Re: DVD+/-R writers
>From: Andy Polyakov <appro@fy.chalmers.se>
>As for DVD-RW on the other hand. If *minimally* formatted for Restricted
>Overwrite, DVD-RW still can be recorded only *sequentially*. This makes
>it virtually impossible to use *minimally* formatted DVD-RW media for
>housing of live read-write file system. Only once fully formated (which
>takes 1 hour for 1x media), DVD-RW permits for random write, but with
>32KB granularity. Latter means that you either have to have special
>kernel driver which would arrange for 32KB granularity or modify file
>system code to do same thing. Now note that no work (at least no visible
>outcome so far) has been done to accomplish either of these two
>alternatives under Linux (or any other Unix implementation), [presumaly]
>because it's damn hard. A.
So DVD+RW drives do things in firmware what you need to do in the kernel
if you like to have 2k granularity with DVD-RW. But this is nothing a new
firmware could not support.
Note that the kernel also first reads a 512 byte sector from a hard disk
if you like to write only 64 bytes.
AFAIK, DVD+RW also use the basic DVD physical sector size of 32k.
Jörg
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EMail:joerg@schily.isdn.cs.tu-berlin.de (home) Jörg Schilling D-13353 Berlin
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