Comment by ergo98 | Hacker News Reader

Comment by ergo98 | Hacker News Reader

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>The only operating system that moves fast enough to add support for something like this in that sort of timeframe is Linux

http://en.wikipedia.org/wiki/ReadyBoost

The ars article isn't very clear, however it isn't talking about a system having a magnetic hard drive and a flash hard drive (in a standard 2.5/3.5 fashion), but rather a magnetic disk and some sort of built-in or extension flash memory. There are new upcoming motherboards that have a decent amount of onboard flash memory for precisely this usage model.

In the SAN market there is a raging trend called Easy Tiering, FAST, or whatever other marketing glop the vendor makes. It allows you to have a couple of SSDs, and then lots of magnetic disks, finding a sweet spot between volume and speed as it automatically moves hot spots to the SSDs. It's a perfect use of varying speed technologies.

The new hybrid hard drives bring this -- to some success -- to the consumer market. They just need a lot more flash and a better algorithm and it's a killer solution: A 2TB magnetic disk with 32GB of high speed flash would be incredible.

You have to remember that the focus is about moving past old hard drive connections like SATA, so even if you got one of the new hybrid hard drives with flash on them, you would be limited by the SATA port it was connected to.

That is why all those companies are moving to PCIe directly, for the extra speed. If the OS were to handle caching and other things so the user didn't have to worry about it, then the experience would be much greater and faster all said.

The gross throughput factor is hugely oversold for the vast majority of uses: In most scenarios IOPS is Godzilla to throughput's mouse. IOPS is reality, and throughput is something that only generally comes up in benchmarks.

What is ReadyBoost? I'm having a hard time finding information about it where the writer seems to know what he's talking about, but it just looks like an extension of Windows's application pre-loading feature. That's nice, but not really the same as a real read/write cache.

Essentially the pagefile.sys (which at a high level is a massive memory mapped file that Windows uses for virtual memory) gets stored on a flash drive. It very much helps the overall responsiveness of a computer that doesn't have enough RAM to do without a pagefile.sys -- especially if they have a slow hard drive (I inadvertently installed Vista on a slow computer and this helped quite a bit).

ReadyBoost is different from PreFetch (they are features you can turn off/on independent of each other) which I believe you are referring to when you mention "pre-loading". The wikipedia article is decent: http://en.wikipedia.org/wiki/ReadyBoost

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