Date: Sat, 4 May 1996 10:47:23 +0200 (MET DST) From: J Wunsch <j@uriah.heep.sax.de> To: scsi@freebsd.org Cc: vernick@CS.SunySB.EDU (Michael Vernick) Subject: Re: Adaptec 3940 and Scatter/Gather Message-ID: <199605040847.KAA21491@uriah.heep.sax.de> In-Reply-To: <199605032215.SAA18813@cs.sunysb.edu> from Michael Vernick at "May 3, 96 06:15:45 pm"
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As Michael Vernick wrote: > The documentation specifies that the 3940 can perform scatter/gather. > Does anyone know how to use this feature? Is it Adaptec specific? I > didn't see anything about scatter/gather in the Scsi spec. If you have it in a FreeBSD machine, it does scatter/gather. :-) Well, it cannot be in the SCSI specs, since it's nothing to care for on the SCSI interface, but it rather refers to the ability to split up a single SCSI transfer into multiple different memory locations on the host bus (as opposed to SCSI bus) interface. This comes really handy in a VM environment, since you can use one scatter/gather segment per page, so you don't need to care for the non-contiguousness of a logical buffer inside the physical memory. -- cheers, J"org joerg_wunsch@uriah.heep.sax.de -- http://www.sax.de/~joerg/ -- NIC: JW11-RIPE Never trust an operating system you don't have sources for. ;-)
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