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Xref: sserve comp.unix.bsd:1859 comp.unix.internals:4922 Path: sserve!manuel!munnari.oz.au!spool.mu.edu!think.com!ames!sun-barr!sh.wide!wnoc-tyo-news!hoffman!jmasgw!green!rai!tetsuji From: tetsuji@rai.juice.or.jp (Tetsuji Rai) Newsgroups: comp.unix.bsd,comp.unix.internals Subject: Re: Writing a device driver for CDROM Keywords: bsd devicedriver cdrom Message-ID: <1992Jul6.113142.436@rai.juice.or.jp> Date: 6 Jul 92 11:31:42 GMT Article-I.D.: rai.1992Jul6.113142.436 References: <1992Jun20.152106.159@rai.juice.or.jp> <24289@dog.ee.lbl.gov> Organization: Rai's home in Tokyo Lines: 38 In article <24289@dog.ee.lbl.gov> torek@horse.ee.lbl.gov (Chris Torek) writes: >In article <1992Jun20.152106.159@rai.juice.or.jp> tetsuji@rai.juice.or.jp >(Tetsuji Rai) writes: > >>The scsi source files coming with BSD/386 are for hard disks and tape >>drives; ie non-removable devices, so "match" and "attach" routine (sdmatch >>and sdattach, internally) are called upon booting. As for CDROM, the >>device is often changed, so I assume sdattach should be called each time >>it is mounted. > >No: match and attach are used to find hardware. The CDROM *drive* is >not physically removed from the bus; only the media are removable. >(Well, it is possible to move hardware with live power, but be *sure* >you know what you are doing.) > Thanks. I've got it. >The interface between a CDROM ``disk'' driver and the rest of the >system is up to you, but once matched and attached, the device entry is >there to stay. (Currently, the configuration code allows devices to >appear `magically' on a bus iff the bus driver code notices and calls >config_found---that is, config_found is intended to be usable at any >time---but there is no support for ``unfinding'' a device. This would >be easy now, but would complicate dynamic driver loading, if anyone >were to implement that.) Thank you. I got the hierarchy, making CDROM driver, and have another problem. I can attach and get the capacity of a CDROM, but cannot read. I cannot explain without the source code, so cannot talk in a newsgroup. Thank you very much! --- RRR Tetsuji Rai tetsuji@rai.juice.or.jp R R aaa i 5-12-21, Toyotamakita, Nerimaku, Tokyo 176, Japan RRR a a i voice: +81-3-3557-3936 fax: +81-3-3993-0323 R R aaaaa i