| gabriel rosenkoetter on Wed, 12 Jun 2002 12:04:47 -0400 |
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On Wed, Jun 12, 2002 at 09:33:00AM -0400, Noah silva wrote: > people often seem to confuse this (gabrial, help out?) I'll try. > SCSI 1, 2, and 3 are COMMAND SETS Sort of. They're bus definitions whose main differences include command sets, but they also run at different frequencies. > I sometimes see a cable marked as "SCSI 2"... and well I have 50 pin SCSI > 1 and 50 pin SCSI 2 devices with the same cable. As far as I know the > numbers only indicate supported command sets. It'd be mighty hard to find a cable that supported only SCSI 1 these days, but it might be possible. (And if you plugged it into a SCSI 2 device, you'd either get mysteriously transmission failures or see the bus step back to 5 MB/s; sort of depends on the conditions, what kind of terminator you've got, so forth.) > Narrow, wide, fast, ultra indicate speed/bitwidth True. But that list is not separate items; the latter two are modifiers of the former two. That is, there's just narrow, fast narrow, wide, fast wide (or maybe not? doesn't feel right), and ultra wide. > Most drives are compatible with faster/slower interfaces. Especially, a drive made for a certain SCSI level by a respected manufacturer (which includes plenty of people whose hardware I'd never actually buy) will almost definitely play at least moderately well with any SCSI level/protocol that existed before the drive was designed. (You may well need a cable adapter to actually connect the drive, of course, and you may need to jumper the drive in a specific way.) > The main importance is that an LVD drive or HVD drive or "normal" drive > will normally not work on a different type of interface > (and likely will fry something). Never, ever, ever plug HVD and LVD together. You may not end up with a melted mess... but do you want to find out? Incidentally, for those who care, I've got a measly fast and narrow bus (20 MB/s) in most of my machines at home. I'm being lazy about it, but I'll be buying LVD cards (160 MB/s) and new disk to go with them just as soon as I price it all out. A change like this can make system performance significantly more enjoyable; as much as if not more than adding memory. -- gabriel rosenkoetter gr@eclipsed.net Attachment:
pgpSBbQon5T5Z.pgp
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