Date: Sat, 14 Jul 2001 02:12:01 -0400 From: Coleman Kane <cokane@freebsd.org> To: Mike Smith <msmith@freebsd.org> Cc: Christoph Kukulies <kuku@gilberto.physik.RWTH-Aachen.DE>, =?iso-8859-1?Q?S=F8ren_Schmidt?= <sos@freebsd.dk>, hackers@freebsd.org Subject: Re: ATAPI support Message-ID: <20010714021201.A7771@evil.apt> In-Reply-To: <200107121825.f6CIPNd00923@mass.dis.org>; from msmith@freebsd.org on Thu, Jul 12, 2001 at 11:25:22AM -0700 References: <20010712121341.D22288@gil.physik.rwth-aachen.de> <200107121825.f6CIPNd00923@mass.dis.org>
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On Thu, Jul 12, 2001 at 11:25:22AM -0700, Mike Smith wrote, and it was proclaimed: > > > We support ATAPI devices and has been for a long time (also CD burners)... > > > > I believe I forgot to do a group reply on my previous reply > > to Søren. > > > > OK, it seems a misunderstanding of the term ATAPI. > > The author of cdrecord, Joerg Schilling, told me - I will translate: > > > > Citation: > > > > "You havn't understood what ATAPI is! > > Schilly has some funny ideas about what ATAPI is as well. > > > ATAPI *is* SCSI over IDE transport. Thus a SCSI system has to have > > a hostadapter driver for the IDE bus. > > There's no "has to" about it. And this isn't entirely correct either; > one needs to read the relevant SFF802x specifications, particularly the > parts where they state their intention to deviate further from SCSI in > the future. > From what I have gathered from reading tech docs, etc... ATAPI is the ATA Packet Interface. SCSI is also a packet-based interface. The original creators of ATAPI created it by using common commands and software interfaces that SCSI used already, basically to simplify things. The ATAPI specification was never a complete implementation of SCSI over ATA. It was rather a seperate packet interface that had a few common features that SCSI did. Basically, the SCSI<->ATA drivers simply create a "false" scsi bus that takes its device channels as the number of ATAPI devices it connects to. > > *All* OSs despite FreeBSD do that right. Under Linux unfortunately > > it isn't the default." > > He's entitled to his opinion; don't mistake it for fact. > I used to be a supporter of the SCSI-over-ATA implementation until I did some reading and realized that it would present problems. Hopefully, rather than trying to create this false SCSI-bus, and using the CAM layer, these software programs will start to use the devices and ioctls, or other interface libs to write CDs. > -- > ... every activity meets with opposition, everyone who acts has his > rivals and unfortunately opponents also. But not because people want > to be opponents, rather because the tasks and relationships force > people to take different points of view. [Dr. Fritz Todt] > V I C T O R Y N O T V E N G E A N C E > > > > To Unsubscribe: send mail to majordomo@FreeBSD.org > with "unsubscribe freebsd-hackers" in the body of the message > To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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