Monday, April 30, 2012

How to use a CD/DVD on a Computer That Doesn't Have a CD/DVD Drive

A friend of mine asked me today how to use a CD on a computer that doesn't have a CD drive.  Luckily, this is an easy, albeit technical, one.  The overall strategy goes like this: create an ISO file of the CD, get the ISO file onto the CD-drive-less computer, open the ISO file with an emulator.

Creating an ISO file of the disc

This is where half the magic happens.  An ISO file is basically a file that exists on your hard drive that contains everything about an optical disc.  It's just like a Word document or an Excel workbook.  Except instead of opening in Word or Excel, you have to open it in a special program (don't worry, it's as easy as double clicking the ISO file).
The first thing to do is download and install ISO Recorder by Alex Feinman.  This will allow you to copy the CD to your computer's hard drive in the form of an ISO file.  After you've installed it, put the disc in your drive and look in 'My Computer'.  You should see the CD-drive icon change to the icon of the disc inserted.  Right click on that drive and click "Create Image from CD/DVD".
ISO Recorder will pop up asking where you want to save the new ISO file.  Pick a good place for it and hit next.  Wait for it to finish and you're ready for the next step.

Moving the ISO file to the CD-drive-less computer

This part can be accomplished via whatever method you choose.  The easiest (and least technical) is to just copy the ISO to a USB flash drive.  Then copy the ISO from the flash drive to the new computer.  Other options are to copy via the network or via torrent (depending on the size).

Opening the ISO File with an Emulator

This is the fun part.  Download and install Daemon Tools Lite on the CD-drive-less computer.  You may need to reboot after the installation; do that before continuing.  Once that's finished, find the ISO file and double click it.  You should get a message saying "Mounting Image to Virtual Drive".  After your mouse stops showing the hour glass and/or the message goes away, look in your 'My Computer'.  You should see a CD-drive.  WHAT?!  This is the virtual drive.  It should have your virtual CD in it.  You can now use the CD as if it were installed in a real drive.  And guess what, this CD can't get scratches on it.

ISO version of discs are a very handy way of keeping backups of discs.  Especially if you are worried that kids may destroy the originals.  Of course, DVDs manufactured by the movie industry usually have copy protection on them, so you might not be able to do this for just any disc.

Thursday, April 19, 2012

Managing NetVoyant through Web Services

Web services can be used to manage NetVoyant devices.  I've had at least one customer who built auto-provisioning of NV monitoring through web services.  It can be a headache, but it is possible.  I won't go into details about how to actually automate the use of the web services; go take a class for that.  This practice actually goes against my preferred method of adding all devices to NV and using class designations, auto-discovery rules, and auto-enable rules to manage what gets monitored.  However, in some cases, that can't be done.  Here are the details on the web services.

In any distributed system, there are two types of systems: NV Master Console and NV Poller.  NV uses scopes to manage the devices to be monitored.  Each scope details an IP address to be monitored, a subnet mask, and the poller responsible for monitoring it.  The process of adding and removing devices from NV involves manipulating the scope that corresponds to the device to be added or removed.

Adding a device to NetVoyant

If you are using web services to add devices to a distributed NetVoyant system, you'll either want to add the device to the poller responsible for polling all the devices in that region OR you'll want to add it to the poller that is least loaded (in terms of total number of devices).  It's also possible that you may have multiple pollers covering a single region and need to determine which poller is least loaded.In order to find out the number of devices on each poller, the GetDeviceCount operation of the NetVoyantService should be invoked on each poller (and not the master console).
The NetVoyantService can be found at /pollerwebservice/NetVoyantService.asmx?WSDL on each poller.  By invoking this procedure without any arguments, the result will be XML indicating how many devices total are on that particular poller.  Unfortunately, this must be run against each poller to get that poller's count.  Below is shown a sample output.

<?xml version="1.0" encoding="utf-8" ?>
<int xmlns="">41</int>

Wednesday, April 11, 2012

Using the browser view to add custom content to NPC

A while ago I started making flash videos using Camstudio as a way of teaching people how to use NPC. Camstudio outputs a swf with accompanying html to make it easy to post the video to a website. I wanted this to be added to NPC so i started using the browser view. I needed a place to post the html and swf files so that the browser view could access the files through a url. So, i went into IIS on the npc system and added a virtual directory pointing to a folder on the D: drive. I put the swf and html files into that folder and pointed the browser view to the url. It worked pretty well. Given a little skill with html, anyone could insert anything into NPC pages.
One handy way to use this would be to insert small snippets that help people understand what specific views mean, or how to use/interpret specific pages.