daryl@ihlpe.UUCP (01/31/87)
> The test is a simple one... simply start with a blank disk, > write out a very large file, then see how long it takes to read it all in. Unless your OS writes contiguous files almost always, this is not a very useful benchmark. Disk performance depends on so many things, it is almost impossible to get a meaningful benchmark. The DMA rate is freqently such a small part of disk bandwidth that it doesn't matter. Some considerations are: Seek time Rotational latency Operating system disk block buffering Seek and latency OS optimizations (only useful in a multiprocessing environment) It is very obvious on my ATARI 8 bit w/810 that even short sessions on the machine fragment the disk files across the disk, significantly increasing the seek time in typical file access. (The sound the 810 makes when it is seeking makes it painfully obvious when it is doing so.) I have found few OS's that allow contiguous files, and none of them wrote them by default. Daryl Monge UUCP: ...!ihnp4!iheds!dlm AT&T CIS: 72717,65 Bell Labs, Naperville, Ill AT&T 312-979-3603