Computer Studies

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This is some notes about computer and my exams are next week.
jason_2431
FlashCards por jason_2431, atualizado more than 1 year ago
jason_2431
Criado por jason_2431 aproximadamente 10 anos atrás
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What is an algorithm? It is a set of instructions independent of any programming language which solves problems or calculates a function.
What are the standard constructs of an algorithm? -Sequence -Assignment -Selection -Repetition
What is a sequence? It means performing an operation each steps consecutively in the order they occur.
What is an assignment? It means giving a value to a variable.
What is a selection? It means to choose a step or to a take a decision.
What is a repetition? It is a sequence of steps which loop until a requirement is met.
What are the different kind of loops? Do...While Loop While...Do Loop Repeat...Until Loop For Loop
What is a pseudocode? A pseudocode uses a combination of programming terminology and plain english to describe algorithms in a form which is easier for people to understand than real programming language code.
What is visual basic(VB) ? VB has very simple programming syntax and it is not case sensitive.
What is a concatonation? This means to add pieces of text(strings) together.
Strings can be manipulated in various ways: - It can be formatted. - It can be made all in uppercase. - Spaces can be removed. - The length of the strings can be counted.
stages of problem solving: 1. Understand the problem. 2. Define the problem. 3. Defining the bounderies. 4. Planning the solution. 5. Check the solution.
What are structure charts? It is a chart which shows the breakdown of a system into its lowest manageable task.
What is an array? An array is set of values which are logically related to each other.
Error types in programming: - Compilation error (syntax error) - Run-time error - Logic error (semantic error)
What is a top down approach? A top down approach also known as a stepwise design is the breaking down of a system into subsystems.
Procedures and function? Procedures and functions allow us to save lots of lines of codes. They allow codes to be reused, to structure programming, easily incooperate other people's code.
Difference between a procedure and a function? Procedures do not return any value whereas function must return a value.
What are calls? Calls allow you to run the code declared in a procedure or function.
What is SQL? SQL stands for structured query or standard query language. It lets you access and manipulate databases.
RDBMS? Relational database management system.
What is an operating system? An os is designed to run the background of a computer system and provides an environment in which application software can be executed.
What are the purposes of an operating system? - The os must manage the physical resources of the computer. - The os provides mean of communication between the user and the computer. - The os provides a platform in which the application software can run. - The os maintain security. - The os hides the complexity of the hardware from the user.
What is a batch processing? A batch processing does not allow interaction between the user and the processor during the execution of a program and lots of programs are collected together to form a batch.
Why is batch processing used? - There are large amounts of data to be processed. - The data are very similar in nature and require similar processing. - The computer system has identifiable time when it is not being used and so has available processing time. - The application does not require interaction by the user.
Examples of batch processing? - Processing in payroll. - The production of bank statements for customer at periodic intervals. - The production of utility bills.
What is real time processing? In real time processing, the processing can be quickly enough to affect the next input for process that needs to be carried out.
What are the two standardised codes used internationally for character representation of data? ascii - american stadard code for information interchange. EBCDIC - Extended binary coded decimal interchange code.
Byte? A byte holds one character.
What are different number system? - Denary number system. - Binary number system. - Hexadecimal number system.
What is a denary? It is a number system consisting of digits from 0 - 9 used to represent numbers either singly or in ordered group.
What is an unsigned integer? An unsigned integer is a whole number whose sign( + , - ) is not represented in the word.
What is a hardware? Hardware refer to the physical electronic and electrical components that make up a computer system.
What are peripheral devices? Peripheral devices are hardware that are outside of the CPU and connected to the computer by internal wiring, cables or wireless technology.
What is a software? A software is a set of instructions that makes the computer hardware usable.
Types of software? - System software. - Application software.
What is a single user OS? A single user os controls a system which has only one use and their programs at any time.
What is multi-user os? A multi-user os has a single powerful computer which is connected to a umber of terminals.
What is a multi-tasking os? A multi-tasking os allows several application to be available simultaneously.
What is network? A network comprises of several computer linked together for the purpose of communications and sharing of resources.
A network os carry out task such as? - control access to the network. - Management of the filling system. - Management of all application programs from the server. - Management of all shared peripherals.
what is a bitmap graphic? It is a collection of pixels from an image mapped to a specific memory location holding their binary colour value.
What is a pixels? It is the smallest possible addressable area defined by a solid colour, represented as binary in an image.
what is an image resolution? It is the number of pixels and image contained per inch or per centimetre.
What is a screen resolution? It is the number of pixels per row by the number of pixels per colour.
What is a digital image? It is composed of pixels arranged in a rectangular array with a certain height and width.
What are vector graphics? Images are represented as mathematical formula that define all the shapes in the image such as lines, polygons and text.
What is sound? Sound is an oscillation of pressure transmitted through a solid, liquid or gas.
ADC? It converts analogue sound into digital signals that can be stored on a computer.
DAC? converts digital signals that can be stored on a computer into analogue sound that can be played through devices such as speakers.
Bit rate? bit rate is the number of bits required to store one second of sound.
sample rate? number of samples per second.
sample resolution? Number of hits per sample.
Bit rate? Number of bits required to store 1 second of sound.
what is a video? A video is an electronic medium for the recording, copying and broadcasting of moving visual images.
Frame rate? It is the number of still pictures per unit time of video, ranges from 6 or 8 frames per second.
RFID reader? It is used to read data without physical contact which has a radio frequency identification chip.
CRT? A CRT is a visual display unit which was mostly used in all fat television.
what is cache memory? cache memory is a type of memory which is very fast and is used to improve the speed of a computer doubling it in some cases.
de morgan's law? de morgan's law are used to simplify boolean's equations so that equations involving one sorted gate generally used in NAND or NOR gates can be built.
Library software? Library software are a collections of resources used to develop programs.
assembler? it translate assembly language into machine code.
adv of assembler? - very fast - take less memory - easy to understand
compiler? translates code written in hll to a lll , machine or object code.
adv of compilor? -the source code is not included. -its faster -it produce executable file.
disv of compilor? -obj code needs to be produced. -the source code must be 100% correct.
interpreter? an interpreter executes other programs directly running through program code executing it line by line.
adv of interpreter? -easy to debug -easy to cr8
disv of interpreter? -usually slower programs -source code required -can be insecure
Processor? a processor is the most complex part of the computer system.
what does the processor contains? - control unit -arithmetic and control unit - registers
registers? they are special memory cell which operate at very high speed.
3 buses? - control bus -address bus - data bus
address bus? it is a signal directional bus that carries address signals from the cpu to main memory and input, output devices.
data bus? it is a bi-directional bus consisting of 32 wires used to transport data and instructions between the 3 components of the cpu.
control bus? it is a bi-directional bus consisting of more than 16 wires used to control signals between the 3 components of the cpu.
Input/output controllers? It is an electronic circuit connected to the system bus and in an i/o device.
I/O ports? I/o ports is a method of performing input or output between the cpu and the peripheral devices and the computer.
control units? The control unit sits inside the cpu and coordinates the input or output devices.
Clock? The processor clock is a timing device connected to the processor which synchronises when the fetch-decode execute cycles run.
clock speed? it is the number of cycles that are performed by the cpu per second.
examples of registors? - general purpose register. - address register. -conditional address register.
4 registers which are important? - program counter (PC). - memory address register. -memory buffer register. -current instruction register.
program counter? An incrementing counter which keeps track of the memory address of which instruction is to be executed next.
Memory address register? Holds the address in memory of the next instruction to be executed.
Memory buffer registor? A two way register which holds data fetched from memory or data waiting to be stored in memory.
current instruction register? A temporary holding ground for the instruction that have just been fetched from memory.
how to increase performance of processor? -Increase clock speed -Increase word length - increase bus width
fetch-decode execute cycle? It is the process by which a computer - fetches a program instruction from its memory -determines what instruction wants to do - carries out those actions.
MAR(memory address register) The address in main memory which is currently being read or written.
MBR ( memory buffer register) A two way register which holds data fetched from memory and ready for the CPU to process or data waiting to be stored in memory.
CIR (current instruction register) It is a temporary holding place being fetched from memory.
register notation? To describe the fetch-decode execute cycle.
Status register? It contains bits which are set or cleared based on the result of an instruction.
Types of interrupt: -Interrupt generated by the running process - I/O interrupt -Timer interrupt -Program check interrupt -Machine check interrupt
3 terms that are used for building data requirements? - entity -attributes -relationship
entity? it is an object, a person, an event or something of interest to an organisation about which data is to be recorded.
attributes? it is a property or characteristic of an entity.
relationship? a relationship is a link or association with two entities.
artificial intelligence? It is a science concerned with the general study of intelligence in all its forms both in living organisms and in present machines as well as future machines.
Digital divide? It is the disparity between groups when accessing information and communication technologies.
several problems of data? -data redundancy -data inconsistency -lack of flexibility -data was not shareable
DBMS(database management system) it is a software used to control access to data in a database.
feature of dbms? -program data independence whereby the storage structure of the data is hidden from each application or user. - restricted user access to the data that is each user is given a limited view of the data according to the needs
data dictionary? a data dictionary describes the structure and attributes of data items to be used within a software application usually a database.
normalisation? it is the process used to keep the database as efficient as it can be without any unnecessary duplication and no redundant data.
rules of normalisation: -organise data efficiently. -eliminate redundant data. -ensure that only related data are stored in a table.
intranet? it is a private network within an organisation which many offer file sharing, printer sharing, private website, etc..
Packet switching? It is the method by which the internet works. It features delivery of packets of data between devices over a shared network.
a domain name service? ( DNS) It translates domain names meaningful to human into IP addresses for the purpose of locating and addressing the devices worldwide.
protocol? it is a set of rules governing the way that devices communicate with each other.
port number? it is an application or process specific communication endpoint to an IP address.
FTP(file transfer protocol) it is a standard network used to copy a file from one host to another over TCP/IP.

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