Computer Science HL Paper 1

One advantage and one disadvantage of SaaS

Define peripheral
Outline two uses of a stack
Outline the importance of user acceptance testing
Outline use of the MAR
Two potential usability problems of mobile phones


Hexadecimal question 11111011 to hex = fb
Convert 89 to binary = 1011001

2 ways to improve accessibility of computer systems

Outline two ways of resource management techniques for an OS [4]





Q12:
Identify two characteristics of fiber optics [2]
Identify two characteristics of wireless transmission [2]

Outline how encryption keeps data secure during transmission [3]

Describe how data is sent using packet switching [5 - marker]

Outline social implications of changes in worker behavior (or smth like that) due to use of a VPN [3]


Hotel chain question:

Two causes of data loss
Impact of data loss on hotel chain
One migration issue
How can hotel prevent data loss (can’t rmb how many ways they asked but this was a 2pointer)
Compare and contrast primary and secondary memory of desktops and tablets [3]
Compare/contrast network connectivity for wired/wireless








Question 13? or 14 idk


They give you a linked list

Describe how an element would be removed [5]




Another question: give you a few numbers. 

When traversed using INORDER the number will be sorted. Sketch binary tree

Identify the leafs in the tree u sketched

Car question

Define NOR operator

Output z is determined by inputs A, B, C

Input
Binary Representation
Condition
A
0
Distance to obstacle in front is greater than 20m 
1
Distance to obstacle in front is less than or equal to 20m
B
0
Car is stationary or reverse
1
Car is going forward
C
0
Faster than 130
1
Car travels between 0-130



Z is 1 only if:

The car is travelling in a forward direction AND distance to obstacle in front is greater than 20m
OR
The car is going faster than 130 km/h
Otherwise z = 0

Construct a logic diagram for z

	A —-- NOT —----|
	B —-----------------| AND—----|
	C —-------NOT—---------------| OR —---- Z smth like this
	

Rule D is to be added so that it checks if the car is going in reverse AND less than 30m away from an obstacle from the car’s rear.

State the rules required to check the condition for rule D [2] (don’t even ask me how to do this idk wtf they were tryna make me do)







Next page after car question (continued):


Variables: 

F: distance from front of car to obstacle in front
S: speed of car
T: true if going forward, false if not


There’s a chain of booleans operations questions. Basically evaluates to true & true & true & true = true

Construct a pseudocode that warns the user if car is going >115 km/h or is < 15 m to car in front. Algorithm exits when car is stationary




Trace Table question (last one)

Functions:

substring(x, y, z): given string x, index y (starts from 0) and z, returns the substring of x beginning at y of length z
E.g. substring(“Hello”, 2, 2) = “ll”

lenString(X): length of input string
revString(X): reverse of input string, so revString(“hello”) = “olleh”
joinString(X, Y): joins X and Y together, no space in between

I DON’t fucking rmb what they gave u but the output is supposedly “COMPUTERSAREFUN” according to my friends but i didn’t get that :(

The shit is crazy, it’s a trace table with 7 columns. Algo is like this (next page)


J = “”

Loop from i = 1 to i = 4:
Input X
Input Y
Input Z
R = substring(X, Y, Z)
S = revString(R)
J = joinString(S, J)


From this construct a trace table [5]. (first row done for you)

You need to get COMPUTERSAREFUN or smth like that


Last pseudocode question (same as trace table)
Using the functions given, create a password-checking algorithm

Rules:
Password must be at least 8 chars long
Password must not have any consecutive letters being the same
User is prompted to re-enter password if the previous 2 rules are passed. This rule passes only if the re-entered password is same as the original password

IF ANY OF THE RULES FAIL U NEED TO START OVER FROM RULE #1

Example:

Please enter a valid password:

“Abccdefg”

Error, consecutive characters. Please try again.

Please enter a valid password:

“Abcdefgh”

Please reenter password:

“Abcdefgh”

Password accepted.