Hardware - wk3 & 4 Flashcards
Define computer?
A device that accepts input, processes it, produces output and may have a storage facility.
What is the input to output cycle?
User – input (Data) – Process (and sometimes stores) – output (info) – user.
What are the forms of input?
- Data (characters, images and sound)
- Instructions from programs
- Commands (direct computer actions)
- User response (Questions such as save document?)
What devices are used to create input?
- Keyboards (QWERTY, Devorak, ergonomic, virtual laser)
- Trackball (CAD, military, aircraft, gaming)
- Light pen (CRT monitors)
- Digital pens
- Bar code readers
- Touch screen (resistive and capacitative)
- Eyes
Where is processing done in the computer?
The system unit. Here the motherboard communicates with other components.
What is a bit?
A binary digit. 8 bits = 1 byte = 1 character.
What is the CPU?
The central processing unit. This is a chip on which transistors and other wires form complex circuitry. It has a system clock which controls electrical pulses at a set rate, measured in Hertz.
What does the control unit and ALU do?
The control unit fetches and decodes information. Between this and the ALU it registers. Then the ALU (arithmetic/logic unit) executes and stores the information.
How are cycle times measured?
They are measured in mips (millions of instructions per second)
What are the different types of cores/processors? (like cpu)
Duel and Quad core - only uses one chip but has more than 1 core.
Multi processor - more than 1 chip
What is word size and bus width?
Word size - (word length) the number of bits the CPU can process at once. Modern computers have 64 bits.
Bus width - transfers the data, must be 64 bits or more, the more the better.
What are the types of memory?
- Registers: tiny and fast in the CPU
- Cache: 1-3 (on/near the CPU)
- RAM: random access memory in MB or GB
In what order does memory recall work?
Registers, cache, RAM, hardware.
What is volatile and non volatile memory?
Volatile: no power=no memory (e.g. registers, cache, RAM)
Non volatile: works without power, such as the ROM power button.
What are the factors that influence computer performance?
Machine cycle times (mips) System clock (Hz) CPu word size (bits) Bus width (bits) Amount and type of memory.
What are the main types of monitors?
LCD (liquid crystal display) and OLED (organic light emitting diode)
What are the two forms of output?
Soft copy and hard copy.
What are the two ways graphics cards are attached to a computer?
They can be integrated or plugged into the motherboard. Some of them have their own microprocessor such as a GPU
Define pixel?
Pixels are the smallest screen display element. The number of these is the resolution. Aspect ratio = the height to width ratio.
What are the types of printers and how do they work?
Inkjet: printers spray tiny droplets of ink
through holes to form images on paper.
Laser: use an electrostatic process to force ink onto page. To keep the image there it is then “burnt” onto the page.
Plotter: large projects and use pen or inkjet.
How does secondary storage work?
The main device is a disk inside a hard drive, the + and - on disk represent 0 and 1. These include disks and USB’s etc. The advantage is that it is more permanent.
