Hacker News Reader

Comment by guptaneil | Hacker News Reader

This is going to be absolutely perfect for educational use. Imagine a university computer lab that lets you remotely login from home after the lab has closed to access all the expensive, specialized software the school has already purchased. I know my university was trying to set something like this up, but couldn't find any user-friendly way of doing this.

View on HN

So, imagine a university computer lab that installed SSH and VNC?

Except only one user can control the computer at a time with VNC. The functionality described here means 20 students could use the same computer in theory.

>Except only one user can control the computer at a time with VNC.

Not true. You can have multiple VNC server/desktop session running on the same box, each listening on a different port, each with it's own user controlling it.

Really? I don't know much about multi-user VNC, but my understanding was that multiple users could control a machine from different ports, but they would still be sharing a single screen. That's definitely useful to know that multiple screens are possible too. I'll have to look into it more.

Don't think screens, think desktops. Each vncserver that launches (and binds to its own unique port) has its own separate desktop. Each runs its own distinct window manager application, and is not tied to a physical monitor or screen. Usually the default is TWM (minimalist window manager that takes up minimal resources), but you can also run GNOME or a host of other window managers if you want.

In OS X case, it's running the Finder.

If you log in as a user on Linux, and launch vncserver as that user, then that VNC session and desktop will be of that user.

One of the huge advantages is that the state is also maintained on the server. I've used it a LOT to install various Oracle software over the years. Fire up a VNC server session as an Oracle user, connect into it at the client site or office and start the installation. You can then disconnect, go home, do whatever, and connect in again remotely from another location (tunnelled over SSH usually), and the install will still be there running. It might have paused waiting for a dialogue to be answered, but it hasn't killed the install like logging out of the main desktop would have done.

You can also set the colour depth to be used by the client, thereby increasing performance over crappy SSH connections. 8-bit colour takes WAY less data than 32-bit, especially when installers have stupid meaningless animated gifs that run all the time.

That's the case on Windows... not sure about Mac OS. It's definitely not the case with X11 on Linux; I run multiple VNC displays all the time in addition to my normal desktop display. You can do several separate displays/desktops per user, even. The only limit is the host's resources.

As code_duck says, on MS Windows VNC just lets you see the existing single-user desktop. It's a different beast to the unix VNC.

On X Windows (X11) VNC runs 'more natively' creating a new desktop for you when you remote in - each new connection creates a new desktop instance for the user logging in. It's actually more configuration work to make it view an pre-existing desktop session :)

Remember that X was developed at MIT to run MIT labs, and that X was originally meant for thin clients that accessed programs in much the same way described. This stuff has been possible for a long time. VNCs are actually much easier to use with its own X server in most instances than running on a living one.

Imagine explaining how to set this up and run it to an entire incoming class of freshmen?

Much of OS X's value comes from taking Unixy technologies and making them much easier to use.

Remote desktop sharing isn't that complicated of a concept. I use it on my Mac all the time - ssh to a server, connect VNC to localhost, you have a desktop. Is that supposed to be an enticement or a drawback? It seems straightforward to me. Apple has stuff for VNC built in, too.

I doubt there are a bunch of user accounts on a uni computer lab Mac, so this wouldn't be much different than regular screen sharing. It's also still a mess to choose which computer to try, doubly so if you're on an outside network.

I doubt there are a bunch of user accounts on a uni computer lab Mac

But they could always just throw a beefy machine in a closet and have it connect to the same network directory service that the lab machines grab their user accounts from.

My old university did the same thing, but did so nearly a decade ago with a Windows terminal server.

Each computer on campus is connected to a user directory, so students can login to any computer with their individual student account. I'm assuming that Lion's multiple login feature will work with networked accounts.

Perhaps, but it's not going to work well to have 100 students logged into the same computer. I think the home example given in the article is a much more likely outcome than a university setting.

That's true, it may have to be limited to 10-20 simultaneous logins at a time (or whatever the machine can reasonably handle), but that is still better than 0. Considering my university has a relatively small student body, this would be definitely be a sufficient solution for us.

Anything has to be better than Microsoft's "Call Our Account Manager To Have Them Explain Appropriate Volume Licensing - Oh You Bought Something Slightly Weird Let Us Pass You Through To The Next Guy Up Who Might Still Fob You Off" licensing methods.

Mac OS X Server had (has?) decent support for proper accounts, with the client machines essentially just diskless terminals that boot from the server, and with all accounts on the server - called netboot. So not like screen sharing at all. This worked pretty well in a lab setup, but didn't support remote logins - this sounds much better.

The OP was talking about doing this so expensive university software... I'm going to go out on a limb here and state that it's just not going to work well when 100 students try and spin up instances of AutoCAD or Mathimatica on the same machine.

RDP on windows. If they can figure out how to use expensive specialized software, they can figure out Windows Remote Desktop.

(My university does this... pretty much so engineering students can use matlab at home... badly winces)

Reply on news.ycombinator.com