What do you mean by SDK and protocol for VDI systems
what sort of driver is it?
so it's a driver in that it's loaded as a module which gets used by Citrix
if you've ever worked with Citrix or with the Citrix Xenapp Virtual Drivers
the Citrix Workspace or Citrix Virtual Channel SDK
also the Citrix Workstation 
so the Citrix Workstation is on the client side
which, thus far, we've had a targer which is a windows environment
The Citrix pattern is a solution for controlling a remote workstation 
Generally other solutions like a remote desktop interface or application are well let's think of a few of them
there is reminmmma
there are the VNC type clients
there are some variations of those, such as solutions created in Go
I haven't used all of them, I'v egenerally loathed using any sort of remote desktop solution because they're sluggish, and I've never had to rely on one
generally if I need to do anything remote, I prefer to use ssh and some sort of a text based session where I can do the specific things that I need without having to think about a graphical user experience
but as far as remote desktops rae concerned, Citrix seems to be the most fluid, performant, responsive, comprehensive that I've tried
that said, i've also seen plenty of flaws in the documentation and in the example code that we're given
I mean thigns work, but the documentation was not so great in the sense that it's written in a very confusing way
which suggests that either  it's written by a developer who isn't very good at technical writing
or is perhaps not very experienced in doing it
or it's written by someone who does technical writing, but isn't a defveloper or an engineer
and in this sense it can be a bit frustrating, because the terms they choose to represent things are ambiguous and inconsistent, sometimes alluding to the possibility that they could be referring to multiple things
causing you to question the progression of working through the components of the tutorial or setting up the examples
that being said, it all worked in the end
it seems that the software is fairly good, and that though there have been some issuesdsiscovered over the years, everthing appears to be gettting resolved eventually
there are even capabilities which we haven't had to wory about, that we've entertained at least having to support in our work, such as the feature of being able to use up to 8 simultaneous monitors for one desktop environment
that's pretty insane, i can't think of anyone who's had to do that, especially not for a remote session
but nevertheless, we made sure we could support several in our testing, using different measurements on each etc..
so in essence it' sa driver which is a module loaded by the Citrix Workspace, previously Citrix Xenapp, and it provides the means of leveraging a session lifecycle with their citrix technology
the way this work si sby registering a virtual channel
a wire to write and read from 
you register your virtual channel, and get a pointer to a C functiointerface
and you write your data on a single thread and have it come out on the other side made available through another Citrix API where you can register another set of functions for use in the other environment
we made this into a library which interfaces with Node JS, allowing you to regisjAvascript functions and import them into a NodeJS application
the goal here was to make an SDK that javascript developers could use to wriet tent applications which are split as two applications in each system environment
so you have a client side application which the user interacts with, such as a messaging or telecommunication program
our use case was video calling application which makes use of the other SDKs provided by our company which couldn't be used by clients who have virtual desktop solutions, such as in banks (at least, our direct client is a major international bank)
and so since they aren't able to use our SDK in their remote session, because the video is unusuable and the media is awful, we set out to create a solution which allows for the commands to be invoked from the user's environment
causing actions in a remote application which is loaded in the user's immediate environment
that remote application is where all of the signalling is performed
then we provide a window from the remote environment which is overlayed in a predictable fashion such that it appears as though it is in the user's remote environment
ie it is over the Citrix Window, and tracks accordingly
so again the idea here is that they needed a video call application to run in a remote desktop environment, where the signalling is being performed locally in an application which could be thought fo as a remote application relative to the primary application
the remote application is run in the driver running in the user's local system, which interfaces with citrix and writes data on a virtual wire which has been registered as what they term a Virtual Channel
the data is split into packets which are somewhat easier to put back together on the other side, as it's not a stream, they are packets with a fixed size which are guaranteed to come out in the same size of chunk
so we essentially referred to that process as packetization, by taking an RFC which detailed the same, and plugged in our numbers, ie the limitation of packet size, and implemented it
our sdk provides several features, including a protocol for messages to be structuredsessions with a lifecycle represented as a progression of states 
the original solution was all built into the same process driver process
this created its own rpocesses however as we were using CEF, Chromium Embedded Framework
Chromium Embedded Framework is another SDK which can be used to create Chromium browsers 
this allows you to leverage the entire Chromium API, which in our case we were using for loading a remote application which was itself a JavaScript application which holds the other SDK of our company
that SDK provides access to our subscription based services Software as a Service SAAS I should say
we decided to refactor all of this, because the original solution had been rushed as a proof of concept and to get a deployed solution available for the client to use as soon as possible
they were happy with the solution and have been using it internally, first with one team in Hong Kong, and eventually ramping it up to I believe a quarter million of their employees
they are actively using this now
we noticed some bottlenecks in the messaging and some issues which might be alleviated if it were not all piggybacking on the citrix viewer's process
so what we did was redesign it with concerns split amongst separate processes which work together as a networking solution
the first is a Communication link which houses a channel port, encoder/decoder and serializer/deserializer 
this would allow us to utilize different serialization solutions in the future, once we adapt the solution for something not involving Citrix
on the radar was,has been and currently is VMWare 
essentially any serializer/deserializer could be used
the communication link handles incoming requests from the client side applicationreceives them, sanitizes them, converts them to our own driver's messaging protocol, and then sensd them forward over IPC to another process called the Orchestrator
the orchestrator is
the orchestrator houses a controller to manage session logic and determine message flow, and a process host which we can use for launching other processes
at the moment those other processes are window hosts and browser hosts
the browser host is a daemon which can launch CEF browsers for any number of ongoing sessions
and manage the state of those browsers to ensure that they are acting in accordance with our sessions and processes
the window host is something which can procure, manage the lifecycle of, and destroy a window
and this has to be implemented for each platform
we have window solutions for linux, windows and mac
the linux solution has been deployed for various thin clients
the windows solution mostly for windows 10 64
and the mac solution is one which we are working on right now, is the project for which I am accountable, and is nearing its deployment
we've had to learn some ObjectiveC in order to implement the window properly on MacOS
using a C bridge to give us access to the ObjectiveC API from our C++ based application
I implemented that as an extern declared constant struct which has functions which create an ObjectiveC UI object, call methods on it, and perform cleanup as is necessary
there is multithreading involved, yes
we have a worker class which can be leveraged anywhere it's needed, such as with our orchestrator, whose use of a worker thread is handy for processing message queues
so there are many processes at play here, all communicating and with one another in a patetrn whic his made to allow for a lot of overhead if needs be
we imeplemnted wthis using ZeroMQ, a messaging library for reliable sockets
it offers a few patterns which can be easily implemented
the one which we settled on was a REQUEST-Reply pattern whereby wherein every message sent has to be responded to before another one can go out
this allows us to track the exact order of a messaging scheme

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having words tos peak
having thoughts to elucidate
having a point of focus
these are things that we take for granted as human beings
based on our understanding of the definition of being human, having consciousness, and having the assumption that these capacities extend indefinitely
of course, this is not always the case, as we see exceptions based on genetic circumstances or events incurred during development
and these become more pronounced as one ages, as we see with our fellow brethren who unfortunately fall victim to neurodegenerative disease and suffer dementia later in life
it may very well be taht they have a point of focus, and in that they are more or less aware of what it is, or that it can be acknowledged, might cloud our ability to discern whether or not they indeed have a point of focus
likely so long as the mind continues to exist with a nervous system, there is a point of focus which is expressed temporally
that being said, it would seem that we are coming to a point where our point of focus might no longer be our own
this is already something that's theorized about and written about
documentaries are made explicating the degree to which our social media companies have provided an interface into human behaviour and human observation
which allows for a human's daily actions to be manipulated based on many methods, with one of the most easily understood examples being content suggestions which are placed in the most opportune view for the human to recognize and observe them
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