(It is a simple Cocoa wrapper around the RDesktop software)

  Does this mean it requires that the Mac RDP Client (from Microsoft) be 
present?

No, CoRD is entirely self contained, and it does not require the Microsoft 
client.

This is what I tend to use to connect to VCL reservations. The caveat is that 
audio is not forwarded over the RDP connection, so if audio is an important 
part of the VCL image, then you will need to use another RDP client.

  Audio is important for accessibility. But if JAWS (the most popular screen 
reader) is installed in the remote computer - I'm not sure how it transmits to 
the local computer so the local computer can give the audio.

This is correct. My understanding, though, is that in order for JAWS to work in 
this context, it needs to be installed and running on both the local and the 
remote machine. And using a Mac as a local machine precludes installing JAWS 
locally in the first place, hence CoRD becomes a non-issue.

The way JAWS works in this environment is by forwarding the audio over "virtual 
channels" [1] (sort of like how disks are forwarded over the RDP port). That 
is, anything the remote JAWS reads is not sent across the RDP channel as 
standard audio (such as if you were to watch a YouTube video), rather it uses a 
special segment of the RDP stream that is picked up by the local JAWS software 
(and it is probably not sending actual audio anyhow -- just some type of 
encoded instructions in text). The actual audio output is handled by the local 
JAWS software.

So, assuming that the client machine is Windows and JAWS is installed locally 
and on the remote image, any RDP client used to connect to the VCL will need to 
understand these "virtual channels". This mostly means using the built-in RDP 
client that ships with Windows (i.e. terminal services).

I have also found that transferring large files between the VM and my local 
machine can occasionally cause CoRD to crash. Otherwise, it is a very nice 
piece of software.

  Thanks, this gives us more information.

Another class of options along this line includes running the RDP connection 
entirely through a web browser, using an HTML5 client. There are some 
commercial solutions out there as well as an open source project called 
guacamole [2]. When I last looked into this, the commercial solutions seemed 
cost-prohibitive and the open source project was still in alpha, but in looking 
at their website just now, they appear to have made a lot of progress. Any of 
these "client-less" RDP connections will require some additional infrastructure 
for the VCL admin to setup (it works by running an intermediate web application 
that converts the RDP stream from the VCL session into a WebSockets stream that 
can be presented on the HTML5 canvas object). I have no idea how (or whether) 
audio is handled. I also doubt that it would work well for JAWS users -- while 
you could cut out the "virtual channel" issue, you are left with a local JAWS 
client needing to extract text from rasterized vector graphics, which probably 
would not work. Nevertheless, it is an interesting option.

-Aaron

[1] 
http://msdn.microsoft.com/en-us/library/windows/desktop/aa383509(v=vs.85).aspx
[2] http://guac-dev.org



FreeRDP http://www.freerdp.com/  which has free Android and iOS ports 
available. (It would be good to hear of any experiences with this, as more and 
more students have mobile devices.)

--henry schaffer



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