Winmodem-like solid state storage

Posted Apr 12, 2009 1:21 UTC (Sun) by dwmw2 (subscriber, #2063)
In reply to: Winmodem-like solid state storage by jzbiciak
Parent article: Linux Storage and Filesystem Workshop, day 2

"The only real issue is that once you give raw flash to the OS and put the smarts in the OS, it'll be harder for dual-boot systems to communicate on the same media, because the likelihood that $VENDOR's Windows driver organizes the disk the way Linux does is slim to none unless $VENDOR works with the Linux community also."

I see two reasons why that wouldn't be a problem, in practice.

Firstly, we've never had many problems working with "foreign" formats. We cope with NTFS, HFS and various bizarre crappy "Software RAID" formats, amongst other things. That includes the special on-flash formats like the NAND Flash Translation Layer used on the M-Systems DiskOnChip devices, which has been supported for about a decade. Are you suggesting that hardware vendors take Linux less seriously now than they did ten years ago, and that we'd have a harder time working out how to interoperate? Remember, documenting the on-medium format doesn't necessarily give away all the implementation details like algorithms for wear levelling, etc. — that's why M-Systems were content to give us documentation, all that time ago.

Secondly, interoperability at that level isn't a showstopper. It's nice to have, admittedly, but I'm not going to lose a lot of sleep if I can't mount my Windows or MacOS file system under Linux. It's the native functionality of the device under Linux that I care about most of the time.

Of course, I see no reason why the device vendors should be pushing their own "speshul" formats anyway — the hard drive vendors don't. But I'm not naïve enough to think that they won't try.

Imagine a world where every hard drive you buy is actually a more like a NAS. You can only talk a high-level protocol like CIFS or NFS to it; you can't access the sectors directly. Each vendor has their own proprietary file system on it internally, implemented behind closed doors by the same kind of people who write BIOSes. You have no real information about what's inside, and can't make educated decisions on which products to buy. Having made your choice you can't debug it, you can't optimise it for your own use case, you can't try to recover your data when things go wrong, and you sure as hell can't use btrfs on it. All you can do is pray to the deity of your choice, then throw the poxy thing out the window when it loses your data.

If the above paragraph leaves you in a cold sweat, it was intended to. That's the kind of dystopia I see in my head, when we talk about SSDs without direct access to the flash.