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

[Stephen Hoffman]

On 2015-03-22 12:32:51 +0000, Dirk Munk said:

> Stephen Hoffman wrote:
>> On 2015-03-21 14:59:18 +0000, Dirk Munk said:
>> 
>> 
>>> Recently there was some discussion about X-Windows, Motif etc. in this group.
>>> I'm not an expert on these matters, but it doesn't stop me thinking 
>>> about good solutions for these problems.
>> 
>> Which particular problems would you be proposing "good solutions" for, 
>> in this case?   Whether inexperienced or expert, some background 
>> information and a summary can help readers better understand the 
>> suggestion, or the proposal, or — if you were asking one — the question.
> 
> Like I explained before, if you can make these kind of graphical 
> connections from a PC without the need for extra software packages, and 
> having to install and pay for them, that in itself would be beneficial.

Yes, and as I mentioned in my plea for background, what you might 
intend for or have in mind for these "graphical connections" can 
determine where these sorts of questions are going.  As a complete 
replacement for X, you can probably now understand my confusion over 
your question, as RDP is not.  Additional background or a proposed 
solution or the problem you are solving — beyond the specific question 
— can help your audience to better understand the intended question, 
and can potentially be a source of alternatives and trade-offs.  What's 
an obvious use case to you was not — clearly — quite so obvious to me.  
(More than a few times, my postings can and do get misconstrued, so...  
This isn't easy.  For anybody.)

Microsoft Windows are a huge market and it'd be nice to have better 
support for Microsoft Windows clients, but VSI is going to have a whole 
pile of work hauling OpenVMS forward, and I'd wager they'll not be 
prioritizing something that can be accomplished using alternatives — a 
Windows-based X Window Server, or a network KVM hardware, or an iLO and 
vKVM, or using just an ssh connection for most purposes — quite as 
highly as some other work.   ssh is much lighter than RDP, though it 
too inexplicably requires a client on Windows.    Beyond some widgets 
such as Availability Manager 64-bit desktop support, I wouldn't expect 
to see all that much work for Windows.  And if VSI is itching to do 
more work, maybe overhauling and updating the OpenVMS Management 
Station (OMS) package.  But VSI has a whole pile of high-priority work 
ahead of them, once they get the V8.4-1H1 "Michael^WBolton" release out 
the door.


> So I wanted to know if this would also be a viable solution from a 
> technical point of view, but it clearly is not.
> 
>> RDP is a software-implemented network-remote KVM.   RDP is useful for 
>> some cases and a common protocol for an RDP client box that needs to 
>> access a remote RDP server box, but it is not what most folks would 
>> consider a "new graphical interface".   RDP is nothing of the sort. 
>> It's far too primitive to be considered a graphical interface.
> 
> I agree. My first impression was that it was a kind of X-Windows 
> variant. I had no idea it would be this primitive.

RDP does what it was intended.  X Windows is a remote procedure call 
that happens to be used for displays.  XRDP is an RDP server that 
targets X displays; a way for X to display via RDP.

Quite seriously, if you really want to learn more about X and its 
problems, watch that Wayland video: 
<http://labs.hoffmanlabs.com/node/1680>

> With an X-Windows server you can run applications on several clients 
> (in X-Windowa terminology), and that will be impossible with RDP I 
> guess.

Correct.

To summarize.... Like a web browser, X Windows server can collect and 
show input from multiple local and remote sources, in one display.    
RDP is a remote view into a frame buffer.  There's nothing associated 
with RDP — unlike X — that allows applications to draw anything into 
that frame buffer.   Using RDP in place of a graphics driver?  Maybe.  
But I'd expect most folks would still want a local graphics driver, as 
some folks using OpenVMS — those looking for local displays for control 
and status displays, or development, or for other existing custom X 
applications — will want that capability.


-- 
Pure Personal Opinion | HoffmanLabs LLC