Date: Thu, 30 Sep 1999 10:34:40 +0200 From: Eric Noulard <noulard@adulis.fr> To: List aic7xxx <aic7xxx@FreeBSD.org> Cc: gregory.hosler@eno.ericsson.se Subject: Re: fast drives. Message-ID: <19990930103440.A27023@bipbip.adulis.fr> In-Reply-To: <XFMail.990930152527.gregory.hosler@eno.ericsson.se>; from Gregory Hosler on Thu, Sep 30, 1999 at 03:25:27PM %2B0800 References: <19990929093341.C4929@elmo.cygnus.com> <XFMail.990930152527.gregory.hosler@eno.ericsson.se>
next in thread | previous in thread | raw e-mail | index | archive | help
On Thu, Sep 30, 1999 at 03:25:27PM +0800, Gregory Hosler wrote: > > In as much as I tend to be more SCSI competent than most of my peers, I > frankly admit I feel very incompetent as regards to some scsi issues. You may find valuable informations in the SCSI FAQ: http://www.scsifaq.org/gary/scsifaq.html > > My 2 discs: > > I have the following: > > (scsi0:0:0:0) Synchronous at 40.0 Mbyte/sec, offset 15. > Vendor: IBM Model: DDRS-39130D Rev: DC1B > Type: Direct-Access ANSI SCSI revision: 02 > Detected scsi disk sda at scsi0, channel 0, id 0, lun 0 > > (scsi0:0:5:0) Synchronous at 40.0 Mbyte/sec, offset 15. > Vendor: SEAGATE Model: ST19101W Rev: 0011 > Type: Direct-Access ANSI SCSI revision: 02 > Detected scsi disk sdb at scsi0, channel 0, id 5, lun 0 as I already posted it my "IBM DDRS-39130D" work at 80.0 Mbyte/sec, I mean aic7xxx driver says that, I did not make any test to verify it's true. I have no SCSI problem in my log. To answer to Gregory, on "how did I manage to make aic7xxx" driver to recognize the drive at 80.0 MBytes I would say nothing special: - plug the drive in the Ultra2-Wide SCSI connector of my ASUS P2B-DS (AIC-7890 chip) - the ribbon used to connect the IBM drive is the one given with the motherboard and is LVD terminated (written on the cable) - plug other SCSI peripheral (CD-ROM and CD-RW) on the narrow SCSI interface of the card. - terminate the SCSI narrow part of the bus with active terminator. (my CD-ROM is internal and CD-RW is external so the terminator is on the external box but it should'nt make any difference) - enable wide, ultra ... negotiation in the Adaptec BIOS put the maximum syncrate at the maximum value in Adaptec BIOS for all devices. - boot (I just put append = "aic7xxx=tag_info:{{,,16}}" in lilo.conf in order to modify the queue depth) > The interface is an motherboard AIC-7896. May be it's the real difference mine is AIC-7890, don't really know what's the differences between those 2. > > more ignorant questions: > > 1) As I am learning, I am now (only now) guessing that it might not be a > good idea to combine LVD and SE on the same scsi bus. > is this true ? Don't really know, in my case I don't really know HOW my motherboard handled all its different interfaces so ... > > 2) are there any special cabling / termination issues with respect to LVD > that are different from SE scsi ? Yes there is. see SCSI FAQ: What is LVD? http://www.scsifaq.org/gary/scsifaq.html#Generic099 SE = Single Ended LVD = Low Voltage Differential. > > 3) How do I get my AIC to recognoze the IBM at 80 Mbs transfer rates ? > (do I need to move the Seagate to a different scsi bus ?) You may try this your motherboard should have a separate interface for Ultra-Wide and Ultra2-Wide devices, right? Put the IBM drive on the Ultra2-Wide interface and put an LVD terminator just after the drive (at the end of the ribbon you use to connect the drive) Put you Seagate drive on the Ultra-Wide interface and terminate this part of the bus with active wide terminator (may be there is a switch on the drive to do this if you don't have a terminator) > > I am really discouraged, and at the point of seriously contemplating > switching adapter cards, the only thing is that the AIC is on the mother > board, and is one of the reasons I bought this particular mb. I'm not an SCSI expert but I think your problem comes from the mixing of SE and LVD drive your LVD drive should be LVD terminated and separate from the other scsi devices. Hope this helps -- Eric Noulard ------------------------------------------------------------------- Groupe ADULIS * Laboratoire PRiSM Tel: +33 1 60 13 06 28 * Tel: +33 1 39 25 40 71 Fax: +33 1 60 13 06 07 * Fax: +33 1 39 25 40 57 E-mail: E.Noulard@adulis.fr * E-mail: Eric.Noulard@prism.uvsq.fr To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe aic7xxx" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?19990930103440.A27023>