On 7/25/05, James Melin <[EMAIL PROTECTED]> wrote: > What, pray tell, is union mount?
Well, for Linux union mount is not there. Other systems (e.g. FreeBSD) have this mechanism where you mount multiple devices on the same mount point in some 'transparent' fashion where you're still able to see things in the devices mounted first. The idea is that you could mount a small R/W disk over a R/O /usr for example. This would allow you to think that you can write into /usr, though in reality these files get deferred into the R/W disk. Reading a file will give you either the one from the R/W disk when it exists, or from the R/O disk. It's not limited to just 2 devices, you could mount an entire stack. Along the same lines, one could in theory imagine one of these devices be a DCSS holding shared code. There's more mind boggling things possible with this technology. This sounds like the solution for all problems with sharing R/O disks. In reality there are quite a few restrictions that you need to follow to make this work. I am currently trying to get a feeling for what you can and cannot do with such technology. Typically you get into the 'but you should not doing things like that with it' answers. But I am pretty excited about this... Rob -- Rob van der Heij rvdheij @ gmail.com ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390
