William Stein wrote: > On Thu, Oct 29, 2009 at 9:05 AM, Jason Grout > <[email protected]> wrote: >> David Guichard wrote: >>> Thanks Robert--works fine. >>> >>> I sort of answered my question about simultaneous connections: >>> apparently one account in the server pool can be used by two users--it >>> appears to just log in twice as that user. There must be a good reason >>> to have more users in the server pool, though, right? What is it? I >>> did notice that when I stopped the server one of the logins stayed >>> alive and I had to kill it manually. >>> >> >> The server pool is just a load-balancing and security thing. When a user >> starts up a Sage session, Sage selects on of the entries in the server >> pool (using random or round-robin load balancing, I think) and uses that >> to start the user's session. >> >> At least, that's how it was used to work. I don't know if the new >> notebook code changed things. > > This is all still true, and the relevant code hasn't changed at all. > >> In general, there is no connection between the number of notebook users >> and the number of server pool entries. The nice security thing about >> having lots of server-pool entries even when on the same server is that >> you can make each a separate unix account. Then simultaneous logins >> likely won't be running on the same unix account, and so can't mess with >> each other's files in a malicious (or nonmalicious) way. At least, I >> think permissions are set up so the workspace is not writeable by other >> people. > > This motivation has changed significantly. When the notebook server > evaluates an input cell, the following now happens: > > (1) The notebook server writes the code to be evaluated to > /tmp/randomstuff/code.py (or something like that). > (2) The worksheet process (which is being controlled over ssh) > changes its current directory to /tmp/randomstuff, which is world > writable.
hmmm...instead of world-writeable, you could also make the tmp directory group-writeable and make the server and worksheet members of the same group. So you make a new temporary directory every time a cell is evaluated, and these copies are done? Wow. No wonder you want this to be a RAM disk. Jason -- Jason Grout --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/sage-support URL: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
