Re: Again... DMA speed too slow

From: Joerg Schilling
Date: Mon Apr 14 2008 - 14:24:09 EST


Alan Cox <alan@xxxxxxxxxxxxxxxxxxx> wrote:

> > OK, I know that a few drives give wrong DMA speed test results on Solaris,
> > so the behavior for these drives seems to be unrelated to the OS.
>
> Controllers don't always get DMA ATAPI right things like that - not
> trivial little speed test details.

Using the term "controller" is not specific enough to understand what you might
like to tell.


> > I am not sure why you mention the term "brave", is it because all known Linux
> > distributions still require suid root? In this case, I encourage you to inform
>
> Last time I checked almost all cd burning was being done non root.

Looks like you are incorrectly informed in this area or you checked only software
that does not work correclty in all cases ....

For your information:

Linux traditionally needed suid root for sending SCSI commands until someone
introduced a bug in late 2.4 kernels. After this bug has been discovered, the
Linux Kernel interface has been changed in an incomatible way. At the same time,
the Linux kernel started to filter SCSI commands. Some commands that are needed
for CD/DVD writing still need root privileges, others don't.

Some people did take my working software and removed security checks.
The fact that it is possible to still write CDs under some conditions
does not prove anything. It justs verifies that the people who removed
those checks are not smart enough to find the assignements of the SCSI command
codes in cdrecord ;-)

Jörg

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