Boosting performance when a read-only disc is in the drive

ZIYAD A. M. AL-BATLY zamb at
Mon May 2 02:47:55 UTC 2005

On Sun, 2005-05-01 at 18:16 -0400, Stephen R Laniel wrote:
> Is there any way to extract meaningful performance gains from a
> DVD/CD-RW drive when a read-only CD-ROM disc is in the drive?
No.  At least not anything that I know about.

> If Linux knows that it will never have to perform any writes while
> that disc is in the drive, can it speed anything up?
Linux always assume that the disc is read-only with the exception[*] of
UDF mounted disk(s).  UDF is a file-system used by CD-RW and DVD media.
This dos *not* mean that all CD-RW and/or DVD out there are UDF as you
can create ISO9660 file-system on those instead of UDF.

In general, if your system is configure correctly (which should be by
default!) then your CD-ROM is functioning at the best speed possible.

> -- 
> Stephen R. Laniel
> steve at
> +(617) 308-5571

      * Technically, you could format a CD with (almost) any file-system
        out there, however it will be hard and pointless to do so and
        you will most likely lose more than what you'll gain from doing
        it.  CD-RW, for example, have a limit on the number of writes
        per sector (about 10,000 if I remember correctly), and that was
        the primary reason for creating the UDF.  Don't think that
        10,000 is a large number, whenever you read (or access) a file
        the super block of the file-system have to be updated even if
        you didn't change the file itself (that's to update the "atime"
        or "access time") and hence you see why using "normal"
        file-system on CD-ROMs is pointless.


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