A Detailed Simulation Model of the Hp 97560 Disk Drive

David Kotz, Dartmouth College
Song Bac Toh, Dartmouth College
Sriram Radhakrishnan, Dartmouth College

Report by Dartmouth Department of Computer Science


We implemented a detailed model of the HP 97560 disk drive, to replicate a model devised by Ruemmler and Wilkes (both of Hewlett-Packard, HP). Our model simulates one or more disk drives attached to one or more SCSI buses, using a small discrete-event simulation module included in our implementation. The design is broken into three components: a test driver, the disk model itself, and the discrete-event simulation support. Thus, the disk model can be easily extracted and used in other simulation environments. We validated our model using traces obtained from HP, using the same “demerit” measure as Ruemmler and Wilkes. We obtained a demerit figure of 3.9%, indicating that our model was extremely accurate. This paper describes our implementation, and is meant for those wishing to understand our model or to implement their own.