Messages in this thread |  | | From | "H. Peter Anvin" <> | Subject | Re: Journaling pointless with today's hard disks? | Date | 26 Nov 2001 16:32:05 -0800 |
| |
Followup to: <Pine.LNX.3.95.1011126151922.29433A-100000@chaos.analogic.com> By author: "Richard B. Johnson" <root@chaos.analogic.com> In newsgroup: linux.dev.kernel > > It isn't that easy! Any kind of power storage within the drive would > have to be isolated with diodes so that it doesn't try to run your > motherboard as well as the drive. This means that +5 volt logic supply > would now be 5.0 - 0.6 = 4.4 volts at the drive, well below the design > voltage. Use of a Schottky diode (0.34 volts) would help somewhat, but you > have now narrowed the normal power design-margin by 90 percent, not good. >
Hardly a big deal since most logic is 3.3V these days (remember, you don't need to maintain VccIO since the bus is dead anyway).
-hpa -- <hpa@transmeta.com> at work, <hpa@zytor.com> in private! "Unix gives you enough rope to shoot yourself in the foot." http://www.zytor.com/~hpa/puzzle.txt <amsp@zytor.com> - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
|  |