[Novalug] linux fundamentals: partitions

Mark Smith mark@winksmith.com
Mon Mar 9 18:39:09 EDT 2015


On Mon, Mar 09, 2015 at 06:34:38PM -0400, Jon LaBadie via Novalug wrote:
> On Mon, Mar 09, 2015 at 04:32:20PM -0400, Derek LaHousse via Novalug wrote:
> > A few details from my knowledge:
> > 
> > Partition table: MSDOS
> > 1st 512: MBR.  Contains the first code executed by the system after
> > BIOS jumps to it.
> > http://en.wikipedia.org/wiki/Master_boot_record#Sector_layout
> > Next 63 sectors: wasted.  So bootloaders could embed here, but there
> > may be other things which use this as storage.
> > Another table at the start of the partition, identified by the
> > pointers in the MBR, is the partition boot record.
> > 
> > In a GUID partition table, those next sectors are used.  So, GRUB
> > can't embed there.  You need a "BIOS" partition type on a GPT disk.
> > Alternately, you need an EFI partition type, formatted with FAT, to
> > boot from UEFI 2.0.  Apple is different.
> > 
> > 
> > So, yes, you could write an ext filesystem directly to /dev/sda.  But
> > you will rue the day you make that decision.
> 
> Over the years I have done that several times.  What problems should I
> have encountered?

i've never rued those times either :-)

i never boot off of those disks so it's not an issue.  i have rued not
using volume management, but that's a separate issue.

-- 
Hei konā mai
Mark Smith
mark@winksmith.com



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