<br><br><div class="gmail_quote"><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"><div><span><font size="2" color="#800000" face="Arial">If you
wait to switch monitors until after the virtual desktop has been switched, the
the new virtual desktop will be displayed on the old monitor! You have to do do
something more like this:</font></span>
<div><span><font size="2" color="#800000" face="Arial"></font></span> </div>
<div><span><font size="2" color="#800000" face="Arial">while
(1) {</font></span></div>
<div><span><font size="2" color="#800000" face="Arial"> tell video demux to ignore new
input</font></span></div>
<div><span><font size="2" color="#800000" face="Arial"> switch virtual desktops</font></span></div>
<div><span><font size="2" color="#800000" face="Arial"> tell video demux to output to new
monitor</font></span></div>
<div><span><font size="2" color="#800000" face="Arial"> sleep</font></span></div><div class="im">
<div><span><font size="2" color="#800000" face="Arial">}</font></span></div></div></div></blockquote><div>A: True, hadnt thought of that, thanks for the heads up! Anyway, it was just a sketch of what will really be done, implementation phase still's far from where I am now :P <br>
<font color="#800000"><font size="2"><font face="Arial"><br></font></font></font></div><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"><div>
<div class="gmail_quote"><span><font size="2" color="#800000" face="Arial">Uh, one of the most fundamental skills an engineer needs to
learn, and learn early, is how to tell his managers their latest "solution"
won't work. It's easier to get away with telling them that if you do have a
working solution. Therefore, let's make this whole problem rest on the HW guys
shoulders:</font></span></div>
<div class="gmail_quote"><span><font size="2" color="#800000" face="Arial"></font></span> </div>
<div class="gmail_quote"><span><font size="2" color="#800000" face="Arial">Tell him that his hardware needs to capture the video
signal into one of six separate frame buffers. Your parallel port interface will
tell him which one or none. His hardware will then provide a continuous video
signal out to each of the six monitors connected to it. Users get nice stable
video, you get easy SW task, and boss gets to prove he's a wiz HW
designer.</font></span></div></div></blockquote><div>A: Let me see if I got this straight: The framebuffers at the HW part will hold the image sent to that specific monitor while it switchs the virtual desktops between the other monitors, until its monitor 1's turn again, is that right? During like 0.1 second, that image will be frozen on that monitor, waiting for its turn to receive new data? Is this possible to be done with HW (Ive heard that you can do everything you do with software on hardware, but at higher costs, but I dont know how true is that :P)?<br>
</div><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"><div><div class="gmail_quote"><span><font size="2" color="#800000" face="Arial"></font></span></div>
<div class="gmail_quote"><font size="2" color="#800000" face="Arial"></font> </div>
<div class="gmail_quote"><span><font size="2" color="#800000" face="Arial">Now, having said all of that, I'd have questioned the whole
approach from the beginning:</font></span></div>
<div class="gmail_quote"><span><font size="2" color="#800000" face="Arial"></font></span> </div>
<div class="gmail_quote"><span><font size="2" color="#800000" face="Arial">Where are the monitors coming from? If you're buying them,
then there is money to buy cheap, modern PCs to run each station. If the
monitors are surplus, then check with you university's surplus property
department about getting ahold of discarded computers.</font></span></div></div></blockquote><div>A: Thats a good point. Even though the project is meant to be "zero cost", there will be monitor purchasing. Since the monitors will be embedded in the tables (like coming from underneath it), they must be LCD monitors, because they're thin, so we couldnt just use old CRT monitors. The "paying for monitors but not paying for graphic cards" thing doesnt make that much sense to me either, but I gotta work with what's given to me :P Besides, my main goal right now is to make this system work through any solution. How is my boss going to manage the costs, its up to him.<br>
</div><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"><div><div class="gmail_quote"><span><font size="2" color="#800000" face="Arial"></font></span></div>
<div class="gmail_quote"><span><font size="2" color="#800000" face="Arial"></font></span> </div>
<div class="gmail_quote"><span><font size="2" color="#800000" face="Arial">Why do users have to log in if all they are going to do is
use a single PDF reader? I assume the student don't have to log in before the
can read a book off the shelves. Instead of using virtual desktops, have your
app map/unmap the N copies of acroread/xpdf/... in sync with you parallel port
output. There's no reason to have a window manager or virtual desktops at
all.</font></span></div>
<div><span></span> <br></div></div></blockquote><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"><div><div class="gmail_quote"></div>
<div class="gmail_quote"><span><font size="2" color="#800000" face="Arial">BTW, what are you doing about input? How are you planning
on handling N keyboards and N mice?</font></span></div>
<div class="gmail_quote"><span><font size="2" color="#800000" face="Arial"></font></span> </div>
<div class="gmail_quote"><span><font size="2" color="#800000" face="Arial">Mike McDonald</font></span></div></div></blockquote><div>A: Im not sure if I understood what you meant about the map/unmap
thing, but anyway.. I must correct something I said earlier, and maybe
make things clearer. Now users won't login into a specific virtual desktop anymore. The machines [by "machine" I really mean the cpu, not the monitors] will be turned on, all of them logged with a standard login. Each one of the 6 monitors will be assigned with a individual virtual desktop from that machine. The only application they'll be able to start will be a browser, and the computers will be connected to an intranet only, accessing an internal server, no internet/external access involved. On this browser, they'll access some page hosted on the university's server, log in with their data and then search for and read books. <br>
This change on the library's system is due to the complicated system that exists currently. Students cant go the book shelves, they must check a book list (paper-made), see if the book they want exists in there, write down its reference number, go to a balcony and ask the lady if there's any book left. She checks out, types your registration number (similar to the login part) on the library's system and lends you the book. Since sometimes the ammount of books isnt enough for all the students (dont even ask me why not just buy more books instead of all of this), this new system would allow students to read pdf versions of those books, in cases of urgent need. My boss also wants this system to gather statistics about students, such as 'most read books', 'most read books by students of that class', 'most read chapters of those books', etc. That's why individual logins are required. But since now they'll log into a service hosted on server, thats not a problem anymore. The main problem now is to make the screen switching possible.<br>
Finally, about the inputs... I'm still now sure how would that be done. Multiterminal systems implement this feature pretty well, as far as I know, so I think I can get something from there.<br></div><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
<div><div class="gmail_quote"><span><font size="2" color="#800000" face="Arial"></font></span></div>
<div class="gmail_quote"><span></span> </div>
<div class="gmail_quote"><span><font size="2" color="#800000" face="Arial"></font></span> </div>
<div class="gmail_quote"><span><font size="2" color="#800000" face="Arial"></font></span> </div></div>
</blockquote></div><br>