coExtra Flashcards
High level
Less efficient
White box
Knows source code
What do viruses do
Damage or delete data
Regulations online to
Keep kids safw
What is the link layer?
This is where the network hardware is located. This layer attaches the MAC addresses of the sender and recipient so the packet can be directed to a specific device on a network.
What are some of the positives of networks?
User profiles and security can all be managed centrally.
All files can be backed up centrally.
Software can be distributed without it having to be installed every time.
Printers can be shares.
internet connection can be shares and files can be stored on a file server so they can be accessed.
What are some of the negatives of a network?
ardware can be expensive
If file server goes down, nobody can access their files
Could lead to loss of data
Viruses can spread easier
Hard to manage
What are some advantages of bus network?
Cheap to set up
Easy to set up
Good for smaller or short term
No reliance on central node
What are the negatives of star network?
Expensive to install
Extra hardware is required
Harder to set up
Name some positives or star topology?
Faster transmission of data
Less likely to experience errors/data traffic problems
A faulty connections disables one computer unless it is the hub or switch
What is cyber security?
Protecting networks, computers, data and programs from attack damage or unauthorized access and is done through processes practices and technologies.
Phising
Impersonating
What are the positives of databases?
Makes processing more efficient, reduces storage requirements.
Characteristics of flat file databases.
Very inefficient, difficult to query and used for small/trivial data sets. Data is often duplicated, also suffers inconsistencies between records. This can compromise the integrity of the data.
What is the difference between using a GUI and CLI?
Command line interface is much quicker.
What is the difference between system and application software?
System is run by system in background for example OS or encryption whereas application is run by user to complete a task.
BIOS
Controlling hardware at start up sequence
What are the two main types of system software?
Operating systems and utility software.(just software is like basic applications like games or browsers which is in the other ring).
How does the operating system do things
User authentication, makes sure users must prove who they are, protect against malware, blocks access to specific vulnerable areas of the pc.
What does WAN have to use
Encryption
Draw the two round dots symbolising the terminators at the end of each side of the BUS.
okay.
Why does everything stop working if the bus goes down?
The cable splits so there are two open ends with no terminators so the data is not absorbed at the end which causes it to reflect and cause problems. Star only impact one node/device UNLESS it is central hub or switch or server as they are connected individually.
PAN
not always wireless but does not need extra hardware unless it is wired as WAP is always required anyway.
What are the advantages of hydrogen fuel cells?
They will produce electricity for as long as you provide hydrogen. They do not get less efficient the more they run and they can be a source of drinkable water for example on a space craft.
What are the disadvantages or rechargeable batteries?
They run out and need to be recharged, they can also store less energy the more charging cycles they go through and eventually need to be replaced.
What are the disadvantages of hydrogen fuel cells?
Run on hydrogen which is explosive and difficult to store safely they produce a relatively low potential difference or voltage so several are needed together.
What are the advantages of rechargeable batteries?
They can produce a large potential difference.
What is another positive of closed source for the user?
Often will have more online help and support as they realised their code is unavailable.
pipette.
Small volume of solution in bottom to make it accurate.
What are anti bumping granules for?
To make the liquid boil more smoothly-small bubbles of vapour form on the corners of the granules and reduce the risk of the liquid boiling over.
What is bandwith?
The maximum rate of data transfer across a given path. The more people online, the more bandwidth is used up.
Make sure electrodes dont touch.
This would create a dangerous short circuit.
What do you always need to say?
Without consent.
What is an example of lossless compression?
.gif
What is an example of lossy compression?
.jpg and .mp3
What is not compression.
.bmp
What is RLE stored as?
Frequency/data pairs
What is system software?
Programs that are needed to enable the computer to function, including the OS, utilities and programming language translators and library routines.
What does the OS manage?
Processors, memory, input/output, applications, security.
How does the OS manage processors?
anages the use of the processors resources, task manager, the OS provides a tiny slice of processor time.
How does the OS manage memory?
OS manages where in memory each program and the data it needs will go.
How does the OS manage input/output devices?
The input is processed and the computer will generate outputs. The OS takes over and controls the sending of data. Each I AND O has a device driver.
How does the OS manage applications?
The OS interacts with applications through an Applications program interface(API) which allows the application to communicate with the operating system. Once an application is installed, it will need t communicate with the operating system to execute modules.
How does the OS manage security?
Controls access to ta computer by setting up passwords for different users, this blocks access to files and software without password. Sets up access rights and privileges for different users. Encrypts files stored on the hard disk and automatically downloads updates to ensure security loopholes are patched.
What do embedded systems use?
No OS and a microprocessor.
What are some strange things about embedded systems?
System held in non-volatile memory and some firmware devices are permanently installed and cannot be changed after manufacture. It is not possible to update hardware or attach peripherals.
What is good about embedded systems?
More reliable, optimised and efficient. And use less resource
Star topology positive?
Consistent performance even when the network is heavily used.
IMAP.
Stores email messages on a server and allows users to view and manipulate the messages.
SMTP?
Sending email messages between servers, used for relaying or forwarding messages form one mail server to another if there are different email service providers.
What is firmware?
Permanent software in read only memory.
What has a lower boiling point nitrogen or oxygen?
Nitrogen.
Why would a company not want to make their source code of the software available?
So third parties cannot insert/modify code and pass it off as original as it affects profitability. Algorithms cannot be copyrighted and therefore need to be protected to preserve commercial advantages. Hacking/cyber security as hackers could identify vulnerabilities in the source code and use them to create targeted attacks. Copyright of code-they may not want others to have access to what they have developed.
What are some advantages of star topology compared to bus?
Less likely to experience transmission errors/data traffic problems(contention issues). Faster transmission data. Fewer/no collisions if a switch is used rather than a hub. Also better security potentially as data is not broadcasted to all machines if a switch is used.
What are some negatives of star topology as oppose to bus?
It is harder to install and requires more cable. It is more expensive to install as more cable and hardware is needed. Switch/hub/central device may fail breaking the entire network.
What are the positives of a network?
Sharing of resources such as printers and storage space. Managed/central backing up of data. Central installation and management of software by network admin. Monitoring of users and network activity centrally by network admin. Hot Desking/users can log onto any machine. Ability to use communication tools between computers and centrally managed access rights. Rapid data sharing and it allows decentralised/home working.
What are the negatives of networks?
Spreading of malware and cost of infrastructure. Cost of network admin required to run network and dependency on network hardware.
Difference between PAN and lan.
you have to cover both to actually state a difference. For example PANs are centred round one person whereas LANs cover a limited geographical area/ larger area. Or one person v more than one usually.
What can networks do?
Increase available storage.
What are the reasons for growth of cloud storage?
Higher bandwidth mobile networks like 4g and there is an increased availability of mobile devices. Reduction in cost of large capacity storage devices and improvements in network security so people have a higher trust in cloud storage. Improvements in web browser software and increased availability of super computers for cloud processing. Companies have managed to develop business models based on cloud computing that allow them to make a profit.
What are the advantages of cloud storage?
Enables the user to access their data from more places/devices and enables the user to more easily share data with others as you can make parts of your cloud storage publicly available. Increases amount of storage available and reduced cost of computing devices for users as no need for as much built in-secondary storage.
What was it like before von neuman?
Instructions had to be hard wired and data went through physical switches.
Advantages of star compared to bus?
ess likely to experience transmission errors/data traffic problems(contention issues). Faster transmission data. Fewer/no collisions if a switch is used rather than a hub. Also better security potentially as data is not broadcasted to all machines if a switch is used.
What is data stored on for optical?
Singal spiral tracks.
Iterative testing?
Tweaked each time it is tested to improve it.
What are the electrodes made of?
Porous carbon.
Shouldering
PHYSICAL
What is a paging algorithm?
Memory management scheme.
What is it called when multiple instructions are being executed at once?
Concurrent.
What else does the OS do?
Scheduling algo.
What is a scheduling algo?
makes sure each instruction get s a slice of cpu time.
What is pipelining?
Method used by CPU to split up tasks and overlap tasks if possible.
What is a positive of client server?
Central backups.
IPV4
32
IPV6
128
Why might a company not give out daTA
It could affect a court case.
What is the first way anti malware detects malware?
Compares definition with definition stored in database of known malware.
What is the second way ant malware detects malware?
Uses a set of rules to detect suspicious behaviour which could suggest a file is malware.
What can heart implants do
May include electrodes for regulating heartbeat, warn of heart attacks and monitor the effects of treatment.
What implants can a quadroplegic get?
Electrodes implanted in his brain which enable him to control a robotic arm, getting it to bring a cup to his mouth simply by thinking about doing it
What are the environmental impacts of cloud storage?
It uses much more energy to keep its storage equipment running, cooling systems also use lots of energy. Cloud storage does save energy for companies that need to store large amounts of data.
What is recognised under the computer missue act?
Unathourised access to computer material, with intent to commit or faciliate a crime and modification of a computer.
Making, supplying or obtaining anything which can be used in computer misuse offences.
What is end-to-end encryption?
It ensures that during transmission, only you, and the person you send the message to can read it.
Used in whatsapp.
What is the problem with organisations or governments using this backdoor?
Providing any backdoor would potentially enable it to be opened by anyone, meaning that anyone’s confidential messages could fall into the wrong hands.
What do you say in SQL to sort?
ORDER BY
What is concurrency in a database?
Many users can query data at the same time.
How do you insert another record in SQL?
INSERT INTO cakes Vaules(..).
What is a transaction?
Change in database.
How does the OS do interface?
User/software and software/hardware
How does the OS do cpu?
Pipelining, scheduling to allow for optimal cpu usage.
How does the CPU do memory management?
Moves data and instruction sbetween primary+secondary storage and also disk defrag.
How does the OS do security?
User profiles/access levels and encyption.
Faster what?
Read write speeds
How do you update SQL?
UPDATE students
SET surname=”Kennedy”
WHERE firstname=”Mark”
How do you make a new record SQL
INSERT into students
VALUES (“Mark”,”Kennedy”,”15”)
How do you delete SQL?
DELETE from students
Where firstname=”Mark”
What is an entity?
Real world data about which data is stored about-whole table-song
What is an attribute?
A field-song name
Two things about peer to peer
Equal status and share data.
Select and from?
When saying select we dont care about where it comes from but with from we do
Query?
Access specific data quickly
What things can DBMS do?
Create a DB, add data, delete data, edit data and search data
Record
Collection of data about a single entity
Field
A unique piece of data about an entity
First principle of GDPR?
must be used for reason it was acquired with the persons consent
Second
Data must only be collected for specified, explicit and legitimate reasons
thurd
Data must be relevant, not excessive and not be held longer than needed
Fourth
Data must be accurate and up to date
fifth?
Data must be kep secure
sixth?
god knows
What else does the link layer do?
Attaches the mac adress
What do databases do
Reduce storage requirements
What is an array?
in computer science, an array data structure, or simply an array, is a data structure consisting of a collection of elements, each identified by at least one array index or key. An array is stored such that the position of each element can be computed from its index tuple by a mathematical formula
What is a record
A record is any document - in any format (paper or electronic, and yes even video) - created or received by you or your department - that allows you to conduct business. The value of a record is determined by content, not by format.
Can a record be in an array?
Yes
Where are records stored?
Hard disk
Where are arrays stored?
RAM
RECORDS SEACRH
requires linear search as can be any data type
etter to number ch
ord(‘f”)
number to letter ch
chr(102)
Showing how Rle works
• the number of consecutive pixels/data points/characters of the same
colour/value/character would need to be counted;
• (pairs of values would be stored), which would consist of a run length and the
colour/value/character of the pixels/data points/text in the run;
Example (max 1 mark)
• Image example of how the specific row of pixels would be compressed eg 9
Black, 11 Red, 8 White;
• Text example of how the specific run of characters would be compressed eg 7
G, 6 Y, 12 $
How is main memory used
it stores instructions whilst a program is being executed;
• it stores data whilst a program is being executed;
• each unique memory location in memory holds one value;
• every memory location has a unique address;
• once data has been stored in memory it can be found again later (when it’s
needed);
• data and instructions are replaced in memory as needed;
What is malware
- (Malware is a blanket/umbrella term for) computer software/program/code;
- with malicious/hostile/intrusive intent;
Explain box two reasons why software companies usually do not make their source code
publicly available. Source code is the code they wrote to create the software.
Algorithms cannot be copyrighted; and therefore need to be protected to
preserve commercial advantage;
Copyright of code; the company has paid for development of the code and
therefore own the code. They may not want others to have access to what
they have developed;
Hacking/cyber security; hackers could identify vulnerabilities in the source
code and use them to create targeted attacks;
So third parties cannot insert/modify code and pass it off as original; as it
affects profitability;
Is black 0
ye
Describe one difference between system software and application software.
System software manages the computer hardware/application software whereas application software is for end-user tasks
Many organisations provide free public access to a wireless network. box
Explain three ethical, legal or data privacy issues that an organisation should be
aware of when allowing this access.
Websites – any inappropriate websites ie pornography, drugs, guns,
terrorism etc. e.g. is it acceptable for the organisation to allow access to this
sort of material when you can’t control who is accessing the service?
Time – limit amount of time, they may not want to provide indefinite access
or may want to charge for access after the time limit has expired.
Preventing file sharing and illegal sharing\use of copyrighted materials.
Accountability – identification of users and actions on a network by
preventing anonymous access.
Prevention of illegal activities such as terrorism and fraud.
The responsibility to keep children safe and protected.
Responsibility to keep users (customers) data safe and secure.
Spoofing of websites, phishing. Responsibility of organisation to put some
kind of protection in place, eg filtering of known fraudulent sites.
Recording of private messages or details if not encrypted.
Recording of usernames and passwords that the user may also use to
access other systems.
Responsibility of organisation to secure their systems from possible attack.
Sales and marketing – providing sales leads to market products
hex more or less space
same
Explain why it would not be appropriate for the café to use MAC address filtering on
their wireless network.
Network is made available to members of the public;
Won’t know the MAC addresses for (most) of the devices connecting to the network
