computer systems Flashcards
who is john von neumann
joun von neumann is a mathemation that described computer archetecture that is still revelant today , he described that there are four components to a computer. the CPU which processes the program, The memory which stores dara and programs, a bus connecting cpu and memort abd the input output devices
What is the CPU
the central processing unit carries out computations on data by following instructions resulting in an output it contains the control unit, the arithmatic logic unit ALU and registers
What is the ALU
the ALU is where arithmetic and logical processing takes place, The ALU receives instructions and data and operates on the data according to the instructions
what are registers
registers are temporary storage locations that CPU can access quickly, register is expensive meaning smaller capacity compared to other memories
What is the program counter
the program counter stores where the CPU is in the program sequence
what is the address registers
address registers store memory addresses . A memory address is a value that indicates a specific location in memory
explain memory
Modern computers can store programs internallly in memory as well as inout and output data (RAM)
what is RAM
random access memory is a temporary memory.. it holds the data and instructions of the program that is being excuted by the CPU and is volatile
what is ROM
read only memory typical use for ROM is the computers BIOS basic input output systems. this is a small amount of ROM that is. used to store the computers startup routines. the BIOS preform necessary check then give control to the operation system
are RAM and ROM primary or secondary
primary
what is the fetch-execute cycle
As the CPU processes instructions. It runs through this cycle over and over again. The CPU fetches next instruction from memory. Instruction is found at a memory address and is stored in binary code. CPU decode the binary code revealing instruction, which is executed
what is the clock
The clock ensures operations of the CPU and other components are timed accuratelly and ensures all the step by step instructions are perfectly sychronised
what is the bus
The bus connects the CPU and memory
input and output devices
all part other than CPU, memory and bus are consided I/O devices
give examples of I/O devices
secondary storage, USB devices, keyboard or printers, screens output, touchscreens input
what is secondary storage
secondary storage is non volatile primary storage is smaller and more expensic=ve than secondary
what are magnetic hard drives
magnetic hard drives consist of a platter rotating at a high speed and a head moves across platter reading information
what are solid state drives
they are faster and more durable with no moving parts SSDs are based on flash memory but are more expensive
what is the motherboard
The mother board is a circuit board that devices mount on(when you plug a usb device into a computer you are physically connecting to the motherboard) - (includes CPU, main memory, hard drives and other I/O devices)
Binary code
computers use binary code to represent all information - binary stands for two. on signal present and off no signal in many devices the signal are high and low signals above certain voltage is high and below that volt is low
what is an analog device
eg black and white tv use a huge range of values, these can get confused making noise
what is electric current
is th eflow of electrons in one place
what is voltage
an electron experiences a force when a difference in charge exiss between its location and another locatation, this difference is called voltage
what is resistance
resistance is a measure of how much a material resists or obstructs the flow of electic current
what are transistors
is a tiny electronic switch
what are resisitors
a resistor is a device that reduces current flow
what are capacitors
a capacitor stores electric energy in the form of electric charge. capacitors are found in touchscreens as finger are weak electrical conductors
explain the CPU and logic Gates
Inside the CPU, the device responisble for manipulating the signals(is the transistor) if a transistor is on electrical current can flow if off the flow stops transistor are arranged in different ways to carry out boolean operations on data. these arrangements are of transistors into circuits are known as logic gates
what is the CPU made up of
mostly a combination of logic gates
what is an operating system
an operating system sonsists of a collection of programs that control the operation of the computer eg mac OS X and windows
functions of operating systems
- managing how the computer interacts with other computers 2. controlling where programs and data are located in the computer memory 3. managing the file system on the computer 4. controlling access and security
what is the internet
global network of computers that are connected in many wyas including copper wires, fibre optic wire lines and wireless
what is WWW
world wide web uses th einternet as a transmission medium, without the internet the web wouldn’t work
What is the TCP
transmission control protocol, the TCP protocol operates at the transport layer, ensuring that binary information is tranported reliably between computer
what is IP
internet protocol, this proctocol handles the creation of the data packets and how they are routed around the network to their destination using IP adresses.
what is an IP address
is a code that identifies a computer network
what is TCP/IP
TCP/IP is one family of protocols. TCP keeps track of the packets of info, IP creates the packetes and addressing and routing across the network
what is WIFI
WIFI is the radio wave technolgoy that allows devices to communicate with each other
What is VOIP
voice over protocol, is a number of protocols which deliver voice data over the internet, facetime uses VOIP
what are the internet components
gateways connects networls that have different protocols, routers forward packets between computer networks eg home router between internet and home computer. network bridges creates a single network from multiple network segments, network switches forward data only to devices that need to recieve it. repeaters recieve data nad re transmit it. these are often used in fibre optic cables to boost the signal strength for transmittion over long distances
what is cloud computing
refers to storing, processing and/or accessing data, programs or servinces over the internet on servers that are specifically designed for these purposes. generally hosted by companies eg google drive
