Is the user space isolated in OS X?

1. For the vast majority of cases, no. The account system in OS X allows shared use of application resources among users, but isolates settings and data so those from one user will not affect or in any way apply to another user. There are some global settings for the system and some system-level programs (ie, firewalls and AV software) where this is not the case, but in most other situations complete isolation applies.

2. If you delete a user and it's account folder, then for most intents and purposes the account is gone. There may be residual instances of its UID associated with some file permissions, but its settings and data (at least that within the user account itself) will be removed from the system and no longer be an applicable storage location or account under which files or running process can be associated.

1. Normally, applications are installed in /Applications, a folder where all users can access to, so applications are available for all users. However, some applications may give you the option to install them for an user.

2. System Preferences will give you the option to remove all the files of the user or to keep a disk image with the files. Note that applications installed with this user in /Applications won't be removed

1, It depends on where you install the application. If you install it in the Application folder in your Home folder then only you will be able to use it. If on the other hand you install it in the Applications folder at Root then anyone can use it.

2, With System Preferences you would will be given the option to do that.

In actually fact the User under OS X are the same as Users in Unix since OS X is derived from Unix.

Allan

Correct. In the case of Parallels, it stores virtual machines in Documents folder, so you will have different virtual machines in each user

Don't worry about that. Everybody has to start.

Respecting to that question, if Parallels stores settings in ~/Library, which is inside the user's folder (and I think Parallels stores settings here), settings will be different in each user

Think of the main Library you see in the root of your Hard Drive (at C:\, if you will) as an "All Users" Library. If an app needs to store stuff that is common to all users, it will do so in that Library.

Anything in a user's Home folder is isolated from everyone else (except the Public and Sites folders, with others can Read).

For almost all apps, each user can set it up as they wish, not affecting any other users. The settings are stored in Preference List (.plist) files in your user/Library/Preferences folder.

The Libraries are for Apps to use for reference data, not necessarily for user data (like Win 7 uses the term "Library").

Welcome to the world of Mac. Some ‘light' reading to help the transition. 😝