Computing Components and Digital Storage

Computing Components

  • Hardware for home and work
  • Input and output
  • Digital storage

Digital Storage: Preserving Your Content

Storage and Memory Uses

  • Computers use both storage and memory to access and save data.
  • Memory: Electronic components storing instructions for the processor, data needed by instructions, and results of processing.
  • Storage: Long-term, permanent access to data and information, similar to a file cabinet for digital content.
  • Storage Medium: Nonvolatile; retains data even when the computer is off.
  • Volatile Memory: (e.g., RAM) stores data temporarily while the computer is on and erases it when switched off.
  • Non-Volatile Memory: Retains data even after the system shuts off.
  • Secondary Storage: Location where a computer keeps data, information, programs, and applications.
  • Examples:
    • Digital storage (cloud)
    • Hard disks
    • Solid-state drives (internal or external)
    • Memory cards
    • USB flash drives
    • Optical discs
    • Tags
  • Cloud Storage: Keeps information on servers on the Internet.

Storage Devices

  • Storage Device: Hardware that records and/or retrieves items to and from storage media.
  • Writing: Transferring data, instructions, and information from memory to a storage medium.
  • Reading: Transferring data, instructions, and information from a storage medium into memory.

Capacity

  • Capacity: The number of bytes a storage medium can hold.
  • Gigabyte (GB) ≈ 1 billion bytes
  • Terabyte (TB) ≈ 1 trillion bytes
  • Terms used to define storage:
    • Kilobyte (KB) ≈ 1 thousand bytes
    • Megabyte (MB) ≈ 1 million bytes
    • Gigabyte (GB) ≈ 1 billion bytes
    • Terabyte (TB) ≈ 1 trillion bytes
    • Petabyte (PB) ≈ 1 quadrillion bytes
    • Exabyte (EB) ≈ 1 quintillion bytes
    • Zettabyte (ZB) ≈ 1 sextillion bytes
    • Yottabyte (YB) ≈ 1 septillion bytes

Access Time and Transfer Rate

  • Access Time: Speed of storage devices and memory.
    • Time it takes for a storage device to locate an item on a storage medium.
    • Time required to deliver an item from memory to the processor.
  • Transfer Rate: Speed with which data transfers to and from a device; stated in KBps, MBps, and GBps.

Storage Hardware

Hard Drives

  • Common storage medium.
  • Stores data magnetically or using solid-state storage.
  • Files stored on the internal hard drive cannot be accessed on other devices.
  • Magnetic Hard Disk Drives (HDDs) have greater storage capacity and are less expensive than SSDs.
  • "Hard drive" refers collectively to hard disks and SSDs.

Hard Disk Drives (HDDs)

  • Contains one or more inflexible, circular platters using magnetic particles to store data.
  • Desktops and laptops contain at least one hard disk.
  • Storage capacity is determined by:
    • Number of platters
    • Composition of the magnetic coating
    • Longitudinal or perpendicular recording
    • Density

Hard Disk Characteristics

  • Tracks
  • Sectors
  • Platters
  • Form factor
  • Read/write head
  • Revolutions per minute (RPM)

Platter Composition and Recording Methods

  • Platter: Made of aluminum, glass, or ceramic with a thin alloy coating for magnetic recording.
  • Longitudinal Recording: Aligns magnetic particles horizontally.
  • Perpendicular Recording: Aligns magnetic particles vertically to the disk’s surface; can store up to 3 times the amount of storage compared to longitudinal recording.
  • Density: Number of bits in an area on a storage medium; higher density means more storage capacity.

Formatting, Tracks, and Sectors

  • Formatting: Dividing the disk into tracks and sectors.
  • Track: Concentric circle on a magnetic hard disk platter.
  • Sector: Wedge-shaped section that breaks tracks into small arcs containing individual blocks of data.
  • Several sectors form a cluster.

Read/Write Heads

  • Typical hard disk has multiple platters, each with two read/write heads (one per side).
  • Read/Write Head: Mechanism that reads and writes items to the drive.
  • Hard Disk Head Actuator: Connects to arms that move the read/write heads to the correct platter location.

Platter Rotation

  • Platters rotate at high speed for nearly instant access to tracks and sectors.
  • The spinning motion creates a cushion of air between the platter and read/write head, preventing contact.

External Hard Drives

  • Separate storage device that connects to a USB or other port.
  • Sizes and storage capacities vary.
  • Enclosed in an airtight, sealed case.

Solid-State Drives (SSDs)

  • Flash memory storage device.
  • Flash Memory: Nonvolatile memory that can be erased electronically and rewritten.
  • Consist entirely of electronic components with no moving parts.

Portable Flash Memory Storage

  • Memory Card: Removable flash memory storage device for transporting digital files.
  • Used with mobile devices and computers; slots accept multiple card types.

USB Flash Drives

  • USB Flash Drive: Removable storage device for folders and files that plugs into a USB port.
  • Storage capacities vary.

Optical Media

  • Optical media includes CDs, DVDs, and Blu-ray discs (BDs); however, their use as storage media is declining.
  • Optical Disc: Flat, round, portable disc made of metal, plastic, and lacquer, written and read by a laser.
  • Optical Disc Formats:
    • CD (CD-ROM, CD-R, CD-RW): Audio, photo
    • DVD (DVD-ROM, DVD-R, DVD+R, DVD-RW, DVD+RW, DVD+RAM): Video
    • Blu-ray: Video (higher capacity than DVD)

Cloud Storage

Cloud Computing Basics

  • Chosen for accessibility, cost savings, space savings, and scalability.
  • Consists of a front end and a back end, connected through a network.
  • Front End: Hardware and software the user interacts with to access the cloud.
  • Back End: Servers and storage devices that manage and store resources.

Cloud Services

  • Allows companies to outsource IT infrastructure to third-party providers.
  • Cloud storage providers enable synchronization, document writing, backup, project sharing, media streaming, and online gaming.
  • Cloud Computing Services:
    • Infrastructure as a Service (IaaS)
    • Storage as a Service (STaaS)
    • Desktop as a Service
    • Data as a Service (DaaS)
    • Platform as a Service (PaaS)
  • Additional Cloud Services: synchronize files, write documents, backup files, stream media

Cloud Storage Options

  • Google Drive and Microsoft OneDrive files can be edited or shared using cloud-based apps.
  • Services like Box primarily are storage locations without providing corresponding apps.
  • Security measures: Passwords, identification requirements, encryption, and backups to other servers to minimize outages.
  • Advantage: No need to purchase and maintain servers.

Provider Considerations

  • Select a provider with sufficient bandwidth for large file transfers (photos, songs, videos).
  • Criteria:
    • Free storage offered
    • Cost to purchase more storage
    • Maximum file size allowed
  • Review the provider’s privacy policy and terms of agreement.

Guidelines for Selecting a Provider

  • Verify the company’s reputation and longevity.
  • Choose a provider that encrypts your files.
  • Ensure compatibility with your computers and mobile devices.
  • Compare pricing plans.
  • Verify support for the types of files you want to back up.
  • Allow file sharing.
  • Consider a mobile app for accessing files.

Secure IT: Secure Your Data on the Cloud

Cryptocurrency and Digital Wallets

  • Cryptocurrency: Digital currency for transferring money between users or corporations which is not backed by a government.
  • Payment apps (e.g., Venmo): Transfer money between credit cards/bank accounts and other users.
  • Digital Wallet: App connected to a payment card or financial account (e.g. Apple Pay).

Protecting Cloud-Based Data

  • Choose cloud providers carefully.
  • Read the user agreement.
  • Set the most advanced privacy settings.
  • Use strong passwords and two-factor authentication.
  • Encrypt sensitive data.

Enterprise and Other Storage Options

Enterprise Hardware

  • Designed for heavy use, maximum efficiency, and availability in large organizations.
  • Highly Available Hardware: Accessible 24/7, 365 days a year.
  • Includes levels of redundancy, meaning that if one component fails, another takes over.
  • Data Center: Secure location with many servers making files available to users.

RAID (Redundant Array of Independent Disks)

  • Organizations manage storage in-house, outsource it, or use a cloud storage provider.
  • RAID: A group of two or more integrated hard drives.
  • May duplicate data to improve reliability.

RAID Levels

  • Level 1 (Mirroring): Writes data on two drives simultaneously to duplicate data, enhancing reliability.
  • Other levels use striping, which splits data across multiple drives to improve access times.

NAS (Network Attached Storage)

  • Server on a network solely for providing storage to users, computers, and devices.
  • A storage appliance with its own IP address, often without a keyboard or display, and configured in a RAID.
  • Administrators can quickly add storage to an existing network.

SAN (Storage Area Network)

  • High-speed network solely for providing storage to attached servers.
  • Includes only storage devices.
  • High-speed fiber-optic cable usually connects other networks and servers for fast access to large storage capacities.
  • Can connect to networks and other servers that are miles away using high-speed network connections.

Other Storage Types

  • Tape
  • Magnetic stripe cards
  • Smart cards
  • RFID tags
  • NFC chips and tags

Tape Storage

  • Magnetically coated plastic ribbon capable of storing large amounts of data and information at a low cost.
  • A tape drive reads and writes data on the magnetic tape.

Magnetic Stripe Cards

  • Credit, entertainment, bank, or similar cards with a stripe containing identification information.

Smart Cards

  • Alternative to magnetic stripe cards that store data on an integrated circuit.
  • Two types: contact and contactless.

RFID (Radio-Frequency Identification) Tags

  • Consist of an antenna and a memory chip containing information transmitted via radio waves.
  • An RFID reader transfers the information to a computing device.
  • Tags are either active or passive.

NFC (Near Field Communication)

  • A technology (based on RFID) that uses close-range radio signals to transmit data between two NFC-enabled devices or between an NFC-enabled device and an NFC tag.
  • NFC-enabled devices contain an NFC chip.
  • NFC tags are self-adhesive.

NFC Uses

  • Using a mobile device to pay for goods or services.
  • Displaying a web page.
  • Making a phone call.
  • Sending a text message.
  • Exchanging contact information.

How Memory Relates to Storage

Memory Components and Function

  • Memory consists of chips on the motherboard or circuit board.
  • Stores three categories of items:
    • Operating system and other programs.
    • Applications.
    • Data being processed.

Bytes and Addresses

  • A byte (character) is the basic storage unit in memory.
  • Instructions and data exist as bytes when transferred to memory from storage devices.
  • Each byte resides temporarily in a location in memory that has an address.
  • Address: Unique number identifying the location of a byte in memory.
  • The computer references the addresses that contain bytes of data or instructions in memory to access the information.

RAM and Cache

  • Memory capacity affects the device’s operating speed.
  • RAM is the most common type of volatile memory.
  • Nonvolatile Memory: ROM, flash memory, and CMOS.
  • RAM (Main Memory): Memory chips that can be read from and written to by the processor and other devices.
  • RAM can accommodate multiple programs and applications simultaneously.
  • Saving: Copying data from RAM to a storage device or to the cloud.
  • Cache: Temporary storage area that helps speed up processing by storing frequently used instructions and data.

ROM (Read-Only Memory

  • Refers to memory chips storing permanent data and instructions.
  • Data on most ROM chips cannot be modified, so it is read-only.
  • Manufacturers record data on firmware chips when manufactured.
  • Contains permanently written data, such as start-up instructions.

Flash Memory

  • Non-volatile memory that can be erased electronically and rewritten.
  • Most computers use flash memory to hold start-up instructions.
  • Stores data and programs on many mobile and peripheral devices.
  • Memory cards contain flash memory on a removable device.

CMOS (Complementary Metal-Oxide Semiconductor)

  • Technology used in RAM, flash memory, and other memory chips that provides high speeds and consumes little power.
  • Uses battery power to retain information when the computer is off.
  • The flash memory chips that store a computer’s startup information often use CMOS technology.

Ethics and Issues: Internet of Things and Privacy

Internet of Things (IoT)

  • Smart electric meters, wearable technology, and vehicles’ black boxes submit data about us.
  • Computers and mobile devices are not the only items that connect to the Internet.
  • Thermostat can adjust temperature remotely via a smartphone app as it sends and receives data.
  • A wireless chip attached to your medicine bottle can send text messages to remind you to take your medication.

IoT Applications and Concerns

  • Smart trash cans in public places have sensors that monitor the amount of trash deposited and then send a message that notifies owners when the containers need to be emptied.
  • Wearable technology (smart watches, wristbands) track pulse and heart rate, accept calls, and display notifications.
  • Retailers use beacons to send low-energy Bluetooth signals to nearby smartphones, alerting customers to personalized offers.

Privacy and Security

  • Devices could have default settings that prevent data sharing without consent.
  • Companies bear the responsibility of ensuring sensitive data is kept secure and confidential.
  • Technology experts believe that the security, health, and productivity benefits outweigh the potential risks.