A Quantitative Analysis of Disk Drive Power Management in Portable Computers

With the advent and subsequent popularity of portable computers, power management of system components has become an important issue. Current portable computers implement a number of power reduction techniques to achieve a longer battery life. Included among these is spinning down a disk during long periods of inactivity. In this paper, we perform a quantitative analysis of the potential costs and bene ts of spinning down the disk drive as a power reduction technique. Our conclusion is that almost all the energy consumed by a disk drive can be eliminated with little loss in performance. Although on current hardware, reliabilitycan be impacted by our policies, the next generation of disk drives will use technology such as dynamic head loading which is virtually una ected by repeated spinups. We found that the optimalspindown delay time, the amount of time the disk idles before it is spun down, is 2 seconds. This di ers signi cantly from the 3-5 minutes in current practice by industry. ...

• Type: Conference
• Year: 1994
• Where: USENIX
• Authors: Kester Li, Roger Kumpf, Paul Horton, Thomas E. Anderson
• Keywords: Disk Drives, Operating System, Portable Computers, Power Reduction Technique, USENIX 1994