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I can firmly state that there are at least two host controllers on the market that support command queuing for ATA devices in hardware. -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Hale Landis Sent: Tuesday, December 07, 2004 2:40 PM To: [EMAIL PROTECTED] Subject: Re: [t13] ATAPI Overlap and Queuing This message is from the T13 list server. Mark Overby wrote: > I object to removing queuing. Overlap I don't object to. Hmmm... Just to make sure we are talking about the same thing and because there has been a long-standing confusion... There are two versions of "overlap"... One version is when a device supports queing but the queue depth is only one - this can work on both ATA and ATAPI devices. The other version is defined only for ATAPI devices and it uses the DSC bit with "immediate" commands. I say that all forms of queuing (including the case of queuing with a queue depth of one) for both ATA and ATAPI devices can/should be made obsolete (because I don't think anyone is currently shipping a host controller product that can support any form of queuing as defined by ATA/ATAPI-x, x=4, 5, 6 or 7). I do not think the non-queuing version of overlap (using the DSC bit on ATAPI devices) should be made obsolete. Hale -- ++ Hale Landis ++ www.ata-atapi.com ++
