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.