On Tue, Jan 31, 2023, 6:44 PM Paul Koning <paulkon...@comcast.net> wrote:
> > > > On Jan 31, 2023, at 8:38 PM, Warner Losh via cctalk < > cctalk@classiccmp.org> wrote: > > > > On Tue, Jan 31, 2023, 5:03 PM Ali via cctalk <cctalk@classiccmp.org> > wrote: > > > >>> I thought Flash could only hold the data in them X amount of years > >>> until > >>> the junctions discharge or whatever? It's less permanent than decent > >>> quality optical or pro magnetic media? > >>> > >>> You have to plug them in every so often to refresh I believe. > >> > >> Does REFRESHING mean reread and rewrite or just keep power to it? If > it's > >> the latter it should be trivial to setup a system with backup battery > just > >> to supply voltage to a bunch of SSD drives. > >> > > > > It depends on the drive's firmware. Some do background scans of blocks > > while idle. Others do not. Since you have no way of knowing which is > which > > (or even when the backgroundscan is done), the safest way to force a scan > > is to read the whole drive... any blocks whose raw error count is too > high > > will be rewritten to fresh blocks. If it's a good SSD you'll likely not > > notice this happening. If it's a crappy thumb drive... you may be better > > off copying to some other media.. > > > > Warner > > Do you know what the likely answer is for "memory sticks", SD or MicroSD > cards, things like that? I assume their firmware is tiny, so are they > likely to need active refreshing? > They are on the "copy it every so often" end of things. Especially if they were slow when released. Warner >
