Computer Systems: Secondary Storage & Processors

Secondary Storage Devices

• Secondary storage provides a way to store large amounts of data and programs more permanently than main memory (RAM).
• Advantages:
  • Nonvolatility: Data is not lost when the power is off, unlike RAM
  • Greater capacity: Can store significantly more data than main memory
  • Cheaper: Less expensive than RAM
• Access: The CPU cannot directly access secondary storage. Data is transferred to the main memory using input/output channels.
• Common types:
  • Magnetic storage:
    • Hard disk drives (HDDs)
  • Optical storage:
    • CD, DVD, and Blu-ray discs
  • Solid-state storage:
    • Solid state drives (SSDs)
    • USB memory sticks

Processor Families

• A processor family represents a set of processors from the same manufacturer that share similar features and capabilities.
• Examples:
  • Intel families:
    • Atom
    • Celeron
    • Pentium
    • Core
    • Xeon

Data Centers

• A data center is a building or set of buildings that houses computer hardware.
• Data centers are climate-controlled and have access control.
• Data centers deliver an organization's data and information services.
• Location considerations when building a data center include mild climates, lower energy rates, and lower land costs.

Construction Considerations

• Key construction consideration is energy efficiency, especially for cooling.

Binary to Hexadecimal Conversion

• Binary number 10101011 can be converted to hexadecimal using the following steps:
  • Group the binary number into groups of four digits starting from the right: 1010 1011
  • Convert each group of four digits into its hexadecimal equivalent: 1010 = A, 1011 = B
  • The hexadecimal equivalent of 10101011 is AB.

Data, Information, and Knowledge

• Data is raw, unprocessed facts and figures.
• Information is processed data that provides context and meaning.
• Knowledge is the understanding and interpretation of information, allowing for decision-making and problem-solving.

Characteristics of Quality Data

• Accuracy: Data must be correct and free from errors.
• Completeness: All relevant data should be included.
• Consistency: Data should be consistent across different sources.
• Timeliness: Data should be up-to-date and relevant to the current context.
• Relevance: Data should be pertinent to the intended use.

Components of an Information System

• Hardware: Physical components like computers, servers, and storage devices.
• Software: Programs and applications that enable the system to function.
• Data: Raw facts and figures used by the system.
• Networks: Communication systems connecting different parts of the system.
• People: Individuals who interact with and manage the system.

Uses of the Hexadecimal System

• Color Representation: Each color is represented as a combination of red, green, and blue values in hexadecimal format.
• MAC Addresses: Unique physical addresses of network devices, expressed in hexadecimal.
• Character Encoding Standards: Characters are represented as hexadecimal values in encoding standards like UTF-8.
• URL Encoding: Special characters in URLs are encoded using hexadecimal.

Converting Binary Numbers

• Binary addition follows the rules of base-2 arithmetic.
• Carry-over is used when the sum exceeds 1.
• Example: 7 + (-3) in binary is 0111 + 1101 = 0100.

Exercise: Binary Operations

• Perform the following binary additions:
  • 11 + 11
  • 1101.10 + 111
  • 11111 + 100011

Anatomy of a Computer

• Hardware components perform input, processing, data storage, and output.
• CPU is the central processing unit that sequences and executes instructions.
• CPU consists of:
  • Arithmetic/logic unit (ALU): Performs mathematical operations and logical comparisons.
  • The control unit: Decodes instructions and coordinates operations within the CPU.
  • The register areas: Small, high-speed storage areas within the CPU for temporary storage.
• Memory provides temporary storage for program instructions and data for the processor to access quickly.
• Input/output devices send data and instructions to the computer, and receive results from it. They also include permanent storage devices.

Processor

• Completing an instruction involves four steps:
  • Fetch: Instruction is fetched from the memory location.
  • Decode: Breaks down the instruction into opcode (operation code) and address code.
  • Execute: Performs the operation specified by the opcode, using data located at the address code.
  • Store: Results of the operation are stored in the memory.
• Opcodes represent a basic set of commands the processor can execute, like ADD, COMPARE, IN, JUMP.
• Decoding involves breaking down the instruction into two parts: opcode and address code.

Memory

• Types of memory:
  • RAM (Random Access Memory): Temporarily stores data and program instructions that the CPU is actively using.
  • ROM (Read Only Memory): Contains pre-written instructions (boot-up instructions) that are permanent.
• Memory sizes:
  • Bytes: Smallest unit of storage.
  • Kilobytes (KB): 1 KB equals 1,024 bytes.
  • Megabytes (MB): 1 MB equals 1,024 KB.
  • Gigabytes (GB): 1 GB equals 1,024 MB.
  • Terabytes (TB): 1 TB equals 1,024 GB.
• Memory speed:
  • Access time: The time it takes to access a data item.
  • Transfer rate: The speed at which data is moved from memory to other computer components.

Input Devices

• Keyboard: A primary input device used for typing text.
• Mouse: Used to control the cursor on the screen and interact with graphical elements.
• Scanner: Converts images or documents into digital form.
• Touchscreen: Allows for interaction with devices using touch gestures.

Output Devices

• Monitor: Displays visual information from the computer.
• Printer: Creates paper copies of digital information.
• Speakers: Produce sound output, like music or audio.
• Projector: Displays images and videos on a larger screen.

Storage Devices

• Hard Drive: Primary storage device for the operating system, software, and other data.
• Solid-state Drive (SSD): Offers faster read/write speeds than hard drives.
• Optical drive: Used to read and write data on CDs, DVDs, and Blu-ray discs.
• USB Flash drive: Portable storage device for transferring files.
• Cloud storage: Stores data on remote servers accessible over the internet.

Processor Speed

• Measured in gigahertz (GHz) - billions of cycles per second
• Most computers operate between 1 to 4 GHz

Processor Architectures

• x86 - Used in desktop computers, by Intel and AMD
• ARM - Used in mobile devices, known for energy efficiency
  • ARM licenses its designs to chip manufacturers
  • Examples: Qualcomm Snapdragon and Apple M1

Processor Families

• Processors with similar features and capabilities from the same manufacturer
• Intel processor families: Atom, Celeron, Pentium, Core, Xeon

Utilizing Multiple Processing Units

• Coprocessor - Executes specific instructions while the CPU works on something else, increasing speed
  • Graphics Processing Unit (GPU) - executes graphics intensive instructions
  • Apple Neural Engine (ANE) - executes deep neural networks
• Multicore Processor - Has two or more cores, allowing for more processing
  • CPUs can have up to 20 cores
  • GPUs can have hundreds or thousands of cores

Parallel Computing

• Simultaneous execution of the same task on multiple processors
• Massively Parallel Processing Systems - Systems with thousands of processors

Grid Computing

• Uses a collection of computers working together to solve a common problem
• Large Hadron Collider (LHC) - 170 computing centers from 42 countries
• Volunteer Computing - Uses personal computers to contribute to research

Main Memory

• Provides the CPU with a working storage area for programs and data
• Also known as Random Access Memory (RAM)
• RAM is temporary and volatile
• Byte (B) - 8 bits that together represent a single character of data

Cache Memory

• High-speed memory on or near the CPU chip
• Accessed faster than main memory

Read-Only Memory (ROM)

• Nonvolatile memory that stores data and instructions permanently
• Stores the essential programming to start up a computer

Secondary Data Storage Devices

• Devices that store large amounts of data and programs more permanently than main memory
• Advantages over Main Memory:
  • Nonvolatility
  • Greater Capacity
  • Cheaper
• Not directly accessible by the CPU, input/output channels are used to access secondary storage
• Most Common Forms:
  • Magnetic (Hard Disk Drives)
  • Optical (CD, DVD, Blu-ray Discs)
  • Solid State (Solid State Drives (SSD), USB Memory Sticks)

Magnetic Secondary Storage Devices

• Magnetic Tape - Sequential secondary storage medium for backups and archives
  • Cost-effective per gigabyte
  • Greater longevity - 10 to 20 year lifespan
• Hard Disk Drive (HDD) - Storage device with rapidly rotating disks, uses magnetic material
• Redundant Array of Independent/Inexpensive Disks (RAID) - Technology that combines multiple hard disk drives
  • Goal is to increase reliability and data availability (Except for RAID 0, which increases performance)
  • RAID 0 - Data spread across multiple disks, advantage is speed, disadvantage is no fault tolerance
  • RAID 1 - Data mirrored across two disks, advantage is fault tolerance, disadvantage is double the disk space
  • Other RAID Types: RAID 5, RAID 10 etc

Optical Secondary Storage Devices

• Data storage that uses lasers to read and write data
• Common Types:
  • Compact Disc Read-Only Memory (CD-ROM)
  • Digital Video Disc (DVD)
  • Blu-ray High Definition Video Disk

Solid State Secondary Storage Devices

• Storage device that stores data in memory chips
• Advantages:
  • Less power consumption
  • Faster access than magnetic storage
  • No moving parts, less fragile
• USB Flash Drive is a common SSD

Enterprise Storage Options

• Attached Storage - Directly connected to a single computer or server, local storage for files and applications
• Network-Attached Storage (NAS) - Directly connected to a network, has its own address, good for small businesses and home users
• Storage Area Networks (SAN) - High-performance network dedicated to storage, used by enterprises that need high availability and scalability
• Storage as a Service (Cloud Storage) - Storage hosted remotely, accessed over the internet, rented space from data storage provider
  • Cloud-based Storage Services:
    • For Consumers: Apple iCloud, Dropbox, Google Drive, Microsoft OneDrive
    • For Enterprises: Amazon's Simple Storage Service (Amazon S3)

Input and Output Devices

• Allow users to provide data and instructions to the computer and receive results
• Part of a computer's user interface
• Organizations should consider business goals when selecting input and output devices

Input Devices

• Common Personal Computer Input Devices: Keyboard and Mouse
• Motion-Sensing Input Devices:
  • Mouse
  • Kinect
  • Wii Remote
• Scanning Devices: Scanner
• Magnetic Ink Character Recognition (MICR) Devices: Reads data printed with magnetic ink, used in banking for checks
• Card Readers:
  • Magnetic Stripe Cards: Credit cards, library cards
  • Chip Cards: ATM cards, debit cards
  • Contactless Payment Cards: Apple Pay, Google Pay
• Bar-Code Scanners:
  • UPC Bar Codes
  • QR Codes
• Radio Frequency Identification (RFID) Devices: Tracks objects with radio waves
  • RFID tags:
    • Passive: obtain power from RFID reader
    • Active: contain their own power source
• Pen Input Devices: Stylus for tablets or touch screens
• Touch Screens: Responsive to finger touch
• Biometric Devices: Uses unique biological characteristics for identification
  • Iris Scanner - Recognizes the pattern in the iris
  • Fingerprint Scanner - Reads and compares fingerprints
  • Heart-Rate Monitor - Measures heart rate

Output Devices

• Display Screens: Show output from the computer
  • LCD (Liquid Crystal Display) and LED LCD:
    • Uses a backlight source, advantages over OLED are brightness, low cost and durability
    • Original LCDs used fluorescent backlights but transitioned to energy-efficient LEDs (LED LCDs)
  • OLED (Organic Light-Emitting Diode):
    • No backlight, each pixel emits light
    • Improved contrast and lower power consumption compared to LCD and LED LCD
  • E-Ink Displays: Found in e-book readers, provide excellent readability in sunlight, minimal power consumption, and reduced eye strain
• Printers and Plotters:
  • **Printers: **
    • Laser Printers: Uses a laser beam to create a pattern on a drum
    • Inkjet Printers: Sprays ink onto paper
  • Plotters: Creates drawings and large format prints
• 3D Printers: Creates three-dimensional objects from a computer file
  • Key Advantages:
    • Prototyping
    • Customization

Multimedia Technologies

• Haptic Technology - Simulates touch sensations for user interaction
  • Applications: Smartphones, VR gloves, gaming controllers
• Virtual Reality - Immersive experience that creates a 3D environment
• Augmented Reality - Overlays digital information onto the real world

Learning Objectives

• Understand different number systems, including binary, octal, decimal, and hexadecimal
• Describe positional number notation and apply it to conversions between bases
• Explain the relationship between base 2, 8, and 16
• Define and apply basic Boolean logic operations
• Identify and describe basic logic gates using Boolean expressions and truth tables
• Demonstrate how to convert a Boolean expression into a circuit

Chapter Overview

• Understanding the binary system is essential for comprehending how computers represent and manipulate numbers.
• The text explains the advantages of using the binary system in computers, including its direct representation of electronic signals.
• It focuses on four number systems: binary (base 2), octal (base 8), decimal (base 10), and hexadecimal (base 16).

Number Systems

• Binary: Uses only the digits 0 and 1. Each position holds a power of 2.
  • The positions in a binary number represent weighted values determined by powers of 2.
• Octal: Uses digits 0 through 7. Each position holds a power of 8.
  • The positions in an octal number have weighted values based on powers of 8.
• Decimal: Uses digits 0 through 9. This is the system we use in everyday life. Each position holds a power of 10.
• Hexadecimal: Uses digits 0 through 9 and letters A-F, representing values 10-15. Each position holds a power of 16.
  • Similar to the other systems, the weighted value of each position in a hexadecimal number is determined by powers of 16.

Decimal to Binary Conversion

• Step 1: Repeatedly divide the decimal number by 2, keeping track of the remainders.
• Step 2: Concatenate the remainders from least to most significant bit (LSB to MSB) to form the binary representation.

Decimal to Octal Conversion

• The same process as binary conversion is applied, but instead of dividing by 2, divide by 8.

Decimal to Hexadecimal Conversion

• The same process as binary conversion is applied, but instead of dividing by 2, divide by 16.

Binary Arithmetic

• The chapter highlights the importance of understanding binary arithmetic for comprehending computer operations.
• This is not covered in detail in this summary.

Fixed-Point and Floating-Point Number Representations

• These representations are not covered in detail in this summary, but are crucial for understanding how computers represent numbers with fractional parts.

Boolean Algebra

• A system for representing and manipulating logical expressions.
• Boolean algebra provides a framework for expressing logical operations in binary terms (true or false).

Logic Gates

• Electronic circuits that perform basic Boolean logic operations like AND, OR, NOT, XOR, and NAND.
• Each gate has a specific function defined by its Boolean expression and truth table, which illustrate the output for different input combinations.

Building Computer Circuits

• The text explains how logic gates can be combined to create more complex circuits that perform various computing tasks.

Summary

• This chapter lays the foundation for understanding how computers work.
• The binary number system and logic gates are essential building blocks for computer hardware and software.
• Understanding how these concepts work is crucial for comprehending the operations and limitations of computing systems.
• Further study of digital logic and computer architecture will build upon these foundational concepts.

Explore the essential concepts of secondary storage devices and processor families in computer systems. This quiz covers the advantages, types of secondary storage, and different processor families like Intel's. Test your knowledge of these fundamental topics in computing!