COMPUTER SCIENCE PAPER 1 (3 Sources)

IB CS Questions Paper 1; IB Computer Science - Paper 1 Revision; ib computer science (sl) | paper one

(Studying Systems) Document Collection

Good quality objective data, documentation may be limited

(Studying Systems) Interview

Detailed with key people, time, consuming

(Studying Systems) Questionairre

Reach large audiences quickly, may not be well designed and could get bad user input

(WAP?)

Provided by wireless router, allows wireless data transfer between device and network

*(Boolean Operators)* And

Put the two variables beside each other

*(Boolean Operators)* Know how to make

(Truth Table!)

*(Boolean Operators)* Logic of Operations

*N*ot operators, *P*aranthesis, *A*nd, *O*r

*(Boolean Operators)* NAND

Not (x and y)

*(Boolean Operators)* NOR

Not (x or y)

*(Boolean Operators)* Not

~

*(Boolean Operators)* Or

+

*(Boolean Operators)* XOR

Exclusive Or (one or the other but not both)

*(Logic Gates)* NOT Gate

*(Windows)* Memory Management

Windows Memory Diagnostics, Task Manager, Defrag, Virtual Memory

*(Windows)* Networking

Windows Network and Sharing Center

*(Windows)* Peripheral Communication

Device Manager

*(Windows)* Resource Monitoring and Management

Windows System Information, Task Manager

1.2.3 Social & Ethical Issues Associated with Networked World

- Loss of jobs due to computer automation
- Digital divide: more confidence with computer use have higher chances for success
than those who don't.
- Distraction: limited face-to-face social interaction
- Security issues
- Privacy issues
- Reliability
- Copyright infringements
- Globalization

A computing system is a

dynamic entity, used to solve problems and interact with its environment

A-D converter

Analog-digital converter; "digitizer"

address bus

pathway from memory to processing unit carrying addressin in memory to and from where data is transferred

Advantages/Disadvantages of Automatic Updates

+ Easier for inexperienced users
+ No software problems because of user not updating or forgetting to update
+ Always done on time
- No choice for users to choose updates
- May not be desired by certain users
- May corrupt user files

Advantages/Disadvantages of Manual Updates

+ Gives users choice on whether or not to update
+ If update is badly made, it may prevent issues if users choose NOT to update
- Important updates may not be done on time
- Inexperienced users may forget to update which may lead to serious issues

analog data

continuous data

arithmetic and logic unit (ALU)

part of the CPU that performs arithmetic, logic, and similar operations

Arithmetic Logic Unit (ALU):​

performs arithmetic and logic operations on data.

Bandwidth

Theoretical speed of data in media

binary search

list/array is divided into halves with half containing sought element again halved until it is found

bit

binary digit

Bit (b)

Binary Digit

Black box testing

Test the functionality of the application

Bluetooth

Uses microwave radio to exchange data at very low power levels. Frequencies change regularly.

BMP

files in bitmap form

Bottleneck

Created by slowest segment of network that affects above

bubble sort

...

buffer

portion of storage used to hold input or output data temporarily

Bus

Connects all devices through a common cable

bus

pathway used for sending signals between internal components of a computer; components may share same bus but can be transmitted simultaneously

Bus topology

bus network consists of single central cable which all computers and other
devices connect

byte

8 bits

Byte (B)

8 Binary Digits

cache

part of main store between main memory and processor; holds copy of data and instructions that are likely to be used next by the processor; faster than main memory

check sum

sum generated using individual digits of a number and employed as an error-detecting device

Checksum

Extra digit added to numerical data (to make sure it is good when transmitted)

client

desktop computer or terminal used to access a computer-based system

Client

Requests service from above connected to same network

client-server

network architecture where a system is divided between server taskes performed on instructions received from clients requesting data

Coaxial Cable

Cheap to install, consists of two copper conductors. Used in networks as well as carrying TV signals.

compiler

translates a program into machine language, returning a list of syntax errors afterwards; produces an executable file that does not require the compiler

Control Unit

​Acts as the stage unit to ensure that all the other components
act in concert.

control unit

controls flow of data into CPU and its operation ?

CPU

contains ALU, control unit, and registers

CPU Scheduling:​

The act of determining which process in memory is given access
to the CPU so that it may execute.

Criticism of Saas Privacy:

Since you must send all your data to the ASP it allows them to access all your data,
furthermore it makes the clients data more vulnerable to attack as hackers may hijack your
connection.

data compression

method of reducing size of data; all redundancy is removed to reduce storage needed or to speed up transfer

Data Compression

Reduction of bits by encoding data using fewer bits than original file/representation

data integrity

correctness of data after processing, storage, or transmission

data packet

part of a transmitted message that is sent separately; might include check digits, destination adress, etc

Data Packet

Portion of messages that is transmitted through network. Has data such as check digits and destination address.

data security

method of ensuring that data is correct, safe, and cannot be read or accessed by those without permission

Debugging

It is done by the automatic program called debugger or the programmer(s)

Define a legacy system?

A system that continues to be used because of the cost of replacing or redesigning it but is large, monolithic, and difficult to modify.

Define term extranet

An external extension to a company's local network with limited access using internet protocols

Define the term concurrent processing.

Concurrent processing means to do more than one activity at the same time;

Define the term data packe?

A unit of data transmission; with a format

Definition - What does Legacy System mean?

A legacy system, in the context of computing, refers to outdated computer systems,
programming languages or application software that are used instead of available
upgraded versions.

defragmentation software

application that reads file segments from non-contiguous sections of a storage device and writes files to same device so that each file segment is contiguous

Describe one way that software developers can ensure that the users are aware of any available updates for their products.

When the software is installed and registered (a cookie is placed on the machine)in the machine. This software communicates with developer automatically on start up;Messages about updates are sent back to the machine and alerts are given;
OR
Send an email;With a link to the update;

Describe the need for change management

The need for change management is based on the need to make sure that new systems
work with the old systems.

Describe three features of Saas?

Data is in the cloud/computing infrastructure, SW necessary for the activities in the client, access to SW is with thin client by web browsing

Describe two advantages to society of the increased availability of WiFi outside the home?

Social - keep up to date while away, Business - work away from home

DHCP

Protocol that allows server to automatically assign IP address to client device. Very effective and convenient.

digital data

discrete data (taken at intervals)

direct access file

file organized that a calculation provides the address of a record so the record may be directly accessed; records in file may be ordered or unordered

Direct changeover:

Replace system without testing.

Disadvantages of a legacy system

- The cost of maintaining an older system can be higher than maintaining a more
updated version. The staff might not be familiar with such an outdated version of the
system.
- Tech support may no longer be available.
- The data in the current system might not be compatible with newer systems and
conversion may not be possible.
- Legacy systems are usually more vulnerable to security threats due to lack of
security patches.
- Integration of newer systems may be a complicated process as the two systems may
have completely different technologies

Disadvantages of data migration

*(1)* Migration addresses the possible obsolescence of the data carrier, but does not
address the fact that certain technologies which run the data may be abandoned
altogether, leaving migration useless.*(2)* Time consuming - migration is a continual process, which must be repeated every
time a medium reaches obsolescence, for all data objects stored on a certain media. *(3)* Costly - an institution must purchase additional data storage media at each
migration." -Wikipedia

Discuss the limitations of SaaS in relation to security.

*(1)* Security in storage; data is stored in server of provider, organization has no direct control of it, legalization in country of provider may be weaker than users, cases of provider's corruption loss are a risk to organization, *(2)* Security in transmission; applications running in site may require data in SaaS, longer transmission times and higher risk of attacks

Discuss the security characteristics of a VPMN

Authentication, tunneling, encrypted, location and IP are masked

disk cache

RAM set aside to speed up access to a hard drive

Distinguish between the use of two types of primary memory?

ROM \= Permanent Instructions, Ram \= Current Instructions

encryption

process of transforming data into meaningless form for added security

Error Checking

Process to determine error

Error Correction

Ability to repair error

examples of application software.

Word processor; spreadsheet; database management system; e-mail; web browser; CAD; graphic processing software;

examples of operation systems

windows, Apple IOS, Linux, Unix.

Explain one advantage and one disadvantage of carrying out a number of tasks concurrently.

Advantages:

Building could be finished faster; By doing some tasks concurrently, the overall time needed to complete the building will be reduced. Since construction workers are paid by the hour, getting the building done sooner will reduce the cost of the building.

Disadvantages:

Workers on concurrent tasks may get in each other's way; If the plumbers and the electricians are both working at the same time and both need to get at the
same place at the same time, one will have to wait. Thus, it may take longer to do the electrical work while the plumbing is being done than it would take to do it alone.

Harder to supervise; The supervisor needs to look at the work being done and make sure that its being done correctly and explain what needs to be done, etc. If there are two (or more) sets of workers the supervisor will have to work harder to watch both of them at the same time.

Explain packet switching?

Files sent over a network are first broken into small parts of data. Each is sent individually and once all are received, they are reassembled. All packets must contain information to help this process, which is in the header. The header contains information such as the address, the senders address, position of data to put it back together, and error checking information (checksum). Packet switching is the process of

Explain the difference between a fat client and a thin client using the idea of a PC and a Chrome Book?

A *fat client* will perform the bulk of the processing required by the end user, such as a user using a program on their PC. Client hardware and software can be streamlined in a *thin client* setup where the bulk of the processing and software is managed directly by the server and the thin client is little more than a screen with a computer that has a graphics card and a network card, such as a chrome book.

Explain what is meant by *beta testing*?

*(1)* Testing prior to product's full release / last stage of testing, *(2)* To see if it works properly / complete functionality / usability, *(3)* Performed by end users (not designers)

Explain why an object is an example of abstraction?

*(1)* An object hides the details *(2)* but preserves the functionality

Explain why data may need to be compressed before transmission

Compression​ ​is commonly used to reduce file sizes and hence reduce the overall amount
of data being transmitted (traffic). This is effective as long as the client receiving the data is
powerful enough to decompress the data quickly. If not, then we can use lossy
compression​, where some details are simply removed (lost). A typical example is to send a
low-resolution version of a video, say 320x200, rather than an HD (high definition) version at
1920x1080.

Explain why data transmission speeds can vary?

*(1)* The packets of a message may take different routes on their way to the final
destination.
*(2)* Therefore, they may arrive in a different order than the way they were sent. The
packets must be put into the proper order once again, and then combined to form the
original message.
*(3)* A packet may make several intermediate hops between computers on various
networks before it reaches its final destination.
*(4)* Network devices called routers direct the packets as they move between networks.
Intermediate routers don't plan out the packet's entire course.
*(5)* Eventually a message reaches a router that knows where the destination machine is.
If a path is blocked due to a down machine, or if a path currently has a lot of network
traffic, a router might send a packet along an alternative route.
*(6)* If a communication line spans a long distance, such as across an ocean, devices
called repeaters are installed periodically along the line to strengthen and propagate
the signal.

Extranet

External extension of Intranet by reaching into the internet. Includes all files, programs, etc a computer needs

fiber optic cables

cables used for networks made from fine strands of glass; can carry large amount of data at high speed; expensive

Fibre Optic Cable

Carries beam of light, used for data transmission and telephone lines. Higher speeds with high security but very expensive.

Firewall

Network security system that determines what data comes in/goes out of network or computer

GigaByte (GB)

2^30 Bytes

Good Put

Transfer rate of usable data

How are colors typically stored?

RGB, 8 Hexadecimal Digits (\#000000 is black for example)