Chapter 2/ Storage Devices and power supplies Flashcards
Hard Disk Drive Systems (HDD)
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A hard disk drive (HDD), hard disk, hard drive or fixed disk, is a data for permanent storage and cuick access.
it can hold more information then other form of storage.
The HDD contains three critical components
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1- controller
2- Hard Disk
3- Host bus adapter (HBA)
Controller
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it controls the drive, this chip controls how the drive operates and how the data is encoded onto the platter,
the must known are PATA and SATA.
Hard Disk.
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this is the physical storage, HDD stores information on small discs also called platters.
Host bus Adapter (HBA)
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it is a translator that converts signals from the controller to signal the computer can understand. the new motherboards incorporate the HBA into the motherboard’s circuitry, offering headers for drive- cable connection, such as 40 pin header IDU (PATA) header , SATA header.
Anatomy of a hard drive.
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The hard drive, which typically provides storage for data and applications within a computer, has four key components inside its casing:
the platter (for storing data),
the spindle (for spinning the platters),
the read/write arm (for reading and writing data).
the actuator (for contro
Hard Disk Drive ( HDD) speeds
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drive Revolutions Per Minute, RPM is used to help determine the access time on computer hard drives. RPM is a measurement of how many revolutions a computer’s hard drive makes in a single minute. The higher the RPM, the faster the data will be accessed; for example, if you were comparing two hard drives, one with 5400 RPM and another with 7200 RPM, the hard drive with a 7200 RPM will be capable of accessing data much faster than the other.
Solid Stat Drives( SSD )
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unlike HDD the SSD have no moving parts.
SSD read more quickly.
consume less power and produce less heat.
less susceptible to damage from shock and heat.
SSD are divided into two kinds.
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1-Volatile DRAM based.
2- Non- Volatile flash based, mad with NAND.
Volatile DRAM based SSD
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A RAM-based solid state drive is a storage device that is made from silicon microchips, has no moving parts and stores data electronically instead of magnetically like HDD.
it uses DRAM or SRAM chips, both of which are volatile. This means that a RAM-based drive will lose its contents when the power is turned off. To preserve the contents of a RAM-based solid state drive, data is copied from volatile memory to nonvolatile memory upon instruction or when the drive is powered down. Generally, a RAM-based SSD have batteries that keep the data alive long enough for it to be copied to nonvolatile memory in the event that power accidentally gets shut off.
Non- Volatile flash based SSD, mad with NAND.
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NAND flash memory is a type of non-volatile storage technology that does not require power to retain data.
An important goal of NAND flash development has been to reduce the cost per bit and increase maximum chip capacity so that flash memory can compete with magnetic storage devices like hard disks. NAND flash has found a market in devices to which large files are frequently uploaded and replaced. MP3 players, digital cameras and USB drives use NAND flash.
Floppy Dick Drives ( FDD)
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A floppy disk drive (FDD), or floppy drive, is a hardware device that reads data storage information. It was invented in 1967 by a team at IBM and was one of the first types of hardware storage that could read/write a portable device. FDDs are used for reading and writing on removable floppy discs. Floppy disks are now outdated, and have been replaced by other storage devices such as USB and network file transfer.
Optical storage Drives.
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Optical storage is any storage method in which data is written and read with a laser for archival or backup purposes. Typically, data is written to optical media, such as:
- The legacy compact disc CDs
- The Digital video disc DVDs.
- The latest is Blu-ray disc (BD)
CD-ROM (Compact Disc, read-only-memory) 1- Definition 2- storage capacity 3- disc format is CD SS SS stand for single sided 2-78
1- Is an adaptation of the CD that is designed to store computer data in the form of text and graphics, as well as hi-fi stereo sound.
2- it can hold approximately 650MB in its original and least capable format. There is 700 MB, that is the must common the 800 MB and 900 MB.
DVD-ROM
1- Definition
2-disc format and there storage capacity
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1- read-only digital versatile disc (DVD-ROM) commonly used for storing large software applications. It is similar to a compact disk-read only memory (CD-ROM) but has a larger capacity. A DVD-ROM stores around 4.38 GB of data. A CD-ROM usually stores 650 MB of data. DVD- R/RW SS, SL is 4.70 GB DVD+R/RW SS,SL is 4.7 GB DVD-R,DVD+R DS, SL is 9.4GB DVD-R SS, DL is 8.5 GB DVD+R ss,DL is 8.5 GB DVD R DS,DL is 17.1 GB
