Date: Fri, 03 Oct 1997 12:20:11 -0700 (PDT) From: Simon Shapiro <Shimon@i-Connect.Net> To: Andrew Reilly <reilly@zeta.org.au> Cc: freebsd-scsi@FreeBSD.ORG, gibbs@plutotech.com Subject: Re: New SCSI Framework Patches Available Message-ID: <XFMail.971003122011.Shimon@i-Connect.Net> In-Reply-To: <199710031157.VAA02092@gurney.reilly.home>
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Hi Andrew Reilly; On 03-Oct-97 you wrote: > On 2 Oct, Justin T. Gibbs wrote: > > Supported peripherals: > > > > Direct Access driver (da): > > 512 byte sectored disk drivers. Support for other sector sizes is > > planned, but further investigation on the "right" approach for this > > is needed. It probably belongs in the disk-slice code. > > Pardon for the unhelpful intrusion, but could someone please explain > the issue here? > > I have hopes that one day my Fujitsu MO drive will be able to use > 2k-sector media. Is the problem that much of the code calculates size > information in sectors, (perhaps for 32-bit length restriction reasons?) > and these sizes will not be appropriate for the information stored in > them if the sectors themselves are not all the same size? Would it hurt > (in a system that wished to use 2k-sector media on at least one drive) > to use 2k sectors for all da drives, even if that meant multiple-sector > writes were done as one? Maybe this has something to do with trying to help me solve the 528 byte sectors... Explanation: The DPT is papable of handling 528 byte physical sectors. They appear as 512 bytes logical size (``normal''). The extra 16 bytes are used for ECC data path between the controller's memory and the disk. Or, are we talking here about supporting the strange (to me) sector sizes available on some CD-ROM drives? Strange as in non power of two sizes. --- Sincerely Yours, Simon Shapiro Atlas Telecom Senior Architect 14355 SW Allen Blvd., Suite 130 Beaverton OR 97005 Shimon@i-Connect.Net Voice: 503.799.2313
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