Thread: Do I really need to recompile ORBit2?

Originally Posted by Jesdisciple

When should extended versus primary partitions be used?

You cannot boot an extended partition, so don't put / there.

According to https://help.ubuntu.com/community/SwapFaq the swap partition should be at least 999MB (my RAM) because I do sometimes hibernate, so here's my new arrangement:

80GB
home (ext4): 10
Ubuntu 1 (ext4): 21 + 2.1 = 23.1
Ubuntu 2 (ext4): 21 + 2.1 = 23.1
Windows XP (NTFS): 21 + 1.4 = 22.4
shared data (NTFS):0.4
swap (ext4): 1

I tried to accomplish this in fdisk, but I'm confused with the cylinders. Must each whole cylinder be assigned to one partition? The sum of the cylinders is less than 80GB; where did the rest go?

Code:

Command (m for help): p

Disk /dev/sda: 80.0 GB, 80026361856 bytes
255 heads, 63 sectors/track, 9729 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0xf404143b

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *           1        9355    75144006   83  Linux
/dev/sda2            9356        9729     3004155    5  Extended
/dev/sda5            9356        9729     3004123+  82  Linux swap / Solaris

Thanks.

Originally Posted by Jesdisciple

I tried to accomplish this in fdisk, but I'm confused with the cylinders. Must each whole cylinder be assigned to one partition? The sum of the cylinders is less than 80GB; where did the rest go?

It will use the cylinder boundaries, yes. As to that second question, I think you have misinterpreted something -- the fdisk output in your post is not missing anything.

[edit] a few of megs (less than 0.1%) is normal, i guess matsp's got the explanation. I think "80 GigaBytes" is a fair approximation by the manufacturer.

You have 78148161 blocks, 1KB each -> 80023716864 bytes. That means you are "missing" 2644992 bytes. Which I'm pretty sure you won't notice.

The difference PROBABLY comes from the difference between ACTUAL sector/head/cylinders and the BIOS-friendly 63/255/16065 CHS numbers. This must be used because of bitfields in the BIOS not allowing more than 63 sectors - bad design, the BIOS should just be given a sector number for which 512 byte block the disk is supposed to read, rather than the BIOS needing to be given the sector, head, cylinder numbers - the BIOS should be doing that conversion. But so be it.

--
Mats

Originally Posted by MK27

It will use the cylinder boundaries, yes.

Then that means I have to calculate the number of cylinders from that of MB, right? Either I'm being dense about the conversion factor or something's messed up in fdisk. EDIT: Yup, I was being dense. I'll explain in my next post.

9729 cylinders (1 cylinder = 8225280 / 1024 ^ 3 = 0.007660389 GB).
home (ext4): 10 / 80 / 0.007660389 = 16.317709192
Ubuntu 1 (ext4): (21 + 2.1 = 23.1) / 80 / 0.007660389 = 37.693908497
Ubuntu 2 (ext4): (21 + 2.1 = 23.1) / 80 / 0.007660389 = 37.693908497
Windows XP (NTFS): (21 + 1.4 = 22.4) / 80 / 0.007660389 = 36.551668845
shared data (NTFS): 0.4 / 80 / 0.007660389 = 0.652708368
swap (ext4): 1 / 80 / 0.007660389 = 1.631770919

Originally Posted by MK27

As to that second question, I think you have misinterpreted something -- the fdisk output in your post is not missing anything.

9729 cylinders with 8225280 bytes each:
9729 * 8225280 = 80023749120
80026361856 - 80023749120 = 2612736

That is still less than one in 10000 bytes on your disk. And I think it's as I explained above (you got a slightly different number than I did, but it's close enough).

--
Mats

You don't have to do math for this. I believe fdisk allows you to input in Gb -- but again, the table produced will adhere to cylinder boundaries and hence if you ask for 20.0 Gb, you will get something pretty close to that.

You can play around with fdisk, you know. Create the table and change it -- nothing is done until you choose "w".

I've never used NTFS with linux.

Originally Posted by Jesdisciple

I can't find any way to input Gb/GB; the closest I see is the 'u' command which uses sectors instead of cylinders.

The fdisk 'l' (lower L) command hints that NTFS is possible, but I don't see any companion commands...

You haven't even tried to add an entry yet. Go ahead. It does not write *anything* to disk unless you choose 'w'. You can make up a whole table then quit, and it will be like fdisk never happened.

When you create a partition, you choose a starting sector. Always use the default, unless you want to leave a gap for some reason. Which you don't. Then you can choose the ending sector, but specified in +Gb.

u is just for changing the display units of the table, not for selecting the units of your input.

After you create a partition (but before you 'w'rite the table to disk) you can change a partition type ('t'). That is how you set the type. But you have to create a table entry first.

Never mind about waiting till tomorrow... When I tried to extract my archive with tar -xpPf it gave errors about insufficient space in the device. EDIT: Does it matter that the archive was at / and included /home (so the contents would have crossed partitions)?

Command (m for help): p

Disk /dev/sda: 80.0 GB, 80026361856 bytes
255 heads, 63 sectors/track, 9729 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x00025eb6

Device Boot Start End Blocks Id System
/dev/sda1 * 1 2809 22563261 83 Linux
/dev/sda2 2810 5618 22563292+ 83 Linux
/dev/sda3 5619 8343 21888562+ 83 Linux
/dev/sda4 8344 9729 11133045 5 Extended
/dev/sda5 8344 9559 9767488+ 83 Linux
/dev/sda6 9560 9681 979933+ 82 Linux swap / Solaris
/dev/sda7 9682 9729 385528+ 83 Linux

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