Assessment 4 Flashcards
List three functions other than memory management, of an operating system
Provides a user interface
Provides security
Manages hardware/peripherals
What is the name of the memory management technique in which the operating system divides the memory into equally sized chunks?
Pagination
Describe how the operating system would use virtual memory to load a program there is not enough space for
The operating system uses an area of secondary storage as virtual memory
And moves unused pages of programs currently in memory to virtual memory
Then loads the program there wasn’t enough space for into physical memory
Explain what happens when a search engine indexes a page
A program called a crawler traverses the web and takes each word in the document
It adds an entry for the page under the word in the index, alongside the word’s position on the page
Explain why using a RISC processor rather than a CISC one is likely to result in increased battery life
RISC has a smaller instruction set than CISC and as such requires fewer transistors. This means less power is required.
Give two reasons why an operating system may be stored in ROM
It cannot be accidentally overwritten or deleted
It will not be lost when the device is switched off
Describe one advantage to a company of using a RISC processor in a product rather than a CISC processor
Costs less to produce because there are fewer transistors
Describe what is meant by a peer to peer network
Devices on the network have equal status and share data
Give one disadvantage of using cloud storage to store photos
Potentially vulnerable to hacking
What are secondary keys used for?
To search for information
What is First Normal Form?
When a database has:
No repeating fields/data
Data is atomic
Data has a primary key
What is Second Normal Form?
When a database is:
In First Normal Form
And where every field is dependent on the primary key
What is Third Normal Form
When there are no transitive relationships
What is a primary key
A unique identifier
What is a hash?
A result generated by applying an algorithmic process to a value
What is are advantages of storing passwords as hashes?
Hash functions are one way
If someone gains access to a database of password they cannot access users’ passwords
What are SQL SELECT related keywords?
SELECT
UPDATE
SET
WHERE
FROM
AND
What is referential integrity?
Ensuring changes are consistent across a database
If a record is removed all references to it are also removed
What is a server?
A device which provides a central point of control
Why is it important for transactions to be checked server-side?
Client side processing can be modified
To prevent malicious code such as SQL injection
Why is it important for transactions to be checked server-side?
Client side processing can be modified
To prevent malicious code such as SQL injection
What is meant by the term ‘Atomic’ in the context of ACID transactions?
A transaction cannot partially complete
What do the letters in ACID stand for
Atomic
Consistency
Isolation
Durability
Give an advantage and disadvantage of changing character sets from ASCII to Unicode UTF-32
Advantage: More characters can be represented
Disadvantage: Text takes up more storage
What is a WAN?
A Wide Area Network - a network between two different geographical locations in which devices are connected to share data
Why are protocols important on a network?
Protocols control the rules of a network
Protocols allow devices to communicate by ensuring all devices follow the same rules
State the name of the four layers of the TCP/IP stack
Application
Transport
Internet
Network Interface
What is the TCP/IP stack?
Stands for Transmission Control Protocol/Internet Protocol
Protocols are a set of rules for communicating across a network
Give one disadvantage of using ASCII rather than Unicode
Characters from different languages can’t be represented
What is compression?
The process of making a file snaller
The following sequence has been compressed using Run Length Encoding:
3C3M4C
Show the result of decompressing the sequence
CCCMMMCCCC
Show the result of using Run Length Encoding to compress the sequence CCCCOLLLCCCCCMOCCCCC
4C1O3L5C1N1O5C
