Chapter 3. Hardware Flashcards
What are the two types of memory and their example
- Primary
-RAM
-ROM
2.Secondary
-HDD
-SSD
-Removable items
Why is RAM called random access memory
Because any memory location can be accessed regardless of the last memory location to be used
What are the two types of RAM
DRAM and SRAM
Explain how DRAM works internally
DRAM has capacitors and transistors. The capacitors hold bits of information (either a 0 or a 1) and the transistors act like switches; they allow the chip control circuitry to read the capacitor or change the capacitors value.
Differentiate between DRAM and SRAM
<b>DRAM</b>
-uses capacitors and transistors
-needs to be constantly refreshed
-less expensive to manufacture
-has a higher memory capacity
<b>SRAM</b>
-uses flip flops to hold data
-no need to be constantly refreshed
-faster data access time
-at high frequencies power consumption can be more than DRAM
Differentiate between RAM and ROM
<b>RAM</b>
-temporary memory device
-volatile
-can be read and written to
-used to store data, files, programs, part of OS currently in use
-can be increased in size to improve operational speed of a computer
<b>ROM</b>
-permanent memory device
-non-volatile
-data stored cannot be altered
-sometimes used to store BIOS and data other data needed at startup
How does PROM work
A type of ROM that can be altered once. It is made up of a matrix of fuses. A prom writer uses an electric current to alter specific cells by burning fuses in the matrix
What are the pros of an embeded system
-small in size and therefore easy to fit in devices
-relatively low cost to make
-usually dedicated to one task, making for simple interfaces and often no requirement of an operating system
-consume very little power
-operate in real time(fast reaction to changing input)
-with mass production comes reliability
What are the cons of embedded systems
-difficult to upgrade
-troubleshooting faults in the device becomes specialist work
-although the interface can appear to be simple, in reality the system will take more steps to do a simple task
-ay device that can be accessed over the internet is also open to hackers, viruses and so on
-wasteful since its difficult to upgrade
What are the three categories of secondary devices and give examples of each
1.magnetic
-HDD
-magnetic tape
-floppy disc
2.solid state
-SSD
-SD cards
-flash drives
3.optical
-CDs
-DVDs
-Blu-ray discs
Define latency
the delay before a transfer of data begins following an instruction for its transfer
Define fragmentation
it is when a collection of data in memory is broken up into many pieces that are not close together
What do you understand by flash memory
solid state storage devices that use NAND technology rather than EEPROM(NOR technology)
Benefits of SSDs
-more reliable as there are no moving parts
-considerably lighter
-lower power consumption
-run much cooler than HDDs
-thinner and faster
Describe birefringence
When dual layering cause light to refract into two separate beams causing reading errors
Describe steps taken by a laser printer
-data from the computer is sent to the computer
-printer driver makes sure that the data is in the right format
-printer driver checks if the printer is ready to start printing
-data is stored in the printer buffer
-printing drum is given a positive charge. the drum rotates and a laser removes the positive charge on certain areas
-drum is coated with positively charged toner(powdered ink)
-negatively charged sheet of paper is put on the roller
-toner sticks to paper
-after one rotation the charge on the paper is removed
-the paper goes through a fuser where the ink is melted and becomes permanent on the paper
-a discharge lamp removes all the charges on the drum
What are the components of an inkjet printer
-a print head consisting of nozzles
-an ink cartridge or cartridges
-a stepper motor and a belt which moves the print head assembly from side to side
-a paper feed which automatically feeds the printer with the pages
Describe the two technologies in inkjet printers
- Thermal bubble
-tiny resistors create localized heat which makes the ink vaporize. this cause the ink to form a tiny bubble, as the bubble expands some pf the ink is ejected from the head. when the bubble collapses it creates a vacuum and more ink is drawn to the head - Piezoelectric
- a crystal is given a tiny electric charge which makes it vibrate . this vibration forces the ink to be injected onto the paper and at the same time the ink is drawn to the ink head
Describe steps in an inkjet printer
-a sheet of paper is fed into the main body of the printer
-the print head moves from side to side across the paper spraying ink on the page
-at the end of each full pass of the print head, the paper is advanced very slightly to allow the next line to be printed
What is the difference between CNC machining and 3D printing
CNC uses subtractive manufacturing whilst 3D printing uses additive manufacturing
What is CNC
Computer Numerical Control (CNC) machining is a manufacturing process in which pre-programmed computer software dictates the movement of factory tools and machinery. The process can be used to control a range of complex machinery, from grinders and lathes to mills and CNC routers
What is the difference between Direct 3D printing and Binder 3D printing
Direct 3D uses inkjet technology whilst binder 3D uses two passes for each of the layers; the first pass sprays dry powder and then the second a binder(a type of glue)
What are the main components of a computer?
- CPU, RAM, Storage (HDD/SSD), Motherboard, Power Supply.
- Input and output devices such as keyboard, mouse, and monitor.
What is the function of the CPU?
- Executes instructions from programs.
- Performs arithmetic, logic, control, and input/output operations.
