Most of these descriptions were extracted from the kernel documentation.
This value denotes the maximum number of file handles that the Linux kernel will allocate. When you get a lot of error messages about running out of file handles, you might want to raise this limit.
This value denotes the maximum number of inode handlers. This value should be 3 to 4 times larger than the value in "Max. file handles", since stdin, stdout, and network sockets also need an inode struct to handle them. If you regularly run out of inodes, you should increase this value.
This value denotes the maximum number of cached disk quota entries. If the number of free cached disk quotas is very low and you have a large number of simultaneous system users, you might want to raise the limit.
Every mounted file system needs a super block, so if you plan to mount lots of file systems, you may want to increase these numbers.
When this option is disabled, ctrl-alt-del is trapped and sent to the ``init'' program to handle a graceful restart. However, when it is enabled, Linux's reaction to this key combination will be an immediate reboot, without syncing its dirty buffers.
Fair Scheduler is a kernel option that greatly improves kernel abilities to handle processes who try to monopolize the processor time.