(1) See also Flash.
(2) A very popular non-volatile, rewritable memory chip. Evolving from the EEPROM chip, flash was invented by Toshiba and named after its ability to erase a block of a data "in a flash." Ironically, this block erasing is one of its least desired features and one the industry is trying to eliminate through the development of newer technologies (see charge trap flash and future memory chips). For more about the architecture of the flash cell, see EEPROM.
Extremely durable, flash is widely used for storage modules such as USB drives and digital camera memory cards (see examples below). It is also packaged as stand-alone chips for circuit board mounting. For example, years ago, flash replaced the permanent ROM chip on a PC motherboard that held the BIOS. Instead of having to open the case and physically replace the ROM BIOS chip, updated BIOS code could be downloaded into the flash chip (see BIOS).
NOR and NAND
Flash chips are constructed of either NOR or NAND logic gates. NOR works like a computer's memory, while NAND is like a hard disk. For example, in a digital camera, an internal NOR chip holds the software, while NAND chips are in the removable memory cards. See logic gate.
NOR Flash for Software (Linear Flash)
Developed by Intel in 1988, NOR flash supports one-byte random access, which means machine instructions can be fetched and executed directly from the flash chip (executed in place) just like computers fetch instructions from main memory. NOR flash uses a "linear flash" interface, which is continuous addressable memory.
Before any writing can take place, both NOR and NAND flash cells must be erased in large blocks, typically 128KB in size. NOR flash has a lifespan of about 10 thousand write cycles.
NAND Flash for Storage (ATA Flash)
Developed by Toshiba a year after Intel's NOR flash, NAND is more durable and less expensive. The cells are denser, and erasing and writing are faster. NAND-based flash memory cards and USB drives use the "ATA flash" interface, which resembles a removable ATA hard disk (see IDE). To the operating system, NAND flash is just another disk drive that reads and writes sectors.
NAND cells can be rewritten about 100,000 times; however, "wear leveling" distributes the writing across all the cells and can greatly improve the chip's longevity. In practice, most users will not wear out a memory card or USB drive. In 2008, Japanese scientists prototyped ferroelectric-based NAND flash (FNF) memory, which is said to be denser, use less power and be capable of tens of millions of writes. See USB drive, CompactFlash, SmartMedia, Memory Stick, SD Card and xD Picture Card.
"Digital Film"
Flash memory cards are used to store images on a digital camera. This is a CompactFlash card.
Flash Card Readers
Memory card readers function like disk drives to the computer and come in a variety of models. The earlier reader (top) supported only CompactFlash and SmartMedia, while newer units (bottom) handle all popular flash memory formats.
(2) A very popular non-volatile, rewritable memory chip. Evolving from the EEPROM chip, flash was invented by Toshiba and named after its ability to erase a block of a data "in a flash." Ironically, this block erasing is one of its least desired features and one the industry is trying to eliminate through the development of newer technologies (see charge trap flash and future memory chips). For more about the architecture of the flash cell, see EEPROM.
Extremely durable, flash is widely used for storage modules such as USB drives and digital camera memory cards (see examples below). It is also packaged as stand-alone chips for circuit board mounting. For example, years ago, flash replaced the permanent ROM chip on a PC motherboard that held the BIOS. Instead of having to open the case and physically replace the ROM BIOS chip, updated BIOS code could be downloaded into the flash chip (see BIOS).
NOR and NAND
Flash chips are constructed of either NOR or NAND logic gates. NOR works like a computer's memory, while NAND is like a hard disk. For example, in a digital camera, an internal NOR chip holds the software, while NAND chips are in the removable memory cards. See logic gate.
NOR Flash for Software (Linear Flash)
Developed by Intel in 1988, NOR flash supports one-byte random access, which means machine instructions can be fetched and executed directly from the flash chip (executed in place) just like computers fetch instructions from main memory. NOR flash uses a "linear flash" interface, which is continuous addressable memory.
Before any writing can take place, both NOR and NAND flash cells must be erased in large blocks, typically 128KB in size. NOR flash has a lifespan of about 10 thousand write cycles.
NAND Flash for Storage (ATA Flash)
Developed by Toshiba a year after Intel's NOR flash, NAND is more durable and less expensive. The cells are denser, and erasing and writing are faster. NAND-based flash memory cards and USB drives use the "ATA flash" interface, which resembles a removable ATA hard disk (see IDE). To the operating system, NAND flash is just another disk drive that reads and writes sectors.
NAND cells can be rewritten about 100,000 times; however, "wear leveling" distributes the writing across all the cells and can greatly improve the chip's longevity. In practice, most users will not wear out a memory card or USB drive. In 2008, Japanese scientists prototyped ferroelectric-based NAND flash (FNF) memory, which is said to be denser, use less power and be capable of tens of millions of writes. See USB drive, CompactFlash, SmartMedia, Memory Stick, SD Card and xD Picture Card.
"Digital Film"
Flash memory cards are used to store images on a digital camera. This is a CompactFlash card.
Flash Card Readers
Memory card readers function like disk drives to the computer and come in a variety of models. The earlier reader (top) supported only CompactFlash and SmartMedia, while newer units (bottom) handle all popular flash memory formats.
 | Reproduced with permission from Computer Desktop Encyclopedia. Copyright (c) 1981-2009 The Computer Language Company Inc. All rights reserved. |
Additional Resources
- Memory Primer for iPhone 1.0.3 (Mobile)
- Memory Primer for iPhone is a fully-featured flash card app that helps you learn about human memory. Individual cards can be added to or removed from a built-in faves deck at any time. Use the faves deck to study only the cards that really give you trouble. Cards can also...
- Software downloads 2009-11-23
- Master Voyager 2.29 (Windows)
- Master Voyager is especially designed to create protected DVD/CD discs and USB Memory Sticks. It creates protected areas on the media and it is needed to enter password to see protected contents. Protected Disc/USB Stick is fully autonomous and does not need any special software installed on computer. It has...
- Software downloads 2009-11-22
- Will Microsoft's Silverlight dampen the appeal of Google's Chrome OS?
- MS is the past Google is the future so NopeGoogle is the old MS, MS is the old IBM. PC_DOS never made it, MS_DOS did. The driving factor was openness and innovation.Today and in the near future, Google has bothToday MS sees profit only and based on thatdrives...
- Discussion threads 2009-11-20
- Google makes Chrome OS open source today
- Contrary to rumors, Google did not release a beta version of its much anticipated Chrome operating system today. And nothing is coming anytime soon: the final version is at least a year away, the mega giant web company said. But there was some significant news for the...
- Blog posts 2009-11-19
- Disks: why size means performance
- OK, Smarty pants...How do I use only the outer-most sectors of my 500GB disk?Performance != reliabilitySeagate has progressively gotten worse with reliability - that's why they cut the 5-year warranty back down to 3 years. Western Digital has made great strides with reliability though. WD isn't focussing on...
- Discussion threads 2009-11-18
- Microsoft to share some details on IE 9 at PDC show this week
- Tabs that dont hang and,1. HTML 5 standards compliance ahead of Chrome and FF2. Better plugins3. CSS 3 compliance4. FASTER!Trying to develop for IE8 is still a pain!Addon supportFor things like AdBlock Plus.Also, an x64 version of silverlight.Grow upso do not read this blog - OK? Prefer Firefox but...
- Discussion threads 2009-11-17
- AMD turbo boosts Flash Player 10.1 with ATI Stream technology
- AMD seems to be the more viable choice nowThey certainly have improved their offerings over Intel and NVIDIA, which both seem to be up in the air at the moment. Intel isn't focused on offering good mainstream performance for the dollar - they're only working on Atom and the...
- Discussion threads 2009-11-17
- Bing 2.0 debuts
- Bing Image SearchSpeaking of Bing, I recently did some Bing Image Searches, and found that they produced better results than Google Image Searches.Just keeps getting better.I don't know how anyone using Bing could find anything to complain about. In fact all the complaints I do see come from people...
- Discussion threads 2009-11-11
- USB Lock RP 5.21 (Windows)
- USB LOCK RP network information protector and centralized endpoint control to protect information in network PCs. Block, or allow removable storage use by class in real-time. Authorize Groups of devices by VID, PID,and/or specific devices by hardware ID to operate on specific clients or across the network. Automatically receive alerts,...
- Software downloads 2009-11-11
- File Encryption XP 1.5.149 (Windows)
- File Encryption XP is password protection software for Windows. Files are encrypted with hack-proof Blowfish algorithm. This tool works with USB drives, flash memory cards, HDDs, ZIP drives, and works with any Windows PC. When encrypting files, the passwords are not "inserted" inside the encrypted files, so if you lose...
- Software downloads 2009-11-11
- Nokia 3711 - sable (T-Mobile)
- Nokia fans in the United States don't get many breaks. Few of the company's phones make it to U.S. carriers and the models that land here tend to be basic handsets for making calls. The Nokia 3711 for T-Mobile is one such phone. Simple in form and function, the 3711...
- Product reviews 2009-11-10
- SoftAmbulance File Recovery 2.7 (Windows)
- Undelete and recover files deleted from hard disks, USB drives and flash memory drives reliably and automatically with SoftAmbulance File Recovery. The recovery tool is simple and easy to use, yet packs sophisticated data recovery technologies under the hood. Pre-recovery preview allows viewing deleted files before recovery, and the proprietary...
- Software downloads 2009-11-10
- CodySafe 1.0.0.92 (Windows)
- CodySafe is a menu utility for portable applications. Turn your USB flash drive to a computer-on-stick. You may add, manage and launch your portable applications with ease and comfort. You can manage documents, multimedia files and pictures. You can keep your disk healthy with Drive Doctor. You will always know...
- Software downloads 2009-11-10
- FlippingBook PDF Publisher 0.5.6 (Windows)
- FlippingBook PDF Publisher is a Windows desktop application that helps you to produce remarkable online and offline Flash books with page flipping effect. No coding is required. Simply import your PDF, configure the look&feel and hit the publish button. Enjoy the real page flipping effect. Independence You are not tied...
- Software downloads 2009-11-10
- Spark Loader 1.0 (Windows)
- Spark Loader is a boot loader for AVR microcontrollers, it is used for programming flash and EEPROM using a serial link between your computer and the microcontroller through any free COM port. Spark Loader consists of two parts: 1. On - chip boot loader: A hex file that resides at...
- Software downloads 2009-11-09
- Snow Leopard Cache Cleaner 5.0.3 (Mac)
- Snow Leopard Cache Cleaner is an award winning general purpose tool for Mac OS X. sLCC makes system maintenance simple with an easy point and click interface to many OS X functions. Novice and expert users alike will appreciate the powerful toolset sLCC provides. Snow Leopard Cache Cleaner is installed...
- Software downloads 2009-11-09
- IronKey reveals new, ultra-secure D200 USB flash drives
- Another bad designIf I can lose the cap and damage the connector, it's not secure. Why would anybody make a flash drive with a separate cap any more? I'll continue to wait for a secure drive with a good physical design that operates reliably with NO software installation on host...
- Discussion threads 2009-11-04
- Task Manager - Free Version (Mobile)
- Task Manager for BlackBerry!TaskManager for BlackBerry brings the familiar interface of Windows TaskManager to your BlackBerry.Now you can view a list of all running applications, view performance chart over time and see detailed system info like Free Flash Memory and Battery Temperature etc. The app allows you to drill down...
- Software downloads 2009-11-04
- Sony Ericsson Equinox TM717 - carbon black (T-Mobile)
- Photo gallery:Sony Ericsson Equinox TM717The Sony Ericsson Equinox is the first phone from the manufacturer to land at T-Mobile since the TM506. In many ways the Equinox is a fitting successor; like the TM506 it has a thin flip phone design and it sports a similar feature set that includes...
- Product reviews 2009-11-03
- What to look for in a Mini-HD camcorder
- Flip tends to get most of the attention when it comes to mini-HD camcorders, but there are more things to pay attention to besides name brand. Here are five things you should consider when purchasing a new Mini-HD camcorder: 1. Quality: Look for resolution and color quality....
- Blog posts 2009-11-02
Neighboring Terms
Premier Vendor Content Whitepapers, webcasts & resources from our Power Center Sponsors
- New Online Dashboard for IT Leaders
-
Read about top issues IT decision-makers face every day, plus get cost-effective solutions to real-life IT problems.
- Learn more >>
- Microsoft Dynamics CRM Online - Free Six-Month Trial for Eligible Organizations
-
Microsoft Dynamics CRM Online provides fast online access, simple contact management and better sales performance for a low monthly cost - the best value on the market today.
- Learn more about the free, six-month trial offer>>
- Save time with automated shipping solutions
-
The Business Essentials Guide provides you useful tools and templates to help grow your business and save you time with automated shipping solutions.
- Visit the UPS Business Essentials Guide
Meet Doc
-
-
Here to help you with your Document Management Needs
- Doc is an enigma. Born to a Russian ballerina and a German electrical engineer, he grew up in various locations in the United States. He’s seen the insides of more brands, versions, and generations of printer and printer-related hardware than almost anyone.
- To learn more about this mysterious figure check out his blog on ZDNet and his Workspace on TechRepublic. You’ll be glad you did.
-
Produced by
ZDNet and -
