Slashdot Mirror

← Back to Stories (view on slashdot.org)

Linux Support for Hybrid Hard Drives?

Posted by Cliff on from the better-storage-tech dept.

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?"

2 of 86 comments (clear)

  1. Re:Write caching in flash... by greg1104 · · Score: 4, Informative

    Samsung's OneNAND design uses some interesting implementation details to run faster than is normally expected with flash. Their specs at http://www.samsung.com/Products/Semiconductor/OneN AND/index.htm suggest writes at 9.3MB/s and reads at 108MB/s; plenty fast for many applications even without running multiples in parallel. It's certainly much slower than writing directly to the drive if the drive is active. However, if the drive isn't spun up at the moment and the amount of data to be written fits in the NAND flash cache, I could see this being a net performance boost over the spinup/seek time combination of the hard drive.

    They also spec 100,000 erase cycles before it's worn out. As was noted by an underrated poster the last time this came up, intelligent flash controller designs like this can cope with bad bits and assuring level usage of the memory much better than what you normally see in random hunk of flash.
    An analysis at http://www.sudhian.com/printdocs.cfm?aid=686 suggests 33 years of usage for a typical worker. When you run the numbers it doesn't sound that difficult to create a design that would likely outlast the mechanical parts of a standard hard drive.

  2. It looks like the answer is "yes" by NetRAVEN5000 · · Score: 2, Informative
    I've got the 2.6.15.4 kernel and there's a spot to enable support for "Memory Technology Devices".

    Here's the description:
    "Memory Technology Devices are flash, RAM and similar chips, often used for solid state file systems on embedded devices. This option will provide the generic support for MTD drivers to register themselves with the kernel and for potential users of MTD devices to enumerate the devices which are present and obtain a handle on them. It will also allow you to select individual drivers for particular hardware and users of MTD devices."

    It's got options for a whole bunch of things, such as "FTL (Flash Translation Layer)", "NFTL (NAND Flash Translation Layer)", and "INFTL (Inverse NAND Flash Translation Layer)".

    Given that it says the hard drives will use "a one-gigabit OneNAND flash chip" (according to the article), it sounds like it will work.

    --
    www.linuxpenguin.net