Client processors run at 200 MIPS and the server CPU at 300 MIPS; these values reflect typical processor speeds expected in the near future. Disks are not modeled explicitly but we assume a server cache hit ratio of 50%. This value is much higher than hit ratios observed in real systems . A lower server cache hit ratio would reduce the stall rate since transactions would take longer to execute and thus dependencies would spread more slowly (we ran an experiment to confirm this). Furthermore, a lower hit rate would reduce the relative impact of stalls on overall execution time. The costs for reading and writing an object are about 64 sec and 128 sec respectively. These times are based on the observation that a transaction operates on an object for some time when it accesses it, e.g., the time spent per object in the OO7 benchmark by Thor  is around 35 sec (and OO7 methods do not perform any significant amount of work). Other costs such as those for validation, cache lookup, etc., are not shown due to lack of space; they are negligible compared to the access and fetch costs. The timeout period is chosen to be 0.5 second. Clock skews are not modeled since they are insignificant compared to the timeout period; the Network Time Protocol  maintains clock skews that are less than 10 milliseconds on LANs and WANs .