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James's answer is correct. Spin-up does take time and power, we should limit un-necessary spin-up and spin-down cycle if we can. During this minimum time, multiple cache misses can be serviced for apps. The maximum time is vendor specific, that is because drive may decide to use this opportunity to flush out data for cache management purpose for both write cache and NV cache. Frank Shu Program Manager Windows - Storage Device Driver [EMAIL PROTECTED] Tel 425-707-1779 Cell 425-301-3614 -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED] Sent: Friday, July 28, 2006 8:26 AM To: [email protected] Subject: Re: [t13] Set NV Cache Power Mode command This message is from the T13 list server. >From one of our engineers: > From my dealing with MS, they intend "Minimum High-Power Time" to be the > minimum time the drive should stay spinning if it was forced to spinup to > service a read or write while in NVC low power mode. My understanding is > that they don't want the drive to spin back down "too quickly", but rather > use this up time to flush to disk or possibly service more accesses to the > disk. It would be valuable for someone from Microsoft to indicate their intentions as well. Thank You !!! ----------------------------------------------------------------- Jim Hatfield Seagate Technology LLC e-mail: [EMAIL PROTECTED] s-mail: 389 Disc Drive; Longmont, CO 80503 USA voice: 720-684-2120 fax....: 720-684-2711 ========================================== "Eschmann, Michael K" <michael.k.eschma To [EMAIL PROTECTED]> <[email protected]> Sent by: cc [EMAIL PROTECTED] rg Subject No Phone Info [t13] Set NV Cache Power Mode Available command 07/25/2006 09:54 PM Hi Folks, The Set NV Cache Power Mode command (cmd=B6h, features=0) specifies a count value that is a "Minimum High-Power Time", but what does this really mean? Does this time mean that the disk shall be spun-down immediately after the disk goes idle for this time period, or is it truly a minimum and a disk may choose to spin-down some time after that minimum? Since the specification says "The maximum amount of time the device shall keep the media spun up is vendor specific", however I observe the Microsoft WDK test for this feature appears to treat this as more of an immediate timer. I'd really like to hear from any disk vendor that implements this feature. Thanks, MKE.
