Re: CD writing in future Linux (stirring up a hornets' nest)

From: Jan Engelhardt
Date: Thu Feb 09 2006 - 12:35:13 EST


>> >> >Please explain me:
>> >> >
>> >> >- how to use /dev/hd* in order to scan an image from a scanner
>> >> >- how to use /dev/hd* in order to talk to a CPU device
>> >> >- how to use /dev/hd* in order to talk to a tape device
>> >> >- how to use /dev/hd* in order to talk to a printer
>> >> >- how to use /dev/hd* in order to talk to a jukebox
>> >> >- how to use /dev/hd* in order to talk to a graphical device
>> >> >
>> >> With /dev/sg, this was possible?
>> >
>> >Of course!
>> >
>> But you need to open the correct /dev/sg[0-9] too, don't you?
>> (otherwise cdrecord would set the jukebox on fire)
>
>This is why the mapping engine is in the Linux adoption part of
>libscg. It maps the non-stable device <-> /dev/sg* relation to a
>stable b,t,l address.
>
Right. The question was rather like this:
Say we have our non-stable /dev/sr0 mapping to /dev/sg0, and it has got BTL
1,1,0. Now, if the user starts `cdrecord -dev=1,1,0`,
`ls -l /proc/$(pidof -s cdrecord)/fd/` should show (and in fact did when I
used ide-scsi back then) /dev/sg0, right?

If so, what's wrong with just opening /dev/sg0 directly (as per user
request, i.e. cdrecord -dev=/dev/sg0) and sending the scsi commands down
the fd?


Jan Engelhardt
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