Input and Output Devices, Memory, and Networking Practice Flashcards

Comprehensive practice flashcards covering input/output devices, sensors, printing technologies, storage media, embedded systems, and network hardware based on the lecture notes.

What components are used in a two-dimensional scanner to focus the image onto the charge-coupled device (CCD)?

A bright light, a scan head, a series of mirrors, and a lens.

What is the purpose of Optical Character Recognition (OCR) software?

It converts scanned documents into a text file format.

In what coordinate system do 3D scanners take images?

They take images at several points: $x$, $y$, and $z$.

In airport applications, which format is used to store text from passport pages after OCR processing?

$ASCII$ format.

How do barcode readers distinguish between different numbers ($0-9$)?

Each number is represented by a unique series of dark and light parallel lines of varying thicknesses.

What is the function of guard bars in a barcode?

They separate the left and right-hand sides of the barcode and allow it to be scanned in any direction.

How much data can a Quick Response (QR) code hold?

Up to $7000$ digits.

What component in a digital camera determines the size of the captured image file?

The number of pixels in the light-sensitive cell.

How does a capacitive touchscreen determined the coordinates of a touch?

When the top layer of glass is touched, the electric current changes, and an on-board microprocessor determines the coordinates.

What is the main difference between a resistive touchscreen and a capacitive touchscreen?

A resistive touchscreen requires physical pressure to complete a circuit between a polyester and glass layer, while capacitive uses electric fields between layers of glass.

What device is required to convert physical values from sensors into digital data for a computer?

An analogue-to-digital converter ($ADC$).

Which sensor would be used to measure the water content in a specific installation site?

A moisture sensor.

How does an active infra-red sensor detect a change in the environment?

It uses an invisible infrared beam; when the beam is broken or disturbed, it changes the amount of light reaching the detector.

What is the role of an actuator?

It converts electrical signals into mechanical processes.

What type of ink is used in laser printers?

Dry powder ink known as toner.

Why is a fuser used in the laser printing process?

It is a set of heated rollers that melts the toner so it becomes permanent on the paper.

What are the three primary colors used in LCD and DLP projectors?

Red, green, and blue.

How does a Digital Light Projector (DLP) create light or dark pixels?

It uses millions of micromirrors that tilt toward the light source to turn a pixel on or away from it to turn it off.

What are three advantages of LED-backlit monitors over CCFL-backlit monitors?

They reach maximum brightness immediately, sharpen the image (higher resolution), and consume very little power.

What is the primary difference between RAM and ROM regarding data volatility?

RAM is volatile (temporary memory lost when power is off), whereas ROM is non-volatile (permanent memory).

What happens when the RAM in a computer becomes full?

The processor must access the hard drive continually to overwrite old data on RAM with new data, causing the system to run slow.

What is the purpose of virtual memory?

It uses $HDD$ or $SSD$ storage to act as memory when RAM runs out, preventing system crashes.

How do Solid-State Drives (SSDs) store data?

By controlling the movement of electrons within NAND chips as $1s$ and $0s$.

Why do Blu-ray disks have a higher storage capacity than standard DVDs?

They use a blue laser with a shorter wavelength, allowing for more data storage.

What is the difference between a public cloud and a private cloud?

A public cloud is managed by a different company than the client, while a private cloud is a dedicated environment behind a company firewall where both entities are integrated.

What is a System on Chip (SoC)?

A microprocessor that includes $I/O$ ports, storage, and memory on a single chip.

What information is contained in the first and second halves of a $48$-bit MAC address?

The first six hexadecimal digits are the manufacturer's code, and the second half is the device serial number.

What are the two types of MAC addresses?

Universally Administered MAC Address ($UAA$) and Locally Administered MAC Address ($LAA$).

Compare the address space of IPv4 and IPv6.

IPv4 provides approximately $4.3 \times 10^{9}$ addresses ($32$-bit), while IPv6 provides approximately $340$ undecillion addresses ($128$-bit).

What networking device determines the most efficient path for data packets and can act as a DHCP server?

A router.