Fast User Switching Questions

Posted:
in macOS edited January 2014
I haven't used Panther yet, but I also haven't seen these questions posed before.



1) With more than one user logged in concurrently, what happens if the current user initiates a soft (regular) restart? Does it attempt to log out all users, or does it prompt each to do so?



2) How memory intensive is the concurrent user feature? How many users can be logged in at a given time before the computer starts paging heavily?
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Comments

  • Reply 1 of 21
    moosemoose Posts: 25member
    Quote:

    Originally posted by Big Mac

    2) How memory intensive is the concurrent user feature? How many users can be logged in at a given time before the computer starts paging heavily?



    How much RAM do you have? What applications are being run by each user? How much of each application's footprint is actually resident at any given point in time?



    That's like asking, "How many roads must a man walk down before you can call him a man?"
  • Reply 2 of 21
    placeboplacebo Posts: 5,767member
    Quote:

    Originally posted by Moose

    How much RAM do you have? What applications are being run by each user? How much of each application's footprint is actually resident at any given point in time?



    That's like asking, "How many roads must a man walk down before you can call him a man?"




    Just because you don't know the answer doesn't mean that the question doesn't have one.
  • Reply 3 of 21
    kedakeda Posts: 722member
    No need to get philosophical. I thin Big Mac is asking a good question.



    When XP released this feature, I heard noise fro the Mac community about how it would be cool to have but would suck up resources. I've heard XP users echo this.



    I'll put it like this...On an average G4 Mac (600-800mhz) with 512MB of RAM how badly would your user session be affected if the other user had been running IE, Word, Mail, and iCal before you switched users? (as I understand it, these processes would still be running in the background)



    How much worse would it be if the other user had also been running PhotoShop? Is the performance hit enough to notice?
  • Reply 4 of 21
    moosemoose Posts: 25member
    Quote:

    Originally posted by Placebo

    Just because you don't know the answer doesn't mean that the question doesn't have one.



    The question was asked in such a manner that it's impossible to give a good answer.



    Or would you prefer I'd just said "three" and left it at that?
  • Reply 5 of 21
    placeboplacebo Posts: 5,767member
    Maybe if you didn't have a clue, you should have not posted in the first place.



    Now, lets end this pissing contest, okay? Okay.
  • Reply 6 of 21
    moosemoose Posts: 25member
    Quote:

    Originally posted by Placebo

    Maybe if you didn't have a clue, you should have not posted in the first place.



    I know you're a little slow, so I'll repeat what I said above for your benefit:



    THE QUESTION WAS ASKED IN SUCH A MANNER THAT IT IS IMPOSSIBLE TO PROVIDE A GOOD ANSWER FOR IT.



    Had more information been given (examples were provided in my original reply), he might have gotten a better answer.

    Quote:

    Now, lets end this pissing contest, okay? Okay.



    I had no intention of starting a pissing contest with you, jackass. I was soliciting more information. Perhaps if you had nothing better to contribute than a smart-assed comment to my reply, you shouldn't have posted.
  • Reply 7 of 21
    groveratgroverat Posts: 10,872member
    I have no experience with Panther but I use XP's fast user switching daily.



    Running lots of apps on a login that isn't active can take up resources, but I haven't noticed it to be much of a problem.



    I'll regularly leave Outlook Express, Mozilla and Word running while my fiancee switches to her login to check her e-mail or play PopCap games. No real slowdowns on the 800mhz Duron running , that's to say nothing of the 2.8ghz P4 the proctors share at work.



    As far as restarts, you are warned that other users are still logged in and apps are running and told you should make sure everything is copasetic with those accounts before restarting.
  • Reply 8 of 21
    chuckerchucker Posts: 5,089member
    Quote:

    Originally posted by Moose

    The question was asked in such a manner that it's impossible to give a good answer.



    Or would you prefer I'd just said "three" and left it at that?




    Maybe you should read his question again, and if you don't come up with a good answer, just don't answer, eh?



    Or you could answer "I don't know. Instead I'll claim that your question sucks."



    What he was presumably asking is: assume the system takes up 150 Megs, and one user's apps take up another 200 Megs. With another user running the very same apps, how much more RAM is required? Just another 200? Less, because some is shared? More, because the system requests more?
  • Reply 9 of 21
    kickahakickaha Posts: 8,760member
    Guys.



    Stop.



    Now.



    Moose: The question could have been more technically accurately asked, but instead of even attempting to provide a) a reasonable answer, b) an explanation of why the question was vague, c) provide an example where the question could be answered clearly... well... stop.



    Everyone else: Let it drop. Now.
  • Reply 10 of 21
    jbljbl Posts: 555member
    I saw all those responses and somehow I thought someone might have actually answered the questions.



    Anyway, could someone answer these questions? Nothing technical necessary for the second one; just something like groovrat's answer about XP.
  • Reply 11 of 21
    kickahakickaha Posts: 8,760member
    Feature resource use: I would expect it isn't memory intensive at all, it's just spawning new apps/threads.



    Paging: It will depend completely on how much RAM you have. *One* user will cause a low-RAM system to page heavily with moderate use. 4GB of RAM, and you could probably have half a dozen people simul-logged on without problem.



    Essentially, your RAM use will be whatever user A is doing + whatever user B is doing. If you have enough RAM to prevent page thrashing with that total, then you're good to go.
  • Reply 12 of 21
    I would guess that except for the overhead to run another system (it wouldn't all be shared memory for security issues) then it would be just like opening another app in your own space. If you have 10 apps open, and then you open BBEdit, no problem, so if user A has 10 apps open and user B opens BBEdit, I don't see how it would be different.



    If user A's apps aren't idle though, that may be another story and I expect the slowdown tot he system would be the same as if you were logged in as that user (unless X will lower their priority compared to yours).
  • Reply 13 of 21
    big macbig mac Posts: 480member
    Some interesting replies, to say the least. I'm sorry I caused a conflict because I wasn't specific enough before. Most knew what I meant, though. . .



    After reading through the replies and giving it some thought, it now makes sense that running the same tasks on two accounts would cause the memory footprint to grow to around twice the amount it would have been with only one open account. I was thinking, perhaps, that the account(s) in the background could have additional portions of their resources paged-out. But since these are true concurrent log-ins, they wouldn't be treated differently from the foreground account.
  • Reply 14 of 21
    krisnephkrisneph Posts: 143member
    Have you guys heard anything else about Apple trying to patent fast user switching



    http://www.theregister.co.uk/content/39/31702.html
  • Reply 15 of 21
    chuckerchucker Posts: 5,089member
    Quote:

    Originally posted by krisneph

    Have you guys heard anything else about Apple trying to patent fast user switching



    http://www.theregister.co.uk/content/39/31702.html




    The headline is absolutely wrong. Apple isn't patenting anything close to user switching, or multiple user accounts. Instead, what they're patenting is a technology similar to, or based off, Location Manager, for mobile devices - such as a future iPod.
  • Reply 16 of 21
    kickahakickaha Posts: 8,760member
    Actually, if you look at Capps' background (Newton), this was for Newton technologies that have already made it to the market, years ago.



    *sigh* Why is it that no one gives that green, bulky, heavy, *wonderful* doorstop its techie due?
  • Reply 17 of 21
    agent302agent302 Posts: 974member
    I know this sounds blatantly obvious, but has anyone who has panther looked at top while using faster user switching?
  • Reply 18 of 21
    Experience shows that under "normal" lite use (Various IM clients, Web browsers, and email) that XP's user switching works fine, 256MB on a 366Mhz Celeron, for 3 users in my experience. It works and works well, I'd expect OS X to be about the same...

    ---

    As for Panther, as long as a regular user can't restart/shutdown the system while an Administrator account is logged on and running an application I'm happy. Or it maybe ok if your not running anything, it should be an option allowing you to select what apps would require your ok to let others interrupt without your ok, or not. For example mail.app is ok to end, but Final Cut is not. No reason why your kids should be able to log you out and interrupt what your doing...
  • Reply 19 of 21
    I've never used Panther before, but I have used fast user switching in XP. Well, it's actually not that fast. You have to go to Start > Log Off, then you click switch user. Basically it goes back to the main screen, and it tells you if the person is logged on, and what apps they are running. It is kind of faster to switch users this way, but it doesn't look nearly as fast as Apple's way.



    As far as performance goes...the computer is a Dell 2GHz Pentium 4, 256MB RAM, 30GB HD...so it's not exactly the fastest computer in the world. But the performance when logged on to another account doesn't seem to take that much of a hit. I figure that the performance loss in OS X will be not nearly as bad, considering how well the OS handles multitasking.
  • Reply 20 of 21
    rraburrabu Posts: 239member
    In XP, you can fast user switch by pressing the window's key and L at the same time. It's considerably faster than a logout which requires that the apps all quit which can take a long time. It also saves you a seemingly VERY slow login afterwards.
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