Samsung eyes latest NAND to lower laptop costs

IDG News Service - A new type of NAND flash storage for consumer electronics that can store data more densely might lower the cost of devices such as tablets and thin "ultrabook" laptops, according to Samsung.

Most manufacturers have not yet started using the so-called TLC (triple-level cell) chips in devices, but as they grow more comfortable with the longevity of flash, they may adopt it, said Ryan Smith, Samsung senior manager of SSD (solid-state disk) product marketing. If TLC is robust enough to handle the average user's daily activity on a device over the time they would typically own it, consumers could benefit from cheaper hardware, Smith said in an interview at the South Korean company's Silicon Valley headquarters on Tuesday.

Flash storage works by applying a high-voltage pulse to modify the charges on individual cells within a chip. SLC or single-level cell flash, used in enterprise storage equipment, applies only one charge to a whole cell, to store one bit. MLC (multilevel cell) can apply a higher or a lower charge and store two bits. TLC takes that to three bits.

TLC lets flash makers get more chips of a given capacity out of one wafer, which is why it's less expensive, according to Forward Insights analyst Gregory Wong. On the other hand, as the number of charges per cell goes up, so do the number of errors, and the number of times a user can reliably write data to the storage goes down, he added. Performance is also lower on TLC than on the other types of flash, though all are faster than hard disk drives, Wong said.

Samsung acknowledges the longevity and error issues, which can be partly solved through error correction and digital signal processing. But the company believes that MLC flash, the kind used in most laptops and tablets today, may be overkill for the needs of the average user. If TLC can keep working for however long a user keeps a machine, that machine may cost the consumer less, he said.

It's up to device makers to decide whether TLC is good enough, Smith added. Whether it can go the distance is a complicated question. A typical rule of thumb in the industry for laptop use is writing 20GB of data per day to the device, over a period of perhaps 3 years, he said. That includes files created or downloaded as well as temporarily cached Web pages and other items.

Using that standard, "TLC is on the borderline unless some special error correction or signal processing gives you some margin," Wong said. But the 20GB rule may be more than the average user needs, he added. With tablets in particular, consumers tend not to create and store much content, though tablets typically have less flash capacity and therefore fewer cells to work with over the life of the product, Wong said.