Today we continue reading from the WRL research report. This time we review the benchmark for opening and closing a particular file. The tests were performed with flat file and nested path file.  The UNIX derivatives were consistently faster than Sprite. The results also showed that in the remote case Sprite is also faster than SunOS, but slower than Ultrix. In any case, this benchmark did not explain the previously discussed anomaly. Another benchmark that was studied involved create-delete  of a temporary file. Data is written to the file on create and read from the file prior to delete. Three different sizes of data were transferred, 0, 10kbytes and 100Kbytes. This benchmarks highlighted a basic difference between Sprite and UNIX derivatives In Sprite, short lived files can be created, used and deleted without any data ever being written to disk. Information only goes to the disk after it has lived at least 30 seconds. In Unix and its derivatives,  the file system appears to be much more  closely tied to the disk.  Even with no data written in the file, the UNIX derivatives create and delete the file.  This benchmark also explains the anomaly involving the poor performance of DS3100 Ultrix on the Andrew Benchmark. The time for creating an empty file is 60% greater in DS3100-Ultrix-local than in 8800-Ultrix-local, and the time for a 100K byte file in DS 3100-Ultrix-Remote is 45 times as long as for DS3100-Sprite-Remote. This relative poor performance may be attributed to slower disks possibly due to NFS writing policy, which requires new data to be written through to the disk when the file is closed.  Note that the DS3100-Ultrix-Remote achieves a write bandwidth of only about 30Kbytes/sec.
Lastly SunOS 4.0 showed a surprising behavior. The time for  a file with no data is 66ms but the time for a 10Kbytes is 830 ms. It seems that when the file size jumps from 8 to 9 kbytes, it jumps to 800-ms range.
This concludes our discussion on this WRL Research report.
#codingexercise
Double GetAlternateEvenNumberRangeSumSqrtCube (Double [] A)
{
if (A == null) return 0;
Return A.AlternateEvenNumberRangeSumSqrtCube();
}