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Xref: sserve comp.unix.pc-clone.32bit:2507 comp.os.386bsd.questions:2006 Newsgroups: comp.unix.pc-clone.32bit,comp.os.386bsd.questions Path: sserve!newshost.anu.edu.au!munnari.oz.au!constellation!osuunx.ucc.okstate.edu!moe.ksu.ksu.edu!zaphod.mps.ohio-state.edu!cs.utexas.edu!uunet!psinntp!fasttech!zeke From: zeke@fasttech.com (Bohdan Tashchuk) Subject: Re: [386bsd] Looking for suggestions for a SCSI controller Message-ID: <C62poo.M49@fasttech.com> Keywords: SCSI, 386bsd Organization: Fast Technology --- Beaverton, OR References: <1993Apr24.165243.10375@sophia.smith.edu> Date: Mon, 26 Apr 1993 04:26:47 GMT Lines: 44 In <1993Apr24.165243.10375@sophia.smith.edu> jfieber@sophia.smith.edu (J Fieber) writes: >I have a new PeeCee running 386bsd (and ms-dog). It is a >486dx-33/ISA with a vesa local bus. Now I would like to hook up >two SCSI drives (both Quantum) and a tape drive (Archive). >What is a good deal on a SCSI controller? I hear that some ISA >controllers (adaptec) that use DMA don't work with more than 16 >meg of ram which would be a Bad Deal. Are there any VL bus >boards that would work? Just to clarify. NO ISA controllers can DMA above 16 MB, because the bus only has that many address bits. This isn't an Adaptec issue. Usually the driver will DMA to below 16 MB and copy to above. You're still MUCH MUCH MUCH better off with a DMA controller than IDE. This is because the IDE requires byte-by-byte service from the processor. If you have used a Unix system with an IDE you will immediately correlate slowed interactive response with disk activity. In general the IDE is much slower than a DMA with copy. This is because it's much slower to read from the IDE disk over the ISA bus. Memory to memory copies normally run flat out at the limit of the processor's memory system. Besides, you didn't indicate in your posting that you HAVE more than 16 MB, so your concerns are probably hypothetical so far. Ultrastor makes the 34F local bus controller. Buslogic apparently also makes a local bus controller, the BT445S. Is there a 386bsd driver for either? If the 154xC now works with 386bsd, I'd get that if I were you. If not, then wait a few months or get the 154xB version. You don't mention which Quantums you have, but two of the smaller ones concurrently transferring just about match the 5 MB/s DMA capability of the ISA bus. You won't have much headroom left for faster disks, but at least you will have SOMETHING. If you do get the Adaptec, make sure you purchase the "bare board" rather than either of the "kits". The kits have an internal SCSI cable you probably won't need. More importantly, they have lots of very useful software for "ms-dog" that you don't need to pay for if you will stick to Unix. Adaptec is rumored to be working on a local bus SCSI controller. -- Bohdan The Clinton Presidency -- America Held Hostage -- Day 96