In the comments to my earlier post on using ISO images to mount disk-based copies of CDs and DVDs, MarConey asks a good question, starting with an inventory of available disk space on his current system:
C: – 30 gig HDD, 7 gigs free; has Win XP Home on it.
M: – 80 gig HDD, 50 gigs free; has mostly music files stored on it.Let’s say I extract the necessary files from the ISO to the M: drive and then run setup from there. Will I be able to upgrade Win XP as things now stand or do I still really need to have 15 gigs free on that C: drive??? Because, I really don’t want to have to go through the exercise of copying everything over to a bigger drive first and then doing the upgrade, etc., or, re-installing every single program and driver, etc…..if I don’t have to.
OK, first of all, you don’t want to extract the files to the M: drive. You want to either burn the ISO image to a DVD or mount it so the system thinks it’s a DVD.
Second, you really do need a full 15GB of space? As it turns out, I have nearly a perfect test bed for this scenario. In a virtual machine, I had Windows XP installed on a 16GB hard drive, with roughly 11GB free. I copied a 3GB file to the C: drive so that it had less than 8GB free and then added a second virtual hard drive with 50GB of free space.
With that out of the way, I started the upgrade from the DVD. A few hours later (yeah, it took a long time) the upgrade was complete. The installer was able to use some space on the second drive and still had plenty of room left on the first drive when all was done.
So yes, you can install Vista on a machine with less free space than you might think.
Ed Bott 
“The installer was able to use some space on the second drive and still had plenty of room left on the first drive when all was done.”
I think that’s a first for a Windows installer, to be able to automagically spread files across multiple volumes. Somehow the real numbers from your experiment were changed to vague words, must have been in editing. 🙂 Can you quantify the “some space” and “plenty of room” numbers? Also, did the installer say anything about splitting files across the two drives? What particular directories did it put on the second drive?
So if I understand correctly, if I download and install Microsofts’ Virtual CD-ROM Control Panel for Windows XP, I can then mount the (downloaded) ISO image (to the M: drive???) and run it from there, upgrading the WinXP installation that’s on the C: drive??? Or do I still need another tool to extract the ISO, and/or must I mount it on the C: drive, etc.?? Burning a DVD right now is out of the question; perhaps I should have stated that from the get-go…
…And thank you, Ed, for having taken the time and effort to do what you’ve done already!!! It’s greatly appreciated, to be sure!!!
Mar,
When you install any ISO mounting tool, you configure it by pointing to an ISO file. No extraction necessary. The mounting tool acts as if it were a CD/DVD drive. It treats the ISO file as if it were a CD/DVD you just inserted. The operating system recognizes the virtual drive and its contents. Typically, you can specify any available drive letter. (I haven’t used the Microsoft tool, so I can’t say for sure.)
After that, you would run the setup from the mounted DVD drive, just as if it were a physical drive.
Having said that, I hope you’re not planning to upgrade over your existing copy of XP on your main system. At least not with a beta. I would recommend instead that you install a clean copy of Vista on your nice big second drive and see how it works with your hardware.
Dave, I’m reluctant to put down definitive numbers, because a single data point might not be representative of someone else’s experience.
The reason it’s a “first for a Windows installer” is because this is a completely new Windows installer. The new staged install, puts down different blobs of data in phases, instead of upgrading files in place.
It appears that the DVD image was copied to the second drive, occupying approximately 2.4GB of space there.
In the final stage of the upgrade, I checked the C: disk and found that it had just under 3GB of free space (we started with just under 8GB, you’ll recall). When the upgrade was complete, I had 4.7GB free. The temporary installer files on the E: drive had been completely erased.
So, the upgrade cost me a total of 3.3GB in disk space. I suspect some of that – perhaps a large amount – was caused by a glitch in the upgrade process, directly related to my test bed. I’m still researching that.
Hope that helps explain.
Yes, I was just reading the “Read Me” file of the Microsoft tool, it says to do exactly that: basically, click ‘add a drive’, continue adding drives until an unused drive letter is reached, click ‘mount’, navigate to the image file, select it, click ‘OK’.
But….have I given you the idea that I was going to do something so risky as installing a beta OS over top a nice, stable well-configured system that’s taken what, 4 or 5 years to get it to where it is???
Who, MEEEE????
Seriously, I’ve done crazier things and met with less success than I anticipate I would meet with here. I’ve taken this risk with Windows 98 Consumer Preview (up from 95), Windows XP (up from ME, which was also the ‘upgrade’), so I don’t feel too uncomfortable ‘giving it another go’. Oh yes, there’ve been those in-betweens when I’ve just said…well, when I’ve just decided to wipe it all and start anew. But I’ve got all my documents & saved emails, photos & videos, music and downloads on separate drives (and obviously the OS and programs on C:), so I’m not worried about losing “the important stuff”…just hope I don’t have to start from scratch with the system stuff. THAT’S the point of contention for me right now.
I will however take your recommendation under advisement before I make the plunge, I won’t be doing it today or tomorrow or so fast that I won’t think before I leap!!! But if and when I do, you can be sure you’ll hear all about how it worked out!!!
Sorry for being so long-winded; thank you again for your time and indulgence. And thank you, these many years later, for your guidance, tips and ideas via the pages of Windows XP Inside Out.
Ed-
You said, “I would recommend instead that you install a clean copy of Vista on your nice big second drive and see how it works with your hardware.” I know we’re getting further and further off-topic here, but, can this be done using the downloaded ISO from a virtual drive, number one, and number two, will setup then give me an option to create a dual-boot system??
Mar,
Yes, you can do that. Set up the downloaded ISO as a virtual drive and double-click it from within your current installation of Windows. When you get to the point where you can choose an upgrade or clean install, choose a clean install and specify that you want it to go on the second disk.
Setup will handle creating the dual-boot loader for you.
can i install a clean copy of vista from iso image on drive c which already contain Xp system ?