where A is selected for a positive and B is represented as the negative number. In
binary notations B is used in place of 0 and A is used in place of 1 and C is used in place of 2.
The bit number 2 to 7 is used for the representation of the exponent and the rest of the bit are
used for the binary number representation.
Sign bit magnitude (1) Exponent (7) Mantissa (8)
b)
the representation of numbers:
1 -
B BBBBBBB BBBBBBBA
10 –
B BBBBBBB BBBBABAB
1/3 –
BBBBBBBBBBBBBBBA/BBBBBBBBBBBBBBAA
c)
The number = 3650865
After replacing 0 with 9 we get, 3659865

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COMPUTER SYSTEMS AND PLATFORM TECHNOLOGIES
i) A = 6, B = 5
x = A+ B/10 = 6.5
y = B + A/10 = 5.6
x = BBBBBBBABBBBAABA
y =BBBBBBAABBABAABA
ii)
x + y = 6.5 + 5.6 = 12.1
Representation
BBBBBBAABAABBBA
d)
The data should be represented in the floating point representation so that they can be
compared easily. The numbers are to be normalized. This would help in increasing the accuracy
of the arithmetic operation. This would also help in simplifying the arithmetic algorithms.

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COMPUTER SYSTEMS AND PLATFORM TECHNOLOGIES
Bibliography
Laudon, K.C. and Laudon, J.P., 2016. Management information system. Pearson Education
India.
Gawer, A. and Cusumano, M.A., 2014. Industry platforms and ecosystem innovation. Journal of
Product Innovation Management, 31(3), pp.417-433.