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How a SSD/HDD works!
Transcript of How a SSD/HDD works!
Host Interface Components Controller -Error Correction -Wear leveling -Bad Block Mapping -Read/Write Caching -Encryption Error Correction is a code that keeps a bunch of binary code called parity code. This parity code can be used to restore the data that was lost back onto the new drive. Error Correction (ECC) Components of HDD Wear Leveling is a mechanism that tries to increase the life of the SSD. Instead of using that same logical sector over and over, Wear leveling changes the coding and sectors to a new logical sector so it doesn't become old and become a bad block. Wear Leveling Each HDD contains a logic board and a HDA(Hard Disk Assembly) Logic board Motor Drive
Connector HDA(Hard Disk Assembly) Bad Block is also known as a Bad Sector on a Hard Disk Drive or Solid State Drive. Bad Block Mapping allows the Operating System to recognize a bad sector so you don't receive a error when it attempts to write in that sector. When that sector is flagged, the OS will simply skip over it. A well known disk utility is called CHKDSK, and it looks for those bad blocks and flags them. Platter(Magnetic Layer) Actuator/Actuator Arm Bad Block Mapping Spindle
Ribbon Cable(connects to logic board)
SCSI Interface Connector
Actuator Axis Pros and Cons of HDD Pro Cheaper than SSD
$1.50/gb(SSD) Cons Cannot open a HDD, if you do it becomes unstable.Results in data loss and physical destruction .
Generate Heat and noise.
Moving parts can cause damage if there is vibration.
Higher Latency(Longer read/write time)
Needs Fragmentation periodically.
Heavier than SSD. Encryption Each SSD has the capability of having a encryption algorithm. Encryption is very useful for when you have very sensitive data on your SSD and someone steals the data. You can always decrypt the data but it takes years to decrypt something. The FBI took 18 months to decrypt a HDD using a Super Computer. Now a regular hacker can spend years trying to decrypt just a file. Encryption is a great feature for SSD's. SSD Most SSD's today have memory installed into it. There are two kinds, DRAM based and Flash Memory based. Flash memory is slower than DRAM but is most popular because it is cheaper than DRAM Memory SSD's. DRAM based memory is much faster and can access data on average, less than 10 microseconds. But you always have to put into consideration that the more you have your computer on without restarting it, the slower it will get. Memory DRAM based memory is the fasted type of memory for a SSD. DRAM has a back-up storage and internal battery. When the SSD loses power it takes the data on the memory onto the backup storage and when the power is restored, it copies the data back onto the memory and continues to operate like normal. This process is very similar to the hibernate feature on the Windows OS, where the data on the Random Access Memory(RAM) is moved to the Hard Drive/Storage Disk when you put the computer on hibernate and when you turn the computer back on, it transfers the data back onto the RAM and goes back to the state prior to hibernation. DRAM memory There are two types of Flash Memory. Multi-level cell(MLC) and Single-level cell(SLC). MLC is usually cheaper than SLC but is slower and less reliable than SLC. But this can also go the other way around depending on the design structure of the SSD. Many ways to reverse this and have MLC faster is by having a interleaving structure, or changes to the writing algorithms, over having a nice wear-leveling algorithm. Flash memory Solid-State Drive SSD vs. HDD Motor Drive Motor Drives is a computer chip
that is like an amplifier. It takes
commands from the controller
to the motor. Since the controller
does not have enough current to turn
on the hard drive motor. Buffer(RAM) The Ram(Random Access Memory)
is a key component in the hard drive's
performance. The more you have, the faster
the data transfer would be from the hard drive to the computer. Controller The controller is the main
thing in the logic board, it controls
the data transfer from the drive to the computer,controlling the motor, or making the head read/write. SATA/ATA Converter The SATA/ATA Converter
is a chip that can convert from ATA into
SATA. Manufactures use an old ATA chip and put
a converter into it rather than a whole SATA chip
since it would be more expensive. This component reads and writes disks. Baxter, Andrew. "SSD vs HDD." StorageReview.com. LatopReviews.com, n.d.
Web. 11 Sept. 2012. <http://www.storagereview.com/ssd_vs_hdd>.
Carlo. "Solid Site Drives." : Solid State Drives, Some Theory and a Selection of Videos.
Happy SysAdm, 11 July 2011. Web. 11 Sept. 2012.
<http://www.happysysadm.com/2011/07/solid-state-drives-some-theory-and.html>. Bibliography Snure. "SSD vs HDD: Pros and Cons." HubPages. HubPages, Feb.-Mar. 2012. Web. 18 Sept. 2012. <http://snurre.hubpages.com/hub/SSD-vs-HDD-pros-and-cons>. Torres, Gabriel. "Anatomy of a Hard Disk Drive." Anatomy of a Hard Disk Drive | Hardware Secrets. Hardware Secrets, July-Aug. 2005. Web. 18 Sept. 2012. <http://www.hardwaresecrets.com/article/Anatomy-of-a-Hard-Disk-Drive/177/2>