Win 8, Mint 13 Mate pitfalls using 2 hard drives?

[rv7charlie]

I've been wandering around the interweb looking for info on dual booting Win8 & Mint. The biggest thing I've noticed is issues with Win8 taking over UEFI & killing access to other operating systems. (It's been so long since I paid attention, I had to look up 'UEFI'.) So here's my question:

I have a spare hard drive that I'm willing to waste on the Win8 install. Hopefully, Win8 will see only very rare use. I'm happy to use the (current version of) BIOS to select preferred boot device on the rare occasion that I need to start Win8, if that's still possible with Win8 & EUFI.

I'd like to temporarily disconnect my Mint hard drive, install Win8 on the currently empty remaining hard drive, and then use the BIOS (UEFI) to select which system to boot. Will the plan work?

Thanks,

Charlie

[srs5694]

I recommend against that plan. The problem is that, if you're booting in EFI mode, the firmware keeps track of boot options in NVRAM entries. When you disconnect one drive and boot the computer, some EFI implementations notice that the NVRAM contains invalid entries and "helpfully" removes them. Thus, the act of disconnecting one disk after installing an OS on it will make that OS unbootable, at least until you restore the NVRAM entries from a boot of another disk or install a boot manager that auto-detects boot loaders or maintains its own list in some other way.

Instead, just plug both disks in, install Windows, and then install Mint. Ideally, this will work correctly the first time just as it would on a BIOS-based computer. Unfortunately, this ideal isn't always met. There are a number of potential pitfalls that can make things go wrong. The most important of these is the boot mode. Most modern EFI PCs support booting in EFI mode or in BIOS mode. The trouble is that installing Windows in one mode and Linux in the other mode will create headaches, so it's important that you install them both in the same mode. I'm not sure which mode Windows is using during installation, but you can tell which mode it did use after the fact by examining the partition table. If it's an MBR partition table, the install is in BIOS mode; if the disk uses GPT, Windows was installed in EFI mode. You should then be sure that Linux uses the same mode when you install it. This you can check by dropping to a shell and looking for a directory called /sys/firmware/efi. If that directory is present, then Linux is booted in EFI mode; if it's not present, then you've probably booted in BIOS mode. You can read more on this topic here.

The boot mode of the installer is controlled by firmware policy and settings. Unfortunately, the user-accessible settings vary greatly from one computer to another, so I can't tell you precisely how to force an installation disc to boot in BIOS mode vs. EFI mode. If you want to select one mode or the other, you'll just have to check out your firmware settings yourself.

You can use either BIOS mode or EFI mode; either will work. If you're comfortable with BIOS boot loaders, you might want to favor BIOS mode. EFI mode offers some advantages over BIOS mode, but they're pretty minor right now. (They may become more significant in the future, though.) The biggest advantage right now is that many of the newest EFIs have a "fast boot" mode that can shave a few seconds off the boot time. Another advantage is that it's easier to set up and maintain multiple boot managers or boot loaders, which can be useful if you want to experiment with this class of software.

[rv7charlie]

Bummer. I'm already running Mint 13 Mate on the computer (manual drive configuration with separate home partition). I bought MS' special deal on Win8 last month so I could continue to use software I'm more or less locked into, like the tax prep software I've been using for many years.

Assuming that this computer can use BIOS mode, would it be feasible to use BIOS mode to load Win8 & not need to re-install Mint? Or am I stuck with starting over?

Thanks for the help,

Charlie

[srs5694]

I presented the case of installing Windows first simply because you didn't mention an existing installation, so I assumed (incorrectly) that the computer had no OS installed. Given that Linux is already set up, I recommend you partition your new disk using the partition table type (MBR or GPT) suitable for your current Linux boot mode (BIOS or EFI, respectively). Also, change the type codes of your Linux filesystem partitions, as described here, to make it less likely that the Windows installer will mess with them. You can then try installing Windows. One of two things is likely to happen when you do this:

• The installer will refuse to install because the boot mode (BIOS or EFI) won't match the disk's partition table type (MBR or GPT). In this case, you can try again but use whatever options your firmware provides to control the installation medium's boot mode, and with any luck get it working....
• The installer will do its job and you'll end up with a system that boots Windows but not Linux. You'll be able to restore Linux to bootability by booting a Linux emergency disc in EFI mode and using the "efibootmgr" utility and its -o option to set the order in which boot loaders are used; or you could install another boot loader of your choice from Windows to gain access to Linux. (See this page for a summary of options.)

Of course, you should be careful when dealing with the installer that it not touch your Linux partitions. Once you learn the basics of the efibootmgr utility in Linux, restoring GRUB as the default boot loader is actually easier than it is on a BIOS-based computer. You'll also want to add Windows to GRUB's menu by using "update-grub" once you've got Linux booting again.

[rv7charlie]

Thanks; I'll read through the links you posted & give it a shot.