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    From
    SubjectRe: PATCH: cdrecord: avoiding scsi device numbering for ide devices
    Date
    Albert Cahalan writes:

    > On Mon, 2004-08-09 at 18:59, Con Kolivas wrote:
    >> Albert Cahalan writes:
    >>
    >>
    >> > Joerg:
    >> > "WARNING: Cannot do mlockall(2).\n"
    >> > "WARNING: This causes a high risk for buffer underruns.\n"
    >> > Fixed:
    >> > "Warning: You don't have permission to lock memory.\n"
    >> > " If the computer is not idle, the CD may be ruined.\n"
    >> >
    >> > Joerg:
    >> > "WARNING: Cannot set priority class parameters priocntl(PC_SETPARMS)\n"
    >> > "WARNING: This causes a high risk for buffer underruns.\n"
    >> > Fixed:
    >> > "Warning: You don't have permission to hog the CPU.\n"
    >> > " If the computer is not idle, the CD may be ruined.\n"
    >>
    >> Huh? That can't be right. Every cd burner this side of the 21st century has
    >> buffer underrun protection.
    >
    > I'm pretty sure my FireWire CD-RW/CD-R is from
    > another century. Not that it's unusual in 2004.
    >
    >> I've burnt cds _while_ capturing and encoding
    >> video using truckloads of cpu and I/O without superuser privileges, had all
    >> the cdrecord warnings and didn't have a buffer underrun.
    >
    > That's cool. My hardware won't come close to that.
    > Burning a coaster costs money.
    >
    > Let me put it this way: $$ $ $$$ $$ $ $$$ $$ $
    >
    > The warning, if re-worded, will save people from
    > frustration and wasted money.

    Sounds good; how about something less terrifying? That warning sounds like a
    ruined cd is likely.

    >> Last time I gave
    >> superuser privilege to cdrecord it locked my machine - clearly it wasn't
    >> rt_task safe.
    >
    > So, you've been working on the scheduler anyway...
    > An option to reserve some portion of CPU time for
    > emergency use (say, 5% after 1 second has passed)
    > would let somebody get out of this situation.

    This breaks the real time policy entirely. That's why I run it SCHED_ISO ...
    but of course this isn't available in mainline linux.

    > Reporting and/or fixing the cdrecord bug is nice too.

    It was a hard lockup and randomly happened during a cd write, creating my
    first coaster in a long time... in rt mode ironically which is how it is
    recommended to be run. So I removed the foolish superuser bit and have had
    no problem since. Yes it was unaltered cdrecord source and it was the
    so-called alpha branch and... Not much else I can say about it really?

    Cheers,
    Con

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