Questions about the disk size of recovery hd

[h3blade]

I have never use recovery hd before (hold down option key method) and have few questions regarding about this recovery hd after updated to Mavericks 10.9

and have also created a new recovery hd for mavericks 10.9

1.
Recovery HD：
容量： 650 MB（650,002,432 字节）
BSD 名称： disk0s3
内容： Apple_Boot

this disk0s3 size looks like unchanged compared to 10.8, however if I go to os x TOOLS from recovery hd(hold options key at start), the disk size shows 1.25 GB? why is that?

and also Mavericks size is over 5gb, if i use the recovery, do i need to download anything since the recovery hd is only 1.25GB.

2. if i use the recovery hd to recovery the system, do i have to backup the applications?

 

[Weaselboy]

As you noticed, the recovery partition is only 650MB. That partition does not contain the actual OS, it is just a set of diagnostic tools plus a utility that allows you to download the 5GB OS from Apples servers. So every time you use that utility to install the OS, the entire 5GB OS gets downloaded again.

A normal OS X install does not erase your applications or data, but you should always backup first anyway just to be safe.