Return to BSD News archive
Xref: sserve comp.os.386bsd.development:1734 comp.os.386bsd.questions:8284 comp.unix.bsd:13342 Path: sserve!newshost.anu.edu.au!munnari.oz.au!spool.mu.edu!howland.reston.ans.net!cs.utexas.edu!swrinde!sgiblab!nec-gw!nec-tyo!wnoc-tyo-news!rena!cnvxjp!omnis.co.jp!specgw!amurai From: amurai@specgw.spec.co.jp (Atsushi MURAI) Newsgroups: comp.os.386bsd.development,comp.os.386bsd.questions,comp.unix.bsd Subject: [Q] Logical vs Phygical Block Message-ID: <CK9wu8.F6r@specgw.spec.co.jp> Date: 27 Jan 94 05:34:56 GMT Followup-To: comp.os.386bsd.development Organization: System Planning and Engineering Corporation, Tokyo, Japan Lines: 31 Dear Netter, I am working around CD-ROM/DA(PhotoCD,Reading Degital Audio) for *bsd now. I've done for PhotoCD with multisession. But Reading Degital Audio, I need your knowledge of Logical vs Phygical Block of *bsd system. For example, when invoke a read function for raw device, Starting point of Data is offset from partition. Read funtion call the phisio in kernel for converting from offset to Logical Block Number (512byte). and then this routine call a stratagey routine in driver is converting Logical Block number plus partition to Phygical Block Number. This implementation will work only Phygical Block size is multiple 512 bytes. ( i.e. CD-ROM block 2048/ SCSI 512Bytes) But block(sector) size for Degital Audio Data on CD is 2352byts. So it will miss reading a block......... I am planning(actually done) to pass a data offset ( uio->uio_offset ) pointer to stratagey routine in cd.c and re-make a new(next) offset and calculating Phygical Block Number.( I beleive other stratagy routine in disk/fd is just ignore extra argument from kern_physio.c ;-) But I would like to get any comment/suggestion for my idea from you just in case. Regards. Atsushi. ---