Run Mac from USB

Discussion in 'MacBook Pro' started by montu_n23, Nov 17, 2015.

  1. montu_n23 macrumors newbie

    Joined:
    Nov 17, 2015
    #1
    All, a question here thats bogging me.
    PLease do not ask my why I did so, I did so for various reason.
    I wiped the MAC clean of the OS Lion and installed Windows 7 pro 64 bit. all of 500 GB for Windows.
    I tested internet recovery, so anyday if I want to get back to MAC OS, I can use internet recovery and reinstall MAC OS.

    My question is - while I have 500 GB full of Windows, is there a way I can run Mac off of a USB drive?

    I was thinking of using a 32gig USB drive, use internet recovery, and install OS on the flash drive using disk utility. But I am concerned about this, with all of 500 GB dedicated to windows, when I use internet recovery, where would it store temporary files if any. Would it save temp files on the 500 GB hard drive? of so, that would hurt my windows installation. If it does not, is the mac accessing everyting everything fro the server directly? and is not using ANY storage on the MAC itself until we get to and choose an option on Disk Utility?

    My objective is, when I start MAC, I want to be able to choose either of two OSs to booot
    1. Windows on the 500 gig drive
    2. MAC OS from 32 gig flash drive (basically for any firmware updates)

    Any suggestions on how to go about this? is internet recovery a good bet (that it wont mess around with windows partitions unless I choose windows drive for installation from disk utility)?

    much appreciated.

    Thanks
    MN
     
  2. Weaselboy Moderator

    Weaselboy

    Staff Member

    Joined:
    Jan 23, 2005
    Location:
    California
    #2
    I have never tested your exact setup, but I know Internet recovery works even with a new and unformatted drive, so I don't see why your suggestion would not work. I know when you do Internet recovery with a new drive the installer downloads to memory as a DMG file then mounts that DMG (disk image) to run the installer.
     
  3. montu_n23 thread starter macrumors newbie

    Joined:
    Nov 17, 2015
    #3
    Downloads to memory - this is my concern - would it download it to the primary 500 gig drive? if it does, that will mess around with my windows installation
     
  4. Weaselboy Moderator

    Weaselboy

    Staff Member

    Joined:
    Jan 23, 2005
    Location:
    California
    #4
    No.... by memory I mean RAM.
     
  5. DeltaMac macrumors 604

    DeltaMac

    Joined:
    Jul 30, 2003
    Location:
    Delaware
    #5
    Another way to look at your situation:
    OS X, and your OS X installer, by default, can't write to a NTFS-formatted drive.
    So, the OS X install won't touch your Windows installation - standard OS X setup can't modify it.
    All you need, when you boot to internet recovery, is to point to your flash drive as the destination.
    A new 32GB USB flash drive will not likely come out of the package with a Mac format, so you would want to erase the flash drive first, using Disk Utility (also available while booted to Internet Recovery), so the drive is configured as GUID, and set for a MacOS Extended format.
     
  6. montu_n23 thread starter macrumors newbie

    Joined:
    Nov 17, 2015
    #6
    Thank you for clarifying this - I assume I will need to format the flash drive - "extended Journeled" format?
     
  7. Weaselboy Moderator

    Weaselboy

    Staff Member

    Joined:
    Jan 23, 2005
    Location:
    California
    #7
    Yup. :)
     
  8. montu_n23 thread starter macrumors newbie

    Joined:
    Nov 17, 2015
    #8
    Worked like a charm..running OS from USB drive..but it runs like C***
    I am guessing 16 gig drive is not sufficient..I have never seen a mac hang..will try the install on a 32 gig drive and see how that works.
     
  9. Weaselboy Moderator

    Weaselboy

    Staff Member

    Joined:
    Jan 23, 2005
    Location:
    California
    #9
    Yeah... that could be part of the problem. Between the OS and swap/cache files I think you are pushing it with 16GB. Are you on a newer Mac with USB3?
     
  10. Samuelsan2001 macrumors 603

    Joined:
    Oct 24, 2013
    #10
    No it's down to the speed of the flash modules in a standard USB drive if you want to get good speeds you'll need an external hard drive or a better quality USB stick.

    Something like this

    http://www.amazon.co.uk/SanDisk-Extreme-Flash-Drive-245MB/dp/B00DZPUOU8
     

Share This Page