Date: Thu, 11 May 1995 18:58:28 -0700 (PDT) From: "Rodney W. Grimes" <rgrimes@gndrsh.aac.dev.com> To: ohki@gssm.otsuka.tsukuba.ac.jp Cc: terry@cs.weber.edu, freebsd-bugs@FreeBSD.org Subject: Re: problem for reading old CD-ROM Message-ID: <199505120158.SAA13806@gndrsh.aac.dev.com> In-Reply-To: <199505120144.KAA00248@smri01.gssm.otsuka.tsukuba.ac.jp> from "ohki@gssm.otsuka.tsukuba.ac.jp" at May 12, 95 10:44:14 am
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> > > rgrimes>> I am not sure, I need to go check my iso 9660 spec, > rgrimes>> but it seems to me > rgrimes>> that 512 byte logical blocks are a violation of of the spec. > rgrimes>> Changing > rgrimes>> the cd9660 code to read non-conformat cd-roms, IMHO, is an ugly hack > rgrimes>> at best. > > terry> I disagree about the ability to read non-conformant CDROMs. > terry> Unfortunately, > terry> there's not a sticker that they can only display if they conform, and > terry> the public doesn't only buy them if they conform. > > rgrimes>> Changing block device code to do unaligned block transfers is even > rgrimes>> worse :-(. > > terry> This I definitely agree with; if the code is going to be bastardized, > terry> better to do the deed in the FS specific code by buffering more than > terry> necessary in and hanging it off the in core version of the vnode after > terry> translation instead of hanging it off the vnode in the normal place. > > I know my hacking is not a good one, and I wanted to hear opinions > about handling of non-conformat cd-roms from members. > > The cd-rom I tried to read is labled as > "This disc was mastered to ISO 9660 Standard. Level 1", > so I thought this is confomat cd-rom. (Is this not true?) Refering to ISO 9660 : 1988 (E) sections 6.1.2 and 6.2.2 tell me that a Logical Sector and Logical Block are of size 2^(n+9) meaning 2048 bytes or longer, thus a 512 byte logical block is infact a violation of ISO 9660 : 1988 (E). You should be able to ftp a copy of that spec from ftp.cdrom.com:/pub/cdrom some place. Check the faq, they might have a pointer in there to the location of the iso spec. Or maybe it is only the RRIP spec you can get online. -- Rod Grimes rgrimes@gndrsh.aac.dev.com Accurate Automation Company Custom computers for FreeBSD
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