Hi, On Thu, 4 Oct 2007 15:47:53 +0200 Alan McKinnon <[EMAIL PROTECTED]> wrote:
> On Thursday 04 October 2007, Liviu Andronic wrote: > > And later on: "Now one problem is > > left. Even with normal RAM a well funded organisation can get the > > contents after the system is powered off. With the modern SDRAM it's > > even worse, where the data stays on the RAM permanently until new > > data is written. > > Pray tell, how does RAM manage to retain data when the power is off? > It's either six transistors or one transistor and a cap per cell = > not persistent. In theory, for the one transistor and one cap case, you have a loaded cap that will take "forever" losing its load, won't it? But in practice, I think, that's not realistic. > I don't know of any magic persistent RAM that's fast enough for use > as main RAM. Flash disks are of course another story but you do > appear to be talking about system RAM There actually are new RAM types being made for solid-state storage. But this is in a proof-of-concept stage, I think. Maybe Liviu's professor had those magnetic drum memory units in mind when saying that? Anyway, cleaning memory on a power-off shut down doesn't make much sense. However, it makes sense to clean up memory after having critical data in it -- e.g. a reboot doesn't necessarily clean up RAM. And I'm not sure if some mainboards even keep the RAM powered in certain situations -- at least, they can as long as the power is not really switched off (e.g. machine only in ATX soft-off mode). -hwh -- [EMAIL PROTECTED] mailing list
