Data Storage Technology Quiz

Storage System Characteristics

• Storage media and storage devices are hardware components where data is stored. Examples include DVD discs, flash memory cards.
• A storage device is a hardware component the medium is inserted into to be used. Examples include DVD drives, flash memory card readers. They can be internal, external, or remote.
• Storage devices are typically identified by a letter.

Logical vs. Physical Representation

• A file is anything stored on a storage medium, such as a program, document, digital image, or song.
• A file name is given to a file by a user.
• A folder is a named place on a storage medium where files can be stored.

Storage System Types Used

• Magnetic storage: conventional hard drives
• Optical storage: optical discs
• Flash storage: flash memory media

Hard Drives

• Used to store programs and data and can be internal, external or encrypted.
• Magnetic hard drives: one or more permanently sealed metal magnetic disks with an access mechanism (read/write heads).
• Mounting shaft: spins hard disks at a speed of several thousand revolutions per minute.
• Read/write heads: for each hard disk surface; they move in and out over the disks together.
• Hard disks have data on both sides of each disk.
• Tracks are concentric paths on a disk where data is recorded.
• Sectors are small pieces of the track.
• Clusters are one or more sectors, the smallest addressable area of a disk.
• Cylinders are a collection of tracks located in the same location on a set of hard disk surfaces.
• Solid State Drives (SSD): use flash memory technology, have no moving parts, are less powerful and appropriate for portable devices.

Internal and External Hard Drives

• Internal hard drives: permanent storage devices located inside the system unit. Removed rarely unless a problem develops.
• External hard drives: commonly used to transport large amounts of data from one computer to another. Portable devices are smaller and easier to transport. Most connect via USB connection, although some are wireless.

Hard Drive Speed, Disk Caching, and Hybrid Hard Drives

• Disk access time: total time a hard drive takes to read or write data; consists of seek time, rotational delay, and data movement time.
• SSDs do not need seek time or rotational delays.
• Disk cache: memory used in conjunction with a magnetic hard drive to improve system performance; consists of memory chips on a circuit board inside the hard drive case.
• Hybrid hard drives: combine flash memory and magnetic hard drives; use flash memory for cache which allows for encryption to be built into the drive.

Hard Drive Partitioning and File Systems

• Partitioning: divides the physical capacity of a single drive logically into separate areas (called partitions).
• Partitions act as independent hard drives and are referred to as logical drives.
• Increases efficiency by using smaller clusters for smaller drives.
• Used to create recovery partition, new logical drive for data and dual boot system.

Optical Discs and Drives

• Three categories: CDs, DVDs, and Blu-Ray Discs (BDs).
• Can be read-only, recordable, or rewritable.
• Almost always downward compatible.
• Can support single or dual-layer discs.
• Recording data onto a disc is called burning.
• External drives connect via USB port.
• Major advantage of optical discs is large capacity.
• CD discs typically hold 650-700 MB.
• DVDs hold 4.7 GB for single layer or 8.5 GB for dual layer.
• BD discs typically hold 25 GB for single layer or 50 GB for dual layer.

Read-Only Optical Discs

• CD-ROM, DVD-ROM, or BD-ROM.
• Can be read from but not written to or erased by the user.
• Typically come pre-recorded. Usually come with software, clip art, and other graphics, music, movies, and games.

Recordable Optical Discs

• CD-R, DVD-R, DVD+R, or BD-R.
• Can be written to, but cannot be erased or reused.
• No physically molded pits.
• Contains organic light-sensitive dye between plastic and reflective layers for most discs.

Rewritable Optical Discs

• CD-RW, DVD-RW, DVD+RW, or BD-RE.
• Can be written to, but cannot be erased or reused.
• Uses phase change technology to heat and cool process to change reflectivity on the disc.
• Capacities are similar to read-only/recordable discs except for BDXL

Flash Memory

• Chip-based storage medium that uses electrons.
• Used in SSDs and hybrid hard drives.
• Embed flash memory chips into products.
• Available in various sizes and formats which are considered not interchangeable: CompactFlash, Memory Stick, MultiMedia Card (MMC), Secure Digital (SD).
• XD Picture Card, Secure Digital High Capacity (SDHC), and Secure Digital Extended Capacity (SDXC).

USB Flash Drives

• Sometimes also called flash memory drives, jump drives, or thumb drives.
• Flash memory media integrated into a self-contained unit that plugs into and is powered by a USB port.
• Designed to be very small and portable.
• Can include biometric features like a fingerprint reader.

Network Storage and Cloud Storage Systems

• Remote storage: uses a storage device that is not directly connected to the computer being used (accessed via the Internet or a network).
• Cloud storage or online storage: accessed via the Internet or online storage sites. Growing in importance because more and more applications are web based. Many provide free online storage.
• Network storage: remote storage is provided via a local network.

Smart Cards

• Credit card-sized piece of plastic containing computer circuitry (processor, memory, and storage).
• Stores a small amount of data (about 64 KB or less).
• Commonly used to store prepaid amounts of digital cash or personal information.
• Smart card readers are built into or attached to a computer, door lock, vending machine, or other device.
• Some smart cards store biometric data.
• Mobile smart card use is an emerging trend.

Storage Systems for Large Computer Systems

• Storage server: hardware device containing multiple high-speed hard drives connected to the computer system or network. Usually based on magnetic hard discs.
• RAID (redundant arrays of independent discs): method of storing data on two or more hard drives that work together. Protect data on large storage systems by recording copies of data and increase fault tolerance. Includes Disk striping (RAID 0) and Disk mirroring (RAID 1) and combinations. A common example would be a Drobo system (new RAID storage system).
• Magnetic tape systems: plastic tape coated with a magnetizable substance. Sequentially accessed. Primarily used as backup and archival storage due to low cost per terabyte. Often in cartridge tape form.

Evaluating Your Storage Alternatives

• Product characteristics considered: Speed, Compatibility, Storage capacity, Convenience, and portability.
• Most users require: Hard drive, Recordable or rewritable optical drive, Flash memory card reader, and USB ports.

Input and Output Devices

Keyboards

• Input device used to enter characters (insertion point or cursor). Can be wired or wireless and contain standard, numeric keypad, function, delete/backspace, control/alternate, and arrow/special keys.
• Mobile devices use slide-out keyboards, pen or touch input (on-screen keyboards), and keyboard docks.

Pointing and Touch Devices

• Pointing devices select, manipulate objects, input data, and issue commands to the computer.
• Common types of pointing devices: Mouse (traditional or touch), Pen / Stylus, and devices that use touch input.

Scanners

• Input devices that read printed text and graphics and transferring them to a computer in digital form.
• Data is input as a single image, can scan photos, documents, and images.
• Types of scanners: flatbed, portable, 3D, receipt, and business card scanners.
• The quality of scanned images is indicated by the optical resolution measured in dots per inch (DPI). Higher resolution = better quality but larger file size.
• Other readers include barcode readers (reading machine-readable codes), optical character recognition (OCR) devices (identifying characters in scanned text and converting them into electronic form), and magnetic ink character recognition (MICR) readers for processing checks.

Biometric Readers

• Used to input biometric data like fingerprints or voice.
• Can be stand-alone or built into other devices for security purposes.
• Used for access control and to authorize electronic payment and secure websites.

Digital Cameras

• Take pictures and record them as digital images.
• Can be still cameras or video cameras.
• Integrated into many portable computers and mobile phones.
• Digital still cameras: images are immediately available, measured in megapixels, use flash memory storage; can be used to read barcodes and for remote deposits.
• Digital video cameras: camcorders, PC video cameras (PC cams), webcams. Built-in or stand-alone. Store images on digital media (flash memory, DVDs, hard drives, etc.).

Audio Input

• Voice Input and Speech Recognition systems; the process of entering audio data into the computer. Voice input is inputting spoken words and converting them to digital form via a microphone or headset. Often used for Podcasts and VoIP (Voice over Internet Protocol). Can also provide spoken instructions to the computer.

Audio Output

• Voice, music, and other audible sound.
• Common output devices: computer speakers, headphones, Earbuds/earphones.

Display Devices

• A display device presents output visually on some type of screen.
• Common device types include monitors, notebook/mobile devices, handheld devices, home entertainment devices, kitchen appliances, digital photo frames, e-book readers, and smart watches, digital signage systems, billboards.

Display Device Characteristics

• Color vs. Monochrome Displays; pixels.
• CRT vs. Flat-Panel Displays. CRT displays are larger, bulky and heavy, while flat-panels take up less desk space and use less power.

Size and Aspect Ratio

• Device size measured diagonally from corner to corner.
• Screen resolution: number of pixels affects the amount of information displayed on the screen; resolution can be changed to match user preference.

Video Adapters, Interfaces, and Ports

• Video cards determine the graphical capabilities of a computer. VGA, DVI, and HDMI are the common interface connections for monitors. Ports exposed on the system unit cases connect monitors. USB ports are a new option.

Wired vs. Wireless Displays

• Wired displays are physically connected using a cable.
• Wireless displays connect using a wireless network connection (Wi-Fi or Bluetooth).

Wearable Displays

• Project images from a mobile device to a display screen built into glasses.

Data and Multimedia Projectors

• Display computer output to a wall or projection screen, often found in classrooms and conference rooms.
• Can be wireless or integrated into devices and some contain an iPod dock.
• Pico projectors are pocket-size to connect mobile devices.
• Hologram and 3D projectors used to display 3D images.

Printers

• Print resolution measured in DPI (dots per inch). More DPI, better quality.
• Printers include personal and network printers. Personal printers connect directly to a single computer, while network printers connect to a home network. Connection options include USB.
• Some printers include multifunction capabilities like copy, fax, scan, print and are often called all-in-ones.
• Common printer types include Laser Printers (toner powder), Ink-Jet Printers (ink droplets), photo printers, barcode, label and postage printers, portable and integrated printers, wide-format ink-jet printers, and 3D printers.

Test your knowledge on various data storage technologies including RAID systems, flash memory cards, USB drives, and SSDs. This quiz covers the essential features and functions of storage devices as well as the latest advancements in data representation. Challenge yourself and see how well you understand these critical components of modern computing.