Date: Sat, 15 Jun 1996 23:35:36 -0700 From: "Justin T. Gibbs" <gibbs@freefall.freebsd.org> To: Beck Peccoz Amedeo <gea@masternet.it> Cc: freebsd-current@FreeBSD.ORG Subject: Re: ahc sincing questions Message-ID: <199606160635.XAA19559@freefall.freebsd.org> In-Reply-To: Your message of "Sun, 16 Jun 1996 04:14:02 %2B0200." <31C36DEA.41C67EA6@masternet.it>
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>Just a couple of silly doubts about the ahc driver... > > While starting up the kernel with the -v option the ahc driver >reports the sinc speed for any attached scsi device in MHz. >Shouldn't be in Mbytes/s? MHz is correct. The sync rate is a measure of the clock rate at which data is transfered. Only when you multiply that by the bus width, do you get MBytes/s. > Why I see no difference when enable the ultra speed? My HD can >sinc at 20 Mbytes/s, but it actually sincs only at 10... what's >wrong? If you have a Wide drive, it does 10Mhz sync on a 16bit bus. If you have an 8bit device, it must do 20Mhz sync in order to do 20MB/s. What is your drive model? The only Ultra drive I know of on the market is a Seagate one, and the person who tried it said it refused to negotiate 20Mhz sync (looking from a SCSI bus analyzer) and that it was the device's fault and not the driver's. > Cheers > >-- > >Beck-Peccoz Amedeo >GEA Software S.r.l. >Via Deffeyes, 1 >11025 Gressoney Saint Jean (AO) >ITALY > >Tel. ++39-125-366302 Fax. ++39-125-366415 > -- Justin T. Gibbs =========================================== FreeBSD: Turning PCs into workstations ===========================================
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