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Message: [QUOTE="Folkert Rienstra, post: 7316621"] Very. There are more expensive ones that have restricted themselfs to using only 1 device per channel and they come with single device cables only. Instead of 2 channels they come with 4 or even 8. In a nutshell that says: ATA can't multitask so lets rant about SCSI. Not very useful. Nothing much changed except maybe Overlapped and Queued feature set which should bring ATA upto speed with SCSI but that never caught on. IDE (I prefer to speak of IDE here, because ATA actually can) cannot start simultanious reads from 2 devices on the same channel or start a read and write simultaniously unless the write goes before the read. What this boils down to is that you can't in some circumstances average your access times (no parallel seeks) and can't use the full bandwidth of the channel (empty bursts) so that your accesses appear simultanious (parallel), instead they are serial (one access after the other) and you get only half the thruput per drive. This isn't so much of a problem for long sequential reads (to start with: no seeks) and no real need to start commands simultaniously(*) because when one drive reads the other caches ahead and buffers, the whole transfer is at 100% interface speed from buffer when the command that requests that data comes. So it looses half by being serial but gains 100% by being able to use the full bandwidth for itself. (*) Only the first commands are in serial, every next one is virtually parallel as long as the read commands are sequencial. Yes, and how they appear on the PCI bus. And this question is about IDE or SCSI or both? Or dual channel SCSI only? [/QUOTE]

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