Hi, I just wanted to open for discussion another idea I've got to solve the problem of having to update a system with a fixed set of pre-installed components, aka the "Gentoo for OSX" problem. I would like to avoid the prefixed approach (which seems to need changes in the system software, i.e. the Portage system). Instead i would like to solve the problem on a lower level.
A (Linux) LiveCD distribution faces a similar problem, because you have a amount of static / read only content on your CD, while you are still able to install packages from the internet. Such Live CDs solve this by the introduction of "read-write" mounted CD-ROM devices, using a mechanism called a "union file system". Such a Union file system (unionfs) provides a unified view from a couple of source trees to a result tree. THis applies to all file system accesses, i.e. read, write, list directory a.s.o.. A unionfs is supported natively by MacOSX. A problem of such an approach is that mounted file systems are visible globally. A better solution would be a file system which is only visible in a local environment. Unfortunately real user space per process file systems are not yet available on Unix like sstems, including Linux and Darwin / MacOSX. For Linux there exist some work to implement such functionality, e.g. in the Plasticfs project on Sourceforge. It seems to be implemented as some kind of clever LD_PRELOAD hack. Regards Dirk -- [email protected] mailing list
