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1.5 Install and configure storage devices and use appropriate media.
There are three primary types of optical storage media in use today. Compact Discs (CD), Digital Versatile Discs (DVD), and Blu-Ray discs. Data is recorded to this type of media by stamping irregularities onto the surface of the disc, or "burned" into it using a laser, in a spiral pattern that runs from the inside to the outside of the disk. The data is read back from the disc using a laser. Differences in reflection caused by the variations in the plastic layer are detected and translated as 0s and 1s.
Most internal drives are designed to fit in a standard 5.25" drive bay. Internal connections may be provided by either a PATA or SATA interface and may require additional outputs to the sound card or the motherboard for audio.
- CD-ROM
Used for digital data storage, Standard CDs have a diameter of 120 millimetres (4.7 in) and can hold up to 80 minutes of uncompressed audio or 700 MB (700 × 220 bytes) of data. Formats include read-only (CD-ROM), write-once audio and data storage (CD-R), and rewritable media (CD-RW).
- DVD-ROM
- 4.7GB capacity(single-sided/single-layer)
- 8.5GB capacity (single-sided/double-layer)
- 9.4GB capacity (double-sided/single-layer)
- 17.1GB capacity (double-sided/double-layer)
- Blu-Ray
- High-density optical disc
- 25-50GB storage capacity single-layer
- 50-100GB storage capacity dual-layer
- Combo drives and burners
- Connection types
- External
- USB
- Firewire
- eSATA
- Ethernet
- Internal SATA, IDE and SCSI
- IDE configuration and setup (Master, Slave, Cable Select)
- SCSI IDs (0 – 15)
- Hot swappable drives
Hot swappable devices can be added or removed from your computer without having to reboot. USB devices, keyboard, mouse, thumb drives, are common examples as well as some SATA hard drives. RAID disk arrays are also configured to be hot swappable to permit the replacement of a failed drive without having to disable the system. Devices that require rebooting or need to have drivers installed to operate are considered non-hot swappable.
- Hard drives
Hard disk drives are sealed units typically mounted inside the computer, providing permanent storage and quick access. They store information either on small disks called platters or in integrated memory chips. The read and write operations of the drive are managed by the controller while data is transferred to and from the motherboard by the host adapter, which is usually integrated onto the motherboard.
Desktop hard drives come in a 3.5-inch form factor and require both 5V and 12V power from the power supply. Both ATA and SCSI drives have been widely used, but the most popular varieties are PATA and SATA.
- Magnetic Drives
- Lower Cost
- Very little heat produced
- Capable of higher storage capacity
- 5400 rpm
- 7200 rpm
- 10,000 rpm
- 15,000 rpm
- Flash Drives
- Compact flash
Commonly used in portable devices, Flash Drives or CompactFlash Cards are found in two form factors:
- Type I (3.3 mm thick)
- Type II (5 mm thick)
- SD
Secure Digital (SD) is a non-volatile memory card format developed for use in portable devices.
SD comprises several families of cards:
- The original, Standard-Capacity (SDSC) card
- High-Capacity (SDHC) card
- eXtended-Capacity (SDXC) card
- SDIO with input/output functions
SD cards are found in several form factors:
- Standard (32 mm × 24 mm)
- Mini (21.5 mm × 20 mm)
- Micro (15 mm × 11 mm)
- xD Picture Card (20 mm × 25 mm)
 
Electrically passive adaptors allow the use of a smaller card in a host device built to hold a larger card.
- SSD
- Uses memory to store data
- Contains no moving parts, quieter
- Resistant to shock and vibration
- Faster read/write speeds
- Lower power consumption
- RAID types
RAID is an acronym for Redundant Array of Independent/Inexpensive Disks. There are 3 levels of RAID addressed on the 220-70x A+ exam series, RAID 0, 1, and 5. RAID Level 10 has since been added to the 220-80x series exam. Not all levels of RAID provide the same level of redundancy. Hardware based RAID provides better performance over software based RAID.
This topic is also open for discussion in our forum.
- RAID Level 0: Disk striping without parity or mirroring
- Splits data evenly across two or more drives
- Provides improved performance
- Has zero redundancy
- Provides no fault tolerance
- RAID Level 1: Disk mirroring
- Mirroring without parity or striping
- Requires at least two drives
- Data is written identically to multiple drives
- Continues to operate as long as at least one drive is functioning
- Can increase read performance
- RAID Level 5: Disk striping with parity
- Requires at least three drives
- Data is distributed across all disks
- Requires all drives but one to operate
- RAID Level 10: Disk striping with mirroring
- Requires four drives
- Data is written identically to multiple drives
- Continues to operate as long as at least one drive is functioning
- Provides better throughput and latency
Though rapidly becoming obsolete, floppy disk drives may be found in some legacy systems and are often still used for archival applications. The most recent configuration accepted a removable 3 1/2" disk with a storage capacity of 1.44 MB and were traditionally assigned drive letters A and B.
Typically, a floppy disk drive is installed into a 3 1/2" drive bay. Data is transferred to and from the motherboard through a keyed 34-pin flat ribbon cable and power to the drive is provided by a 4-pin polarized Berg connector.
- Tape drive
- Can be installed internally or externally
- Uses either digital or analog magnetic tape
- 100GB capacity / 200GB compressed
- Slower than most medium
- Primarily used for archives
- Media capacity
| Media | Capacity |
|---|
| CD | 700 MB |
| CD-RW | 700 MB |
| DVD-RW | 4.7 GB |
| DVD | 4.7 GB |
| Blu-Ray | 50 GB |
| Tape | 500 GB |
| Floppy | 1.44 MB |
| DL DVD | 8.55 GB |
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