09. Memory, Storage (RAM, Cache, HDD, ODD, SSD, Flashdrives)

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RAM, Cache, HDD, ODD, SSD, Flashdrives - Storage, Memory - Computer, Hardware, පරිගණක, දෘඩාංග, Information Technology, තොරතුරු තාක්ෂණය :)

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Computer Memory/Storage:

Computer Memory/Storage

Measuring Units:

Measuring Units BIT : BInary digiT (0 or 1) Word : Natural unit of data used by a particular processor design. The number of bits in a word (the word size, word width, or word length ) is an important characteristic of any specific processor design or computer architecture. Majority of the registers in a processor are usually word sized. (32 bit, 64 bit) Kilobit : 1000 bits Byte : 8 bits KiloByte (KB) : 2 10 Bytes Kibibyte ( KiB ) : 2 10 Bytes Binary_prefix : 1 KiB = 2 10 B, 1MiB = 2 20 B, 1GiB = 2 30 B (1 gibibyte ) = (2 10 mebibytes ) = (2 20 kibibytes ) = (2 30 bytes) 2

Memory/Storage Categories:

Memory/Storage Categories Category 1 Main Memory Primary Memory/Storage Internal Memory/Storage Category 2 Secondary Memory/Storage Auxiliary Memory/Storage External Memory/Storage 3

Characteristics:

Characteristics Volatility Volatile Non-volatile Mutability Read/Write Read Only Accessibility Random Access Direct Access Sequential Access 4

Volatile Memory:

Volatile Memory Requires power to maintain the stored information Retains the information as long as power supply is on, but when power supply is off or interrupted the stored memory is lost RAM 2 main categories DRAM (Dynamic RAM): RAM, Registers SRAM (Static RAM): Cache Memory, Registers Memory Refresh is needed in DRAM and not needed in SRAM 5

Non-volatile Memory:

Non-volatile Memory Can retain stored information even when not powered ROM : Read Only Memory Flash Memory F-RAM Most Secondary Storage Devices 6

ROM :

ROM Read Only Memory Types Optical Storage ROM (CD/DVD/BD ROM) Semiconductor based PROM: Programmable Read-Only Memory EPROM: Erasable Programmable Read-Only Memory EEPROM: Electrically Erasable Programmable Read-Only Memory EAROM Flash Memory 7

Read/Write:

Read/Write HDD: Hard Disk Drives Flash Drives Re-Writable Optical Disks SSD: Solid State Drives Also RAM, Cache, Registers 8

Read Only:

Read Only Optical ROM (CD/DVD/BD ROM) Semiconductor ROM http://en.wikipedia.org/wiki/Write_Once_Read_Many 9

Random, Direct, Sequential Access:

Random, Direct, Sequential Access Random Access Main Memory: RAM, Cache Direct Access Disks: HDD, Optical Disks Sequential Access Tapes: Magnetic Tapes (Cassette, VHS) 10

Random vs. Sequential Access:

Random vs. Sequential Access 11

SDRAM - DIMM:

SDRAM - DIMM Generally in practical world, the term RAM mostly used regarding SDRAM/DIMM 12

SDRAM:

SDRAM Synchronous DRAM SDRAM is DRAM synchronized with the system bus while classic DRAM has an asynchronous interface 13

DIMM:

DIMM Dual In-line Memory Module Series of DRAM integrated circuits Successor of SIMM ( Single IMM ) 14

Generations of SDRAM:

Generations of SDRAM SDR SDRAM : Single Data Rate SDRAM DDR SDRAM : Double Data Rate SDRAM DDR DDR2 DDR3 DDR4 15

DDR SDRAM Comparison:

DDR SDRAM Comparison DDR SDRAM Standard Bus clock (MHz) Transfer Rate (MT/s) Voltage (V) DIMM pins DDR (1) 100–200  200–400  2.5/2.6 184 DDR 2 200–533  400–1066 1.8 240 DDR 3 400–1066 800–2133 1.5 240 16

DDR SDRAM Comparison:

DDR SDRAM Comparison 17

Key Values of a DIMM:

Key Values of a DIMM 18 Generation (DDR2, DDR3) Frequency/Data Rate (1333, 1600) Capacity (2048 MB, 4 GB)

Determine Generation/Data Rate:

Determine Generation/Data Rate Some vendors do not print DRAM generation/frequency in labels directly But most of them label module names which contains generation and bandwidth info PC X - # The Generation is X and the memory bandwidth is # Memory Frequency and Data Rate can be determined using memory bandwidth Examples PC-3200 : DDR, 400 (3200/8=400) PC2-6400: DDR2, 800 (6400/8=800) PC3-12800: DDR3, 1600 (12800/8=1600) 19

DIMM Vendors:

DIMM Vendors Kingston G.Skill Toshiba Samsung Hynix Corsair + many more (Not in Particular Order :) 20

HDD:

HDD Hard Disk Drives

HDD: Hard Disk Drives:

HDD: Hard Disk Drives Direct Access Storage Used for storing and retrieving digital information using rapidly rotating discs ( platters ) coated with magnetic material Records data by magnetizing a thin film of ferromagnetic material on a disk Consists of a spindle that holds flat circular disks, also called platters , which hold the recorded data Platters in most consumer HDDs spin in the range of 5,400 rpm to 7,200 rpm Information is written to and read from a platter as it rotates past devices called read-and-write heads that operate very close over the magnetic surface Modern drives there is one head for each magnetic platter surface on the spindle 22

HDD Capacity:

HDD Capacity Capacity measured by GB, TB Vendors and Operating System uses 2 different methods to measure HDD capacity Vendors use 1000 metric (SI) method (1KB=1000B) as a marketing trick and OS uses 1024 method (1KB=1024B) which is similar to binary prefix method Therefore labeled size is different from the size we see from the size shown by the OS Examples: 1TB : 931.32 GB 500GB : 465.66 GB (Actual Usable Size may also differ…) 23

HDD Performance:

HDD Performance RPM : Rotations Per Second 5400, 7200, 10000… etc. Latency : The delay for the rotation of the disk to bring the required  disk sector Seek Time : The time for the actuator arm to reach the desired  disk track Access Time = Seek Time + Latency Data Transfer Rate 24

HDD Interface:

HDD Interface http://en.wikipedia.org/wiki/Hard_disk_drive_interface (P)ATA: Parallel ATA SATA: Serial ATA 25

SATA vs. PATA:

SATA vs. PATA 26

External HDD:

External HDD External/Portable HDDs typically connect through USB or eSATA ports Most External HDDs now use USB 3.0 interface External HDDs are Slower, compared to Internal HDDs Certain Portable HDDs have extra features such as special Encryption methods, Security Options, Shock Protection, etc… 27

HDD Related Terms:

HDD Related Terms ECC : Error Correcting Code http://en.wikipedia.org/wiki/Forward_error_correction S.M.A.R.T : Self-Monitoring, Analysis and Reporting Technology http://en.wikipedia.org/wiki/S.M.A.R.T Disk Buffer/Cache: Embedded memory acting as a buffer between the computer and the physical hard disk platter. Usually 8 to 128 MiB RAID : Redundant Array of Independent Disks http://en.wikipedia.org/wiki/RAID 28

HDD Vendors:

HDD Vendors 29 Samsung Seagate Western Digital Hitachi Quantum Toshiba + many more [Not in Particular Order :]

Optical Storage:

Optical Storage CD, DVD, BD

Optical Storage Devices:

Optical Storage Devices Optical storage is a storage method in which data is written and read with a optical beam ( laser ) ODD : Optical Disk Drive Typically used for archival or backup purposes Slower than HDDs Less vulnerable to environmental conditions Data stream is placed in a spiral path. The data begins at the innermost track and works its way out toward the edge of the disc Data is read by a laser beam always Data is also written/burned by laser beams, but in industrial mass produced discs, the data is placed on the disc by a stamping machine 31

Optical Disc Generations:

Optical Disc Generations First-generation CD Second-generation DVD Third-generation BD Fourth-generation HVD 32

CD: Compact Disc:

CD: Compact Disc Developed by: Philips , Sony Read mechanism: 780 nm wavelength ( infrared and red edge) semiconductor laser (Speed 1200 Kib /s = 1×, Generally 52×) CD-R ( Compact Disc-Recordable ) CD-RW ( Compact Disc- ReWritable ) Capacity: ~ 700 MiB 33

CD: Compact Disc:

CD: Compact Disc 34

DVD:

DVD Developed by: Philips , Sony , Toshiba , and Panasonic in 1995 Read mechanism: 650 nm laser, (Speed 10.5 Mbit/s = 1×, Generally 16×) Recordable DVDs: DVD-R and DVD+R Re-Writable DVDs: DVD-RW , DVD+RW , and DVD-RAM Capacity: ~ 4.7 GiB DVD was an acronym ( initialism ) for the unofficial Digital Video Disk . Later the Backronym Digital Versatile Disc was introduced to express that DVD goes beyond video (Data, Software, Audio). However it was not universally accepted and a 1999 report decreed that DVD was "simply three letters" and stood for "nothing". Today, usage varies and there is no universal agreement. Digital Versatile Disc has gained wide acceptance 35

DVD:

DVD 36

BD: Blu-ray Disc:

BD: Blu -ray Disc Designed to supersede DVD BD is 120 mm in diameter and 1.2 mm thick, the same size as DVD and CD Developed by: Blu -ray Disc Association Read mechanism: 405  nm diode laser . (Speed 36 Mbit/s = 1×, Generally 2×) Capacity: ~ 25 GB BD-ROM (read-only) - for pre-recorded content BD-R (recordable) - for PC data storage BD-RE (rewritable) - for HDTV recording BD-RW (rewritable) - for PC data storage Blu -ray 3D , BD-XL , Printable Blu -ray 37

BD: Blu-ray Disc:

BD: Blu -ray Disc 38

Optical Staroge Read-Write:

Optical Staroge Read-Write 39 http://www.howstuffworks.com/blu-ray2.htm http://www.cd-info.com/blu-ray/

HVD: Holographic Versatile Disc:

HVD: Holographic Versatile Disc The Holographic Versatile Disc ( HVD ) is an optical disc technology developed between April 2004 and mid-2008 Can store up to several terabytes of data on an optical disc 10 cm or 12 cm in diameter Media type: Ultra-high density optical disc Capacity: ~ 6 TB 40

HVD: Holographic Versatile Disc:

HVD: Holographic Versatile Disc 41

Flash Drives:

Flash Drives

Flash Drive Types:

Flash Drive Types 43 Generic Solid-State Drives USB Flash Drives and Memory Cards Specific CompactFlash (CF) Multimedia Card (MMC) Memory Stick (MS) Secure Digital (SD, SDHC, SDXC)

SSD:

SSD Solid-State Drives

SSD: Solid State Drives:

SSD: Solid State Drives A data storage device using integrated circuit assemblies as memory to store data persistently Unlike HDDs, SSDs have no moving mechanical components SSHD Hybrid drives or solid state hybrid drives (SSHD) combine the features of SSDs and HDDs in the same unit, containing a large hard disk drive and an SSD cache to improve performance of frequently accessed data 45

SSD vs HDD:

SSD vs HDD SSD (Compared to HDD)… High Cost High Speed Low Access Time Low (No) Noise Less susceptible to physical shock and magnetic fields Less Power Consumption and Less Heat Generation Smaller in Physical Size Smaller in Capacity https://duckduckgo.com/?q=SSD+vs+HDD https://www.google.com/search?q=SSD+vs+HDD 46

USB Flash Drive:

USB Flash Drive Pen Drive Jump Drive Thumb Drive

USB Flash Drives:

USB Flash Drives AKA: Pen Drive, Jump Drive, Thumb Drive Uses a Flash Memory Chip Has a USB Connector, Mostly USB 2.0 or 3.0 Usually very small in physical size and come in different shapes 48

USB Flash Drives:

USB Flash Drives 49

Memory Cards:

Memory Cards 50 Used by Mobile Phones, Digital Cameras, Music players , etc. Memory Cards use a Flash Memory Chip Memory Card Types CompactFlash (CF) Multimedia Card (MMC) Memory Stick (MS) Secure Digital (SD, SDHC, SDXC) (More)

SD Card: Secure Digital Card:

SD Card: Secure Digital Card Most mobile devices uses SD cards now SD specification (Capacity) SD – SDSC (SD Standard Capacity) SDHC (SD High Capacity): Up to 32 GB SDXC (SD eXtended Capacity): Up to 2 TB Physical Size Standard: SD Mini: miniSD Micro: microSD 51

SD, miniSD, microSD Comparison:

SD, miniSD , microSD Comparison 52

Card Readers:

Card Readers Memory Card readers are used to read/write singe or multiple types of Cards (CF, MMC, MS, SD) USB and PCI Card Readers are available Most Notebook Computers and some desktop PCs Contain Internal Card Readers USB microSD card readers much similar to a Pen Drive 53

Card Readers:

Card Readers 54

Online Storage:

Online Storage

Online Storage:

Online Storage http://en.wikipedia.org/wiki/Online_file_storage http://en.wikipedia.org/wiki/Cloud_storage Google Drive: https://drive.google.com SkyDrive https://skydrive.live.com DropBox https://www.dropbox.com SugarSync https://www.sugarsync.com Amazon Cloud Drive http://www.amazon.com/gp/feature.html?ie=UTF8&docId=1000828861 56

Thank You! :):

Thank You! :) Ayubowan !

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