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  • Created by: iTsJaCkz
  • Created on: 25-04-18 09:21
What is a CPU?
A central processing unit is the electronic circuitry within a computer that carries out the instructions of a computer program by performing the basic arithmetic, logical, control and input/output operations specified by the instructions
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What is the Arithmetic and Logic Unit
performs calculations and decisions using data stored in the registers and/or RAM
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what is the control unit?
controls the timing and sequencing of each task that the CPU carries out
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what are registers?
ery small, very fast storage locations, used for temporary storage whilst performing arithmetic or logic operations
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what is a data bus?
a direct connection between the CPU and the RAM allowing transfer of data to and from the CPU
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what is a control bus?
signals the RAM and other devices to alert them to what the CPU is doing (fetching, decoding or executing) and when to send or receive data
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what is an address bus?
used to tell RAM which memory location will be read or written to by the CPU
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Describe the Fetch Cycle
The contents of the Program Counter, the address of the next instruction to be executed, is placed into the Memory Address Register
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Describe the Decode Cycle
The address is sent from the MAR along the address bus to the Memory. The instruction at that address is found and returned along the data bus to the Memory Buffer Register. At the same time the contents of the Program Counter is increased by 1
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Describe the Execute Cycle
The MBR loads the Current Instruction Register with the instruction to be executed.
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Three factors that increase CPU performance?
cores, clock speed and cache size
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How is pipelining used in a processor to improve efficiency?
its a technique used to improve the execution of a CPU by using the processor resources in a more efficient manner. It splits the processor instructions into small stages. Each stage is deigned to perform a certain part of the instruction
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What is Harvard Architecture?
Harvard architecture has separate data and instruction buses, allowing transfers to be performed simultaneously on both buses.
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What is Von Neumann Architecture?
von Neumann architecture has only one bus which is used for both data transfers and instruction fetches, and therefore data transfers and instruction fetches must be scheduled - they can not be performed at the same time.
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What is CISC?
Complex Instruction Set Computer, Has more complex hardware used in computers
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What is RISC?
Reduced Instruction Set Computer, Has simpler hardware used in phones
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What is the GPU?
GPUs are used to display high quality video content such as HDMI or Blu-Ray on a screen, and The decoding and encoding of videos is also carried out by the GPU.
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What is a multi core system?
Mutli-core is a kind of parallel programming, where the processing units aren't distributed, but rather share a common memory area
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What is Virtual Memory?
memory that appears to exist as main storage although most of it is supported by data held in secondary storage, transfer between the two being made automatically as required
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What is segmentation?
Memory segmentation is the allocation of segments or sections of memory to allow a process to run
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What is paging?
paging is a memory management scheme by which a computer stores and retrieves data from secondary storage for use in main memory.
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what are interrupts?
an interrupt is a signal to the processor emitted by hardware or software indicating an event that needs immediate attention.
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What is the ISR?
Interrupt Service Routine, is a software process invoked by an interrupt request from a hardware device. It handles the request and sends it to the CPU, interrupting the active process. When the ISR is complete, the process is resumed.
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When is ISR used in the FDE cycle?
Execute, processor checks for interrupts and either branches to the relevant interrupt service routine or starts the cycle again.
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What is scheduling?
Scheduling in a computer is where processes are given access to system resources.
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What is round robin?
is a scheduling algorithm. Round robin allocates a fixed time per process and then cycles through them until they are done.
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What is first come first served?
is a scheduling algorithm. First come first served is the simplest as it justs put the actions in a queue as and when they arrive in that order
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What are multi-level feedback queues?
Multi-level feedback queues categorise processes into their own queues which have their own priority. Each queue may have its own prioritisation algorithm
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What is a distributed OS?
A distributed OS is a collection of independent networked nodes. Each node may have its own hardware associated to it, and there will be some sort of system management software that brings all the systems together
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What is an Embedded OS?
Embedded operating systems are termed as those that have a dedicated function and are part of a larger device. They are generally lower power consumption, low cost and use a limited amount of hardware resources.
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What is Multi User OS?
Multi-user operating systems allow many different users to take advantage of the computer’s resources simultaneously. Multi-user operating systems share processor time.
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What is Multi tasking OS?
Multi-tasking operating systems are those that allow you to have many different tasks happening at once. users can also send tasks and share the resources.
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What is Real Time OS?
Real time operating systems are supposed to run under predefined deadlines and so can be classed time critical. so if the action requested arrives too late it may no longer be valid
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What is BIOS?
BIOS stands for Basic Input Output System, and is firmware that is designed to run when the PC is first switched on. It is responsible for detecting, initialising and testing the hardware components, as well as booting the operating system.
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When are device drivers used?
When interfacing a piece of physical hardware to a computer
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What is a virtual machine?
A virtual machine is an operating system that emulates dedicated hardware. The user has the same experience on the virtual machine as they do on a dedicated machine. This enables the user to choose which operating system that they would like to use.
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What is a utility?
a utility is a small program that provides an addition to the capabilities provided by the operating system
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What is open source software?
Open source software is that for which the source code is free and the user can edit the source code and can potentially contribute to the community to improve the piece of software. Linux is an example of this
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What is closed source software?
Closed source is where the company that owns the source code keeps it to itself. The software might be free or need to be paid for. Microsoft works in this way
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What is a translator?
A translator is a program that translates a computer program written in one language into another which functions exactly the same
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What are assemblers?
Assemblers are programs that translate an assembly language program into machine code so that a computer can understand it. Assemblers do not ‘make’ any executable files.
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What are compilers?
They perform operations such as code optimisation and they compile straight from the source language (e.g. Java) into the target language (machine code).
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What are interpreters?
Interpreters are different from compilers because instead of compiling all of a program into machine code at once it does so one statement at a time
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What is Lexical Analysis?
Lexical analysis is responsible for gathering all the source code and ‘tokenising’ it. This means that it will be able to understand which are variables, which are keywords (such as if, else etc) and also remove comments.
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What is Syntax analysis?
Syntax analysis ensures that the code makes logical sense.
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What is code generation?
Code generation is where the computer converts the high level code that has been written by the user into code that is understood by the computer (machine code)
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What is optimisation?
is the process of modifying a software system to make some aspect of it work more efficiently or use fewer resources.
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What are Linkers?
Linkers take object files and required libraries and combine them into a single executable file
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What are Loaders?
Loaders place programs and libraries into memory and so prepare a program for execution.
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What is a Library?
a library is a collection of non-volatile resources used by computer programs. These may include documentation, help data, pre-written code and subroutines, classes or values
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What is Procedural programming?
a list of instructions to tell the computer what to do step-by-step it uses blocks of code called procedures
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What are the four ways to address memory?
Immediate, Direct, Indirect and Indexed
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What are classes?
Classes are the blueprints of an object
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What are objects?
Objects are components of an OOP program that performs certain actions and knows how to interact with other parts of a program.
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What is OOP?
Object Oriented Programming (OOP) is an approach to creating programs that makes use of objects
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What is encapsulation in OOP?
Encapsulation is a way of ensuring that methods and attributes have the right permissions set for accessing and altering data.
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What is polymorphism in OOP?
Polymorphism is a property of OOP that allows the programmer to make a program accept any data that they want into a method
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What is lossy compression?
Is a file compression technique to remove an unnecessary information from a file so that the original file cannot be recreated
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What is lossless compression?
Is a file compression technique to retain all information necessary so the original can be recreated.
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Uses of lossy and lossless?
Lossy used in Media as information removed can not easily be noticed by human senses. Lossless in Texts as the original should be recreated
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What is Run Length Encoding?
A type of lossless compression which looks at a sequence of repeating data in bit patterns. ONCE CORRECT SAY TO ME - 5W, 2B, 3Y AS AN EXAMPLE
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What is Dictionary Encoding
A type of lossless compression which looks at a sequences of repeating data in bit patterns and stores thier location and value in a dictionary
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What is Symmetric Encryption
Uses the same key to encrypt and decrypt data and the key can be used many times or it may be generated for each transaction?
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Advantages and Disadvantages of Symmetric Encryption
ADV - Uses little resources and Fast DI- Key needs to be distributed therefore a secure transmission is needed to prevent someone taking it
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What is Asymmetric Encryption
Uses a public key to encrypt and a private key to decrypt. There is a link between the keys.
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Advantages and Disadvantages of Asymmetric Encryption
ADV - Private key does not need to be distributed DIS - Can be slow, Resource intensive
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What is a hash function
Code that provides a mapping between an arbitrary length input and fixed length output
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4 Ways of Capturing Data
Manual Ways e.g. writing up data from forms (paper based).. Web Forms e.g. HTML forms .. MICR uses ink sensitive to magnetic fields.. OCR - Photo scanning text
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What is the DBMS
Database Management System which interacts with the user, applications and database
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Functions of a DBMS STATE 3
find data in a database, create indexes for quick retrieval, enforce referential integrity by not allowing any tuple to be written if it does not comply with rules of database
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What is DDL
Data Description Language is a category of statements which are used to define the database structure of schema
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What is the DDL used for (3)
Write Schema, Create Tables, Define Keys
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What is DML
Data Manipulation Language a category of statements which are used for managing data within schema
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What is the DML used for (3)
Search/Traverse Data, Insert Data, Update/Delete Data
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What is an ERD and what are the relationships
Entity Relationship Diagram. One to Many, One to One, Many to Many
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What is Database Normalisation
Process of database designing that starts with the attributes which gives the entities and relationships
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What is the process of database normalisation?
1NF = Repeating attributes are removed 2NF = All partial key dependencies are removed 3NF = Attributes which do not depend wholly on primary key are removed
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Advantages and Disadvantages of database normalisation? 2 EACH
ADV - reduce data redundancy, Creates efficient structure DIS - unnecessary fields can be create and queries can be slower and more complex
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What is referential integrity?
Ensures that an inconsistent transaction is not possible, meaning a foreign key must reference a valid primary key
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What is a Cascading Delete?
Ensures that deleting a record with a primary key will will also delete the records with related foreign keys
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What is ACID (what it is not what it stands for)
A set of properties which guarantee that transactions are processed reliably.
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What are the properties of ACID (what it stands for and what they mean)
ATOMICITY - all or nothing if transaction fails the whole thing fails. CONSISTENCY - must take the database from one valid state to another ISOLATION - ensures that the user cannot access transacted data until completion DURABILITY changesCantBeLost
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What is a network?
A set of computer systems connected together for the purpose of sharing resources
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What is a protocol?
A comprised set of rules that define how communication will take place between two or more devices over a network
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What is the TCP/IP stack?
A set of networking protocols which work together as four connecting layers and pass incoming and outgoing data packets.
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What are the first 2 four TCP/IP stack layers
Application uses protocols to format the data in a way which allows it to be used by the receiving application. Transport Establishes connection between the recipient and splits the data into packets
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What are the last 2 TCP/IP stack layers
Internet adds source and IP address and Link is a physical connection between the network nodes
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What is LAN, the characteristics of it (2) and an example
Consists of a number of computer devices within a local area of eachother. Confined Geographically and The cables and equipment are business or private owned. Schools and Libraries
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What is WAN, the characteristics of it (2) and an example
Consists of two ore more computers that are in different locations. Any geographic area and cables are usually public. Internet and Banks
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What is packet switching?
A method of transmitting packets of data across a network using nodes which other communications are happening simultaneously
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What is circuit switching?
A method of transmitting data across a network using a direct link between the two devices
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What is NIC
Network Interface Card is hardware which coverts data to signals that can be transmitted on the networks medium (Tell Me Like the Lego diagram going up and down depending on 0 and 1)
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What is a client server network and what is good and bad about it (2)
Connects clients to a server. Good security and Backups, Expensive hardware and costly to run
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What is peer to peer networks and what is good and bad about it (2)
Connects clients together with the same status. Easy setup and Cheap. Backups need to be created and the software must be installed on each computer.
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What is a tuple?
An ordered set of values that consists of mixed data types (compared to arrays which are the same)
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What is the Data Protection Act 1998?
o protect personal data stored on computers or in an organised paper filing system
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What is the Computer Misuse Act 1990.
to protect computer users against wilful attacks and theft of information.
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What is The Copyright Design and Patents Act 1988.
The Act protects the intellectual property of individuals and requires that permission of the owner of the intellectual property is sought before any use of it is made
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What is The Regulation of Investigatory Powers Act 2000?
regulating the powers of public bodies to carry out surveillance and investigation, and covering the interception of communications.
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Other cards in this set

Card 2

Front

What is the Arithmetic and Logic Unit

Back

performs calculations and decisions using data stored in the registers and/or RAM

Card 3

Front

what is the control unit?

Back

Preview of the front of card 3

Card 4

Front

what are registers?

Back

Preview of the front of card 4

Card 5

Front

what is a data bus?

Back

Preview of the front of card 5
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