Slashdot Mirror

← Back to Stories (view on slashdot.org)

More On The 2.6 Kernel

Posted by timothy on from the dull-roar dept.

Jan Stafford writes points out an article in which "SearchEnterpriseLinux.com expert Ken Milberg digs under the hood of the upcoming 2.6 Linux kernel and examines the benefits and opportunities it presents for Linux in the enterprise." And Semaphore writes "Linux.com is running a great article on the future of ide-scsi in 2.6. It seems Linus and Joerg Schilling, author of cdrtools disagree on whether the problems are with Linux or the application software. Interesting read.."

58 comments

  1. Sound Support by voss · · Score: 5, Funny

    Wow it only took 10 years to get reliable sound support into the kernel ;-)

    1. Re:Sound Support by Spoing · · Score: 3, Insightful
      Wow it only took 10 years to get reliable sound support into the kernel ;-)

      That's not insightful, it's funny.

      On a serious note, I've used the OSS modules for 5+ years, and it's worked well for me. Alsa is quite nice and I'm glad to see it as the default in the kernel now, though OSS is not unreliable by a long shot.

      --
      A firewall can not protect you from yourself. Turn off what you do not need. Do not use the firewall to do your work.
    2. Re:Sound Support by MrHanky · · Score: 3, Informative

      No, it didn't. At least not in the way the article describes. Playing mp3s went quite well when I started using Linux, back in 1999 (Red Hat 6.0, Linux 2.2.5, on a 166 MHz Pentium MMX). The OSS sound drivers weren't great, but they were enough to let an IT manager listen to System Of A Down, even though their debut album from 1998 wasn't quite as good as Toxicity (2001). mp3 folks shouldn't notice much of a difference, despite what TFA says.

      ALSA is a good architecture, with a proper API, and should provide better support for the kind of audio musicians need: lower latency, better mixing, MIDI control, and so on. It should be used in conjunction with JACK, the low latency audio server, for that kind of application. Yes, for real multi-media work, ALSA is a lot better than OSS, and probably a necessity, but OSS was quite reliable for just playing or recording sound.

    3. Re:Sound Support by norkakn · · Score: 2, Funny

      wait.. isn't alsa oss?

      "ALSA is released under the GPL (GNU General Public license) and the LGPL (GNU Lesser General Public License)."

      am I missing something obvious?

    4. Re:Sound Support by natmsincome.com · · Score: 2, Informative

      OSS = Open Sound System (I think) not open source software :-)

      OSS was fine for playing music but you couldn't do things like fade from one song to the next so you'd get a "hss" or "pop" between songs if you had a cheap sound card.

    5. Re:Sound Support by Anonymous Coward · · Score: 0

      OSS is not unreliable-- if you have a sound card which is used by a kernel hacker. Otherwise...

    6. Re:Sound Support by Spoing · · Score: 1

      I can compile kernels, but I'm not a kernel hacker. For the most part, I don't compile kernels I use the binaries.

      --
      A firewall can not protect you from yourself. Turn off what you do not need. Do not use the firewall to do your work.
    7. Re:Sound Support by axxackall · · Score: 1

      MIDI is poorly supported by both linux kernel and open-source applications. It's barely useful even for teaching my kid some simple music basics.

      --

      Less is more !
    8. Re:Sound Support by Anonymous Coward · · Score: 0

      i would just hope that those 10 years had arrived already at BSD arena :>

      sound still get a little glimpsy in freebsd 5.x series mainly because of vendors...

      like NVIDIA's that isnt ashamed of releasing drivers for his nforce's products only for linux

    9. Re:Sound Support by Crazy+Eight · · Score: 1

      You could always use a guitar or a piano...

    10. Re:Sound Support by axxackall · · Score: 1

      you could always use paper instead of computers.

      --

      Less is more !
    11. Re:Sound Support by Crazy+Eight · · Score: 1

      You mean, like, wrapped around a comb? And then ya hum into it like a harmonica? Oooh! That's fun!

  2. 2.6 by MikeCapone · · Score: 1

    Hopefully 2.6.0 will be decently stable from the get go and won't get the bad reputation that early 2.4 had.

    I'm glad that they could improve the kernel from both ends at the same time; big(ger) irons and the deskptop.

    It should be a nice xmas.

    --
    Treehugger? Treehugger... Treehugger!
    1. Re:2.6 by spectre_240sx · · Score: 1

      Personally, I've been thrilled with 2.6. It's running quite a bit better on my laptop than 2.4 did. :-)

    2. Re:2.6 by SanityInAnarchy · · Score: 2, Informative

      It already runs great on my laptop _and_ my webserver. As long as I stay away from decidedly unstable things (preempt, swsusp, intermezzo) it works.

      Some say it's already more stable than 2.4 is.

      --
      Don't thank God, thank a doctor!
  3. usb-storage and ntfs by asteinberg · · Score: 4, Interesting
    The first article mentions a rewritten NTFS driver that supports read/write - I thought that the NTFS driver is still (and always will be, aside from the recent story about using Windows' ntfs.dll) considered "experimental", right? Perhaps it will still be labeled that way but will actually be solid enough to use? Anyone know?

    Also, the second article mentions potential problems with usb mass storage devices (flash card readers, digital cameras, etc.) but never really draws any conclusions about how they will work - any ideas here?

    --
    The first ever Ultimate Frisbee video game: here (now
    1. Re:usb-storage and ntfs by molo · · Score: 1

      Normal usb-storage devices will work. The only issue is for ATAPI devices that have been using ide-scsi in the past. (cd-r drives, ide tape drives, ide zip drives, etc.)

      -molo

      --
      Using your sig line to advertise for friends is lame.
    2. Re:usb-storage and ntfs by Josh+Booth · · Score: 5, Informative

      A while ago the NTFS guys announced that you can indeed write to NTFS, as long as you don't make any new files and don't extend or shorten the length of any existing ones. Not really full write support, but something.

      About the usb mass storage devices etc., I suppose that certain features depend on having a SCSI interface, which is provided for non-SCSI devices by ide-scsi. I didn't realize that they need ide-scsi or a SCSI-like interface, and maybe they don't, but if they need ide-scsi and ide-scsi is broken, then people are in trouble. The reason I say that they might not need ide-scsi is that there apparently was an older SCSI interface that used bus/dev/lun addressing (Ex.: 0/1/0) and newer interfaces have been created. Linus wants to keep in the Unix spirit and just use device files (Ex.: /dev/sg0).

    3. Re:usb-storage and ntfs by AJWM · · Score: 2, Informative

      I didn't realize that they need ide-scsi or a SCSI-like interface, and maybe they don't

      They don't need ide-scsi. They (eg, USB storage devices, which might well be flash rom rather than actual disks) need some kind of interface so that they look like something you can put a filesystem on -- and the SCSI protocol (command level) is it. However, the non-IDE devices (USB, 1394, etc) that need it have their own interfaces to the SCSI module, not ide-scsi.

      --
      -- Alastair
    4. Re:usb-storage and ntfs by jensend · · Score: 1

      The ntfs driver's read support isn't really "experimental" these days, it's quite reliable. However, it can only write to an existing file, and only if it's not changing the length. (This sounds like it would be useless, but a loopback file could be created under Windows and then used from Linux for pretty much any purpose- I'm not sure but I think you can even use it to share files from Linux with windows if you use the FileDisk loopback driver under Windows.) The reason is that NTFS does a lot of weird stuff with metadata, so while it's not very hard to glean from all that metadata where files are on the disk, it's hard to get all the metadata right when writing. Writing to an existing file without changing the length, however, doesn't require any change to the metadata.

    5. Re:usb-storage and ntfs by Crazy+Eight · · Score: 1
      ...you can indeed write to NTFS, as long as you don't make any new files and don't extend or shorten the length of any existing ones.

      [smartass] So that'll come in handy for hex editing. [/smartass]

    6. Re:usb-storage and ntfs by drinkypoo · · Score: 1
      usb mass storage devices are already broken in 2.4. You don't get a remove event when you unplug them in many if not all cases. The solution, given by various members of linux-hotplug-devel, is to move to 2.6, so I suspect that those people either don't know or don't care about any work being done to fix usb on 2.4.

      The NTFS driver has been patched to do r/w on NT4 pretty well, but not on NT5/5.1, which I believe it will corrupt if you even mount it rw.

      In 2.4 USB mass storage devices show up as a scsi device. I don't think they're using ide-scsi though, just SCSI emulation.

      --
      "You're right," Fisheye says. "I should have set it on 'whip' or 'chop.'"
    7. Re:usb-storage and ntfs by mickwd · · Score: 1

      "[smartass] So that'll come in handy for hex editing. [/smartass]"

      Very funny

      But what it will come in handy for, amongst other things, is having a linux-filesystem-within-an-NTFS-file (a bit like the old UMSDOS filesystem) for those people who want to try out Linux, but who don't want to go to the trouble of re-partitioning their disks (with the associated risks of losing data).

      Not an ideal solution (certainly performance-wise) - but faster than running (Knoppix-style) from a CD-ROM drive, and allows you free use the CD-ROM drive, too.

  4. both their fault.. by molo · · Score: 4, Informative

    ide-scsi is mainly used by cd-burning software such as cdrdao and cdrecord (and their frontends). This works fairly well in the 2.2 and 2.4 kernels. However, it does lack some serious functionality: DMA support. Not having DMA support for ide-scsi means that burning takes up a lot of cpu time and it is very easy to cpu-starve the cd-burning software resulting in a bad burn.

    This might have never came up if ide-scsi was properly functioning.. but somewhere along the 2.5 series, it became mostly broken.

    Linus's solution? Fix the ide-cd interface to pass ATAPI generic instructions (analogous to SCSI generic) and enable DMA for those devices. This requires userspace software changes in cdrecord and cdrdao's scsilib (they share that code). This enables you to run cdrecord --dev=/dev/hdc and have it work.

    ide-scsi in 2.6 remains mostly broken. This is a problem for people who use ide-scsi for devices other than cd-r drives, such as zip drives or IDE tapes. A lot of zip drive and tape software was written only for scsi interfaces. ide-scsi lets people use their cheaper ide components with that software.

    Where does this leave us?
    1. the kernel should have supported burning to atapi devices directly a long time ago.
    2. the cd-r software should certainly support burning to atapi devices now (cvs versions of cdrecord and cdrdao support this).
    3. ide-scsi should be fixed, but NO ONE IS SENDING PATCHES.
    4. ide-cd works for most people, but is not 100%. It doesn't work with my hardware (even for reading CDs). This makes me go back to 2.4 for CD burning.

    What should be done?
    1. if you use ide-scsi for things other than cd burning and you want to upgrade to 2.6, take a look at the driver and try to fix it. Submit a patch.
    2. upgrade your cd-r software.
    3. report ide-cd problems to Jens Axboe and the LKML.

    Oh, and the author of cdrtools (cdrecord) just wants to talk SCSI to everything and not care what the device actually is. I'm not quite sure why.

    Thats it. End of story. Try ide-cd. Drop ide-scsi.

    -molo

    --
    Using your sig line to advertise for friends is lame.
    1. Re:both their fault.. by Phexro · · Score: 1

      "However, it does lack some serious functionality: DMA support. Not having DMA support for ide-scsi means that burning takes up a lot of cpu time and it is very easy to cpu-starve the cd-burning software resulting in a bad burn."

      Bzzt. You lose, DMA works just fine with ide-scsi.

      Just use hdparm on /dev/hdN or whatever the regular IDE device would be to enable DMA (if it isn't enabled at boot-time).

    2. Re:both their fault.. by molo · · Score: 1

      Doesn't work with my hardware. If I leave DMA on, it breaks. I have to specificly disable DMA with hdparm to be able to burn cds.

      -molo

      --
      Using your sig line to advertise for friends is lame.
    3. Re:both their fault.. by PyromanFO · · Score: 2, Informative

      "Oh, and the author of cdrtools (cdrecord) just wants to talk SCSI to everything and not care what the device actually is. I'm not quite sure why."

      I don't want to sound like a troll but basically the guy is an ass. Just go read some of his posts and draw your own conclusions, but there are alot of things wrong with cdrecord that could be fixed and he simply refuses to do it.

    4. Re:both their fault.. by advocate_one · · Score: 2, Insightful
      "but there are alot of things wrong with cdrecord that could be fixed and he simply refuses to do it"

      Why does he have to fix it??? You have the source code... isn't that what all the fuss is about Open Sorce Software... the big advantage you have in having the source code available???

      If he ain't gonna fix it, then fork it and get on with it...

      --
      Donald 'Duck' Dunn: We had a band powerful enough to turn goat piss into gasoline.
    5. Re:both their fault.. by arkanes · · Score: 1

      That doesn't make him not an ass.

    6. Re:both their fault.. by advocate_one · · Score: 1
      "That doesn't make him not an ass."

      not relevant to my comment... You'll notice I didn't comment on him being an ass at all. In fact, I'm not in a position to call him an ass but those who are bitching about him have got the solution in their own sticky little mitts...

      Just imagine if it were a highly usefull but entirely closed source piece of utility software that had problems, you knew what they were, but the author refused to fix them... you'd be up the swannee then without a paddle.

      --
      Donald 'Duck' Dunn: We had a band powerful enough to turn goat piss into gasoline.
    7. Re:both their fault.. by Anonymous Coward · · Score: 0

      The guy may be an ass, but cdrecord is portable to 1000 different Unix operating systems and SCSI is the portable way to burn CDs.

      He's probably sick of Linux kiddies (including Linus himself in this case) demanding that all Unix software be converted to Linux-specific APIs.

    8. Re:both their fault.. by arkanes · · Score: 0
      ...and the author would be an ass.

      Your comment wasn't relevent to the parent - it's reasonable to call him an ass whether or not they fork or not.

    9. Re:both their fault.. by Brandybuck · · Score: 1

      I agree. I use FreeBSD so I have a different perspective. The FreeBSD kernel does support burning to atapi devices directly. The base system includes burncd, which is a very good CD/DVD burning tool for IDE. Unfortunately, no third party tool supports it, since all the third party tools are written for SCSI-only cdrecord.

      Linus is right when he said "ide-scsi has always been broken. You should not use it, and indeed there was never any good reason for it existing AT ALL." FreeBSD has recently gotten a similarly redundant SCSI-to-ATA layer. I'm glad it's there, because I can now use all the myriad cdrecord-based tools. But it should never have been necessary in the first place.

      The problem is not with the Linux kernel, it's with cdrecord. It's use of SCSI as a universal drive API is silly. It's implicit belief that ATA CDRW drives don't exist places a large burden on the user.

      --
      Don't blame me, I didn't vote for either of them!
    10. Re:both their fault.. by Phexro · · Score: 1

      Then your hardware (or IDE driver for that hardware) is likely broken. ide-scsi has zero to do with DMA. DMA is handled by the lower-level IDE driver which ide-scsi talks to.

    11. Re:both their fault.. by ameoba · · Score: 1
      like the one where he says :


      The more I try to explain them how a decent SCSI transport interface should look, the more I fail. I never did check a 2.6 Linux kernel and as SuSE did stop giving away free SuSE distributions to developers more than half a year ago, it is very unlikely that I will install a newer Linux kernel.


      ???

      So he, as the developer of a major application, os not going to upgrade his kernel because he's no longer getting free copies of commercial Linux distros? Sounds to me like it's time for a replacement to cdrecord.
      --
      my sig's at the bottom of the page.
    12. Re:both their fault.. by Anonymous Coward · · Score: 0
      Why does he have to fix it?


      He doesn't, and no one, the parent included, said that he did. They just said he is an ass because he chooses not to fix those problems.
  5. Linux SCSI subsystem a gripe of JS for years by Spoing · · Score: 3, Insightful
    Linus and Joerg Schilling, author of cdrtools disagree on whether the problems are with Linux or the application software.

    Joerg has complained about Linux for years (4? +5?), and generally perfers the SCSI subsystem in Solaris.

    --
    A firewall can not protect you from yourself. Turn off what you do not need. Do not use the firewall to do your work.
    1. Re:Linux SCSI subsystem a gripe of JS for years by natmsincome.com · · Score: 1

      From what I've read Linux had a fairly bad SCSI implimentation in 2.4 that was a mess. I rememmber reading in one of the articles that they wanted to just dump the mess but for the fact the people have SCSI devices :-) If I remmember they rewrote the entire subsystem for 2.6

    2. Re:Linux SCSI subsystem a gripe of JS for years by Anonymous Coward · · Score: 1

      An "entire" rewrite is probably an overstatement. However, you're right -- SCSI on Linux is a known sore point. Linus has been begging for rewrite since kernel 2.0, but nobody's stepped up to the plate.

  6. Two Things. by dalutong · · Score: 1

    One -- I didn't know usb storage used ide-scsi. Stupid me.

    Second -- What is the "good" way for me to get my usb-storage digital camera to work? Or for that matter my USB harddrive?

    Woe is me!

    --

    What comes first, finding a teacher or becoming a student?
    1. Re:Two Things. by Col.+Klink+(retired) · · Score: 1

      > One -- I didn't know usb storage used ide-scsi. Stupid me.

      I don't believe it does. I have machines that access USB Mass Storage Devices and do not have IDE-SCSI enabled.

      --

      -- Don't Tase me, bro!

    2. Re:Two Things. by Col.+Klink+(retired) · · Score: 1
      What is the "good" way for me to get my usb-storage digital camera to work? Or for that matter my USB harddrive?

      USB hard-drives, digital cameras, even all-in-one printers work the same way, so once you've solved it for one you've solved for all. The only headache I have is that /dev/sda will always be the first thing you plug in after a reboot...

      To get them to work, see the The Linux USB sub-system Chapter 2. How to get USB devices working under Linux

      --

      -- Don't Tase me, bro!

    3. Re:Two Things. by MacJedi · · Score: 2, Informative
      You can solve this by putting labels in /etc/fstab rather than a direct reference to /dev/whatever (at least for certain fs types.
      From the fstab manpage:

      Instead of giving the device explicitly, one may indicate the (ext2 or xfs) filesystem that is to be mounted by its UUID or volume label (cf. e2label(8) or xfs_admin(8)), writing LABEL= or UUID=, e.g., `LABEL=Boot' or `UUID=3e6be9de-8139-11d1-9106-a43f08d823a6'. This will make the system more robust: adding or removing a SCSI disk changes the disk device name but not the filesystem volume label.

      --
      2^5
    4. Re:Two Things. by dalutong · · Score: 2, Interesting

      I have them working -- and i also find it annoying that i can't make my /dev/sda ALWAYS be my camera and /dev/sdb always be my external drive. (you'd think there would be a way... i could grep the scsi bus... but i don't know how to make scsi0 be sda or anything else)

      --

      What comes first, finding a teacher or becoming a student?
    5. Re:Two Things. by cbcbcb · · Score: 2, Informative

      I think udev (user space replacement for devfs) is supposed to solve this.

    6. Re:Two Things. by Zocalo · · Score: 1
      Replying to a sig, but what the hell: Todo: Get Linux to boot on a Black And Decker Appliance.

      I'd guess we'd have to call it "Linux for Workbenches".

      --
      UNIX? They're not even circumcised! Savages!
    7. Re:Two Things. by Crazy+Eight · · Score: 2, Informative

      Supposedly it will also allow dalutong to call his usb devices "camera" and "external_drive" (or whatever he wants). Very cool stuff.

  7. Can someone tell me by amarodeeps · · Score: 1

    ...what exactly are the issues that Joerg has with Linux's SCSI layer? I've heard about this in bits and pieces for years, but never really understand what the beef is. I've heard it mentioned that he wants to only talk to devices as if they are SCSI, but I don't know how true this is, nor what the real issues he has beyond this are. Anyone?

    1. Re:Can someone tell me by Spoing · · Score: 1
      2. ...what exactly are the issues that Joerg has with Linux's SCSI layer? I've heard about this in bits and pieces for years, but never really understand what the beef is. I've heard it mentioned that he wants to only talk to devices as if they are SCSI, but I don't know how true this is, nor what the real issues he has beyond this are. Anyone?

      I'm with you. I don't get the complaint except that he doesn't like how Linux implements SCSI. He seems really annoyed, though I don't understand the technical nature of his complaint.

      --
      A firewall can not protect you from yourself. Turn off what you do not need. Do not use the firewall to do your work.
    2. Re:Can someone tell me by Anonymous Coward · · Score: 0

      It seems to be "linux doesn't look like Solaris". And "it makes perfect sense to have a completely different special-case way of dealing with scsi device identification compared to almost everything else on linux. Look at networking- they get their own special way! Why can't SCSI! wah!"

    3. Re:Can someone tell me by Wolfrider · · Score: 2, Interesting

      IIRC:

      o It has to do with error-reporting (or the lack of it) in Linux

      o Talking to everything as "0,0,0"-type SCSI makes cdrecord easier to port.

      --
      .
      == WolfriderV6 == I'm willing to admit that *I just might* be wrong... Are you??
  8. Re:FreeBSD by Anonymous Coward · · Score: 0

    Flamebait perhaps, but its true. I have continually challenged BSD zealots to show me somewhere FreeBSD is faster than Linux. They can't. They change the subject, dismiss its relevance, attack the most minor points of my posts, but NEVER, not ONE has admitted that Linux is faster than FreeBSD. Even when faced with facts.

    Of course, when FreeBSD users believe they have the performance advantage, its the best thing since sliced bread. Like when they all thought FreeBSD runs Linux binaries faster than Linux... it actually didn't, but you get the idea.

  9. Is this the line to bash Principal Skinner? by Crazy+Eight · · Score: 1

    Count me in then. I remember reading his site back when I got my first burner. He's got (had?) a chart outlining his opinion of varied *nix SCSI implementations. IIRC, Solaris and BSD came out pretty good and Linux was roundly trashed. Yet there were no reasons offered for his remarkably low opinion. When I say "remarkably" I mean that Linux failed in a class of B+ to A students (according to him). I know nothing about comparative SCSI transort layers so I assume he could be correct, but I have never found any technical clue as to what inspires his distaste.

  10. ACPI by osho_gg · · Score: 3, Informative

    This chap seems to have completely missed the new and much improved support for ACPI. This is a significant feature addition for linux on laptops. APM does leave a lot to be desired.

  11. Re:FreeBSD by Anonymous Coward · · Score: 0

    FreeBSD folks are very quiet about objective benchmarks. FreeBSD consistently gets its ass creamed by the benchmark results.

  12. Would read the artical but.. by Anonymous Coward · · Score: 0

    There's a dirty big ad for IBM covering the text and any links to the story that might be there.

  13. ide-scsi bug is also in 2.4, causes DATA LOSS by linefeed0 · · Score: 1
    The ide-scsi bug mentioned is also in earlier versions of linux, including 2.4. In addition, it causes data loss.


    If you burn a data CD without padding on the end, and the size is just wrong for your kernel/buffer/hardware combination, and you then rip it on a CD-R drive which is driven by the ide-scsi driver (rather than ide-CD) using "dd" without specifying the actual size, the iso image you rip may very well be truncated by up to 300K!. Read the cdrecord manpage if you don't believe me! The problem is that at the end of the disk, an i/o error is flagged, and data in a certain buffer is not returned.


    FUCK ide-scsi. Something with that kind of bug shouldn't be in the kernel.