Digital Media Guide; Portable digital media for computers, digital cameras, and other devices Page 2
· High-Quality Connectors: Kingston's flash storage devices have connectors rated for more than 10,000 insertions.
· Operating Temperature and Humidity: 0° C ~ 60° C, 5% ~ 95% humidity
· High-Capacity: Flash storage devices can provide large storage capacities in a very small form factor. This flexibility makes them ideal for consumer uses, such as digital film or storage for MP3 music, where portability and convenience are important.
Please note: Some of the listed capacity is used for formatting and other functions and thus is not available for data storage. Please see Section 2 for details.
· High-Performance: Kingston's Elite Pro and Hi-Speed DataTraveler USB flash drives are faster than many standard flash products and many competitive products. Kingston's engineers test and select high-performance controllers to ensure that Kingston's flash cards are among the performance leaders. Please see the Appendix for information about USB and Hi-Speed USB performance. Kingston standard flash products offer moderate performance levels for general purpose applications.
· Low Power Consumption: Unlike standard DRAM memory that needs to be constantly powered on to maintain its data, flash memory is non-volatile and does not require power to maintain its data. Flash memory's low power consumption results in longer battery life for the host device.
· Plug and Play Support: Kingston's flash memory line supports plug and play. With plug and play technology and compatible computer operating systems, a flash storage device can be inserted into a computer or a flash media reader and be quickly recognized and accessed by the computer.
· Hot-Swapping Support: Hot-swapping allows for plugging or unplugging flash storage devices into a compatible computer or reader without needing to power off and restart the computer. This feature enhances the portability and convenience of flash storage devices for transferring data, pictures or music between two computers or devices.
4.0 Non-Volatile NOR and NAND Flash Technologies
Unlike Dynamic Random Access Memory (DRAM), flash memory is non-volatile. Non-volatile memory retains data even without being powered-on. For example, when a computer is turned off, all data that was in the computer's DRAM memory is lost; however, when a flash storage device is removed from a digital camera, all data (and pictures) remains saved on the flash storage device. The ability to retain data is key for flash memory applications such as digital film for digital cameras, cell phones, PDAs and other transportable devices.
There are two major technologies of flash memory: NOR and NAND. Each technology has its strengths that make it ideal for different kinds of applications, as summarized in the table below:
|Page-Mode Data Access||
|Random Byte Level Access||
BIOS Storage for PCs
Networking Device Memory
Solid State Disk Drives
Set Top Boxes
4.1 NOR Flash Memory
NOR, named after the specific data mapping technology (Not OR), is a high-speed Flash technology. NOR Flash memory provides high-speed random-access capabilities, being able to read and write data in specific locations in the memory without having to access the memory in sequential mode. Unlike NAND Flash, NOR Flash allows the retrieval of data as small as a single byte. NOR Flash excels in applications where data is randomly retrieved or written. NOR is most often found built into cellular phones and PDAs and is also used in computers to store the BIOS program that runs to provide the start-up functionality.
4.2 NAND Flash Memory
NAND Flash was invented after NOR Flash, and is named after the specific mapping technology used for data (Not AND). NAND Flash memory reads and writes in highspeed, sequential mode, handling data in small, block sizes ("pages"). NAND Flash can retrieve or write data as single pages, but cannot retrieve individual bytes like NOR Flash.
NAND Flash memory is commonly found in solid-state hard drives, audio and video digital media devices, television set-top boxes, digital cameras and other devices where data is generally written or read sequentially.
For example, most digital cameras use NAND-Flash based digital film, as pictures are usually taken and stored sequentially. NAND-Flash is also more efficient when pictures are read back, as it transfers whole pages of data very quickly. As a sequential storage medium, NAND Flash is ideal for data storage.
NAND Flash memory is less expensive than NOR Flash memory, and can accommodate more storage capacity in the same die size.
Flash memory which stores a single bit per cell is known as Single-Level Cell (SLC) Flash.
5.0 Die-Stacking and Multi-Level Cell/Multi-Bit Cell Flash technologies
In order to economically increase the amount of bit-storage that a flash memory chip can accommodate, manufacturers often utilize die-stacking and multi-level cell or multi-bit cell technologies. These technologies result in a flash memory chip having the capability to store more data in a single chip.
Many semiconductor manufacturers use a "die-stacking" technique to double a flash memory chip's capacity. After the semiconductor wafer fabrication process, they cut out the flash memory silicon "die" and then attach or stack two separate dies together.
For example, when a semiconductor manufacturer stacks two 128-megabit dies together, they form a single 256-megabit flash memory chip.
Die-stacking allows for cost-reduced chip alternatives to the larger-capacity, single-die chips (called "monolithic" chips). Stacking two 1-gigabit chips together, for example, typically costs far less than buying a low-volume monolithic 2-gigabit chip. The 2- gigabit chip can then be used to build a 256 MB flash card (single chip card), or a 512 MB flash card (two chips on one card).
Die-stacking is similar to the DRAM chip-stacking technology that Kingston utilizes to produce high-end server modules. As a result, Kingston's die-stacked flash cards are reliable and deliver high performance.
5.2 Multi-Level Cell (MLC) Flash Technology
NAND and NOR Flash memory chips typically store one (1) bit value (a `0' or a `1') in each cell. In multi-level flash technologies, three (3) or more values are stored into each cell.
Intel Corporation has introduced NOR StrataFlash™; AMD has introduced NOR MirrorBit™ Flash. Other semiconductor manufacturers also manufacture their own multi-level cell technologies.
NAND MLC Flash technologies were introduced in late 2002, and Kingston has incorporated MLC Flash memory into its line of standard Flash cards.
5.3 Multi-Bit Cell (MBC) Flash Technology
Multi-bit technology is a competing technology to Multi-Level Cell (MLC), and accomplishes the same goal by storing 2 bits per cell (or 4 values per cell). MBC technology is presently used in Infineon's TwinFlash™ memory.
6.0 Flash Storage Device Performance
Flash card storage device performance depends on the following three factors:
· The specific Flash memory chips used: Generally, there is a tradeoff between the high-speed and more expensive Single-Level Cell (SLC) flash chips, and the standard speed and more affordable Multi-Level Cell (MLC) or Multi-Bit Cell (MBC) flash chips. Kingston's high performance flash cards (Elite Pro) and Hi- Speed USB flash drives all utilize the high-performance SLC Flash memory.
· The Flash storage device's controller: With the exception of SmartMedia, today's flash storage devices have a built-in flash memory controller (see Section 7 for more details). This special chip manages the interface to the host device, and handles all the reads from and writes to the flash chips on the flash storage device. If the host controller is capable of supporting faster data transfer speeds, the use of optimized flash controllers can result in significant time savings when reading or writing data into the flash memory. For example, Kingston uses optimized, high performance flash controllers in its Elite Pro Flash cards and DataTraveler Hi-Speed USB flash drives.