Digital Devices and Computer Basics

Digital Devices Overview

• Digital devices include processors, memory (RAM & ROM), and storage.
• Expansion ports connect peripherals.

What is a Computer?

• A computer is a multipurpose device that follows stored instructions.
• It accepts input, processes data (via CPU), generates output, and stores data temporarily and long-term.
• The IPOS model illustrates the flow: Input -> Process -> Output -> Store.
• All computers, regardless of size, operate using the IPOS model.

Digital Device Options

• Digital devices are categorized as enterprise computers, personal computers, and niche devices.

Enterprise Computers

• Supercomputers are the fastest at the time of construction, used for complex tasks such as code-breaking and weather modeling, and their speed is measured in petaflops (PFLOPS), with 1 PFLOP equaling 1 quadrillion calculations per second.
• Mainframes are large, expensive computers for massive data processing, supporting hundreds or thousands of simultaneous users in sectors like banking and healthcare.
• Servers are designed to store and serve data to networked computers, powering websites, email, and cloud computing, and range from small rack-mounted devices to large-scale data centers.

Personal Computers

• Desktops are stationary with separate keyboards and monitors, ideal for offices and homes, and run on Windows, macOS, or Linux.
• Laptops are portable, battery-powered computers, including Chromebooks, that rely on cloud storage.
• Tablets & Smartphones are touchscreen devices running iOS or Android and come in compact sizes with GPS, apps, and communication features.

Niche Devices

• Game Consoles (Xbox, PlayStation, Nintendo).
• Smartwatches & Fitness Trackers (wearable tech).
• Smart Speakers (Alexa, Google Nest).
• Raspberry Pi (mini computers for programming & robotics).
• Smart Appliances (IoT-enabled fridges, washers, etc.).

Factors Affecting the Price of Digital Devices

• Microprocessors are the most expensive component; newer, faster models add hundreds of dollars in cost (GHZ).
• More memory typically means more cost (e.g., doubling smartphone memory can increase the price from $199 to $299).
• Larger screens increase cost (e.g., a 27-inch iMac is $300 more than a 21-inch version).
• Thinner, lighter laptops are priced higher due to consumer demand.

Microprocessors

• A microprocessor is an integrated circuit that processes instructions.
• It is one of the most important and most expensive components in digital devices.
• Two main types of microprocessors: x86 and ARM.
• x86 (Intel, AMD) processors are common in Windows-based PCs and laptops.
• Examples of x86 processors include Intel Core i3, i5, i7, and AMD Ryzen.
• ARM (Apple, Qualcomm) processors are energy-efficient and used in mobile devices.
• Examples of ARM processors include Apple M1, M2, and Qualcomm Snapdragon.
• Windows 11 displays processor specs via the "About your PC" option in Settings.
• On a Mac, processor specifications, along with memory capacity, are in "About This Mac".

How Processors Work

• Microprocessors execute specific tasks using instruction sets
• They convert programs to binary (0s & 1s) for execution.
• Programs/games for ARM-based smartphones won't run on Intel laptops, and vice-versa.
• ARM processors use a Reduced Instruction Set Computing (RISC) approach with ~35 instructions.
• x86 processors use a Complex Instruction Set Computing (CISC) approach with 100+ instructions.
• Integrated Circuits (ICs) are miniaturized chips containing multiple logic circuits on a single semiconductor chip (usually silicon).

Microprocessor Instruction Execution

• Fetch: Retrieving an instruction.
• Interpret: Decoding instruction.
• Execute: Performing the instruction.
• Next Instruction : Proceeding to the next instruction.
• ARM (RISC) fetches a fixed-size instruction in 32-bit or 16-bit (Thumb mode) and performs simple decoding.
• x86 (CISC) fetches a variable-size instruction (1-15 bytes) and involves more complex decoding.
• ARM (RISC) executes most instructions in one clock cycle.
• x86 (CISC) may require multiple cycles to execute some instructions.
• x86 - CISC assembly uses complex, variable-length instructions to perform multiple operations in a single command.
• RISC uses simple, fixed-length instructions that complete in one clock cycle.

Memory (RAM)

• RAM, also called Main Memory, is a temporary memory for quick CPU data access.
• It is volatile, losing data when power is off.
• DRAM (Dynamic RAM) uses capacitors and requires refreshing.

Memory (ROM)

• ROM is a non-volatile memory chip on the system board that retains data when a device is powered off.
• Devices have ROM to store the boot loader which is essential for starting the device, executing hardware self-tests, and loading the operating system into RAM.
• The boot loader isn't stored in RAM because RAM is volatile and loses data when powered off.
• ROM ensures device startup without external input.

Cache Memory

• Cache is small, high-speed memory inside the CPU, stores frequently used instructions
• Cache reduces the need to access slower RAM, improves CPU efficiency and system speed.
• It is made of SRAM (Static RAM), which uses flip-flops for storage.

Storage

• Storage is designed to hold data permanently, unlike RAM.
• It is non-volatile storage and retains data even when powered off.
• Storage is used for saving documents, photos, playlists, software, and the operating system.
• Local Storage is directly attached to the device.
• Remote Storage refers to Cloud-based solutions.

Local Storage

• Hard Drives (HDDs) offer high capacity but are slower than SSDs.
• Solid State Drives (SSDs) are faster and more durable but more expensive.
• Flash Drives & Memory Cards are portable and convenient with limited capacity.
• CDs & DVDs are good for archiving but are outdated for everyday use.

Evaluating Storage Options

• Key factors include durability, dependability, speed, capacity, and cost per gigabyte (GB).

Cloud Storage

• It is a technology for transporting, synchronizing, and managing data.
• Data is stored on high-performance servers in a provider's data center.
• Cloud storage is accessible from multiple devices.

Drawbacks of Cloud Storage

• Security & Privacy Risks: Data stored in multiple locations is more vulnerable to hacking or surveillance.
• Service Outages: If a cloud provider goes down, files become temporarily inaccessible.
• Discontinuation of Service: Some providers have shut down services with little notice.
• Never rely on cloud storage as the only backup.
• Cloud storage is convenient and useful but should be used wisely; always keep multiple backups.

Backup

• A backup is a copy of important files made in case originals are lost or damaged.
• Ideal to back up everything, but not practical
• Focus on essential files like documents, photos, software, and settings.
• Backup pairings include backing up hard disk to cloud or external drive, handheld to hard disk or cloud, and cloud to hard disk.

Backup Options for Android Users

• Android devices typically include built-in backup tools that include: Cloud Backup (Google One): Stores data on Google servers, SD Card Backups to an SD card, and Local Backups to PC via manufacturer software.
• To enable Google Backup, open Settings, go to Google > Backup (or System > Backup), and turn on Back up to Google One.

Backup Options for iOS Users

• iPhone & iPad users back up using iCloud Backup (automatic to Apple's cloud) or Finder(Mac) or iTunes (Windows) for local backups.
• To enable: Open Settings, tap Apple ID, select iCloud > iCloud Backup and toggle iCloud Backup to On.

Expansion Ports

• Connect devices to a computer.

Types of Expansion Ports

• General-Purpose Ports
• Video Ports
• Audio Ports
• Network Ports

General-Purpose Ports

• Connect multiple devices like keyboards, mice, and external drives.
• Lightning vs. USB-C ports look similar but are not interchangeable.

Video Ports

• Used for external displays and projectors -- HDMI, DVI, VGA, DisplayPort.
• Specialized video ports free up USB ports.

Audio Ports

• Audio Out: For headsets or earbuds.
• Audio In: For microphones.

Network Ports

• An Ehternet port is for wired internet connections.
• Wireless adapters can be added via USB ports.