P Witte wrote: > Your explanation made reminded me that a considerable amount of buffering > is already going on (the hard disk, Windoze, and Smsq). iof.load is possibly > not much more efficient under those circumstances than iob.fmul.
Yes, it's not that much of a difference anymore. In the past iof.load was much faster on machines with much RAM because it didn't invoke the slaving mechanism. Now with slaving limited to only a little ram area the data is effectively just copied around one more time in the case of iob.fmul. > But I thought that PIO mode hard disks, the current norm, actually pushed > the data into memory with barely any intervention from the CPU. PIO mode is the slow stuff where the CPU has to fetch the data. Ultra DMA does its writes directly at the location the data is needed. > Hehe, youre probably right, though I think I'll rely on my test results in > this particular case. I suppose my real question was whether there is some > "sweet" buffer size pertaining to Qdos/Smsq, that minimises fiddly > edge conditions and the like. It mostly depends on what you're doing. But I'd use a nice 16k or 32k buffer for most purposes. Marcel
