Re: Journaling pointless with today's hard disks?

Ian Stirling
2001-11-27T01:05:44Z

>
> At 12:49 AM +0100 11/27/01, Martin Eriksson wrote:
> >I sure think the drives could afford the teeny-weeny cost of a power failure
<snip>
> converter, which is expensive. If you simply detect a drop in dc
> power, there simply isn't enough margin to reliably write a block.
>
> Years (many years) back, Diablo had a short-lived model (400, IIRC)
> that had an interesting twist on this. On a power failure, the
> spinning disk (this was in the days of 14" platters, so plenty of
> energy) drove the spindle motor as a generator, providing power to
> the drive electronics for several seconds before it spun down to
> below operating speed.

I have a (IIRC) elantec databook from 1985 or so, that I've found chips in
disks from the MFM/RLL PC era.
These are motor driver chips aimed at PCs, which support generation
using the motor.