Date: Fri, 31 Jan 1997 11:24:09 -0800 (PST) From: Simon Shapiro <Shimon@i-Connect.Net> To: dyson@FreeBSD.ORG Cc: freebsd-scsi@FreeBSD.ORG, joerg_wunsch@uriah.heep.sax.de, "John S. Dyson" <toor@dyson.iquest.net> Subject: Re: XXXminpys question Message-ID: <XFMail.970131133214.Shimon@i-Connect.Net> In-Reply-To: <199701310221.VAA06077@dyson.iquest.net>
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Hi John S. Dyson; On 31-Jan-97 you wrote: > > As Peter Dufault wrote: > > > > > > The adapters _are_ the reason for a minphys, so there should only be > > > > one at all. We should probably add it to the cdevsw entries. It can > > > > default to minphys (64 KB). > > > > > > You still want an overall system minphys to prevent a rogue driver / rogue > > > dd from crashing the system. It is the maximum amount you're willing to > > > guarantee to lock down for a raw transfer. > > > > I remember that David Greenman once said that the main reason for the > > existing minphys was the limitation of the SCSI adapters. > > > > Maybe there should be another minphys, but more something like 1 MB or > > larger then. The existing 64 KB limitation is something seriously > > small. > > > It will require some restructuring of the pbuf (physical I/O buffer) > code, but isn't that bad to do. It has been in my queue for a while. > If the driver-savvy people can work out a way to query the driver for > the maximum I/O size, I can/will implement the upper level changes. > > John Dyson Is this not the purpose of the xxx_minphys entry point to the driver? Simon
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