To add to what rspanbauer figured out...
I have Win7 Pro 64-bit.
Initially, I went straight to ModelSim 11.1sp2 installer - that was a no-go as it was looking to attach to a root ModelSim install. Then, I noticed the file size difference, too. So, I am thinking I'll do this ordered install of ModelSim 11.1, then 11.1sp1, and finally 11.1sp2.
The install of 11.1 went fine - the process created a directory in C:/altera/11.1/modelsim_ase
The install of 11.1sp1 appeared to go fine - directory C:/altera/11.1sp1/modelsim_ase. In fact, this appeared to be a full install. In fact, I found both 11.1 and 11.1sp1 directories at the end my path variable:
...;
c:\altera\11.1\modelsim_ase\win32aloem;c:\altera\11.1sp1\modelsim_ase\win32aloem
But wait, if you attempt to execute one of the modelsim binaries, it will find 11.1 version first instead of 11.1sp1. Looks like a bad cleanup process.
The install of 11.1sp2 appeared to take a different route - one would think this would be a full install, too!! Not so. It decided to look for
C:\altera\11.1 - never saw the
C:\altera\11.1sp1 directory - HUH?? Continue to install 11.1sp2, I find that it installs something in
C:\altera\11.1\modelsim_ase and left both the 11.1 and 11.1sp1 directory references in my PATH variable.
So, why didn't the
C:\altera\11.1sp2\modelsim_ase directory get created?
Why wasn't ModelSim 11.1sp2 a complete install?
Why didn't the installer clean up the previous version - or even a give choice to do so?
For the record, it looked like Quartus 11.1sp2 was a full install - why doesn't this also apply for ModelSim 11.1sp2?
I really don't have enough disk space or time to experiment with what versions are a full install versus a partial install. Altera, if you are listening, figure out the software install policy - you have two choices:
1. All installers are full versions. If it is a service pack, it includes all previous service pack updates. When someone picks the most current release - they get a complete package.
2. Base installer plus cumulative/ordered service pack installers (i.e., you have to install sp1, then sp2, then sp3, etc...
I prefer option one myself - that way, I can blow away the old versions without having to think about it...