» 
Arabic Bulgarian Chinese Croatian Czech Danish Dutch English Estonian Finnish French German Greek Hebrew Hindi Hungarian Icelandic Indonesian Italian Japanese Korean Latvian Lithuanian Malagasy Norwegian Persian Polish Portuguese Romanian Russian Serbian Slovak Slovenian Spanish Swedish Thai Turkish Vietnamese
Arabic Bulgarian Chinese Croatian Czech Danish Dutch English Estonian Finnish French German Greek Hebrew Hindi Hungarian Icelandic Indonesian Italian Japanese Korean Latvian Lithuanian Malagasy Norwegian Persian Polish Portuguese Romanian Russian Serbian Slovak Slovenian Spanish Swedish Thai Turkish Vietnamese

definition - Non-volatile_memory

definition of Wikipedia

   Advertizing ▼

Wikipedia

Non-volatile memory

                   

Non-volatile memory, nonvolatile memory, NVM or non-volatile storage is computer memory that can retain the stored information even when not powered. Examples of non-volatile memory include read-only memory, flash memory, ferroelectric RAM (F-RAM), most types of magnetic computer storage devices (e.g. hard disks, floppy disks, and magnetic tape), optical discs, and early computer storage methods such as paper tape and punched cards.

Non-volatile memory is typically used for the task of secondary storage, or long-term persistent storage. The most widely used form of primary storage today is a volatile form of random access memory (RAM), meaning that when the computer is shut down, anything contained in RAM is lost. Unfortunately, most forms of non-volatile memory have limitations that make them unsuitable for use as primary storage. Typically, non-volatile memory either costs more or performs worse than volatile random access memory.

Several companies are working on developing non-volatile memory systems comparable in speed and capacity to volatile RAM. IBM is currently developing MRAM (Magnetoresistive RAM). Not only would such technology save energy, but it would allow for computers that could be turned on and off almost instantly, bypassing the slow start-up and shutdown sequence. In addition, Ramtron International has developed, produced, and licensed ferroelectric RAM (F-RAM), a technology that offers distinct properties from other nonvolatile memory options, including extremely high endurance (exceeding 1016 for 3.3 V devices), ultra low power consumption (since F-RAM does not require a charge pump like other non-volatile memories), single-cycle write speeds, and gamma radiation tolerance. Other companies that have licensed and produced F-RAM technology include Texas Instruments, Rohm, and Fujitsu.

Non-volatile data storage can be categorized in electrically addressed systems (read-only memory) and mechanically addressed systems (hard disks, optical disc, magnetic tape, holographic memory, and such). Electrically addressed systems are expensive, but fast, whereas mechanically addressed systems have a low price per bit, but are slow. Non-volatile memory may one day eliminate the need for comparatively slow forms of secondary storage systems, which include hard disks.

Contents

  Electrically addressed

Electrically addressed semiconductor non-volatile memories can be categorized according to their write mechanism. Mask ROMs are factory programmable only, and typically used for large-volume products not required to be updated after manufacture. Programmable read-only memory can be altered after manufacture, but require a special programmer and usually cannot be programmed while in the target system. The programming is permanent and further changes require replacement of the device. Data is stored by physically altering (burning) storage sites in the device.

  Read-mostly devices

An EPROM is an erasable ROM that can be changed more than once. However, writing new data to an EPROM requires a special programmer circuit. EPROMs have a quartz window that allows them to be erased with ultraviolet light, but the whole device is cleared at one time. A one-time programmable (OTP) device uses an EPROM chip but omits the quartz window in the package; this is less costly to manufacture. An electrically-erasable programmable read-only memory EEPROM uses electrical signals to erase memory. These erasable memory devices require much time to erase data and to write new data; they are not usually configured to be programmed by the processor of the target system. Data is stored by use of floating gate transistors which require special operating voltages to be applied to trap or release electric charge on an insulated control gate for storage sites.

  Flash memory

The flash memory chip is a close relative to the EEPROM; it differs in that it can only be erased one block or "page" at a time. It is a solid-state chip that maintains stored data without any external power source.[1] Capacity is substantially larger than that of an EEPROM, making these chips a popular choice for digital cameras and desktop PC BIOS chips.

Flash memory devices use two different logical technologies—NOR and NAND—to map data. NOR flash provides high-speed random access, reading and writing data in specific memory locations; it can retrieve as little as a single byte. NAND flash reads and writes sequentially at high speed, handling data in small blocks called pages, however it is slower on read when compared to NOR. NAND flash reads faster than it writes, quickly transferring whole pages of data. Less expensive than NOR flash at high densities, NAND technology offers higher capacity for the same-size silicon.[1]

  Ferroelectric RAM (F-RAM)

Ferroelectric RAM (FeRAM, F-RAM or FRAM) is a random-access memory similar in construction to DRAM but (instead of a dielectric layer like in DRAM) contains a thin ferroelectric film of lead zirconate titanate [Pb(Zr,Ti)O3], commonly referred to as PZT. The Zr/Ti atoms in the PZT change polarity in an electric field, thereby producing a binary switch. Unlike RAM devices, F-RAM retains its data memory when power is shut off or interrupted, due to the PZT crystal maintaining polarity. Due to this crystal structure and how it is influenced, F-RAM offers distinct properties from other nonvolatile memory options, including extremely high endurance (exceeding 1016 for 3.3 V devices), ultra low power consumption (since F-RAM does not require a charge pump like other non-volatile memories), single-cycle write speeds, and gamma radiation tolerance.[2]

  Magnetoresistive RAM (MRAM)

Magnetoresistive RAM is one of the newest approaches to non-volatile memory and stores data in magnetic storage elements called magnetic tunnel junctions (MTJ's). MRAM has an especially promising future as it seeks to encompass all the desirable features of the other popular types of memory (non-volatility, infinite endurance, high-speed reading/writing, low cost).[3]

The 1st generation of MRAM, such as Everspin Technologies' 4 Mbit, utilized field induced writing. The 2nd generation is being developed mainly through two approaches: Thermal Assisted Switching (TAS)[3] which is being developed by Crocus Technology, and Spin Torque Transfer (STT) which Crocus, Hynix, IBM, and several other companies are developing.[4]

  Mechanically addressed systems

Mechanically addressed systems utilize a contact structure ('head') to read and write on a designated storage medium. Since circuitry layout is not a key factor for data density, the amount of storage is typically much larger than for electrically addressed systems.

Since the access time depends on the physical location of the data on the device, mechanically addressed systems may not be "random access" as are electrically addressed semiconductor NVRAM. For example, magnetic tape stores data as a sequence of bits on a long tape; transporting the tape past the read/write head is required to access any part of the storage. Tape media can be removed from the drive and stored, giving indefinite capacity at the cost of the time required to retrieve a dismounted tape.

Hard disk drives use a rotating magnetic disk to store data; access time is longer than for semiconductor memory, but cost per stored data bit is very low. Formerly, removable disk packs were common, allowing storage capacity to be expanded. Optical discs store data by altering a pigment layer on a plastic disk. Read-only and read-write versions are available; removable media again allows indefinite expansion, and some automated systems were used to retrieve and mount disks under direct program control.

  Nanodrive

  Holographic storage

  Organic

There are polymer printed ferroelectric memory.

Thin Film Electronics ("Thinfilm") produces rewriteable non-volatile organic memory based on ferroelectric polymers. Thinfilm successfully demonstrated roll-to-roll printed memories in 2009.[5][6][7]

In Thinfilm's organic memory the ferroelectric polymer is sandwiched between two sets of electrodes in a passive matrix. Each crossing of metal lines is a ferroelectric capacitor and defines a memory cell. This gives a non-volatile memory comparable to ferroelectric RAM technologies and offer the same functionality as flash memory.

  Specifications

Specification (March 2007)[8] 2.5" HDD 1" microdrive Flash memory Optical disc Tape MRAM
Device model Hitachi Travelstar 5k160[9] Hitachi Microdrive 3k8[10] Hynix HY27UH08AG5M[11] Blu-ray HP Ultrium 960[12] Everspin (formerly of Freescale Semiconductor) MR2A16A[13]
Density (GBit/cm2) 20.3 18.4 6.7 3.8 0.047 0.0021
Capacity (GByte) 160 8 2 50 400 0.004
Price per bit (Eur/GByte) 1.5 9.0 6.0 1.25 0.075 35000
Price per unit (Eur) 110 87 14 635 2340 17.4
Price per medium (Eur) (For removables) nd nd nd 40 30 nd
Data rate (Mbit/s) 540 80 23 144 640 436
Access time (ms) (Average/typical) 11 12 0.025 180 72000 1.000035
Power consumption (W) (Average) 1.8 0.6 0.1 25 20 0.08
Form factor (h x w x d) (cm) 0.95x7x10 0.5x3x4 0.1x1.2x2 4x15x19 2x10x10 0.1x1x1.8

  References

   
               

 

All translations of Non-volatile_memory


sensagent's content

  • definitions
  • synonyms
  • antonyms
  • encyclopedia

Dictionary and translator for handheld

⇨ New : sensagent is now available on your handheld

   Advertising ▼

sensagent's office

Shortkey or widget. Free.

Windows Shortkey: sensagent. Free.

Vista Widget : sensagent. Free.

Webmaster Solution

Alexandria

A windows (pop-into) of information (full-content of Sensagent) triggered by double-clicking any word on your webpage. Give contextual explanation and translation from your sites !

Try here  or   get the code

SensagentBox

With a SensagentBox, visitors to your site can access reliable information on over 5 million pages provided by Sensagent.com. Choose the design that fits your site.

Business solution

Improve your site content

Add new content to your site from Sensagent by XML.

Crawl products or adds

Get XML access to reach the best products.

Index images and define metadata

Get XML access to fix the meaning of your metadata.


Please, email us to describe your idea.

WordGame

The English word games are:
○   Anagrams
○   Wildcard, crossword
○   Lettris
○   Boggle.

Lettris

Lettris is a curious tetris-clone game where all the bricks have the same square shape but different content. Each square carries a letter. To make squares disappear and save space for other squares you have to assemble English words (left, right, up, down) from the falling squares.

boggle

Boggle gives you 3 minutes to find as many words (3 letters or more) as you can in a grid of 16 letters. You can also try the grid of 16 letters. Letters must be adjacent and longer words score better. See if you can get into the grid Hall of Fame !

English dictionary
Main references

Most English definitions are provided by WordNet .
English thesaurus is mainly derived from The Integral Dictionary (TID).
English Encyclopedia is licensed by Wikipedia (GNU).

Copyrights

The wordgames anagrams, crossword, Lettris and Boggle are provided by Memodata.
The web service Alexandria is granted from Memodata for the Ebay search.
The SensagentBox are offered by sensAgent.

Translation

Change the target language to find translations.
Tips: browse the semantic fields (see From ideas to words) in two languages to learn more.

last searches on the dictionary :

5162 online visitors

computed in 0.046s

I would like to report:
section :
a spelling or a grammatical mistake
an offensive content(racist, pornographic, injurious, etc.)
a copyright violation
an error
a missing statement
other
please precise:

Advertize

Partnership

Company informations

My account

login

registration

   Advertising ▼