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Re: [Libcdio-devel] lsn versus lba versus msf


From: Rocky Bernstein
Subject: Re: [Libcdio-devel] lsn versus lba versus msf
Date: Tue, 20 Nov 2012 12:24:46 -0500

Thanks for the information.

The text in the section that Thomas refers to now reads:

When programming, unless one is working with a CD-DA (and even here, only
> in a time-like fashion), is generally more cumbersome to use an MSF rather
> than a LBA or LSN described below, since subtraction of two MSF's has the
> awkwardness akin to subtraction using Roman Numerals.
>
> A simpler way to address a block is to use a ``Logical Sector Number''
> (@term{LSN}) or a ``Logical Sector Number'' (@term{LBA}). In the MMC-5
> glossary these are synonymous terms. However historically it has been used
> differently. In libcdio, to convert a LBA into an LSN you just subtract
> 150. Both LBA's and LSN's can be negative.
>

If folks want to further changes, have at it.


On Tue, Nov 20, 2012 at 8:28 AM, Thomas Schmitt <address@hidden> wrote:

> Hi,
>
> for what it is worth, MMC-5 has in its glossary:
> "
> 3.1.45 Logical Block Address (LBA)
> The LBA is the number that a Host uses to reference Logical Blocks
> on a block storage device.
> 3.1.46 Logical Sector Number (LSN)
> A sector's LBA is referred to as LSN in some references.
> "
>
> So for getting in sync with MMC one would have to give up
> the distinction of LBA and LSN. Both would be -150 at MSF 0:0:0.
>
>
>
> In http://www.gnu.org/software/libcdio/libcdio.html#Sectors.
> i read: "fix me: LSNs can be negative up to the pregap size?"
>
> There appear MMC-LBAs below -150 with writing of CD-TEXT to the
> Lead-in of a SAO session. E.g. -11635. This address varies
> because it also identifies the manufacturer and the product type
> of CD media.
> Whatever, reading of that CD-TEXT is done via 43h READ TOC/PMA/ATIP
> Format 0101b. This command does not need a block address.
> (Details taken from libburn's doc/cookbook.txt and doc/mediainfo.txt)
>
> So i am not sure whether MSF 0:0:0 should be considered to be
> the lowest possible address in the context of libcdio.
>
>
> Have a nice day :)
>
> Thomas
>
>
>


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