[Info-vax] Could XRDP be the next graphical interface for VMS?

[Stephen Hoffman]

On 2015-03-21 13:12:34 +0000, Dirk Munk said:

> I recently had a discussion about VDI. If you don't know what it is, 
> VDI is a virtual desktop PC on a server, and you can connect to it from 
> a PC, or a thin client, or a tablet, or... It is a very expensive way 
> to get the functionality you want.

OpenVMS had a similarly expensive approach with EWS: 
<http://www.digiater.nl/openvms/freeware/v50/ews/>

> The communication between server and client uses the same protocol as 
> with Windows Terminal Server. It is comparable to X-Windows, but of 
> course it is different.
> 
> In the Unix world there is a project called XRDP to give Unix servers 
> the same kind of interface, so you can connect to a Unix server as if 
> it were a Windows Terminal Server.
> 
> I guess this could be the best way for VMS as well, no need for special 
> drivers and software on PC's, just standard Windows protocols. Always a 
> good selling point!
> 
> You can find more about XRDP here:
> 
> < http://www.xrdp.org/ >

XRDP is a version of an RDP server that is integrated with an X Window 
system environment.  As was stated above.

RDP is arguably comparable to X only in that there are displays around, 
and that there are displays operating over a network.   Being a remote 
transport for an existing physical or virtual GUI, RDP (and xrdp) do 
not provide any application display capabilities, and requires a local 
X Window manager and a local display, or some other local graphical 
display or virtual display.   In other words, RDP has to have something 
running on the RDP server to render remotely.  In OpenVMS 
configurations, the DECwindows X Window client and DECwindows X Window 
server capabilities provide this, either entirely on one server with 
both the client and the server running locally, or remotely with the X 
Window clients on OpenVMS and with the displays available via the X 
Window server.  This remote server could be Microsoft Windows with 
xming <http://en.wikipedia.org/wiki/Xming> or one of the other 
available X Window server packages installed, OS X with x11.app 
installed, or most Unix and Linux systems with the respective native X 
Window servers running.

Something similar to RDP is already available on various Integrity 
servers running OpenVMS, via vKVM.  
<http://h71000.www7.hp.com/openvms/journal/v15/vkvm_ovms.pdf>  vKVM 
displays the DECwindows interface from the X Window software remotely, 
using RDP protocols.

For related information and discussions, search the Google Group 
archives for the comp.os.vms newsgroup for the Sun Ray discussions.  
<http://en.wikipedia.org/wiki/Sun_Ray>

For discussions of a virtual frame buffer for OpenVMS, see 
<http://www.digiater.nl/openvms/freeware/v50/virtcfb/>.  Something 
similar to this would be necessary for a Windows Terminal Server 
implementation on OpenVMS, if you didn't want to install X Window 
Server packages on the remote systems and the associated X network 
transport.

TL;DR:  RDP would avoid the need for an X Window Server in the target 
box — on the target box, not on the OpenVMS box.  As a replacement for 
the OpenVMS graphics system, a configuration with RDP still needs some 
sort of a virtual or physical graphical interface operating on the 
OpenVMS system, and the APIs that applications would necessarily use to 
render display information into the virtual or physical frame buffer.   
In OpenVMS terms, this rendering system is DECwindows, and the 
DECwindows APIs.


Does Betteridge's law of headlines apply to comp.os.vms newsgroup 
subject lines?


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