Date: Sun, 21 Aug 2005 02:35:16 +0200 From: Hans Petter Selasky <hselasky@c2i.net> To: freebsd-hackers@freebsd.org Subject: Re: Parking disk drive heads Message-ID: <200508210235.17608.hselasky@c2i.net> In-Reply-To: <20050820.171238.122195775.imp@bsdimp.com> References: <200508200359.j7K3xoHF015718@ambrisko.com> <200508201230.37976.hselasky@c2i.net> <20050820.171238.122195775.imp@bsdimp.com>
next in thread | previous in thread | raw e-mail | index | archive | help
On Sunday 21 August 2005 01:12, M. Warner Losh wrote: > In message: <200508201230.37976.hselasky@c2i.net> > > Hans Petter Selasky <hselasky@c2i.net> writes: > : On Saturday 20 August 2005 10:18, Mike Silbersack wrote: > : > On Fri, 19 Aug 2005, Doug Ambrisko wrote: > : > > Flash is nice but it has some issues. Atleast dropping it isn't one! > : > > > : > > Doug A. > : > > : > I'd be really happy if I could get a USB flash drive to last more than > : > 8 months. Luckily, I started weekly backups after the first failure. > : > That helped a lot when the second failure happened. > : > : Flash drives does usually not last more than 10000 writes, per bit, from > : what I know. Probably you need some kind of special file-system that > : moves the files around as the write quoute gets used up! Eventually the > : size of the disk will reach zero, and you have to move the files > : elsewhere :-) But this is probably off topic. > > Actually, 10,000 writes per bit is one or two orders of magnitude too > low these days. It was more typical for the Linear Flash PCMCIA cards > from 10 years ago. Today, typically flash devices are good for more > like 100,000 or 500,000 writes per cell, and all the fobs you'd buy > these days have built-in wear averaging. I've tried three times now > to wear out a flash by writing an incrementing counter to a single > location only to give up after weeks of hammering due to external > factors (power failure, network failure, etc). Are you sure that the flash drive is not caching the writes in RAM? --HPS
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?200508210235.17608.hselasky>