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Old 14th July 2014
cravuhaw2C cravuhaw2C is offline
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Join Date: Jul 2014
Posts: 45

Originally Posted by jggimi View Post
From the table you provided above, you have four primary partitions:
Originally Posted by jggimi View Post
  1. Partition 0, type 83 (linux files), 58,591,232 512-byte sectors, or 28,609 Megabytes.
  2. Partition 1, type 83 (linux files), 87,889,920 512-byte sectors, or 42,915 Megabytes.
  3. Partition 2 - empty
  4. Partition 3 - empty
My SSD was first partitioned when I was installing Ubuntu. I partitioned /dev/sda1 with 30 GB, /dev/sda2 with 45 GB and remaining was unpartitioned, that is free space.

Using OpenBSD's terminology, partition 0 would correspond to /dev/sda1 and partition 1 to /dev/sda2. Based on this assumption, how did partition 0 end up with only 27.94 GB (28,609 MB divided by 1024 MB = 27.94 GB) ?

and partition 1 yields 41.91 GB (42,915 MB divided by 1024 MB = 41.91 MB) ?

Why is there such a great difference in calculating partition sizes using Ubuntu and OpenBSD? Either the calculation method used by Ubuntu or OpenBSD is correct, but not both.

I don't understand how you arrived at 512-byte sectors. You see:
58,591,232 divided by 28,609 gives 2048-byte sectors, no?

Originally Posted by jggimi View Post

5. Having previously done some calculations, begin your OpenBSD MBR partition at sector 146496735, which happens to be the first sector (if I've done the math right, and I may not have) of Cylinder 9119: the address Cylinder 9119 / Head 0 / Sector 1 for the "geometry" indicated by your MBR. These geometries have been virtual, and meaningless for everything except BIOS programs, for decades. But generally, MBR partitions should begin on Cylinder boundaries to prevent BIOS boot issues.

Am I right to assume you were referring to partition 2 that corresponds to id #2? If yes, shouldn't I start on Cylinder 9118 and not 9119?

Using C/H/S method, shouldn't the starting values be 9118 /40 /11?

If using LBA method, how did you arrive at sector

Special note: I appreciate all that you have done for me thus far and also for writing lengthy explanations for the questions that I asked. If anyone is to be the face of OpenBSD, I would nominate you for you have shown that you are able to interface with the public and help guide novice users. Your job title at OpenBSD should be "official ambassador".
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