Section 1.0 - Hardware.

SubSection 1.1 is devoted to some pieces of hardware.

NEWS about Storage Devices

Categorize storage devices and backup media


  • FDD stands for Floppy Disk Drive.
  • A Floppy Disk Drive is the PC component that reads data from and writes data to floppy disk.
  • A floppy disk s a removable data storage medium composed of a thin plastic disk contained within a stiff or rigid plastic case.
  • Data is stored on the disk using magnetism. The disk is coated with a magnetic material that retains its magnetic polarization even when power isn't present.
  • Read/write heads are small electromagnets that either sense the current polarization to read the data or set new polarization to write to the disk.
Internal parts of a 3 1⁄2-inch floppy disk.
1) A hole that indicates a high-capacity disk.
2) The hub that engages with the drive motor.
3) A shutter that protects the surface when removed from the drive.
4) The plastic housing.
5) A polyester sheet reducing friction against the disk media as it rotates within the housing.
6) The magnetic coated plastic disk.
7) A representation of one sector of data on the disk.

Form Factors

  • Original floppy disks measures 5.25" in diameter.
  • The disk had a soft, flexible outer cover. They didn't hold much data.
  • Later floppy disk measured 3.5" in diameter and were protected by a hard outer cover.
  • They held more data then a 5.25" floppy disks.


  • The capacity of a floppy drive vary by siza and recording techniques.The two biggest factors in capacity are:
    • The number of tracks
    • The number of sectors in each track.
  • Tracks are the concentric circular areas called tracks.
    • Floppy disks use either 40 or 80 tracks.
    • Each track is divided into sections, called sectors, where the actual data is recorded.
    • Each sector stores the same amount of data.

Write Protection

  • You can prevent writing to floppies by engaging write protection.
  • With the 3.5" floppies you slide open a small "door" to enable write protection.
  • If the LED light can shine through the door then writing is disabled.



  • HDD stands for Hard Disk Drive

Magnetic Drives

  • Magnetic hard drives are made up of 4 parts. They are the platters, spindle, read/write, and voice coil actuator.
  • The platter is the metal or plastic disks where the magnetic material is coated. Data is recorded on the magnetic material.
  • The spindle is the part of the hard drive that the platter spins around.
  • The read/write heads write and read data on the platter. The read/write head is attached to the arm.
  • The voice coil actuator is the part of the hard drive that moves the heads VERY carefully to position the heads on the correct part of the platter to be written on.


  • Considerably lower cost
  • Greater storage capacity then solid-state drives available today
  • Faster write speeds
  • Lower power required than for solid-state drives
  • Powers all the way off with the PC (Solid-state drives continue to draw power when the PC is off)


Solid-state drives

  • Solid-state drives use memory chips to read and write data on the disk instead of using a rotating disk.
  • Solid-state drives have no moving parts. This makes them less fragile than magnetic drives and are silent.
  • Memory-based drives use less power so the solid-state drives come with a backup batteries.


  • Faster start up time, because they don't need to spin like magnetic hard drives
  • Faster read speeds, because the drives don't have to move a read/write head
  • Lower power consumption while in use
  • Generate less heat
  • Ability to operate in higher temperatures
  • Less risk of failure because there are no moving parts.

Hard Drive Geometry


Use the picture above for reference.
  • Data is written on tracks located on the platter.
  • Each track is divided into sectors. Each sector contains identification information at its beginning and end. The data is stored in between the beginning and end. A sector holds about 512 bytes of data.
  • A group of sectors is called a cluster. A cluster usually has 4 to 64 sectors in it.



  • Partitioning divides a hard drive into one or more logical drives also called volumes.

Master Boot Record (MBR)

  • The Master Boot Record is the first sector on the bootable hard drive.
  • The Master Boot Record contains partition information used by the computer after the POST has finished.

Primary and Extended Partitions

  • Primary partitions are directly accesses by the operating system as volumes.
  • You can create one primary partition per hard drive.
  • An extended partition contains one or more logical drives. The Operating System accesses file storage through these partitions.

Optical Drives

CD Drives

  • CD drives are standard on computers today.
  • CD drives come in two types:
    • CD-ROM drive- these can only read CDs
    • CD-RW drives- these can read and write to CDs
  • The CD drives contain three major parts:
    • The drive motor- this motor spins the disc
    • The Laser Lens and Laser Pickup- The Laser focuses in on and reads the disc.
    • The Tracking Drive and Tracking Monitor- This part moves the laser to follow the track on the CD.
  • The speed of a CD drive is expressed in #X. The # represents how many times the drive moves times the rate of how many times the CD spins.



  • There are four layers of a CD.

  • The Graphics Layer, also known as the Label Layer, is the part of the CD where the name of the CD, the artist, and graphics will be on a CD. This is the only part of a CD that someone could write on.
  • The Laquer Layer, also known as the Acrylic Layer, is there to protect the reflective layer that is underneath it.
  • The Reflective Layer, as known as the Aluminum Layer, is there to reflect the laser that is used to read and write on the disc.
  • The Polycarbonate Layer is the the layer of the CD that has the data on it. The top part of the layer is where the data is located and the bottom part of this layer is the part that the laser reads.

Recording Processes

  • Commercially produced CDs are created through mastering.
  • Masteringis the process in which a glass template is made by deposting a thin film of nickel onto a glass disc.
    • A high powered laser then removes portions of the nickel coating to create pits and "lands" (which are high flat spots).
    • After they are created a nearly melted plastic disc is pressed against the glass master disc using 40 tons of force to form the disc. After this is done a layer of aluminum is deposited on them to increase reflectivity.
    • Before the manufacturing process is complete a graphic layer is put on top.
  • Writable CDs are written through a process called burning.
  • CD-R discs can be read many times but only written to once. They are also known as single-session discs.
  • These discs are made of gold metal alloy and a organic dye. The dyes ca be cyan (blue), pythalocyanine (aqua), metalized azo (dark blue), formazan (green).
    • The dye is heated with a laser and this process causes the pits and bumps.
  • CD-RW disc have a silver alloy layer. The alloy has a polycrystalline structure.
    • The Laser melts the crystal in the alloy and create the "land" areas.
  • CD-RW can be written to multiple times so they are multisession discs.

DVD Drives

  • DVD drives are becoming standard in computers today.
  • DVD drives have higher speeds then CD drives. A DVD running at 1X transfers data at 1.38 MB per second.
  • DVD drives use red and infrared lasers with a 650 nm laser beam.
  • DVDs can be single sided or double sided. They sides can be single or double layered.
  • The following table summarizes the sides, layers, and capacities of various DVD types:
DVD Type
4.7 GB
8.5 GB
Single on both sides
9.4 GB
Double on one side, single on the other
13.3 GB
Double on both sides
17.1 GB

Blu-Ray Discs

  • Blu-ray discs are optical discs created with a "blue" (violet) laser.
  • The violet laser's shorter wavelength make it possible for Blu-ray disc to hold more data.
  • A dual sided Blu-ray discs can hold 50 GB of data and a single sided disc can hold 25 GB.
  • Blu-ray discs are mostly used for high definition videos and large amounts of data.

Removable Storage

  • External CD-RW and hard drive

    • An external hard drive works the same way a normal, internal hard drive works it is just external.
    • External hard drives usually have a outer cover to protect it when it is being moved.
    • External hard drives can be connected through SATA, eSATA, USB, or IEEE 1394 (FireWire). Some external hard drives come with multiple connections so you can choose the best one for your computers.

    • External CD-RW drives can be connected through IEEE 1394 or USB 2.0.
    • They usually have an outer hard cover to protect them and aren't as popular as they used to be because most computers come with an internal CD-RW drive.


  • Hot swappable devices

    • Hot-swappable devices are devices that you can attach and detach from a computer without tuning off the computer.
      • Some examples are USB/ Thumb drives and SD cards.
  • Non-hot swappable devices

    • A non-hot swappable device requires the computer to be shut off before removing the device.
      • Some examples of this are the internal hard or any internal component.
  • Tape Drive

    • Tape drives are used to create backups of data on hard drives
    • Magnetic Tapes are used to record information in burst mode.
      • Data is written in blocks in burst mode.
    • There are interblock gapsto help prevent data from being overwritten.
      • An interblock gap is a physical space between blocks on the tape.
  • Tape Formats

    • Quarter-inch cartridge, or QIC, are belt driven instead of having the tape attached to reels.
      • This tape sometimes needs to be retensioned.
        • Retensioning means winding the tape to the end then rewinding it in a single operation.
    • Digital Audio Tapeor DAT, was designed for audio recording.
    • Digital Data Storage, or DDS, contain two read heads and two write heads. The data is read and if an error is detected it is rewritten.
    • Digital Linear Tape, or DLT, uses linear serpentine recording.
      • With Linear Serpentine Recording data tracks are written in alternating bands from the beginning of the tape to the end.
    • Super DLT, or SDLT, just has a higher capacity then DLT.
    • Linear Tape Open, or LTO,can hold 100 GB in a data cartridge.
    • Advanced Intelligent Tape, or AIT uses helical-scan recording in which the head is tilted and data is recorded in diagnosal stripes across the head.
      • SAIT is an upgraded version of AIT.

  • Solid State

    • USB/Thumb Drive/ Flash Drives

      • USB stands for Universal Serial Bus.
      • USB drives are also known as thumb drives or flash drives.
      • USB drives are composed of:
        • A controller with a USB interface.
        • A non-volatile memory interface connected to memory
        • An LED light to indicate drive activity
      • USB is supported by Windows 2000 Professional, all versions of Windows XP, and Windows Vista.
      • Some USB drives come with encryption, password protection, or a fingerprint scanner for security purposes.
      • KeyGhost-USB-512KB-Plugs.jpg
    • SD cards

      • SD stands for Secure Digital.
      • SD cards are non-volatile memory cards used in portable devices such as cell phones.
      • SD cards are available in three sizes. They are:
        • Standard size
        • Mini Size
        • Micro Size

"Created By: Krystal"