External hardware devices: Practice Questions

• a.An electron beam is scanned across the surface to detect the physical depth of the printed bars
• b.The reader uses magnetic induction to sense the metallic ink used in the black bars
• c.The reader uses a camera to take a high-resolution photo and uses OCR to identify the digits
• d.A laser light is reflected off the barcode, and a sensor measures the intensity of the light reflected back

• a.It uses NAND flash memory and a controller to manage data in pages and blocks
• b.It uses an array of capacitors that must be constantly refreshed to retain data
• c.It uses a read/write head to magnetise small areas on a spinning platter
• d.It uses a laser to burn small pits into a reflective surface to represent bits

• a.Data can only be written to an SSD when it is in a 'low power' state to prevent heat damage
• b.An SSD can write data to a page, but it must erase an entire block before a page within it can be overwritten
• c.Pages can be overwritten individually, but blocks must be erased before being read
• d.An SSD must be formatted every time a single file is deleted to maintain speed

• a.I/O Controller
• b.Graphics Processing Unit (GPU)
• c.Digital-to-Analogue Converter (DAC)
• d.Analogue-to-Digital Converter (ADC)

• a.It uses a larger cache memory which stores the entire contents of the drive
• b.It has no moving parts and does not need to wait for a disk to rotate to the correct sector
• c.It uses a faster serial bus than the magnetic platters used in an HDD
• d.It uses magnetic induction which is inherently faster than electrical charging

Write your answer out first, then check it against the worked solution.

Write your answer out first, then check it against the worked solution.

Write your answer out first, then check it against the worked solution.

Write your answer out first, then check it against the worked solution.

Write your answer out first, then check it against the worked solution.