Mobile Device Basics

Question 1

What type of memory do mobile devices use?

Answer 1

Mobile devices use CHIP memory to store all their data.

There are two main types:

RAM

FLASH

Question 2

Summarise what RAM is in mobile devices

Answer 2

RAM is like the phone’s short term memory. It temporarily stores data that the phone is actively using (such as open apps).
When you open an app for example the phone loads that app from the main storage into the RAM. RAM allows the pphone to switch between apps quickly without reloading each one from scratch.

It is VOLATILE memory meaning that when you turn off the mobile device the RAM is cleared.

Question 3

Summarise Flash storage in terms of mobile devices

Answer 3

Long term (persistant) storage which remains even when device is powered off (non volatile).
Solid state (no moving parts)
It is faster, uses less space than traditional HDD and power efficent

Flash storage is entirely electronic (no mechanical moving parts like HDD). Data is still stored digitally as 1s & 0s but stored in memory cells built from transistor gates.

Most commonly used type in mobile devices is NAND flash memory (and NOR)
NAND is a specific form of flash memory that makes use of NAND gates (a type of logic gate) to store and access data.

The basic structure:
Cells - store individual bits (0 or 1)
Pages - the smallest unit of storage (usually 2kb to 16kb) containing multiple cells
Blocks - a group of pages (typically 64 to 256 pages). Blocks are the smallest unit that can be erased.

Data gets written and read at the page level but erased in blocks.

Wear levelling is used to distribute writing evenly across all cells (to extend life span)

Memory chip stacking is used to increase storage in small spaces

Question 4

List the Different Types of Mobile Device Frequencies

Answer 4

• 2G or GSM frequencies. Mostly only used for SMS now.
• 3G or UMTS frequencies.Provided better date speeds for mobile internet
• 4G or LTE frequencies. High speeed internet suitable for streaming & more data intensive applications. VoLTE for voice over LTE.
• 5G . Ultra fast speeds with low latency.
• WiFi frequencies (2.4 GHz old, 5GHz & 6GHz (fastest WiFi 6E)
• Bluetooth Frequencies. Operates in the 2.4 Gz Industrial, Scientific & Mechanical ISM band)
• GPS Frequencies

Question 5

CDMA and GSM - outdated

Answer 5

CDMA (Code Division Multiple Access) and GSM (Global System for Mobiles) are shorthand for two older radio systems (both also known as 2G and 3G) used in cell phones