Re: Journaling pointless with today's hard disks?

[Ian Stirling]

> 
> 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.