Newsgroups: alt.cd-rom Path: cdrom.com!barrnet.net!parc!biosci!agate!library.ucla.edu!europa.eng.gtefsd.com!uhog.mit.edu!news.kei.com!world!mv!mv.mv.com!kaikow From: kaikow@standards.com Subject: Re: What's a multisession CD? Originator: kaikow@mv.mv.com Message-ID: Nntp-Posting-Host: mv.mv.com Sender: kaikow@standards.com Reply-To: kaikow@standards.com Organization: MV Communications, Inc. Date: Tue, 14 Jun 1994 04:19:58 GMT References: <2smt7f$cb3@d243f1036.sietec.de> Lines: 34 In article <2smt7f$cb3@d243f1036.sietec.de>, Rudolf Genieser wrote: > >What's a multisession CD? A FAQ? > >I guess the structure on a CD with multi sessions looks like this: > > | lead-in | session 1: ISO | TOC | lead-in | session 2: ISO | TOC | > >So there are 2 sessions and each with a ISO9660 file system. >I am interested in two parts of questions: > >Does a recorder normly merge both sessions via the TOC or is the TOC only >related to the last written session? There is no standard addressing how such a disk is to be read. ISO 9660 only knows about the volume descriptor set at logical sector 16 of the disk. Anything else is treated subject to agreement 'tween the interchange parties. ISO/IEC 13490 (applies to CD-ROM and CD-WO) does specify that it is the volume descriptor set in the latest session that matters, however, not all disks that may be produced in conformance with ISO 9660 are in conformance with ISO/IEC 13490. A forthcoming, in our lifetimes, revision of ISO 9660 will address the multisession issue. In the interim, it likely makes sense to follow the algorithm in ISO/IEC 13490, which is the one I understand that Photo CD uses. >Normaly both ISO sessions may be independent. Is there a common >way or standard to merge the new ISO contents to the last one? See above.