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UNIT 1 LO1, The most common is a NETWORK INTERFACE CARD (NIC) which sends…
UNIT 1 LO1
Units of Measurement
BIT: BINARY DIGIT - SMALLEST UNIT OF STORAGE CONTAINS A 0 OR 1
NIBBLE: 4 BITS - 15 DIFFERENT NUMBERS CAN BE REPRESENTED
BYTE: 8 BITS - CAN REPRESENT A NUMBER UP TO 255
KILOBYTE: 1,000 BYTES / BINARY VALUE KIBIBYTE: 1,024 BYTES
MEGABYTE: 1,000,000 BYTES / MEBIBYTE: 1,048,576 BYTES
GIGABYTE: 1,000,000,000 BYTES / GIBIBYTE: 1,073,741,824 BYTES
TERABYTE: 1,000,000,000,000 BYTES / TIBIBYTE: 1,099,511,627,776 BYTES
PETABYTE: 1,000,000,000,000,000 BYTES / PEBIBYTE: 1,125,899,906,842,624 BYTES
Types of Computer System
Desktop/server
Commonly used in schools, workplaces, homes etc. As cheap as they are powerful, desktop computers are able to run multiple bits of software and are also very customisable.
Servers are used by highly-trained IT staff and are meant to provide service to computer systems. Common features of a server include: Internet Filter (The filtering server), Sharing files from private to public (File server), Email access (Mail server) and Running a virtual machine (Hypervisor server).
Tablet/hybrid
A tablet is a portable, as well as compact computer system. Unlike computers and laptops, tablets do not come with physical keyboards because tablets are touchscreen. Most apps that are not already built-in are installed from the app store.
A hybrid device is a fusion between a computer and a tablet. It can be taken apart and put back together with ease. It might also come with what's called a stylus. A stylus can be described as a digital pen that acts as an input device.
Smartphone
Embedded Computers/Internet of Things
Embedded Computers are a type of computer system with a
single
purpose, and this purpose cannot be changed.
Internet of Things attempts to incorporate internet connectivity into things that never had it in the first place e.g. doorbells, locks mirrors etc. This makes them a lot more technologically advanced. While this could be considered very advantageous, it does not come without downsides. For instance, a lack of security - people can easily hack into them and steal personal data.
Mainframe
A type of computer system. It has a large storage capacity, is able to handle a lot of data traffic, has various separate components that can run for long periods of time, can hot swap components without causing disruption and in general, are able to run important tasks for the organisation.
Quantum
Computer Components
power supply unit- makes sure the computer system has the right amount of power
processor- CPU, carries out instructions
motherboard- where all components are connected. sockets included determine what CPUs it can connect to and memory capacity.
STORAGE
woweee
ports- allow additional devices to be connected to the computer system
Communication Hardware
Hub
A hub is a cheap, small scale device which is used to allow a group of nearby computers to connect to each other.
Hubs are usually slower than other communication options such as switches. They traditionally allow data to transmit at either 10 Mbps or 100 Mbps
Hubs are usually simple devices which broadcast any packet of data they receive to all other connected devices
Switch
A Switch can connect a LOT more devices than a hub can (32-128 devices)
A switch is generally the centre point of a network or network segment
Switches perform "packet switching" so that instead of broadcasting data to every connected device, data is channelled and sent only to the desired recipient
Data can flow through a switch at up yo 10Gbps. These items are essential when managing larger quantities of connected devices and maintaining performance
Cables
Copper
The most common modern cabling standards for data connection is known as CAT-5 or CAT-6.
Comprises of twisted pairs of cables. when the wires are twisted, they're less likely to conduct electricity from outside sources (e.g. lightning strikes). They also suffer less from interference
CAT-6 is the latest version of Copper cabling. It reduces interference more than CAT-5. CAT-6 can operate at speeds of up to 10Gb's per second. CAT-5 can operate at speeds of 10 Mb's, 100Mb's or 1000 Mb's
Copper wire has been used to transmit data over computer networks. It has also been the most used material for transmitting voices on public phone connection
Fibre Optic
Cabling that allows data to transmit at light speed
Data is transmitted as light beams which bounce of the sides of the cable and are interpreted by the recipient
The limiting factor is the speed at which the recipient (or any hardware between) can read the data that has been sent by the sender.
It is possible to send data at 10's of Terabits per second using fibre optic.
Wi-Fi
Wi-Fi standards of communication are continually improving. New protocols for how devices interconnect are being developed which offer ever-higher potential speeds.
Hardware
An INPUT device is something that sends data and signals into a computer system. E.g a mouse or a keyboard. :three_button_mouse:
OUTPUT device is something that takes data and presents it to a user. E.g screen, speaker :speaker:
A communication device is is a device which can send data and signals to other computer systems. :file_folder: :signal_strength:
Number Systems and Conversions
DENARY TO HEX
BINARY
Hardware Troubleshooting
Identifying Faults - IT technicians/help desk must log issue on log sheet, to include: Machine, User, Fault, Date, Symptom, Problem history and Back-up documentation
Troubleshooting tools
Event viewer - updated with info including: What problem is, date and time, seriousness, what caused it, event ID and who was logged into machine at time
Self test programs - POST (Power On Self Test) - checks memory, power supply, hardware CPU, BIOS and heat cooling. Beep Code - one beep means all okay, more than one beep = error detected. POST codes visual, two character read out of stage the POST is at. Ping tests the connectivity between the requesting and destination hosts, it uses the ICMP (Internet Control Message Protocol) to send an Echo request message to the destination host and listen for response called 'Echo respond message'. ipconfig identifies specific IP of host affected by problem. Useful if IP of host can change. NS look-up aids diagnosis of issues which DNS addresses. This utility looks up IP address associated with particular domains e.g. bbc.co.uk. If utility cannot determine information there is a DNS issue
Diagnostic software (third party), some are free and others require payment. They include memory testers.
When investigating faults look for simplest explanation - heck it's plugged in, does battery need charging then record the steps taken to identify the fault, state tools used, record actions taken e.g. replaced hard disk, re-installed software, replaced motherboard. Note product spec of any mew software/hardware, record time taken and costs involved
Connection Methods
The most common is a NETWORK INTERFACE CARD (NIC) which sends packets of data across a network. They can use Ethernet cables or be wireless. Another example is a switch or a modem.
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