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Does Linux "Fail To Think Across Layers?"
John Siracusa writes a brief article at Ars Technica pointing out an exchange between Andrew Morton, a lead developer of the Linux kernel, and a ZFS developer. Morton accused ZFS of being a "rampant layering violation." Siracusa states that this attitude of refusing to think holistically ("across layers") is responsible for all of the current failings of Linux — desktop adoption, user-friendliness, consumer software, and gaming. ZFS is effective because it crosses the lines set by conventional wisdom. Siracusa ultimately believes that the ability to achieve such a break is more likely to emerge within an authoritative, top-down organization than from a grass-roots, fractious community such as Linux.
Personally, I think the Linux kernel manages these issues quite well, if (by conventional standards) rather inefficiently.
The practice, as I see it is: "The current rules (layering, etc.) are enforced rigourously (at least in Linus' tree) but radical rewrites
of the rules take place relatively often"
So if ZFS really does achieve wonderful things by violating the current layering it WON'T be accepted for Linux's kernel, but, if Linus can be convinced (via an appropriate chain of lieutenants, usually) that the layering is really an obstacle to achieving these things, we might see a completely new layering appear in 2.6.25 or somewhere, into which ZFS can fit. The inefficiency
comes from the number of substantial pieces of work that get dropped because they don't fit in, or were misconceived. A more economically rational system would try to kill them sooner. Also, inefficiency arises from the fact that changing the filesystem layering would require every existing filesystem to be rewritten. Linux is notoriously unfazed by this, but in a commercial world, I suspect this would be too hard to swallow and you'd end up with all your filesystems fitting into the model except one, from whence come bugs and code cruft.
Linux will "support gaming" once games are supported for Linux. Linux has OpenGL, OpenAL, all the illusionary walls are market-made. Linux is a platform to build on without the fear of being obsolete in 2 years. DOS games nowadays run on DosBox, as do early Windows games. Even XP needs tweaks to run Win9X games. How is targeting a moving sucky platform preferable to one that is open? Easy. Games sell for 6 months tops. You get the initial sales, you get the money. After that it's tough shit if it won't work after next Windows Update(tm). I have used Linux since 1994, but work in the IT industry. I am constantly amazed by the amount of BULLSHIT the windows folks put up with. For weird quirks "shit happens" is the most common reply.
'Once scientists, even the dim-witted social scientists, get muzzled, the Western Civilization is finished.' - oldhack
Reiser4 introduced us to all sorts of interesting capabilities never before seen in a file system (at the time) but I believe this same "layering violation" attitude pretty much put a stop to any of it getting into the kernel. The Reiser guys were forced to pretty much cripple their file system feature wise if they were to have any hope of getting it included in the kernel.
See Reiser4 Pseudo Files as one example.
I can understand that in certain cases "layering violations" are bad, but Linux kernel developers don't even seem to be willing to experiment or think outside the box at all.
Both sides have valid arguments... I don't think there is any easy solution, but it would be nice to see more forward thinking in the community.
Open Source Time and Attendance, Job Costing a
Linux and other open source projects are getting a harsh lesson in what it is like to ship consumer grade software products.
um, you do know that linux has been the operating system of choice for supercomputers, webservers, special effects production, scientific computing etc. for a number of years now, don't you? because you seem to think that linux, freebsd, openbsd or whatever just suddenly turned up yesterday or something. are you also aware of the fact that a lot of people who write free and open-source software get paid good money to do so?
Lovely biting sarcasm aside, to be honest, our storage layering in Linux leaves much to be desired. As witness the slow pace of improvement of the volume manager in recent years. This does not prove that layering is bad, but it suggests that our current conception of layering sucks pretty badly. For example, we are burdened with a ridiculously complex interface between application programs and kernel-level volume management support. Managed volumes live off in their own name space. Why can't I say "/dev/hda, you are now snapshotted, shazam"?. No, instead I have change my system over to use /dev/mapper/snapshotted-hda or some such nonsense. Similarly, we are unable to manage all block devices using the same administration interface. No higher level raid integrated with the volume manager, instead this is a separate subsystem that fights a lot with LVM. Partition support hopelessly misfactored and broken. It goes on and on. Nothing unfixable but lots of unfixed brokenness. Compared to this mess, Sun's massive layering violations seem like a breath of fresh air.
But the thing to do is fix our broken implementation of layering and not be fooled into thinking that layers are bad. What is bad is exactly as the author here claims: it is bad to have no powerful capability to cross layer boundaries so that applications see a simple, powerful model instead of the current situation, where one's face is constantly rubbed in the minutae of layering administrivia. ZFS actually has layering, it just bypasses some traditional Unix subsystems and takes care of the functionality itself. But is wrong to conclude that this must therefore be the optimal approach just because it improves on the mess that preceded it. If ZFS internal interfaces are worth using, then they are worth using as core interfaces, not ZFS-only interfaces. Translated into Linux terms, the implication is that it is high time to get busy and rectify some of the serious deficiencies in our storage model. Not by mashing all the layers together, but by teaching them how to get along more efficiently and powerfully, and not be so layered that important things don't even work.
Note: perhaps the biggest design distinction between Linux and other Unixen is that, internally Linux is all just one big flat function space where anything can call anything else and share any data. This is said to be a reason why Linux is more efficient than, say, the Mach kernel with its microkernel layering. If being all one big hairball of functions is good for memory management, vfs, scheduling and so on, then why is it not also good for volume management? I don't know the answer to this, but I do know that we have plenty of bogus layering in our storage stack that has really slowed progress in recent years and needs a good dunging out. Any nonbogus layering can stay.
Have you got your LWN subscription yet?
"Ease of use. Nobody has sat first time users in front of a linux desktop and watch them puzzle over what those multiple desktops do, or how to switch between them.......If there is one thing I would suggest, get Ubuntu played with by ordinary grandma's so you can see how they get confused."
Just because your grandma is a little slow (okay, ALOT SLOW) does not mean all of them are.
My grandmother WAS sat in front of an Ubuntu box for the first time, and after 5 minutes, she asked me why her windows PC did not have Desktop switching, as it only makes sense, rather than constantly minimizing countless windows. Since she already has Firefox on her PC, there was no great hunt for the Big Blue "E" aka "the internet", and after a short explanation about how she, as a user, has her own little piece of the computer called a HOME FOLDER, and can save all her stuff there, she was set.
I am so tired of this myth that only people with a Mensa I.Q. are capable of understanding how to use a non-windows based system. Granted, she wont be editing config files or writing code, but how many outside the IT industry do that on a regular basis?
Mod me insightful (or fraking obvious, take your pick)