Can someone explain what is the difference between X server and Remote Terminal servers in simple terms?
For example, Hummingbird Exceed is an X server and Citrix is a Remote Terminal Server. How do these servers work?
A terminal server runs at the "other" machine while you use a remote desktop client to view the other machine's screen.
A X server (of the X11 Window System) runs on your machine while another machine (or several thereof) send their output to your computer.
The most important difference to the end user is probably "culture": With the X Window system you typically work with windows that run on several hosts. (You often sit in front of a quite stripped down workstation, get one application from one computer, another one from another computer.) When working with X things feel very heterogeneous - a special application only runs on a HP workstation while your company is stuffed with suns or linux boxes? No problem, just buy one HP, everone can use that application over the network like as it was local.)
Remote terminal services feel more like another computer sends its complete screen to you, more like you have a 100-Mile-Long monitor and usb cable (with a little lag built in). You typically use a remote desktop client that sends a complete desktop to you.
However in recent times both techniques get close to another - windows remote desktop (which is based on citrix) can send only application windows to your desktop, while a lot of programs based on X11 are theoretically network transparent but practically need to run on the local machine. (Sorry, no 3D shooter over the network - an extreme example).
Which one is better? I don't dare to say. White X11 is a lot more flexible (it was designed with network transparency in mind - it makes absolutely no difference if an application runs local or remote - it is in many aspects more complicated. As long as there was no remote desktop sharing there was a clear advantage, but slowly the gap is closing, for example by terminal services now allowing you to do many things that were available with X11 only in earlier times.)
By the way, the main reason many X11 application still feel a little "snappier" over the network than windows counterparts is the thing that many application programmers on windows still think they always run local and dump a lot of bitmap graphics on the screen - like custom toolbars in ZIP tools. X11 applications did not do this for a long time and chose "ugly but fast" because X11 forces you to think about the network. But as X11 applications get more pretty and Windows programmers more aware about terminal services the difference will dwindle.
Oh and an important point: X11 is deeply ingrained in the Unix way of things, Citrix is mainly used on Windows (in the form of Microsoft's Windows Terminal Services - which originated in Citrix code). So lock a terminal services admin and a X11 operator into a cage and step back watching bloodshed when they figure out who they are locked in with ...
An X server most likely refers to the X11 windowing system, which is the GUI that most unix flavors (including linux) use. It's a client/server setup, and has been around for a very long time
A remote Terminal Server in the case of Citrix is a remote windows instance that can be connected to with a special Citrix client. The Citrix environments I'm familiar with are all MS Windows solutions, ie they work similar to X, but are for Windows Servers only
They both sort of operate in similar fashions, which is serving a remote client a windowing solution. IE, they both let a server run the actual application while the display of that application is sent back over the network to a client PC.
A 'Terminal Server', as it's called, basically allow you to connect to a Windows session remotely. They employ a bit of magic to make the experience snappy over connections with latency. The Windows GUI system isn't network transparent like X, so it took a while longer to get this feature. Windows Server 2008 and Citrix products have the ability to let you use a single application, unlike the traditional Terminal Server.
X is the GUI protocol for Unix/Linux. The X server accepts connections and displays their windows. The clients are actually the programs themselves. These clients can be local or remote, it doesn't matter to X. X just displays them as requested, on the local screen or over a TCP connection. This is lower level stuff than terminal servers, and allows graphical programs to run on one machine and display on another. X11 doesn't compress or encrypt the traffic like RDP does (although SSH can help you out there).
The linux equivalent of RDP is NX. They provide free software to run NX servers/clients. I've used it and it works pretty well.
Related
I automate processes on a remote computer. When I start a process from the control room, that works totally fine. But as soon as I minimize or close the remote computer (I don't shut it down, I just close the window), the remote computer crashes. The log contains entries like that elements cannot be found. The reason is, that the remote computer does not even open the applications.
So, what's the reason for that? The computers state is on desktop, so there is no screensaver or logon screen.
Expected result: The robot should work finely even when the remote desktop session is not on screen, like in production environment.
You haven't specified, but the below answer extrapolates your statements regarding how you've "[minimized] or [closed]" your "remote computer" to assume you're leveraging Microsoft's Remote Desktop Connection utility/protocol.
Blue Prism specifically discourages the use of Remote Desktop to manipulate remote Runtime Resources within a Blue Prism-based environment, as the use of the protocol itself causes the methodologies Blue Prism uses to locate elements in the Windows desktop environment to stop working entirely. This is explicitly spelled out in Blue Prism's official documentation on Remote Access Tools:
The following tools have been deemed to be specifically unsuitable for
providing remote access to Blue Prism environments:
Remote Desktop Connection (RDP)
The way that this Windows tool (and other tools that
use the RDP protocol) handle session management is not compatible with
Blue Prism:
The underlying operating system is aware as a connection is established which can, subject to the automation techniques being
applied, result in the executing automation being interupted.
It requires the remote access credentials to be aligned with the credentials used to authenticate the target system against the network
which presents a potential security risk.
As a user authenticates any previously connected users are locked out.
Each connection creates a separate desktop session.
The connection is not maintained throughout a system reboot.
Hi I have one program that I need to run on my server but the problem is that my server don't have any monitor, keyabord and mouse attach to it so I can confirn when windows 7 ask me to run program so is posible to just plug USB Mass Storage device in a computer and computer would execute this without any qestions?
Perhaps you could look into using autorun or some variant thereof (e.g. a program that would monitor the USB bus for devices, and automatically run some program when it detects that an appropriate storage device has been connect).
Bear in mind that, depending on the physical setup, this could be used as an attack vector.
As Celeriko said, you should try to find a way into connecting to your server remotely. Whether that be through SSH or a tool such as PUTTY (basically SSH right? I'm not sure off top of my head).
Having a usb automatically execute something would be a security risk and I believe it is restricted for that reason.
Best of luck trying to connect remotely into your server, it shouldn't be too difficult.
I want to see remotely some running GUI application without kill the current process, I have tried vnc and xrdp, xrdp opens a new blank session, so it is not for me, vnc is good, but not exactly what I need, it uses the screen and devices presents, someone could mess with me moving the mouse or typing on the keyboard.
Therefore I figured out the only way I could do what I need is managing to shift a running X window from one display to another, thus even on a SSH -X (X11 forwarding) I would be able to see it.
I am on this quest for a long time and I didn't found out a conclusive solution, that is the reason I am appealing to you. Could you help me to solve this trouble?
Thanks,
I've never used it myself, but Xpra appears to be the commonly suggested solution; you might also consider xmove. Both of these work by proxying the X client's connection to its server, and keeping track of enough state so that you can switch the proxy's server-side connection among servers and get a sensible result. Without such a proxy, as in "stock" X, it is not possible to disconnect a client from one server and connect it to another, except in the case of a client which is designed specifically to support such behavior.
If you look at the Wikipedia page on the subject there are several apps mentioned.
Xmove
excerpt
xmove is a computer program that allows the movement of X Window
System applications between different displays and the persistence of
X applications across X server restarts.[4] It solves a problem in the
design of X, where an X client (an X application) is tied to the X
server (X display) it was started on for its lifetime. Also, if the X
server is shut down, the client application is forced to stop running.
xmove lets the client disconnect from its current X server, and
connect to a new one, at any time. The transition is completely
transparent to the client. xmove works by acting as a proxy between
the client and server. It is a "pseudoserver" which stores enough
server state so that clients can connect to a new server without being
disrupted.
Xpra
excerpt
xpra or X Persistent Remote Applications is a tool which allows you to
run X clients usually on a remote host and then direct their display
to your local machine without losing any state.1
It differs from standard X forwarding in that it allows disconnection
and reconnection without disrupting the forwarded application. It
differs from VNC and similar remote display technologies in that xpra
is rootless: i.e., applications forwarded by xpra appear on your
desktop as normal windows managed by your window manager, rather than
being all "trapped in a box together". Xpra also uses a custom
protocol that is self-tuning and relatively latency-insensitive, and
thus is usable over worse links than standard X.
Guievict
excerpt
guievict is a computer program which enables the GUI of any
application for XFree86 implementation of X Window to be transparently
migrated to or replicated on another display. Unlike some program
providing similar functionalities, it requires neither prearranging
steps such as re-linking the application program binary nor
re-directing the application process's window system communication
through a proxy like xmove does.
Guievict is based on a small X server extension that enables an
application to retrieve its window state from the X server and a
library of GUI migration functionality that is injected in the
application process at run time. Code injection or runtime
code-patching can be done via the DynInst API. However, guievict
contains its own implementation to avoid requiring users to install
DynInst.
Of the 3 of these, Guievict sounds like what you're looking for, mainly that it can checkpoint the state of X application AppX and migrate it to another X server where it can be restored.
(This answer comes from slm at unix.stackexchange)
I'm looking for a way to allow potential customers to try my application before they buy it.
The product is a windows forms application that requires an SQL Server database to operate.
Although I have a functional demo that the customer can install on their network, I want to make it easier for them by have them "play" with it at my environment.
I remember Microsoft had (has?) something similar. I was testing Visual Studio a few years ago in a virtual environment where I was connecting to a server at Microsoft.
They setup the environment this way so when a user logs off after using it rollback his actions. Or to explain it better: when a user logins it starts with a new, clean environment.
So any projects I've created testing Visual Studio were lost after I logged off.
Any suggestions?
Thanks.
Some solutions that come to mind:
Provide remote access
You could provide access to a running instance of your application via some sort of remote connection protocol, e.g. via RDP or via VNC.
For example, there is a Java VNC client which can run as a Java applet; you could put that on a webpage and have it connect to a VNC session you host on your servers.
Or use Windows Terminal Server, and allow connection via RDP.
Both solutions of course have the drawback that people need to open the appropriate ports, if they are behind a firewall. There might be ways around that, however (e.g. you can run VNC over HTTP).
VM image
A completely different solution: Provide a ready-to-run VM image (for VMWare, VirtualBox or similar) of your application, including server and everything. You would need a demo version of your app though, plus getting redistribution rights for all the proprietary components (Windows OS, SQL server) might get hairy.
Offer videos
Often people do not really need to actually use the app; they are mainly interested to see how it works. So maybe it is enough to host videos of the app in operation. That allows you to put in some advertising for your features, and lets you show the users what they might miss when testing on their own.
The joys of multimonitor programming are countless, I think there are about 5 blog posts on Coding Horror on the topic alone!
I often code in Windows on my main machine, and have my Mac laptop set up to the side. I use the Mac both to compile Mac builds but also as my "reference web browser". There's no KVM or anything.
However a casual conversation at a conference led me to the question, could I use two independent machines to share windows? Literally move some windows from one machine to another, so I could use one PC's display as "overflow" from the other.
Some googling suddenly shows that this is possible in some situations for sure:
Synergy and Maxivista
My question is whether any programmers have tried such a setup. We have unique needs especially with multiple text windows and editors, and this kind of tool may be a huge win or a huge hassle.
This solution feels like a combination of easy KVM switching AND multiple monitors.. it sounds like a programming dream! So advice or especially reports of actual experience in a programming environment would be greatly useful before I invest in the rather complex setup.
Followup:
Sounds like I'm asking for something that doesn't exist! It's kind of combination of a software KVM and VNC. But the VNC would need to break out the app windows and allow individual manipulation (like that maxivista commercial tool, which is Vista only).
Thanks for all the feedback. Looks like there's demand for a cool app if anyone has the drive to be first in this new nich!
Synergy doesn't allow you to move windows between machines (that would require a silly amount of work behind the scenes), but it does allow you to share a keyboard and mouse between two machines so they "appear" to be all one machine, but actually run separately.
I personally use Input Director, as I found it more stable than Synergy. I have my laptop with an external monitor to the right, and my desktop to the left as an Input Director slave. My desktop runs a different O/S and is basically my guinea pig box for testing stuff and for anything I need to keep running when I leave the office. Cut + paste is pretty seamless, so I can quite happily fire up an RDP session to a server on my desktop, and cut+paste SQL scripts from that to my laptop.
It's a very useful thing to have if you have a few physical boxes and monitors kicking around :)
I've actually managed to use spare notebook as a second monitor to Desktop PC. This allows to move windows to second PC, but not vise-versa.
Solution would work basically with any OS.
The only requirement is a spare VGA (or DVI-I/DVI-A) port on server PC.
Make a dummy VGA plug http://www.overclock.net/t/384733/the-30-second-dummy-plug
This will also work for DVI-I/DVI-A port + DVI-VGA adapter
Detect virtual monitor with your OS. Monitor will be detected as very generic monitor, so you can set up any resolution. Set it to slave PC resolution.
Use any remote control software to connect from slave to server PC. Set it to display only "virtual" monitor.
That's all. Your slave PC is a second monitor for server PC.
I've used this on Windows 7 + TeamViewer. I've additionally set up Mouse Without Borders (Microsoft Synergy analog) to be able to use slave PC with same mouse&keyboard, though this is not required if you intend to transform it to monitor-only.
Xdmx - Distributed Multihead X Project (linux only)
Provides native X display on external machines, no VNC cons.
The following is not exactly what you want, but pretty close:
You can start a VNC server on the Windows machine, which will let you "export" its graphical screen.
Then, unplug the monitor from the Windows machine and use it as external laptop monitor instead, with your Mac laptop.
There, on your Mac, you just connect to the VNC session using Chicken of the VNC, which will give you the graphical screen content of the Windows machine as a Mac window (interactively, so you can actually control the windows machine as if you were working on it directly). You can put that on the external monitor, and you can also put other windows there, so you really have a shared environment.
I believe this solution also lets you copy and paste content from the Windows screen to Mac windows and vice versa.
I use MaxiVista on WinXP while programming. It works fantastically and lets me add a third screen to my multi-monitor configuration.
There is hope, here for windows users: http://virtualmonitor.github.io/ Looks like a work-in-progress and only supports windows 2000 - windows 7, but he's looking for help with windows 7 - 8.
Unfortunately, synergy doesn't allow moving windows across screens currently. It only forwards mouse&keyboard events from one set of physical devices to different computers.
Yes, and I love it. It allows you get past 2 screens on a laptop, and really I find 3 a great amount.
If your main machine is a Mac you want ScreenRecycler. You can then use monitors on other Mac, Windows, and Linux machines (anything with a VNC client). You will want something better than the Mac's crappy windows management though. I suggest Many Tricks' Moom and Witch.
On Windows, as #LachlanG said, MaxiVista works great. And it supports adding monitors from Windows, Mac, and Linux machines.
I am reusing my old laptop as a second monitor to see the live preview while coding. I am using SpaceDesk, which is free.
I use barrier and open source fork of synergy. Its a little hard to use but works really well. (To find it just search google for 'barrier github').