Date: Tue, 26 Nov 1996 07:42:17 -0600 (CST) From: David Kelly <dkelly@hiwaay.net> To: Joe Greco <jgreco@brasil.moneng.mei.com> Cc: hackers@FreeBSD.ORG Subject: Re: Holy Moley Batman... I love ccd. and BTW, if you need 4gb d Message-ID: <XFMail.961126075034.dkelly@hiwaay.net> In-Reply-To: <199611260323.VAA16194@brasil.moneng.mei.com>
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On 03:23:43 Joe Greco wrote: >>> Building the internal SCSI cable isn't going to be too hard but the >> power routing looks like it could be a disaster if I try to do it >> the easy way and buy bunches of 1-in-2-out power splitters. Have >> seen insulation-displacement style floppy/hard drive power >> connectors on some systems lately but haven't found a source. It >> would be pretty easy to run a power bus with those power connectors >> pressed on at each hard drive, much like the 50 pin connector on >> ribbon cable for SCSI. >> >> Anybody know of a source of these power connectors? > >I think DigiKey. Looked. Haven't called. Also checked the Mouser catalog. Would you believe neither lists *any* standard HD/Floppy power connectors? >But you do NOT want to do this, I think! > >I strongly suspect that you will find that the voltage at the end >of your "power bus" will be sufficiently less than the power you are >feeding into it... you would be better off getting a bunch of old >power supply leads, connecting them all to a 4 pole barrier strip, >and feeding them that way. > >I am sure someone will tell me I am wrong ;-) Actually I'm more concerned about the power supply driving 5 or 6 hard drives. This is probably near the design limit of what should be a 60W power supply. Three of my drives are labeled "8 watts". Say each pulls 1.5A on the 5V line, the voltage drop on 18" of 18ga at 7.5A or 9.0A isn't going to be much. OTOH thats getting to be a bunch of current. Not sure if these drives support "spinup on demand" or not. Am fairly sure the PS won't tolerate all drives trying to spin up at once. :-) Also keep in mind this isn't a serious task. These parts are laying around and I'm going to see what I can do with them.
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