Removing iOS SDKs from OSX

Question

This isn't a programming question but it's about the SDKs and the IDE. I've accumulated a ton of different XCode installs over the past couple of years and now my hard drive is nearly full. With each SDK clocking in at around 5 gigs, and my storage space getting low, I have a couple of questions

3 Questions:

1. Can I remove old ones?
2. Where are they stored?
3. Does the newest SDK overwrite base classes from previous SDKs? (Does NSString.h now reside in two different SDKs or will the newest one take precedence?
4. What about beta 1, beta 2, beta 3 SDK versions? Does installing the GM/official eliminate the beta version from my Mac?
5. Most importantly, Can I still target 3.0 if I install the 4.2 SDK? (I understand the difference between base SDK and target SDK)

I want to clean my hard drive and I have about 18 GB remaining on a 160 GB drive. I'd like to just start over and reinstall OSX, download a fresh SDK, but I still have apps that are targeted to 3.1.2 and I don't want to be forced to only support 4.0.

Thank you

Answer 1

Can I remove old ones?

Sure.

Where are they stored?

/Developer/Platforms/iPhone*/Developer/SDKs/ usually.

Does the newest SDK overwrite base classes from previous SDKs? (Does NSString.h now reside in two different SDKs or will the newest one take precedence?

No, you're fine to delete them. Each SDK is self contained.

What about beta 1, beta 2, beta 3 SDK versions? Does installing the GM/official eliminate the beta version from my Mac?

Sometimes, you can choose to reinstall them though

Most importantly, Can I still target 3.0 if I install the 4.2 SDK? (I understand the difference between base SDK and target SDK)

Yes

Answer 2

As of May 2016:

Where are they stored?

• /Library/Developer/CoreSimulator/Profiles/Runtimes
• /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs
• /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/Library/CoreSimulator/Profiles/Runtimes