Messages in this thread |  | | Date | Sun, 29 Sep 1996 18:48:26 -0400 | From | "Steven N. Hirsch" <> | Subject | Re: Please Advise: SCSI vs. IDE (fwd) |
| |
Linus Torvalds wrote: > > On Sat, 28 Sep 1996, Steven N. Hirsch wrote: > > > > > This is a tough issue. It really it really depends on several things. > > > 1) If your controller is a busmastering SCSI controller - I believe that > > > the 1542 is not (but I might be wrong) > > > > You are. It is. > > Well, the aha1542 is busmastering the same way a Trabant is a car. >
Greetings, oh kernel-meister!
> The aha1542 is _ISA_ busmastering, which means that if you have the choice > between a reasonable modern PIO device and a aha1542, the PIO device is > likely to be much faster. Especially as most people tend to have more than > 16MB in their machines these days..
Actually, with a modern SCSI drive it gives even the quickest IDE drives a good run for their money (on an ISA-only machine). Don't get me wrong, I'm not suggesting that anyone run out and buy one - this thread has gotten _real_ jumbled, and I was only correcting the person that didn't think the 1542 was a bussmaster..
> With ISA busmasters, the kernel has to double-buffer the IO memory for the > 16MB+ area, which makes the whole idea with DMA fail completely. The extra > copy is _worse_ than the CPU doing the reading by hand in the first place.
Yes, absolutely true. OS/2, Win/DOS and the rest also switch modes with large amounts of memory installed. Not to mention that a lot of older ISA buss machines didn't cache memory above the 16-meg line either.. <blech>.
> > My personal opinion: get IDE if it's a single-user machine and you don't have > any special requirements like SCSI tapes or scanners anyway. It's likely to > be faster than any but the high-end SCSI setups, and it's cheaper and easier > to find. And despite SCSI proponents saying that SCSI is so trouble-free, I > get a lot more trouble-reports about SCSI cabling problems than I get about > IDE cabling.
I suppose YMMV. I have experienced mucho grief of all sorts with IDE drives, and have never seen problem number one with SCSI cabling.. Variety of experience is the spice of life!
> > If you're going to set up a multi-user machine and/or a web server, get a > high-end PCI SCSI card. In no case get something like a aha1542 these days > (they were fine 5 years ago, and I still have one, but they really aren't > worth it any more).
Agreed. I have two EISA 486 boxes with 2742 Adaptecs and a new 6x86 unit with embedded AIC7880 (~2940UW). You are preaching to the choir on this point <g>.
> Oh, the ncr SCSI chipset is cheap, and works for a lot of people, but it's > also the chipset I get the most complaints about. There is something wrong in > NCR land (and I'm not necessarily blaming the hardware, it might be a driver > problem or a combination of hardware+driver - you might have to try one or > the other of the two drivers that are available for it). > > Personally, if I bought a SCSI card, I'd buy one of the supported PCI > BusLogic cards.
Per my posting response to Leonard, I totally concur that the BusLogic controllers are the best. Now, all they need to do is strike an OEM deal to get them situated as an on-board controller with someone's P5/P6 motherboard..
Regards,
Steve
|  |