Recovery HD A spare wheel not really convenient.
To overcome the lack OS X DVD or installation key that allowed particularly easily reinstall the OS X on your Mac, APPLE offers from LION a new tool that allows system recovery. This "Recovery HD" tool is unfortunately far from having the flexibility and simplicity that can have the DVD or the installation key. It is also necessary to be online to use certain features of "Recovery HD". Better to provide alternative solutions in case something happens and avoid resorting to this not necessarily convenient tool.
Introducing "Recovery HD"
Up to 10.6 SNOW LEOPARD, reinstall Mac OS X on her in case of necessity, it was enough to bring the DVD bootable OS X installation, start holding the "C" key to have started on the DVD, which allowed to launch "Disk Utility" to initialize (or partition) hard disk and proceed in the wake of the re-installation OS X.
With the arrival of Lion, the situation has changed. OS X is no longer sold on DVD bootable installation or as bootable USB drive, but by default via download from the Mac App Store. Therefore, to reinstall OS X if necessary, it is possible to us as in the past...
To face this new, APPLE has decided to propose a different system from LION for reinstalling OS X on your Mac if necessary. This tool is called "Recovery HD".
This is actually a small partition that is automatically created on your hard drive, just when you install YOSEMITE on this hard drive. You do not require same account, and may not know you now that you have such a partition! This is unfortunately not surprising, because this partition is very well hidden and nobody will tell you that it exists on your Mac!
NB: In some cases, this partition "Recovery HD" will however not be installed on your Mac during installation YOSEMITE: When the hard drive on which you install YOSEMITE is partitioned, in the case of a RAID volume, or if the disk has a partition configuration Boot Camp nonstandard, in which partitioning was performed after the execution of the Assistant Boot Camp or the configuration created by the Boot Camp Assistant has been manually changed.
This partition "Recovery HD" just lodge next to your OS X YOSEMITE system. So if you have YOSEMITE installed on your Mac, you have de facto of this small hidden partition.
Even the launch "Disk Utility" you cannot view it! But if you have a tool like "iPartition" you can do so through the "Partition Map" menu. Here on my main hard drive:
To access the partition, you must start the Mac is holding the "R" key pressed (in this case you will automatically start on that partition "Recovery HD") or holding down the "alt" key (in this case, Then select the partition "Recovery 10.10" that will appear on the screen).
If you have enabled "FileVault", access to the "Recovery HD" cannot be done by holding down the "alt" key when booting the Mac. It must indeed start the Mac by holding the "cmd" and "R" keys down.
What is this partition "Recovery HD"?
Once you have started on this partition "Recovery HD", you go (like the good old days of the DVD) to a certain tools.
At the top of the screen, in the menu bar, the "Utilities" menu include access to "Terminal" in the "Network Utility" and "Password Utility Firmware". You probably will not need these utilities, if perhaps not to reset the administrator password:
Reset the administrator password
· Start the "Terminal."
· Enter this command: resetpassword
· A new window appears allowing you to change the administrator password.
· When you restart the Mac, you can use the new password.
Now look at the main window that appears when you start up your Mac in "Recovery HD":
"Recovery HD" allows you to run a restore from backup "Time Machine" to launch "Safari" to surf and have particular online help, launch "Disk Utility" to repair minor injuries your OS X system and also boot / partition hard drives connected to the Mac, and perform a re-installation of OS X if necessary.
So finally, you will tell me if your Mac YOSEMITE faces some problems, well instead of starting as in the past on the installation DVD, you'll be able to boot to that partition to start small basic repairs via "Disk Utility". Certainly it is possible, but since you have a clone having many more powerful maintenance tools, I'm sure you already Demarrias more on the DVD to perform this type of basic maintenance operation ... then you will not start on that partition "Recovery HD", right?
And to re-install the system in case of need? In the past, yes, actually the best way to conduct a clean install of your OS X system was started on the installation DVD and do so to the re-installation of OS X. But now I urge you to do not go through "Recovery HD" to re-install OS X on your Mac.
Indeed, although it is of course possible to re-install OS X via the "Re-install OS X" function offered by "Recovery HD" This solution is not, in my opinion, not the best nor the most practical. If you have a clone, then preferably use the clone to make an OS X re-installation.
By default this partition "Recovery HD" is installed on the same hard drive where you installed OS X YOSEMITE. But what happens there if unfortunately your hard drive were to let go? Without clone bootable USB drive without installation YOSEMITE (crafted by you), it will NOT POSSIBLE not boot from this partition "Recovery HD”!!! So what?
Apple offers to download HERE a "Disk Recovery Wizard". This wizard let’s just clone the partition "Recovery HD" to another hard disk (external drive) or even a USB drive. But be careful, in this case, this key will IN NO EVENT key USB bootable installation YOSEMITE, but it will just be a clone of the partition "Recovery HD" you already have on your hard drive. You can use this partition clone "Recovery HD" if you cannot use the partition "Recovery HD" located on your hard drive.
It's a little spare tire of the spare wheel.
NB: It is necessary to make the partition clone "Recovery HD" before the partition "Recovery HD" is no longer operational, of course.
Important note about the Mac market after the release of LION 10.7
Macs sold since the release of LION and therefore come with LION MOUNTAIN LION, MAVERICKS or YOSEMITE now installed on the machine, also have a function "OS X Internet Recovery" that allows you, in case of failure your hard drive and / or hard disk change, start your Mac directly from APPLE servers to process resettlement OS X. This feature is not available for Macs before the release of LION and therefore that had been purchased with a previous version of the system (or SNOW LEOPARD LEOPARD).
"OS X Internet Recovery" checks your machine, including its serial number (to verify that your Mac is allowed), and then automatically downloads and launches an image of the hard drive recovery.
To do this, you must have an Internet connection because you will have to download more than 5 GB of data necessary for the relocation YOSEMITE!!
More on "Internet Recovery OS X" HERE.
Why make it simple when you can make it complicated? Some will no doubt think that this system is practical and modern because it avoids having to annoy to re-install OS X, but I honestly think that APPLE would be much better to continue to offer the sale of bootable USB keys OS X and especially to slide one in every Mac sold in cartons YOSEMITE, rather than forcing new buyers to go through this function "OS X Internet Recovery" really not practical. Everyone does not necessarily have a high speed Internet connection, and how to re-install OS X and its MacBook Air or MacBook Pro when you are in a place without an Internet connection?
Indeed, the new Mac buyers have no choice but to go through Apple's servers to re-install OS X if something goes wrong with their hard drive, they have neither USB Bootable of installation or installer (downloaded from the Mac App Store) they could use from a clone.
In short, after reading the above, it is better to take all possible precautions to deal with any difficult situation. I do know strongly advise you to urgently provided a clone of your YOSEMITE installer and / or you make a bootable USB installation YOSEMITE key.
Indeed, the new Mac buyers have no choice but to go through Apple's servers to re-install OS X, if something goes wrong with their hard drive, they have neither Bootable USB key to installation or installer (downloaded from the Mac App Store) they could use from a clone.