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Full Discussion: How raw disks are read?
Top Forums UNIX for Advanced & Expert Users How raw disks are read? Post 302802765 by methyl on Saturday 4th of May 2013 06:13:54 PM
Old 05-04-2013
Point: With modern hardware a "raw disc" can be multiple physical discs which the Operating System sees as one physical disc.

Some research ideas:

Consider the case of a virgin disc. There are no filesystems unless your software creates a filesystem. You can write or read whatever you like within the physical dimensions of the disc.

The very basic filesystems follow the pattern of the original IBM tape format VOL1 HDR1.

For research purposes it is worth a look at CAFS (Content Addressable File Store). That's the way to use a raw disc! It's so much better than "Binary Tree", "Hash Random" or "Index Sequential" file systems when dealing with disorganised data.
 

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CDDB::File(3pm) 					User Contributed Perl Documentation					   CDDB::File(3pm)

NAME
CDDB::File - Parse a CDDB/freedb data file SYNOPSIS
my $disc = CDDB::File->new("rock/f4109511"); print $disc->id, $disc->all_ids; print $disc->artist, $disc->title; print $disc->year, $disc->genre, $disc->extd; print $disc->length, $disc->track_count; print $disc->revision, $disc->submitted_via, $disc->processed_by; foreach my $track ($disc->tracks) { print $track->number, $track->title, $track->artist; print $track->length, $track->extd; } DESCRIPTION
This module provides an interface for extracting data from CDDB-format data files, as used by freedb. It does not read data from your CD, or submit information to freedb. METHODS
new my $disc = CDDB::File->new("rock/f4109511"); This will create a new object representing the data in the file name specified. id / all_ids my $discid = $disc->id; my @discid = $disc->all_ids; Due to how freedb works, one CD may have several IDs associated with it. 'id' will return the first of these (not necessarily related to the filename from which this was read), whilst 'all_ids' will return all of them. title / artist The title and artist of this CD. For eponymous CDs these will be identical, even if the data file leaves the artist field blank. year The (4-digit) year of release. genre The genre of this CD. This is the genre as stored in the data file itself, which is not related to the 11 main freedb genres. extd The "extended data" for the CD. This is used for storing miscellaneous information which has no better storage place, and can be of any length. length The run time of the CD in seconds. track_count The number of tracks on the CD. revision Each time information regarding the CD is updated this revision number is incremented. This returns the revision number of this version. processed_by / submitted_via The software which submitted this information to freedb and which processed it at the other end. tracks foreach my $track ($disc->tracks) { print $track->number, $track->title, $track->artist; print $track->length, $track->extd; } Returns a list of Track objects, each of which knows its number (numering from 1), title, length (in seconds), offset, and may also have extended track data. Tracks may also contain an 'artist' field. If this is not set the artist method will return the artist of the CD. SEE ALSO
http://www.freedb.org/ AUTHOR
Tony Bowden BUGS and QUERIES Please direct all correspondence regarding this module to: bug-CDDB-File@rt.cpan.org COPYRIGHT
Copyright (C) 2001-2005 Tony Bowden. All rights reserved. This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License; either version 2 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. perl v5.10.1 2005-10-04 CDDB::File(3pm)
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