-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Deepak Saxena wrote: > On the XO, if we try to edit two documents concurrently on Write, we should > in my opinion only have on instance of write running which can switch quickly > between document objects so the user percieves it as two separate instances.
I disagree strongly, for several reasons. 1. Bitfrost requires that each instance be isolated from every other. Each instance only has access to the Journal items to which the user has explicitly granted it access. Allowing multiple "apparent instances" to share data behind the scenes represents a privilege-combining attack. This is especially apparent if one instance has been launched with P_NETWORK but not P_CAMERA, and the other has been launched with the reverse privileges. 2. A key feature of the Sugar Activity system is that writing Activities is _easy_. The goal is to minimize the amount of work required to write an Activity. Asking Activity authors to juggle multiple virtual instances creates tremendous complexity that is likely to produce bugs even when performed by experts (e.g. Browse), for no user-visible gain. 3. Two separate Activity instances already share a great deal, because the Linux kernel automatically uses CoW to keep only one copy of read-only memory needed by multiple processes. Each Write instance uses no CPU when idle, so RAM is the only overhead. As a matter of efficiency, there is certainly more we can do to decrease the memory overhead of running multiple instances. People are working to improve the efficiency of our X icon caching system and python launcher. Even better would be to work on the python interpreter upstream to improve memory usage and reduce the dirtying of pages that could be shared. - --Ben -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.9 (GNU/Linux) iEYEARECAAYFAkkI/pQACgkQUJT6e6HFtqTCBgCfQg0RDoRC38U1mWmwzQSgfxJe i+AAn1nWN9EyvkYNJGSniZ5xfOxviyRd =Upkp -----END PGP SIGNATURE----- _______________________________________________ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
