I wonder how things have changed since this article? It talks of a big divide between cheap flash drives (USB sticks, SD cards, etc) and 'real' SSDs (e.g. the non-removable 2.5" hard drive replacements).
At the time, all but the worst 'real' (for want of a better word) SSD hard drives had enough local RAM and firmware smarts to do proper I/O ordering, buffering and manipulation. This effectively hides all the complexities of the flash storage, allowing any OS to work well.
The cheap USB sticks and their ilk couldn't do this because of their lack of RAM, decent firmware and all associated money-saving build choices. But as the hardware gets cheaper, I wonder if this is still true? Do USB sticks and SD cards nowadays have more RAM & better firmware?
I have a lot of development experience in this area. I have done SSD/flash firmware with RAM between 16KB and 8GB. The algorithm for each of these approaches give different perform characteristics. But you can implement hybrid algorithms in between for example 32KB or 256KB adding more performance features. The complexities are the most in these hybrid algorithms. It is certainly feasible to do these in single chip products in USB sticks. I know for example there are some USB drives with SandForce controllers. But the reality is the USB stick market is quite price competitive. They tend to use bargain basement NAND quality. People rarely write the drives to fill capacity before tossing them into their desk drawer. In summary, it is technically feasible but the market base is price sensitive.
There's been a lot of blurring the lines on the hardware side. There's now a whole category of "portable SSDs" using USB3 to SATA bridge chips to make low to mid-range internal SSDs into external drives. There are also several internal SSD controller designs that can provide far better performance than a typical USB stick even without any external DRAM on the drive.
Silicon Motion's SM2246XT is a 2-channel DRAM-less variant of their SM2246EN 4-channel mainstream SSD controller. The -XT is used in both SanDisk's SSD Plus internal SATA SSD and their Extreme 500 Portable SSD: http://anandtech.com/show/9847/sandisk-extreme-500-portable-...
Phison's new S11 controller is also a DRAM-less design that will be used in low-end internal SATA SSDs.
At the time, all but the worst 'real' (for want of a better word) SSD hard drives had enough local RAM and firmware smarts to do proper I/O ordering, buffering and manipulation. This effectively hides all the complexities of the flash storage, allowing any OS to work well.
The cheap USB sticks and their ilk couldn't do this because of their lack of RAM, decent firmware and all associated money-saving build choices. But as the hardware gets cheaper, I wonder if this is still true? Do USB sticks and SD cards nowadays have more RAM & better firmware?