21 Feb
2017
21 Feb
'17
10:55 p.m.
Random832 <random832(a)fastmail.com> wrote:
Why does that make them more useful for end users than
device filenames,
especially for non-SCSI devices? USB or ATA bus numbers - or USB device
identifiers - might be more useful than SCSI bus numbers, for end users
who have USB or ATA devices. ATA bus numbers had a deterministic mapping
to /dev/hd* device filenames, once upon a time.
You know that Linux implements several different competing methods to access
these drive types?
You know that some of them do not (or not correctly) support DMA?
You know that DVD drives will not work for writing if you do not have DMA?
Why does that mean the correct solution is
"require the user to type in
the bus number on a program's command line" rather than "configure a
particular bus number to have a particular filename"?
Why do people always repeat the same questions that have been answered many
times in the past already?
1) CAM is a standard, why not use it? full stop
2) **Most** Operating systems do not support /dev/* based access to SCSI.
This includes a POSIX certified system like Mac OS X.
3) **Most** Operating systems do not even support a file descriptor based
interface to SCSI commands.
This includes a POSIX certified system like Mac OS X.
4) CAM is the only interface method that can be mapped to all
existing operating system specific implementations.
Jörg
--
EMail:joerg@schily.net (home) Jörg Schilling D-13353 Berlin
joerg.schilling(a)fokus.fraunhofer.de (work) Blog: http://schily.blogspot.com/
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