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More On The 2.6 Kernel 58

Posted by timothy 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.."
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More On The 2.6 Kernel More

More On The 2.6 Kernel

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  • Sound Support (Score:5, Funny)

    by voss ( 52565 ) on Tuesday December 09, 2003 @07:40PM (#7675308)
    Wow it only took 10 years to get reliable sound support into the kernel ;-)

    • Re:Sound Support (Score:4, Insightful)

      by Spoing ( 152917 ) on Tuesday December 09, 2003 @08:30PM (#7675737) Homepage
      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.

    • Re:Sound Support (Score:4, Informative)

      by MrHanky ( 141717 ) on Tuesday December 09, 2003 @08:50PM (#7675884) Homepage Journal
      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 [sourceforge.net], 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.
  • 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.
    • Personally, I've been thrilled with 2.6. It's running quite a bit better on my laptop than 2.4 did. :-)

    • Re:2.6 (Score:2, Informative)

      by SanityInAnarchy ( 655584 )
      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.

  • usb-storage and ntfs (Score:5, Interesting)

    by asteinberg ( 521580 ) <ari.steinberg@sA ... d.edu minus poet> on Tuesday December 09, 2003 @08:00PM (#7675511) Homepage
    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?

    • 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

    • Re:usb-storage and ntfs (Score:5, Informative)

      by Josh Booth ( 588074 ) <joshbooth2000 AT yahoo DOT com> on Tuesday December 09, 2003 @08:11PM (#7675599)
      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).

      • Re:usb-storage and ntfs (Score:3, Informative)

        by AJWM ( 19027 )
        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.
      • ...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]

        • "[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
    • 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 [insidewindows.info] loopback driver under Windows.) The reason is that NTFS does a lot of weird st
    • 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 de

  • both their fault.. (Score:5, Informative)

    by molo ( 94384 ) on Tuesday December 09, 2003 @08:01PM (#7675519) Journal
    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
    • "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).
      • 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
        • 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.
    • "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.
      • "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...

        • That doesn't make him not an ass.

          • "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.

      • 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

    • 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 simil

  • Linux SCSI subsystem a gripe of JS for years (Score:4, Insightful)

    by Spoing ( 152917 ) on Tuesday December 09, 2003 @08:25PM (#7675696) Homepage
    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.

    • ...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. ...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 nat

        • 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

      • Re:Can someone tell me (Score:3, Interesting)

        by Wolfrider ( 856 )
        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.
    • 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
      • 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.
  • 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!
    • > 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.
    • 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 [linux-usb.org]

      • Re:Two Things. (Score:3, Informative)

        by MacJedi ( 173 )
        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: addin

        • 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".

      • Re:Two Things. (Score:3, Interesting)

        by dalutong ( 260603 )
        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)

  • ACPI (Score:3, Informative)

    by osho_gg ( 652984 ) on Friday December 12, 2003 @12:32AM (#7698122)
    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.
  • 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 th

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