Anyone using SDHC for booting the 2010 Mini?

Discussion in 'Mac mini' started by mangrove, Sep 12, 2010.

  1. mangrove macrumors 6502

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    #1
    I was toying with this idea mostly for a backup boot drive for my 2010 Mini.

    Since SDHC memory cards are so small, that's why they appeal for this use. I have 32GB ones that should work just fine since I'm now using 40GB SSD's for boot drives. My current boot requirement is only around 27GB with OSX, Home, all Applications, etc.

    Think what a nice compact size you could have for a boot drive. The question is can you boot to SDHC's. If you can boot to an USB stick, why not an SDHC?

    If it routinely works, then I could use both internal drives for lots of data storage.

    Hey, maybe that could replace SSD's for boot drives. Or maybe the transfer rate is too slow for SDHC's.

    Any ideas? Opinions?
     
  2. Baby Mac macrumors regular

    Baby Mac

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    #2
    I've thought about uses for the SDHC slot, in particular, putting my mp3s there or using it as a backup. The gastest/largest-capacity cards seem about as pricey as SSD drives, but they are amazingly small and I wonder why SSDs are relatively so much bigger.

    You could run an experiment and see if you can boot from the SDHC. You could save yourself from having to uninstall any SSD/HDD if you can go into BIOS and tell it to boot to the SHDC. (I am assuming that any computer goes through the BIOS before starting an OS.
     
  3. Beaverman3001 macrumors 6502

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    #3
    Those cards aren't meant to take that much activity, they would quickly die.
     
  4. mangrove thread starter macrumors 6502

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    #4
    Must be why they are so much cheaper than SSD's. Have you ever seen any wear usage data or reports?
     
  5. hitekalex macrumors 68000

    hitekalex

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    #5
    It's not just wear/usage frequency but the poor read-write speeds of the Flash (SDHC or USB-attached) storage. Flash storage is fine to do an initial OS install or store document files.. But not for booting your system OS - your whole machine is going to crawl.
     
  6. mangrove thread starter macrumors 6502

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    #6
    So I guess I'm back to my original thought -- to have a bootable SDHC only for use as an emergency backup.
     
  7. iDave macrumors 6502a

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    #7
    Has anyone here actually done it? Interesting concept.
     
  8. hitekalex macrumors 68000

    hitekalex

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    #8
    Yeah, I have booted my MacBook of a USB flash key a few times. It works like crap. Booting off SDHC won't be much different (assuming SD boot is even supported by EFI - don't have any machines with SD slot so haven't actually tried).
     
  9. mangrove thread starter macrumors 6502

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    #9
    I asked because the 2010 mini has an SDHC slot in the back so I thought in case of an emergency I could at least get it booted with the SDHC card. I just might try and let you know how many hours it took to boot up. Hope I can hold down the option key long enough to get it to show up in the first place.
     
  10. hitekalex macrumors 68000

    hitekalex

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    #10
    To be honest, I fail to see a benefit to your emergency SDHC boot idea.. If your system drive crashes - you can always boot off your MacOS install DVD.. or you can make a bootable USB flash stick, and boot off that. SDHC slot doesn't really offer anything that couldn't be done without it..

    If it's just a matter of curiosity - make a bootable SD card (copy your SL install DVD on it), put it in, go to System Prefs / Startup Disk. If your SD card shows up as one of the choices - then you can boot off of it..
     
  11. reebzor macrumors 6502a

    reebzor

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    #11
    The Card Reader runs off the USB bus, so speed wise booting from an SD card will be comparable to booting from a USB flash drive, not that of an SSD.

    This will probably will run slower than a 5400rpm sata drive and will certainly die sooner. Seems not worth it to me.
     
  12. mangrove thread starter macrumors 6502

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    #12
    Now that's good information. Thanks. Was just wondering out loud.:D
     
  13. DewGuy1999 macrumors 68040

    DewGuy1999

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    #13
    Somewhere in the back of my head is the memory that the SD card on the unibody minis isn't on the USB bus like the MBP and the iMac, but is on the Ethernet bus. Whether or not this makes a difference to being able to boot from it I do not know.

    In this :apple: Apple support doc that doesn't list the mini, Apple says:

    Can I install Mac OS X on an SD storage device and use it as a startup volume?

    Yes. Change the default partition table to GUID using Disk Utility, and format the card to use the Mac OS Extended file format to do so.

    and here's an article from MacLife.com: Build a Bootable Rescue SD Card For Your Mac that may be helpful.
     
  14. dolphin842 macrumors 65816

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    #14
    Ah, that's good to know. I was curious as to what the max throughput of the card reader was (and whether or not it was fast enough for someone to make a SATA->SD converter :p). Looks like it wouldn't be worth it.

    As for making an emergency boot card, it could work if you didn't feel like making an emergency partition within an existing external drive. Given the cost of high capacity SD cards though, I'll just keep saving for an SSD instead ;).
     
  15. mangrove thread starter macrumors 6502

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    #15
    Yeah-sounds like saving is the way to go. BHW, OWC just lowered their 40GB a bit to like $109. As you may recall it was on sale in Aug for $99. I still think for a boot drive, my 40GB is great for my needs and it is still blazingly fast at everything thrown at it.
     
  16. hitekalex macrumors 68000

    hitekalex

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    #16
    The "bottleneck" here is not the USB 2.0 bus bandwidth, but the read-write IO of the SD card itself. The USB 2.0 can transfer up to 60MB/s, which is much higher than most Flash media I/O capabilities. The best Class-10 SD card can write up to 10MB/s, just to give you an idea.. That's an order of magnitude slower than any old hard drive, not to mention SSD. And that's why you don't want it for your main system drive.
     
  17. Baby Mac macrumors regular

    Baby Mac

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  18. mangrove thread starter macrumors 6502

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    #18
    Thanks for those articles. The MacLife article was especially encouraging. I think the comments from those using an 8GB SDHC for an 8.1GB boot needed for install, did not go far enough. I have been doing many customized boot installs on my SSD's and I notice I get an 8+GB msg, but then when I do the actual install it comes out at around 5-6GB. That's what I mean by did not go far enough unless they were prohibited from the install due to that msg.
     

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