94-413: The IBM Simon Personal Communicator (simply known as IBM Simon ) is a handheld, touchscreen PDA designed by International Business Machines (IBM), and manufactured by Mitsubishi Electric . Although the term " smartphone " was not coined until 1995, because of Simon's features and capabilities, it has been retrospectively referred to as the first true smartphone. BellSouth Cellular Corp. distributed
188-419: A CompactFlash slot or a combination of the two. Although designed for memory, Secure Digital Input/Output (SDIO) and CompactFlash cards were made available that provided peripheral accessories like Wi-Fi or digital cameras to devices with software support. Some PDAs also have a USB port, mainly for USB flash drives . Some PDAs use microSD cards, which are electronically compatible with SD cards, but have
282-535: A calculator , and some sort of memo (or "note") program. PDAs with wireless data connections also typically include an email client and a Web browser, and may or may not include telephony functionality. Many of the original PDAs, such as the Apple Newton and Palm Pilot , featured a touchscreen for user interaction, having only a few buttons—usually reserved for shortcuts to often-used programs. Some touchscreen PDAs, including Windows Mobile devices, had
376-471: A liquid-crystal display (LCD) and has PC Card support. Its internal hardware includes the Vadem VG230 ( CMOS ) system-on-a-chip (SoC) from NEC , MOS random-access memory (RAM) chips from Sony and Hitachi , flash memory ( floating-gate MOS ) chips from Intel and Hitachi, and Cirrus Logic modem chips. Each Simon was shipped with a charging base station, a nickel-cadmium battery , and
470-640: A 1024 GB flash chip, with eight stacked 96-layer V-NAND chips and with QLC technology. Flash memory stores information in an array of memory cells made from floating-gate transistors . In single-level cell (SLC) devices, each cell stores only one bit of information. Multi-level cell (MLC) devices, including triple-level cell (TLC) devices, can store more than one bit per cell. The floating gate may be conductive (typically polysilicon in most kinds of flash memory) or non-conductive (as in SONOS flash memory). In flash memory, each memory cell resembles
564-489: A 16 GB flash memory chip that was manufactured with 24 stacked NAND flash chips using a wafer bonding process. Toshiba also used an eight-layer 3D IC for their 32 GB THGBM flash chip in 2008. In 2010, Toshiba used a 16-layer 3D IC for their 128 GB THGBM2 flash chip, which was manufactured with 16 stacked 8 GB chips. In the 2010s, 3D ICs came into widespread commercial use for NAND flash memory in mobile devices . In 2016, Micron and Intel introduced
658-433: A 64 MB NOR flash memory chip. In 2009, Toshiba and SanDisk introduced NAND flash chips with QLC technology storing 4 bits per cell and holding a capacity of 64 Gbit. Samsung Electronics introduced triple-level cell (TLC) technology storing 3-bits per cell, and began mass-producing NAND chips with TLC technology in 2010. Charge trap flash (CTF) technology replaces the polysilicon floating gate, which
752-508: A PDA with digital cellphone functionality, the 9000 Communicator . Another early entrant in this market was Palm , with a line of PDA products which began in March 1996. Palm would eventually be the dominant vendor of PDAs until the rising popularity of Pocket PC devices in the early 2000s. By the mid-2000s most PDAs had morphed into smartphones as classic PDAs without cellular radios were increasingly becoming uncommon. A typical PDA has
846-517: A PDA, reducing the number of textbooks students were required to carry. Brighton and SUSSEX Medical School in the UK was the first medical school to provide wide scale use of PDAs to its undergraduate students. The learning opportunities provided by having PDAs complete with a suite of key medical texts were studied with results showing that learning occurred in context with timely access to key facts and through consolidation of knowledge via repetition. The PDA
940-415: A boom in the 1990s and 2000s, PDA's were mostly displaced by the widespread adoption of more highly capable smartphones , in particular those based on iOS and Android in the late 2000's, and thus saw a rapid decline. A PDA has an electronic visual display . Most models also have audio capabilities, allowing usage as a portable media player , and also enabling many of them to be used as telephones. By
1034-548: A certain number of faults (NOR flash, as is used for a BIOS ROM, is expected to be fault-free). Manufacturers try to maximize the amount of usable storage by shrinking the size of the transistors or cells, however the industry can avoid this and achieve higher storage densities per die by using 3D NAND, which stacks cells on top of each other. NAND flash cells are read by analysing their response to various voltages. NAND flash uses tunnel injection for writing and tunnel release for erasing. NAND flash memory forms
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#17327795491801128-517: A charge-trapping mechanism for NOR flash memory cells. CTF was later commercialized by AMD and Fujitsu in 2002. 3D V-NAND (vertical NAND) technology stacks NAND flash memory cells vertically within a chip using 3D charge trap flash (CTP) technology. 3D V-NAND technology was first announced by Toshiba in 2007, and the first device, with 24 layers, was first commercialized by Samsung Electronics in 2013. 3D integrated circuit (3D IC) technology stacks integrated circuit (IC) chips vertically into
1222-490: A detachable stylus to facilitate making selections. The user interacts with the device by tapping the screen to select buttons or issue commands, or by dragging a finger (or the stylus) on the screen to make selections or scroll. Typical methods of entering text on touchscreen PDAs include: Despite research and development projects, end-users experienced mixed results with handwriting recognition systems. Some found it frustrating and inaccurate, while others were satisfied with
1316-425: A more typical 10,000 or 100,000 erase cycles, up to 1,000,000 erase cycles. NOR-based flash was the basis of early flash-based removable media; CompactFlash was originally based on it, though later cards moved to less expensive NAND flash. NAND flash has reduced erase and write times, and requires less chip area per cell, thus allowing greater storage density and lower cost per bit than NOR flash. However,
1410-474: A much smaller physical size. While early PDAs connected to a user's personal computer via serial ports and other proprietary connections , later models connect via a USB cable. Older PDAs were unable to connect to each other via USB , as their implementations of USB did not support acting as the "host". Some early PDAs were able to connect to the Internet indirectly by means of an external modem connected via
1504-578: A photo on the front page of the Money section showing Frank Canova, IBM's lead architect and inventor of the smartphone, holding the Sweetspot prototype. After a very successful prototype demonstration at COMDEX, IBM began work on the commercial product, code named "Angler". The IBM device was manufactured by Mitsubishi Electric , which integrated features from its own wireless personal digital assistant (PDA) and cellular radio technologies while building
1598-518: A planar charge trap cell into a cylindrical form. As of 2020, 3D NAND flash memories by Micron and Intel instead use floating gates, however, Micron 128 layer and above 3D NAND memories use a conventional charge trap structure, due to the dissolution of the partnership between Micron and Intel. Charge trap 3D NAND flash is thinner than floating gate 3D NAND. In floating gate 3D NAND, the memory cells are completely separated from one another, whereas in charge trap 3D NAND, vertical groups of memory cells share
1692-425: A protective leather cover. Optional accessories included a PCMCIA pager card designed by Motorola, an RS-232 adapter cable for use with PC-Link to access files from a personal computer, and an RJ11 adapter cable to allow voice and data calls to be made over POTS landlines. The RJ11 adapter helped users reduce expensive cellular phone bills or make calls where cellular coverage didn't exist in 1994. The Simon used
1786-463: A separate flash memory controller chip. The NAND type is found mainly in memory cards , USB flash drives , solid-state drives (those produced since 2009), feature phones , smartphones , and similar products, for general storage and transfer of data. NAND or NOR flash memory is also often used to store configuration data in digital products, a task previously made possible by EEPROM or battery-powered static RAM . A key disadvantage of flash memory
1880-421: A separate die inside the package. The origins of flash memory can be traced back to the development of the floating-gate MOSFET (FGMOS) , also known as the floating-gate transistor. The original MOSFET was invented at Bell Labs between 1955 and 1960, after Frosch and Derick discovered surface passivation and used their discovery to create the first planar transistors. Dawon Kahng went on to develop
1974-489: A single 3D IC chip package. Toshiba introduced 3D IC technology to NAND flash memory in April 2007, when they debuted a 16 GB eMMC compliant (product number THGAM0G7D8DBAI6, often abbreviated THGAM on consumer websites) embedded NAND flash memory chip, which was manufactured with eight stacked 2 GB NAND flash chips. In September 2007, Hynix Semiconductor (now SK Hynix ) introduced 24-layer 3D IC technology, with
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#17327795491802068-424: A single memory product. A single-level NOR flash cell in its default state is logically equivalent to a binary "1" value, because current will flow through the channel under application of an appropriate voltage to the control gate, so that the bitline voltage is pulled down. A NOR flash cell can be programmed, or set to a binary "0" value, by the following procedure: To erase a NOR flash cell (resetting it to
2162-409: A single supply voltage and produce the high voltages that are required using on-chip charge pumps . Over half the energy used by a 1.8 V-NAND flash chip is lost in the charge pump itself. Since boost converters are inherently more efficient than charge pumps, researchers developing low-power SSDs have proposed returning to the dual Vcc/Vpp supply voltages used on all early flash chips, driving
2256-488: A standard metal–oxide–semiconductor field-effect transistor (MOSFET) except that the transistor has two gates instead of one. The cells can be seen as an electrical switch in which current flows between two terminals (source and drain) and is controlled by a floating gate (FG) and a control gate (CG). The CG is similar to the gate in other MOS transistors, but below this, there is the FG insulated all around by an oxide layer. The FG
2350-482: A technology known as CMOS Under the Array/CMOS Under Array (CUA), Core over Periphery (COP), Periphery Under Cell (PUA), or Xtacking, in which the control circuitry for the flash memory is placed under or above the flash memory cell array. This has allowed for an increase in the number of planes or sections a flash memory chip has, increasing from 2 planes to 4, without increasing the area dedicated to
2444-843: A time. NAND flash also uses floating-gate transistors , but they are connected in a way that resembles a NAND gate : several transistors are connected in series, and the bit line is pulled low only if all the word lines are pulled high (above the transistors' V T ). These groups are then connected via some additional transistors to a NOR-style bit line array in the same way that single transistors are linked in NOR ;flash. Compared to NOR flash, replacing single transistors with serial-linked groups adds an extra level of addressing. Whereas NOR flash might address memory by page then word, NAND flash might address it by page, word and bit. Bit-level addressing suits bit-serial applications (such as hard disk emulation), which access only one bit at
2538-453: A time. Execute-in-place applications, on the other hand, require every bit in a word to be accessed simultaneously. This requires word-level addressing. In any case, both bit and word addressing modes are possible with either NOR or NAND flash. To read data, first the desired group is selected (in the same way that a single transistor is selected from a NOR array). Next, most of the word lines are pulled up above V T2 , while one of them
2632-402: A touchscreen for navigation, a memory card slot for data storage, and IrDA , Bluetooth and/or Wi-Fi . However, some PDAs may not have a touchscreen , using soft keys , a directional pad, and a numeric keypad or a thumb keyboard for input. To have the functions expected of a PDA, a device's software typically includes an appointment calendar , a to-do list , an address book for contacts,
2726-473: A touchscreen or small-scale keyboard was slower than a full-size keyboard. Transferring data to a PDA via the computer was, therefore, a lot quicker than having to manually input all data on the handheld device. Most PDAs come with the ability to synchronize to a computer. This is done through synchronization software provided with the handheld, or sometimes with the computer's operating system. Examples of synchronization software include: These programs allow
2820-506: A type of flash memory with a charge trap method. In 1998, Boaz Eitan of Saifun Semiconductors (later acquired by Spansion ) patented a flash memory technology named NROM that took advantage of a charge trapping layer to replace the conventional floating gate used in conventional flash memory designs. In 2000, an Advanced Micro Devices (AMD) research team led by Richard M. Fastow, Egyptian engineer Khaled Z. Ahmed and Jordanian engineer Sameer Haddad (who later joined Spansion) demonstrated
2914-413: A user to make and receive telephone calls, facsimiles, emails and cellular pages. Not only did the prototype have many PDA features including a calendar, address book and notepad, but also demonstrated other digital services such as maps, stocks and news before they were widely available. COMDEX show attendees and the press showed interest in the device. The day after Sweetspot's debut, USA Today featured
IBM Simon - Misplaced Pages Continue
3008-450: A variation, the floating-gate MOSFET, with Taiwanese-American engineer Simon Min Sze at Bell Labs in 1967. They proposed that it could be used as floating-gate memory cells for storing a form of programmable read-only memory ( PROM ) that is both non-volatile and re-programmable. Early types of floating-gate memory included EPROM (erasable PROM) and EEPROM (electrically erasable PROM) in
3102-444: Is an electrically insulating tunnel oxide layer between the floating gate and the silicon, so the gate "floats" above the silicon. The oxide keeps the electrons confined to the floating gate. Degradation or wear (and the limited endurance of floating gate Flash memory) occurs due to the extremely high electric field (10 million volts per centimeter) experienced by the oxide. Such high voltage densities can break atomic bonds over time in
3196-525: Is interposed between the CG and the MOSFET channel. Because the FG is electrically isolated by its insulating layer, electrons placed on it are trapped. When the FG is charged with electrons, this charge screens the electric field from the CG, thus, increasing the threshold voltage (V T ) of the cell. This means that the V T of the cell can be changed between the uncharged FG threshold voltage (V T1 ) and
3290-556: Is often employed in scenarios where cost-effective, high-capacity storage is crucial, such as in USB drives, memory cards, and solid-state drives ( SSDs ). The primary differentiator lies in their use cases and internal structures. NOR flash is optimal for applications requiring quick access to individual bytes, like in embedded systems for program execution. NAND flash, on the other hand, shines in scenarios demanding cost-effective, high-capacity storage with sequential data access. Flash memory
3384-636: Is programmed in blocks while EEPROM is programmed in bytes. According to Toshiba, the name "flash" was suggested by Masuoka's colleague, Shōji Ariizumi, because the erasure process of the memory contents reminded him of the flash of a camera . Masuoka and colleagues presented the invention of NOR flash in 1984, and then NAND flash at the IEEE 1987 International Electron Devices Meeting (IEDM) held in San Francisco. Toshiba commercially launched NAND flash memory in 1987. Intel Corporation introduced
3478-422: Is pulled up to V I . The series group will conduct (and pull the bit line low) if the selected bit has not been programmed. Despite the additional transistors, the reduction in ground wires and bit lines allows a denser layout and greater storage capacity per chip. (The ground wires and bit lines are actually much wider than the lines in the diagrams.) In addition, NAND flash is typically permitted to contain
3572-484: Is sandwiched between a blocking gate oxide above and a tunneling oxide below it, with an electrically insulating silicon nitride layer; the silicon nitride layer traps electrons. In theory, CTF is less prone to electron leakage, providing improved data retention. Because CTF replaces the polysilicon with an electrically insulating nitride, it allows for smaller cells and higher endurance (lower degradation or wear). However, electrons can become trapped and accumulate in
3666-510: Is that it can endure only a relatively small number of write cycles in a specific block. NOR flash is known for its direct random access capabilities, making it apt for executing code directly. Its architecture allows for individual byte access, facilitating faster read speeds compared to NAND flash. NAND flash memory operates with a different architecture, relying on a serial access approach. This makes NAND suitable for high-density data storage but less efficient for random access tasks. NAND flash
3760-513: Is thus highly suitable for use in mass-storage devices, such as memory cards and solid-state drives (SSD). For example, SSDs store data using multiple NAND flash memory chips. The first NAND-based removable memory card format was SmartMedia , released in 1995. Many others followed, including MultiMediaCard , Secure Digital , Memory Stick , and xD-Picture Card . A new generation of memory card formats, including RS-MMC , miniSD and microSD , feature extremely small form factors. For example,
3854-485: Is used in computers , PDAs , digital audio players , digital cameras , mobile phones , synthesizers , video games , scientific instrumentation , industrial robotics , and medical electronics . Flash memory has a fast read access time but it is not as fast as static RAM or ROM. In portable devices, it is preferred to use flash memory because of its mechanical shock resistance since mechanical drives are more prone to mechanical damage. Because erase cycles are slow,
IBM Simon - Misplaced Pages Continue
3948-554: The NOR and NAND logic gates . Both use the same cell design, consisting of floating-gate MOSFETs . They differ at the circuit level depending on whether the state of the bit line or word lines is pulled high or low: in NAND flash, the relationship between the bit line and the word lines resembles a NAND gate; in NOR flash, it resembles a NOR gate. Flash memory, a type of floating-gate memory,
4042-502: The "1" state), a large voltage of the opposite polarity is applied between the CG and source terminal, pulling the electrons off the FG through Fowler–Nordheim tunneling (FN tunneling). This is known as Negative gate source source erase. Newer NOR memories can erase using negative gate channel erase, which biases the wordline on a NOR memory cell block and the P-well of the memory cell block to allow FN tunneling to be carried out, erasing
4136-712: The 1970s. However, early floating-gate memory required engineers to build a memory cell for each bit of data, which proved to be cumbersome, slow, and expensive, restricting floating-gate memory to niche applications in the 1970s, such as military equipment and the earliest experimental mobile phones . Modern EEPROM based on Fowler-Nordheim tunnelling to erase data was invented by Bernward and patented by Siemens in 1974. And further developed between 1976 and 1978 by Eliyahou Harari at Hughes Aircraft Company and George Perlegos and others at Intel. This led to Masuoka's invention of flash memory at Toshiba in 1980. The improvement between EEPROM and flash being that flash
4230-414: The 1990's to 2006, typically had an IrDA ( infrared ) port allowing short-range, line-of-sight wireless communication. Few later models used this technology, as it had been supplanted by Bluetooth and Wi-Fi. IrDA allows communication between two PDAs, or between a PDA and any device with an IrDA port or adapter. Some contemporary printers have IrDA receivers, allowing IrDA-equipped PDAs to print to them, if
4324-438: The FG is charged. The binary value of the cell is sensed by determining whether there is current flowing through the transistor when V I is asserted on the CG. In a multi-level cell device, which stores more than one bit per cell, the amount of current flow is sensed (rather than simply its presence or absence), in order to determine more precisely the level of charge on the FG. Floating gate MOSFETs are so named because there
4418-540: The I/O interface of NAND flash does not provide a random-access external address bus. Rather, data must be read on a block-wise basis, with typical block sizes of hundreds to thousands of bits. This makes NAND flash unsuitable as a drop-in replacement for program ROM, since most microprocessors and microcontrollers require byte-level random access. In this regard, NAND flash is similar to other secondary data storage devices , such as hard disks and optical media , and
4512-672: The IBM Simon in the United States between August 1994 and February 1995, selling 50,000 units. The Simon Personal Communicator was the first personal digital assistant or PDA to include telephony features (make phone calls ). The battery lasted only an hour, and flip phones became increasingly slim which led to its demise. With advances in MOSFET (metal–oxide–semiconductor field-effect transistor, or MOS transistor) technology enabling smaller integrated circuit chips be powered and
4606-731: The IBM device. IBM initially approached Motorola to manufacture the product, but Motorola rejected the offer, concerned that IBM could become a potential rival mobile manufacturer. IBM then approached Mitsubishi to build the device. BellSouth executives gave the finished product its final name, "Simon Personal Communicator", before its public debut at the Wireless World Conference in November 1993. BellSouth Cellular had planned to begin selling Simon in May 1994, but due to problems with
4700-740: The PDA and Google's servers. RIM sells BlackBerry Enterprise Server to corporations so that corporate BlackBerry users can wirelessly synchronize their PDAs with the company's Microsoft Exchange Server , IBM Lotus Domino , or Novell GroupWise servers. Email, calendar entries, contacts, tasks, and memos kept on the company's server are automatically synchronized with the BlackBerry. The most common operating systems pre-installed on PDAs are: Other, rarely used operating systems: Some PDAs include Global Positioning System (GPS) receivers. Other PDAs are compatible with external GPS-receiver add-ons that use
4794-715: The PDA directly, using a cable, or may use wireless technology such as infrared or Bluetooth to connect to the PDA. Newer PDAs, such as the HTC HD2 , Palm Pre , Pre Plus , Pixi , and Pixi Plus , as well as devices running the Android operating system, include more advanced forms of touchscreen that can register multiple touches simultaneously. These " multi-touch " displays allow for more sophisticated interfaces using various gestures entered with one or more fingers. Although many early PDAs did not have memory card slots, later models had either some form of Secure Digital (SD) slot,
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#17327795491804888-458: The PDA manufacturers (for example, GoldMine and IBM Lotus Notes ). Some PDAs can synchronize some or all of their data using their wireless networking capabilities, rather than having to be directly connected to a personal computer via a cable. Devices running Palm's webOS or Google's Android operating system primarily sync with the cloud . For example, if Gmail is used, information in contacts, email, and calendars can be synchronized between
4982-528: The PDA to be synchronized with a personal information manager, which may be part of the computer's operating system, provided with the PDA, or sold separately by a third party. For example, the RIM BlackBerry came with RIM's Desktop Manager program, which can synchronize to both Microsoft Outlook and ACT!. Other PDAs come only with their own proprietary software. For example, some early Palm OS PDAs came only with Palm Desktop, while later Palm PDAs—such as
5076-432: The PDA's operating system supports it. Universal PDA keyboards designed for these older PDAs use infrared technology, due to cost and a lack of wireless interference. Most PDAs can synchronize their data with applications on a user's computer, allowing the user to update contact, schedule, or other information on their computer, using software such as Microsoft Outlook or ACT! , and have that same data transferred to
5170-421: The PDA's GPS functions can be used for navigation. Underwater divers can use PDAs to plan breathing gas mixtures and decompression schedules using software such as "V-Planner". Flash memory Flash memory is an electronic non-volatile computer memory storage medium that can be electrically erased and reprogrammed. The two main types of flash memory, NOR flash and NAND flash , are named for
5264-927: The PDA's processor and screen to display location information. PDAs with GPS functionality can be used for automotive navigation. Integrated PDA's were fitted as standard on new cars throughout the 2000's. PDA-based GPS can also display traffic conditions, perform dynamic routing, and show known locations of roadside mobile radar guns. TomTom , Garmin , and iGO offered GPS navigation software for PDAs. Some businesses and government organizations rely upon rugged PDAs, sometimes known as enterprise digital assistants (EDAs) or mobile computers , for mobile data applications. These PDAs have features that make them more robust and able to handle inclement weather, jolts, and moisture. EDAs often have extra features for data capture, such as barcode readers , radio-frequency identification (RFID) readers, magnetic stripe card readers, or smart card readers. These features are designed to facilitate
5358-615: The PDA's serial port or "sync" connector, or directly by using an expansion card that provided an Ethernet port. Most PDAs use Bluetooth, a popular wireless protocol for mobile devices. Bluetooth can be used to connect keyboards, headsets, GPS receivers , and other nearby accessories. It is also possible to transfer files between PDAs that have Bluetooth. Many PDAs have Wi-Fi wireless network connectivity and can connect to Wi-Fi hotspots. All smartphones, and some other PDAs, can connect to Wireless Wide Area Networks, such as those provided by cellular telecommunications companies. Older PDAs, from
5452-513: The PDA—or transfer updated information from the PDA back to the computer, eliminating the need for the user to update their data in two places. Synchronization also prevents the loss of information stored on the device if it is lost, stolen, or destroyed. When the PDA is repaired or replaced, it can be "re-synced" with the computer, restoring the user's data. Some users found that data input was quicker on their computer than on their PDA since text input via
5546-499: The Treo 650—have the ability to sync to Palm Desktop or Microsoft Outlook. Microsoft's ActiveSync and Windows Mobile Device Center only synchronized with Microsoft Outlook or a Microsoft Exchange server. Third-party synchronization software was also available for some PDAs from companies like CommonTime and CompanionLink . Third-party software can be used to synchronize PDAs to other personal information managers that are not supported by
5640-466: The cell block. Older memories used source erase, in which a high voltage was applied to the source and then electrons from the FG were moved to the source. Modern NOR flash memory chips are divided into erase segments (often called blocks or sectors). The erase operation can be performed only on a block-wise basis; all the cells in an erase segment must be erased together. Programming of NOR cells, however, generally can be performed one byte or word at
5734-502: The cell by increasing the MOSFET's threshold voltage. This, in turn, changes the drain-source current that flows through the transistor for a given gate voltage, which is ultimately used to encode a binary value. The Fowler-Nordheim tunneling effect is reversible, so electrons can be added to or removed from the floating gate, processes traditionally known as writing and erasing. Despite the need for relatively high programming and erasing voltages, virtually all flash chips today require only
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#17327795491805828-402: The cells are logically set to 1. Data can only be programmed in one pass to a page in a block that was erased. The programming process is set one or more cells from 1 to 0. Any cells that have been set to 0 by programming can only be reset to 1 by erasing the entire block. This means that before new data can be programmed into a page that already contains data, the current contents of the page plus
5922-584: The control or periphery circuitry. This increases the number of IO operations per flash chip or die, but it also introduces challenges when building capacitors for charge pumps used to write to the flash memory. Some flash dies have as many as 6 planes. As of August 2017, microSD cards with a capacity up to 400 GB (400 billion bytes) are available. The same year, Samsung combined 3D IC chip stacking with its 3D V-NAND and TLC technologies to manufacture its 512 GB KLUFG8R1EM flash memory chip with eight stacked 64-layer V-NAND chips. In 2019, Samsung produced
6016-404: The core of the removable USB storage devices known as USB flash drives , as well as most memory card formats and solid-state drives available today. The hierarchical structure of NAND flash starts at a cell level which establishes strings, then pages, blocks, planes and ultimately a die. A string is a series of connected NAND cells in which the source of one cell is connected to the drain of
6110-468: The device's software, the Simon did not become available to consumers until August 16, 1994. BellSouth Cellular initially offered the Simon throughout its 15-state service area for US$ 899 with a two-year service contract or US$ 1099 without a contract. Later in the product's life, BellSouth Cellular reduced the price to US$ 599 with a two-year contract. BellSouth Cellular sold approximately 50,000 units during
6204-456: The early 2000s, nearly all PDA models had the ability to access the Internet, intranets or extranets via Wi-Fi or Wireless WANs , and since then generally included a web browser . Sometimes, instead of buttons, later PDAs employ touchscreen technology. The first PDA, the Organiser , was released in 1984 by Psion , followed by Psion's Series 3 , in 1991. The latter began to resemble
6298-503: The file system from Datalight ROM-DOS along with file compression from Stacker . IBM created a unique touch-screen user interface for Simon; no DOS prompt existed. This user interface software layer for Simon was known as the Navigator. The Simon could be upgraded to run third party applications either by inserting a PCMCIA card or by downloading an application to the phone's internal memory. PDA Dimensions developed "DispatchIt",
6392-497: The first commercial NOR type flash chip in 1988. NOR-based flash has long erase and write times, but provides full address and data buses , allowing random access to any memory location . This makes it a suitable replacement for older read-only memory (ROM) chips, which are used to store program code that rarely needs to be updated, such as a computer's BIOS or the firmware of set-top boxes . Its endurance may be from as little as 100 erase cycles for an on-chip flash memory, to
6486-462: The flash storage device (such as SSD ), the data actually written to the flash memory may be 0011 1100. Vertical NAND (V-NAND) or 3D NAND memory stacks memory cells vertically and uses a charge trap flash architecture. The vertical layers allow larger areal bit densities without requiring smaller individual cells. It is also sold under the trademark BiCS Flash , which is a trademark of Kioxia Corporation (formerly Toshiba Memory Corporation). 3D NAND
6580-418: The floating gate. This is why data retention goes down and the risk of data loss increases with increasing degradation. The silicon oxide in a cell degrades with every erase operation. The degradation increases the amount of negative charge in the cell over time due to trapped electrons in the oxide and negates some of the control gate voltage, this over time also makes erasing the cell slower, so to maintain
6674-435: The high Vpp voltage for all flash chips in an SSD with a single shared external boost converter. In spacecraft and other high-radiation environments, the on-chip charge pump is the first part of the flash chip to fail, although flash memories will continue to work – in read-only mode – at much higher radiation levels. In NOR flash, each cell has one end connected directly to ground, and
6768-415: The higher charged FG threshold voltage (V T2 ) by changing the FG charge. In order to read a value from the cell, an intermediate voltage (V I ) between V T1 and V T2 is applied to the CG. If the channel conducts at V I , the FG must be uncharged (if it were charged, there would not be conduction because V I is less than V T2 ). If the channel does not conduct at the V I , it indicates that
6862-813: The large block sizes used in flash memory erasing give it a significant speed advantage over non-flash EEPROM when writing large amounts of data. As of 2019, flash memory costs greatly less than byte-programmable EEPROM and had become the dominant memory type wherever a system required a significant amount of non-volatile solid-state storage . EEPROMs, however, are still used in applications that require only small amounts of storage, e.g. in SPD implementations on computer memory modules. Flash memory packages can use die stacking with through-silicon vias and several dozen layers of 3D TLC NAND cells (per die) simultaneously to achieve capacities of up to 1 tebibyte per package using 16 stacked dies and an integrated flash controller as
6956-659: The microSD card has an area of just over 1.5 cm , with a thickness of less than 1 mm. NAND flash has achieved significant levels of memory density as a result of several major technologies that were commercialized during the late 2000s to early 2010s. NOR flash was the most common type of Flash memory sold until 2005, when NAND flash overtook NOR flash in sales. Multi-level cell (MLC) technology stores more than one bit in each memory cell . NEC demonstrated multi-level cell (MLC) technology in 1998, with an 80 Mb flash memory chip storing 2 bits per cell. STMicroelectronics also demonstrated MLC in 2000, with
7050-610: The more familiar PDA style, including a full keyboard. The term PDA was first used on 7 January 1992 by Apple Inc. CEO John Sculley at the Consumer Electronics Show in Las Vegas , Nevada , referring to the Apple Newton . In 1994, IBM introduced the first PDA with analog cellular phone functionality, the IBM Simon , which can also be considered the first smartphone. Then in 1996, Nokia introduced
7144-422: The new data must be copied to a new, erased page. If a suitable erased page is available, the data can be written to it immediately. If no erased page is available, a block must be erased before copying the data to a page in that block. The old page is then marked as invalid and is available for erasing and reuse. This is different from operating system LBA view, for example, if operating system writes 1100 0011 to
7238-414: The next one. Depending on the NAND technology, a string typically consists of 32 to 128 NAND cells. Strings are organised into pages which are then organised into blocks in which each string is connected to a separate line called a bitline. All cells with the same position in the string are connected through the control gates by a wordline. A plane contains a certain number of blocks that are connected through
7332-474: The nitride, leading to degradation. Leakage is exacerbated at high temperatures since electrons become more excited with increasing temperatures. CTF technology however still uses a tunneling oxide and blocking layer which are the weak points of the technology, since they can still be damaged in the usual ways (the tunnel oxide can be degraded due to extremely high electric fields and the blocking layer due to Anode Hot Hole Injection (AHHI). Degradation or wear of
7426-413: The number of bits increases, the number of possible states also increases and thus the cell is less tolerant of adjustments to programming voltages, because there is less space between the voltage levels that define each state in a cell. The process of moving electrons from the control gate and into the floating gate is called Fowler–Nordheim tunneling , and it fundamentally changes the characteristics of
7520-415: The only aftermarket , third-party application developed for Simon. It was an early predecessor to "Remote Desktop" software. The DispatchIt application costs were US$ 2,999 for the host PC software and US$ 299 for each Simon software client. Personal digital assistant A personal digital assistant ( PDA ) is a multi-purpose mobile device which functions as a personal information manager. Following
7614-516: The other end connected directly to a bit line. This arrangement is called "NOR flash" because it acts like a NOR gate: when one of the word lines (connected to the cell's CG) is brought high, the corresponding storage transistor acts to pull the output bit line low. NOR flash continues to be the technology of choice for embedded applications requiring a discrete non-volatile memory device. The low read latencies characteristic of NOR devices allow for both direct code execution and data storage in
7708-435: The oxides is the reason why flash memory has limited endurance, and data retention goes down (the potential for data loss increases) with increasing degradation, since the oxides lose their electrically insulating characteristics as they degrade. The oxides must insulate against electrons to prevent them from leaking which would cause data loss. In 1991, NEC researchers including N. Kodama, K. Oyama and Hiroki Shirai described
7802-413: The performance and reliability of the NAND chip, the cell must be retired from use. Endurance also decreases with the number of bits in a cell. With more bits in a cell, the number of possible states (each represented by a different voltage level) in a cell increases and is more sensitive to the voltages used for programming. Voltages may be adjusted to compensate for degradation of the silicon oxide, and as
7896-433: The product's six months on the market. In addition to its ability to make and receive cellular phone calls, Simon was also able to send and receive faxes , e-mails and cellular pages . Simon featured many applications, including an address book, calendar, appointment scheduler, calculator, world time clock, electronic notepad, handwritten annotations, and standard and predictive stylus input screen keyboards. It features
7990-481: The proliferation of wireless mobile networks , IBM engineer Frank Canova realised that chip-and-wireless technology was becoming small enough to use in handheld devices . IBM debuted a prototype device, code named "Sweetspot", on November 16, 1992, at the COMDEX computer and technology trade show in Las Vegas , Nevada, United States. The Sweetspot prototype combined a mobile phone and PDA into one device, allowing
8084-541: The quality of the recognition. Touchscreen PDAs intended for business use, such as the BlackBerry and Palm Treo , usually also offer full keyboards and scroll wheels or thumbwheels to facilitate data entry and navigation. Many touchscreen PDAs support some form of external keyboard as well. Specialized folding keyboards, which offer a full-sized keyboard but collapse into a compact size for transport, were made available for many models. External keyboards may attach to
8178-459: The relatively thin oxide, gradually degrading its electrically insulating properties and allowing electrons to be trapped in and pass through freely (leak) from the floating gate into the oxide, increasing the likelihood of data loss since the electrons (the quantity of which is used to represent different charge levels, each assigned to a different combination of bits in MLC Flash) are normally in
8272-410: The same bitline. A flash die consists of one or more planes, and the peripheral circuitry that is needed to perform all the read, write, and erase operations. The architecture of NAND flash means that data can be read and programmed (written) in pages, typically between 4 KiB and 16 KiB in size, but can only be erased at the level of entire blocks consisting of multiple pages. When a block is erased, all
8366-407: The same silicon nitride material. An individual memory cell is made up of one planar polysilicon layer containing a hole filled by multiple concentric vertical cylinders. The hole's polysilicon surface acts as the gate electrode. The outermost silicon dioxide cylinder acts as the gate dielectric, enclosing a silicon nitride cylinder that stores charge, in turn enclosing a silicon dioxide cylinder as
8460-418: The tunnel dielectric that surrounds a central rod of conducting polysilicon which acts as the conducting channel. Memory cells in different vertical layers do not interfere with each other, as the charges cannot move vertically through the silicon nitride storage medium, and the electric fields associated with the gates are closely confined within each layer. The vertical collection is electrically identical to
8554-432: The use of these devices to scan product or item codes. Typical applications include: PDAs and handheld devices were allowed in many classrooms for digital note-taking. Students could spell-check, modify, and amend their class notes on a PDA. Some educators distributed course material through the Internet or infrared file-sharing functions of the PDA. Textbook publishers released e-books , which can be uploaded directly to
8648-559: Was an important addition to the learning ecology rather than a replacement. Software companies also developed PDA programs to meet the instructional needs of educational institutions, such as dictionaries, thesauri , word processing software, encyclopedias, webinars and digital lesson planners. PDAs were used by music enthusiasts to play a variety of music file formats. Many PDAs include the functionality of an MP3 player. Road rally enthusiasts can use PDAs to calculate distance, speed, and time. This information may be used for navigation, or
8742-417: Was first announced by Toshiba in 2007. V-NAND was first commercially manufactured by Samsung Electronics in 2013. V-NAND uses a charge trap flash geometry (which was commercially introduced in 2002 by AMD and Fujitsu ) that stores charge on an embedded silicon nitride film. Such a film is more robust against point defects and can be made thicker to hold larger numbers of electrons. V-NAND wraps
8836-616: Was invented by Fujio Masuoka at Toshiba in 1980 and is based on EEPROM technology. Toshiba began marketing flash memory in 1987. EPROMs had to be erased completely before they could be rewritten. NAND flash memory, however, may be erased, written, and read in blocks (or pages), which generally are much smaller than the entire device. NOR flash memory allows a single machine word to be written – to an erased location – or read independently. A flash memory device typically consists of one or more flash memory chips (each holding many flash memory cells), along with
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