11)Define CPU(central processor unit)
2)Define control unit
1)has number of different components which enables it to carry out its tasks of executing instructions.
2)Controls and co-ordinates activities of CU and directs data flow between CPU and devices
21)Define bus
2)Define control bus? what way data?
3)Define data bus
4)Define address bus
1)set of parallel wires connecting two or more components of computer. Typically consist of 8,16,32 or 64 lines.
2) sends control signals .sends data both ways
3)sends data that’s at the address to the processor or back to the memory
4)sends addresses from the processor to the memory
31)What control lines include?
bus request: device request use of data bus
bus grant: CPU gains access to data bus
memory write: data from addressed location placed on data bus
memory read: data from location placed data bus
interrupt request: indicate device is requesting
clock: syncs operations
41)What path does data bus take ?
2)Address bus memory is divided up into what ?
3)what does address bus transmit?
1)bi-directional path for moving date and instructions between components
2) units called words.16,32 or 64 bits. Each word has own address and word size.
3)transmits mem address of word used as operand in program instruction lads to results sorted in mem location and instruction transmit via data bus
51)What's the ALU(arithmetic-logic-unit)?
1)Performs arithmetic and logical operations on data.
on fixed or floating number such as: ADD,SUBRTACT,MULITPLY,DIVIDE
Performs Boolean operations comparing two values such as :AND,OR,NOT,XOR
61)Define Current instruction register(CIR)?
1)Holds current instruction being executed divided into operand(data or memory location used
to execute that instruction) and opcode (instruction that is executed by the CPU)
71)Define Program counter(PC)
1)Holds address of next instruction to be executed
81)Define single accumulator
2)Define Memory address register (MAR)?
3)Define memory data register (MDR)?
1)Stores a single value.
2)Holds address of memory location from which data (or instruction)to be fetched or to which data to be written.
3)Used to temporally store data read from or written to memory. Also known as buffer register.
9Describe the Fetch-Decode-Execute Cycle.
Fetch:
1. Load the address in the PC to the MAR.
2. Increment PC 3. Load instruction given by MAR into MDR 4. Load instruction in MDR into CIR
Decode:
5. Decode instruction in CIR
Execute:
6. Execute instruction
101)Define Clock speed
2) Does clock speed affect CPU performance?
1)Number of cores, or duplicate processors, linked together on single chip.-frequency which clock generator of a processor generate pulses
2) Bigger clock speed = more cycles per second, so more instructions executed per second.
111) How does cache affect CPU performance.
Cache is an area of very fast memory that links the CPU with main memory. It temporarily stores data and instructions the CPU is likely to need soon or more than once
More cache = more instructions can be stored. Faster cache = instructions can be read quicker
121)What does pipelining allow?
2)Define instruction pipeline?
3)Define Arithmetic pipeline?
1)next instruction to be fetched while processor performing operations in ALU. buffer close to processor to store instruction until performed.
2) holds stages move through processor
3)holds stages of arithmetic and broken down and overlapped as performed.
131) Width of the address bus determine what?
2)What does the largest operand held in word
relate to?
3)In assembly language how is operation code expressed ?
1)Maximum memory capacity of system
2)The size of the data bus
3) mnemonic such as ADD,SUB,LDA
141)What is Von Neuman architecture?
1)single control unit sequentially works through instructions.
Data and instructions are stored in memory together and sent with data bus
Address bus transfers address of data and instructions. Same word length regardless.
151)Name features of Von Neumann architecture
1.Data & instructions are stored in memory together
2.instructions fetched from memory one at a time and in order - serially.
3.processor decodes & executes an instruction, before cycling around to fetch the next instruction 4.programs can be optimized in size
161)What's Harvard architecture?
1.Used in digital processing ,embedded ,mobile coms, audio ,speech , image processing systems.
2.Instructions held in separate memories from Data
3.Parrel data and instruction buses may be used
4.Programs tend to be large
171)What's embedded system?
2)What's contemporary processor architecture?
1)Faster than Neumann because data and instructions fetched in Parallel instead of competing for same bus made for special purpose e.g. traffic lights
2)Modern chips e.g. Main memory hold data and instructions ,cache is divided into instructions and cache and data cache
18What are the features of a RISC CPU?
Simpler instructions.
Further away from high level languages.
More efficient at simpler tasks.
Longer code requiring more RAM.
Lower clock speed
Perform simpler tasks quicker.
Use less power, Smaller, cheaper
19What are the features of a CISC CPU?
More complex instructions.
Closer to high level languages
Smaller code requiring less RAM
higher clock speed.
Intensive tasks will be better.
Use more power, Larger , More expensive.
201)What's a co-processor system?
2)What can co-processor be used to perform?
3)What can't co-processors do ?
1) Extra processor used to supplement function of primary processor (CPU)
2)Floating point arithmetic, graphics processing, digital signal processing, other functions
but has limited range of functions
3)not fetch its own instructions or do input/output operations
211)What is parallel system?
2)What are advantages of parallel systems?s?
1)Parallel processors use multiple CPUs to complete more tasks in a certain amount of time. works by many processors
working together to perform a single job, which is split up into tasks
.2)Increased speed ,Complex tasks done efficiently, Many instructions at once,
Different processors can handle different tasks/parts of the same job
22
What are disadvantages of parallel systems
Not suitable for some programs
Programs need to be written specially for it.
Operating system is more complex.
More complex OS.
231)What do Multiple cores allow?
2)What do Multiple cores require to see improvement?
3)How maximise multiple cores?
1)To distribute workload which leads to significant higher performance.
2)Based on software being used and might not ne able advantage on multiple cores.
3)both operating system and application software
24What are GPUs and their uses?
A graphics processing unit is specifically designed to perform calculations associated with graphics. Other than rendering graphics, they can be used for:
Modelling physical systems. Audio processing. Breaking passwords. Machine learning.
25GPU As a Co-processor
used to accelerate scientific, engineering, Analytics ,other applications ,offloads compute-intensive parts of applications to GPU Remainder of code run on CPU
Significantly improve performance
261)Types of barcodes and what they are
2)What's a laser scanner?
3)Radio frequency id (RFID)?
1)Linear barcode- Like on packet of crisps
2D barcode -Like QR code
2) uses laser as light source
3)uses tags both inputs and outputs and stores data
271)Features of Active RFID?
2)Features of passive RFID?
1)large as need battery ,transmits signal for reader to pick up, track things far away
2)Cheaper as no battery, rely on radio waves to provide electromagnetic power using antenna, once has energy activates tags and sends data
281) Define outputs
2)Name 5 Outputs
1)Take data by computer and turn it into form someone can understand
2)Screens,printers,speaker,projector,accumulator
291)Why are LCD monitors and LED better than older tech?
Reach max brightness almost immediately,Sharper image with more realistic color,brighter light =better definition, LEDs are very small, screens can be much thinner,Last longer as more durable
,consume less power and produce less heat=cheap to run
301)Define OLED
2)Pros of OLED
3)Cons of OLED
1)organic screen,plastic rather than grass
2)Flexible(able print on clothing)Thinner,Brighter no need for back lighting=less power ,200 times faster refresh rate than LCDS .larger viewing angle.
3)Wear out 4x as fast as LCD, Sensitive to water
311)features of laser printer
• High quality, high speed printing
• Uses powdered ink called toner
• Affordable and often used as home, business and professional printer
•Colours more expensive than black and white Four toner cartridges (Cyan, Magenta, Yellow and Black Aka CMYK
• Paper must go through a the same process for each
colour (up to x4)
• Quality can be limited compared to inkjet printers.
321)Ink jet features
1)Works by spraying minute dots of ink onto paper to
create an image
• Cheaper than laser
• Better quality image printing
• Replace cartridges more often
331)Features of Dot matrix printers (impact printers)
Printer head has a matrix of pins which strike the
surface of paper through an inked ribbon
• Can operate in damp or dirty environments
• Noisy, Slow and low print quality
34Features of 3D printers
Can create a lot of different things from aeroplane parts to working guns
• Creates a physical object from a three-dimensional digital model
• Lays down many thin layers of a material in succession.
35Whats a multimedia projector?
• Displays like a monitor but projected from the device to a large surface for multiple people to see
• Used in schools, revolutionary
• Considered an essential teaching tool
36Features of computer speakers
• Can be inbuilt
• Used to output voice, music, sound from video, etc
• External speakers disable inbuilt speakers when used
37Define Actuator
Used in conjunction with sensors to control a
mechanism e.g.
• Opening a window or valve
381)Define primary storage
2)Define secondary storage
1)component of the computer that holds data , programs and instructions that are currently in use.
2)Retains data when computer is turned off -stored externally Secondary storage is not directly accessible to the processor • Secondary storage has slower access speeds
391)How do hard disks work?
• Uses rigid rotating platters coated with magnetic
material • Ferrous (iron) particles on the disk are polarized to become either a north or south state. This represents 0 and 1. • The disk is divided into tracks in concentric circles and each track is divided into sectors.
• The disk spins very quickly (up to 10000 RPM)
• A drive head moves across the disk to access different
tracks and sectors.
401)how is data read/written on hard disk?
2)what happen when disk is not in use?
3)Features of a hard disk?
1)Data is read or written to the disk as it passes under
the drive head.
2)When the disk is not in use, the drive head is parked to one side of the disk to prevent damage from movement. A hard disk can have several platters, each with it'sown drive head.
3) Hard disks are less portable, Hard disks have a capacity
411)What formats do optical disks come in?
2)How are optical disks made
1)Read-only, recordable and rewritable
2) high powered laser to "burn" to make them
less reflective .Laser at a lower power is used to read the disk by shining light onto the surface and
a sensor is used to measure the amount of light reflected back •
42What's the difference between CD-ROM and Blue ray?
CD-ROM hold around 700mb, Blue ray
can hold up to 50gb.• However the same size physically.
• Different data can be held due to the shorter wavelength of the laser used ,which means tighter pits and lands
431)How do Recordable disks work?
2)How do Rewritable disks work?
3)How do DVD-RW disks work?
1)Use a reflective layer with transparent dye coating that becomes less reflective when a laser "burns" a spot in the track.
2)• use a laser and a magnet in order to heat a spot on the disk and then set its state to become 1 or 0 using a magnet before it cools again.
3)• DVD-RW uses a phase change alloy that can change between amorphous and crystalline states by changing
the power of the laser
441)Pros and cons of optical storage
Pros: Optical storage is cheap to produce, portable
Cons: Easily corrupted or damaged by excessive sunlight and scratches
451)How is data stored on SSD(Solid state drive)?
2)How do SSD work?
3)How do each cells work in SSD?
1)Data stored in pages (typically 4KiB
each) .Grouped into blocks (say 512KiB)
2) Full of millions of NAND flash memory cells. a controller that manages pages and blocks of memory.
3) Each cell works by delivering a current along the bit and word lines to activate flow of electrons from the source towards drain.
Current word line is strong enough to force a few electrons across an insulated oxide layer into a floating gate
461)What happen when current is switched of for SSD?
2)How is the NAND cells determined ?
3)How write data on SSD which has old data ?
1) electrons are trapped
2) by measuring the charge in the floating
gate No charge = 1 some charge = 0
3)• Old data must be erased before data can be written to the same location, although data can be written in pages, the technology requires the whole block to be erased. pages, the technology require whole block to be erased.
• Writing to a specific block of NAND cells cannot be done directly, separate block is created to mirror data and transferred to the solid state memory and then the data is then written to a new block.
471)What happens when original data from SSD is removed?
2)Positives of SSD
3)Cons of SSD?
1)contents of the original block are marked as "invalid" or "stale" and are erased when the user wants to write
new data to the drive.
2)Faster access speeds ,fragmentation not cause issues .less power ,emit less heat, ,light and highly portable
3)capacity low, more expensive
481)Features of RAM
2)Features of ROM
1)• Random Access Memory, Used to store programs and data that are currently being used.
Volatile- contents are lost when it's switched off.
2)• Read-Only Memory Used to hold information that needs to be permanently in memory. E.g. bootstrap loader (loads operating system) • Embedded systems might use ROM for the software it uses e.g. washing
machine
491)What is virtual memory?
2)When is virtual memory?
1) This is where the Hard Disk is used as an extension of the RAM • This will store software and data that is not currently being used and will switched back to the RAM when it regains focus.
2)If you do not have enough RAM you can extend it with virtual memory.