Exam 2014

Question 1

Which designer of the first IBM computer said, that only six computers will ever be
sold in the commercial market of the United States?

a. Howard Aiken
b. George Boole
c. John von Neumann
d. Charles Babbage

Answer 1

a -> he built ASCC

Question 2

Which of the following laws of computer science is an example of "No free lunch in 
computer science"?
a. Moore's Law
b. DeMorgan's Law
c. Metcalfe's Law
d. Rock's Law

Answer 2

c -> Metcalfe’s Law: network becomes more valuable the more nodes you add + means you have to work to get something

Question 3

How many of the following statements are true?

 0000010000102 = 1028 = 6610 = 4216
 0001101001012 = 6258 = 42110 = 19516
 0011000001102 = 14068 = 77410 = 30616
 0101001110012 = 24718 = 133710 = 53916
 1010100101012 = 52258 = 271110 = A9516

ATTN: The notation 1238 means: the value 123 in octal representation.)

a. 0
b. 1 of 2 / 1 or 2
c. 3
d. 4 of 5 / 4 or 5

Answer 3

d -> Only the first statement is incorrect.

Question 4

An 8-bit register contains in two’s-Complement notation the value -39.
After executing an “arithmetic shift right” the register contains the value:
a. +19
b. -20
c. -19
d. +108

Answer 4

d ->
Steps:

1. 39 = 32 + 4 + 2 + 1 → 0010 0111
2. 2s complement of 0010 0111 → 1101 1001 (represents -39)
3. “Shift right” → 0110 1100
4. 0110 1100 → 64 + 32 + 8 + 4 = +108

Question 5

S = 1 01111110 10000000000000000000000
is a number in IEEE754 floating point representation.

What is the value of S?

a. -3
b. -0.375
c. -0.5
d. -0.75

Answer 5

Sign = 1

Exponent = 01111110

Mantissa = 100000000000000000000000

Steps:

1. Find the exponent value
   
   1. Convert to decimal = 64 + 32 + 16 + 8 + 4 + 2 = 126
   2. Subtract exponent bias = 126 - 127 = -1
2. Shift mantissa
   
   1. Add 1 in front of mantissa 1.100000000000000000000000
   2. 1.100000000000000000000000 x 2^-1 = 0.1100000000000000000000000
3. Convert to decimal
   
   1. 0.1100000000000000000000000 → 0.75
4. Apply sign → -0.75

Question 6

How many of these assembly instructions (src, dst):
• Move (R1), R0
• Move R1, R0
• Move #0x440, R0
• Move -440(R1), R0
have as effect that after execution the register R0 contains the value 440, if before execution the registers R1 and the memory locations 0, 440 and 880 contain the following values:
• R1 : 880
• 0 : 440
• 440 : 880
• 880 : 440

a. 3
b. 2
c. 1
d. 0

Question 7

Consider the performance equation of a generic program:
Time/Program = Time/Cycle ∙ Cycles/Instruction ∙ Instructions/Program

Which of the following sentences are correct?

• CISC architectures in general increase term 2 of the equation.
• RISC architectures in general reduce term 3 of the equation.

a. onjuist / incorrect juist / correct
b. juist / correct juist / correct
c. juist / correct onjuist / incorrect
d. onjuist / incorrect onjuist / incorrect

Question 8

The address bus of a computer has 16 address lines, A15-A0. If the hexadecimal
address assigned to a device on this bus is 0xBEEF and the address decoder for that
device ignores lines A4 and A8, which of the following addresses will the device not
respond to?
a. 0xBEFF
b. 0xBFEF
c. 0xBFFF
d. 0xBEEE

Question 9

A computer with a byte addressable memory of 4GB is using an 8-way associative cache of 1MB, divided into 1024 sets.

How many bits are respectively the tag and the word field?

a. 15 & 7
b. 12 & 10
c. 10 & 12
d. 14 & 9