Flashcards
4.7
Cards in this deck (26)
- 1ProcessorFetches and executes instructions from the main memory
- 2Main memoryStores data and instructions for the processor. It is addressable meaning it is split into sections each given a memory address. The contents at each address can be read or written by the processor
- 3Address busCarries address signals from the processor to the main memory and controllers
- 4Data busCarries data between the processor, main memory and IO controllers
- 5Control busCarries control signals (either clock signals or commands for read and write mode) between the processor, main memory and IO controllers.
- 6IO controllersInterface directly with input and output devices
- 7BussesA set of wires and connections that enable communication between the processor, main memory and IO controllers
- 8Stored program conceptMachine code instructions are stored in the main memory and are fetched and executed serially by the CPU that performs arithmetic and logical operations
- 9Harvard Architecture-Used in most embedded systems such as digital signal processors.
-Stores instructions and data in separate memory, allowing an instruction to be executed in 1 clock cycle as data and instructions can be fetched at the same time and avoids bottlenecks at data bus.
-More complex control unit meaning it is more expensive - 10Von NeumanUsed in general purpose machines
-Data and instructions are stored in the same memory meaning they have to be fetched at different times. 2 Clock cycles. Bottleneck busses.
-more simple control unit meaning it is cheaper - 11OpcodeAn instruction from the CPU's instruction set
- 12OperandA value that applies to the opcode. Could either be data or an address location
- 13Immediate addressinguses the operands value as the data
- 14Direct addressinguses the operands value as the memory address containing the data
- 15InteruptsUsed to pause a current program and run a high priority routine
- 16IRSInterrupt service routine. A hardware interrupt is sent to the CPU. Memory registers are backed up during an IRS and restored afterwards.
- 17Magnetic Hard DiskA platter of spinning disks with magnetic particles who's polarity determine whether the data there is a 1 or 0.
-large, cheap, slow, noisy, fragile, power hungry, 1-3TB - 18Optical DiskA spinning disk is coated in a reflective layer with holes punched to disturb the reflections. A laser is shone at the surface and whether or not a reflection is detected determines a 1 or 0.
-Cheap, slow, easily damaged, - 19SSDChips containing NAND flash memory and a controller that manages reading and writing. Data is stored by floating gate transistors that trap and store charge. Data cannot be overwritten easily. An entire block must be removed for each change, reducing the lifespan of the flash memory. The controller minimises this by spreading out the data across all available flash memory.
-Faster, reliable, power efficient, Expensive. - 20Barcode readerA laser scans across a series of black and white lines. The intensity of light reflected, indicates a black or white strip. The length of the strip then represent a number which can be linked to a product.
- 21Digital CameraLight is focused through a lens onto a CMOS sensor which has an array of pixels with red blue and green filters. Each pixel produces a voltage proportional to amount of light hitting it. RGB value of each pixel can then be used to form a colour.
- 22Laser printerBitmap of image is built in memory from page description
Charge applied to the drum
Laser beam directed at the drum
Mirror is used to direct laser beam
Where laser strikes, the drum charge is neutralised
Negative charge applied to the toner
Toner sticks to drum based on charge
Paper passed over drum and toner transfers to it
Heater fuses toner to paper
For coloured printing, four different colour toners are required. - 23RFIDA small microcontroller with a larger antenna is embedded in a tag. Radio frequency induces enough power in the antenna to produce a current in the chip. Chip reads the data in the radio frequency and transmits a response
- 24Why is a laser printer with wireless network adapter a good choice?Low cost per page
Toner does not expire as quickly as ink
Prints many pages per minute
Printer can be remotely managed
Printer can communicate with devices wirelessly, no need for cabled connection - 25Role of the control unitExecutes some instructions
Decodes instructions
Handles interrupts
Sends control signals - 26Explain the need of secondary storageUsed to store programs and data indefinitely as it is non volatile meaning it will not lose its data when power is turned off. Also cheaper than primary and can store larger amounts of data. Without it, all the programs on a computer would be lost when the computer is turned off.
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- Flashcards on 4.7, created by James John on 08/04/2022.
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