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MLC adds muscle to NAND

Posted: 01 May 2008 ?? ?Print Version ?Bookmark and Share

Keywords:solid-state drives? hard disk drives? multilevel-cell technology? NAND flash SSDs?

As solid-state drives (SSDs) change the way data is stored, several major memory chip vendors are applying their multilevel-cell (MLC) technology prowess to this burgeoning market, helping to bring the NAND-based storage architecture forward, particularly for mobile electronics.

Compared with traditional HDDs, SSDs feature lower power consumption, faster boot times, increased reliability, improved performance and no mechanical noise.

Micron Technology, Toshiba America Electronic Components (TAEC) and Lexar Media recently entered the SSD market with lines offering a range of form factors and capacities. Competitors Intel and Samsung Electronics rolled out products claimed, respectively, to be the smallest and fastest in their class.

Micron RealSSD
Designed for computing, enterprise server and networking applications, Micron's RealSSD family varies in density from 1-64Gbytes. Micron's 1.8-inch and 2.5-inch RealSSD products for notebook and desktop computing applications will be offered in 32Gbyte and 64Gbyte densities. Micron is now sampling both devices.

The devices in the RealSSD family include SSDs, embedded USB products and module products. RealSSD devices feature a native serial ATA II interface, allowing for improved performance. The products use a single-chip controller specifically targeted at the SSD application and do not require a serial ATA bridge chip, unlike most current products. The controller is optimized for four-channel control of the NAND and supports advanced serial ATA features such as native command queuing, which allows the drive to reorganize read and write commands. It also features a serial ATA hot plug, allowing the drive to be removed from the system without cutting power.

Toshiba uses MLC technology in its 1.8-inch form factor 128Gbyte SSD.

RealSSD embedded USB products range in density from 1-8Gbytes of storage and are designed to be integrated into systems through an embedded USB 2.0 interface. This provides a cost-effective solution to storing and booting an entire OS within an industrial PC or blade server system and can also be used as a reserve for frequently accessed files.

The RealSSD module is essentially an SSD in a low-profile module form factor. Using a commonly available serial ATA interface, the modules measure 25mm x 133.5mm x 4mm, allowing for increased system airflow, said Micron.

TAEC's flash SSDs
TAEC jumped into the emerging market for NAND flash-based SSDs with a series of products designed primarily for notebook PCs. Toshiba's first SSDs offer three capacities (32-, 64- and 128Gbytes) in three form factors: an embedded module, and 1.8-inch and 2.5-inch drive enclosures.

Toshiba's SSDs integrate an original MLC controller supporting fast read/write speed, parallel data transfer and wear leveling, achieving performance levels comparable to those of single-level-cell NAND flash SSDs.

By applying MLC technology, Toshiba has realized a 128Gbyte capacity in a 1.8-inch form factor. Toshiba expects the launch of its MLC NAND-based lineup to speed the acceptance of solid-state memory in laptops and digital consumer products. The products use NAND flash memory fabricated with 56nm process technology, along with controller chips and DRAM, on a 70.6mm x 53.6mm x 3mm platform. The maximum read speed is 100MBps, and the maximum write speed is 40MBps with the serial ATA II interface (at a transfer rate of 3Gbit/s), which is compliant with a high-speed serial interface. The rated operating life is 1 million hours. Samples and mass production will follow from Q1.

Samsung eyes 128Gbyte
Samsung Electronics is also applying its NAND memory technology prowess to developing an MLC flash-based 128Gbyte SSD, which it will produce this year in 1.8-inch and 2.5-inch versions for notebook and desktop PCs and for other mobile applications.

The drive offers a data writing speed of 70MBpsthe industry's highest for MLC-based SSDs, claims Samsung. The write speed was achieved by using optimized controller technology and highly efficient flash-management firmware technology. Samsung's 128Gbyte SSD reads data at 100MBps.

Samsung's 128Gbyte SSDs will be available in a thin-standard 1.8-inch version that is 5mm thick, as well as in a conventional 1.8-inch version for mobile consumer applications and a 2.5-inch version for standard-sized notebooks.

Featuring a 3Gbit/s serial ATA II interface, the 128Gbyte SSD uses native command queuing and spread-spectrum clocking to improve its already higher-performance levels. It also features device/host-initiated power management to reach a low power consumption level of 0.5W in active mode.

Samsung's wear-leveling technology, combined with its advanced flash management technology, provides high reliability for its MLC-based-SSD and a mean-time-between-failure (MTBF) rate of 1 million hours.

Intel goes mobile
To Intel, serving the mobile device market is key. The company recently launched the Z-P140 PATA SSD, one of the tiniest in the industry and one aimed squarely at handheld mobile devices. The device comes in 2Gbyte and 4Gbyte capacities and has an industry standard parallel ATA (PATA) interface. It is optimized to enhance Intel-based computers and will be an optional part of Intel's Menlow platform for mobile Internet devices, debuting this year.

According to Intel, the Z-P140 is the smallest SSD in its class, making it attractive to designers and manufacturers of mobile and ultramobile devices. It is 400x smaller than a 1.8-inch HDD and, at 0.6g, is 75x lighter. It is also a much more durable alternative, Intel said.

Here's an inside look at Micron's 1.8-inch RealSSD device, featuring a native-serial ATA II interface for improved performance in notebooks and desktop apps.

The 2Gbyte and 4Gbyte capacities can store mobile OS, applications and data, and are extendable to 16Gbytes.

The Intel Z-P140 PATA SSD offers read speeds of 40MBps and write speeds of 30MBps.Its active power usage is 300mW, and the device requires only 1.1mW in sleep mode, extending its battery life. With a 2.5 MTBF rate, the PATA-based chip-scale package delivers reliable solid-state performance with a tiny footprint. The Intel Z-P140 is currently sampling. The 4Gbyte version will follow the 2Gbyte product.

Crucial drives
Lexar Media, a wholly owned subsidiary of Micron, has launched the Crucial line of SSDs, which will be available in capacities of 32Gbytes and 64Gbytes in an industry-standard 2.5-inch drive enclosure with a native serial ATA 3Gbit/s interface. Lexar Media will also offer the Crucial SK01 external drive kit and various online customer tools.

Crucial SSDs have no spin-up time, seek time or rotational latency, causing shorter system boot and application load times. Other features include less than 2W power consumption when active, resistance to high levels of shock (1,500G/0.5ms) and vibration (20G/20-2,000Hz), MTBF rate of 2 million hours, and low latency with access time of less than 1ms.

Weighing 82g and offering silent operation and an operating sound of 0dB, SSDs run cool, having no moving parts that might create heat. In hot-swap capable systems, they can be removed from desktop drive bays without the need to cut power to the host computer, a feature that allows for immediate, portable data security. Products hit the market in Q1 08.

- Ismini Scouras

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