February 25, 2011-Milpitas, CA-we recently sat down with Doreet Oren, director of product marketing at SanDisk, to talk about trends and industry drivers in the CE space. The major trends for portable computers is towards thinner, lighter, and longer battery life. At the same time, phones are moving up to have larger screens and higher performance.
The latest evidence of these trends are tablet computers and smartphones. Both of these product categories have insufficient space and battery power for hard disk drives. The tablets are emerging as a downsized laptop for content creation and consumption or as upsized smart phone for digital content consumption. Although first-generation SSD's might meet the operating requirements, the 2.5 or 1.8 inch HDD form factor will not fit in these products. As a result, these devices use some type of flash memory for storage.
Some of the smart phones and the iPad use raw NAND flash, which requires the systems to take care of the data storage wear leveling requirements. Having full control of the storage system permits better optimization and efficiency at the cost of more involvement of the CPU for storage operations.
The Android-based tablets and most cell phones use eMMC (embedded Multi-Media Card) drives with capacities from 2 to 64 GB. These storage subsystems are relatively low power but suffer from fairly low performance. They only require connections to the data and address bus, and unlike raw NAND, manage the wear leveling tasks internally.
For the highest performance systems, developers are using SATA interfaces. Current expectations are that some of the tablets will migrate to SSDs (Solid State Disks) in the near future, because of the higher performance and the integrated controllers perform the wear leveling, offloading this task from the CPU.
SSDs come in a number of form factors--standard 2.5-inch housings for plug-in replacements or easy conversion from HDD to SSD. PCBs with SATA connector for applications that need thinner storage modules, and now in a BGA package. The BGA has dimensions of 16 x 20 x 1.8 5mm.
Sandisk SSD products
The PCB and BGA versions come in capacities from 4 to 128 GB, and can read at up to 160 MB/s and write up to 100MB/s. Performance for a 4K random read is up to 2300 IOPs and a 4K random write (Burst) is up to 800 IOPs. To improve performance, the internal architecture uses a mix of single- and multi-level NAND Flash. This architecture provides the random write and endurance of a page-based system with the cost structure of an SSD without DRAM.
Sandisk SSD SLC/MLC Architecture
This non-volatile write implementation boosts performance and enables faster boot. Compared to a 1.8 inch drive, an ISSD is ~ 60 x smaller, ~ 50 x lighter, ~ 6 x more reliable, ~ 3 x faster, uses half the power, and costs less than the equivalent HDD.
One interesting new direction is cloud-enabled computing. Here the computer only need enough storage to boot and store local apps and temporary content. The actual applications as well as high volume storage all reside in the cloud. Because the local compute and storage requirements are so low, the computer can operate all day on a single charge. The computer requires some sort of wireless connectivity to get access to the programs and storage.