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Linux Support for Hybrid Hard Drives?
christoofar asks: "HHDD (Hybrid Hard Disk Drive) technology has been receiving some buzz lately. The concept is not new, but Samsung has been working on a consumer version of HHDD that everyone can use. HHDDs are disk drives that carry onboard RAM (in this case, NAND flash) which is non-volatile and offers to speed boot times and writes to the disk. This carries enormous benefit to laptop users who need to keep their disk activity to a minimum in order to preserve battery life.
Given that Microsoft is adding support for Hybrid Hard Drives in their upcoming Windows Vista release, what efforts are being undertaken in the Linux realm to use this new storage technology?"
Why aren't the drives designed in a way that the drive technology worries about the details of retrieving and writing files, and sends them the way USB, IDE, SATA, or SCSI drives already do? Why would these drives need special drivers?
Saskboy's blog is good. 9 out of 10 dentists agree.
I'm sure they will be support for it by the time it is really *needed*. If it is an open and available spec, support could be coding before these things start becoming popular. Otherwise, as the linux community doesn't enjoy the advantages of MS, it will be reverse engineered after release as someone's need dictates. Honestly, how is this a useful question? These drives seem to have limited use outside of laptops and there shouldn't *Need* to be special support, as other posters have said. It should adhere to already existing SATA standards or what not and handle everything on the inside.
Right like, perhaps in addition to the kernel, or other essential boot files, it would also store the journal for journaled filesystems - it will cache the writes and commit them the next time that power supply and demand warrant. Consider a 1 Gbyte flash, in addition to your 100+ Gbyte drive, that's alot of non-volatile write cache.
This could IMPROVE the situation you're talking about.
First of all, you know that right now your writes are cached in your computer's memory for up to 30 seconds before they are flushed to disk. This is done so that synchronous read calls are less disrupted by writes.
It's possible that this new technology would allow the OS to commit writes to disk immediately (or at least much sooner). The disk writes to NVRAM or flash, at which point it should be stable through power loss or crash. The disk doesn't need to commit it to the actual platter right away for it to be safely stored.
i should add, if a couple million writes is true, even if you were to randomize or even out the bits algorithmicly, I still would be afraid of failure.
With all of the improvements in RAM, on-die cache and processor speed, the bottleneck in performence is HD speed. Anything that helps boot that is a welcome improvement.
So I see a completely different picture here. There are a lot of files on the HDD that are never rewritten. System files, etc. This is where having hybrid drives really helps. Put the main boot files, executables and libraries which are accessed when staring things up in there. So no fast saves, but no load time.
If I understand Dirac correctly, his meaning is this: there is no God, and Dirac is his Prophet. -Pauli
Maybe someone doesn't want their operating system on the RAM-ified part. Maybe they want swap space there instead. Maybe they want the reserved journal space of a journaling filesystem that is frequently updated to be there. Of course all of these needs could be addressed in some way (at least I know some journaling filesystems let you put the journal in a different partition). You'd have to choose which sectors (don't think in cylinders anymore, it's all fake anyway) would be RAM-ified in a way that would fit various needs in various operating systems, including that one with the largest market.
now we need to go OSS in diesel cars
Pretty much nobody wilfully uses a flash medium for swap space or transaction logs. Remember, each sector is only good for a limited number of write cycles, so they're only well suited for mostly read-only data (like system binaries or audio/video playback).
Cameras resort to using flash as a space and power tradeoff, and they can only get away with it because users don't fill and erase the same card ten thousand times.