Quick question asked of how to install ubuntu on top of unbut?

[Arlen Holder]

I'm confused how to proceed.
All I want to do is install Ubuntu on top of Ubuntu (to start fresh).

There's nothing wrong with the Ubuntu except that I'm writing an apnote on
how to interface with iOS devices. For the past couple of days, I have been
experimenting with ifuse and libimobiledevice-utils, where I want to start
fresh on Ubuntu, from scratch to test out the apnote from scratch.

Hence, I just want to install Ubuntu 18.04 on top of the existing 18.04.

What's the best way to go about doing that?
It won't let me pick any disk I want (where I want sda5).

I have 3 HDDs, each with Windows and two with Ubuntu.
<http://img4.imagetitan.com/img.php?image=18_dualboot102.jpg>

Here are some screenshots where I'm not sure what buttons to press:
http://img4.imagetitan.com/img.php?image=18_install01.jpg

Notice it's permanently stuck on SCSI4 which isn't the disk I want to use.
http://img4.imagetitan.com/img.php?image=18_install02.jpg

If I click around haphazardly, I can finally get to sda5:
http://img4.imagetitan.com/img.php?image=18_install03.jpg

Do I format the 40GB sda5 on Ubuntu first? As ext4?

Fundamentally, I have a basic dual boot situation where I just want to
re-install Ubuntu on top of Ubuntu.

I'm confused how to proceed.
Any suggestions?

[Paul]

OK, say we shut down the computer and unplug /dev/sdb and /dev/sdc.

That will leave /dev/sda as the only possible target.

You have a primary left which could be sda3.

When UB1804 was installed, the logical might have filled the extended,
leaving no room for sda6 or sda7 or sda8...

You have to use GParted and arrange things as desired. There might
not be any space to speak of, at the moment. But a partition
probably has some slack ("white space") which you can acquire via
shrinking. Because you've been using the automation, that
pretty well guarantees that work will be needed now.

+-----+-----------------+---------+ - - - - - +-----------------------------+
| MBR | System Reserved | Win10 | | Extended as sda4 |
+-----+-----------------+---------+ - - - - - + - - - - - - - + - - - - - - +
sda1 sda2 | Logical UB1804| |
+---------------+ - - - - - - +
/dev/sda5 /dev/sda?

Once you've fixed that mess ("too much auto is a bad thing"),
you can use the "something else" button in the installer.

In fact, you should probably always be using the "something else"
button, but I suppose that's a matter of taste. Automation
tends to be wasteful, especially when it doesn't know what
your "final plan" is.

On a legacy DOS partitioned disk, the MBR has room for four partitions.
You could make three primaries. And the fourth slot can hold an Extended.
The Extended then has a small amount of info which provides pointers to
the first Logical. And I think the end of one Logical links to the next
or so. You can have a larger number of logicals than Primaries.

But generally, you want to use up the primaries first, create
the extended as sda4, and then all the rest of your partitions
are made out of the "size" of sda4. The way I've drawn it
in the above diagram, I left room for an sda6 for UB1804b .

When you multiboot, you're always taking chances. You *must*
know where critical data (for booting) is stored. If you
erase or format the wrong thing, it stops booting. Then
you need to learn the various boot repair methods.

My best guess right now, is /dev/sda5 contains /boot files
for grub. The grub menu is in there. We can add /dev/sda6
and os_prober and friends will add stuff to the /dev/sda5
boot files. This means, when the install is finished, you
can erase /dev/sda6 later.

If you wanted to delete /dev/sda5 and keep /dev/sda6, then
you know "some" kind of complicated surgery will be required.

Paul

[Arlen Holder]

On 24 Jun 2018 10:41:01 GMT, Paul wrote:

> When you multiboot, you're always taking chances.

Hi Paul,
To let you know what happened, I decided to leave the original dual-boot PC
alone (let's call that PC1 - which is the one that had the RAID turd
files).

I decided today to add Ubuntu to PC2, which is another Windows 10 system
that I have which has been working just fine for a month or so.

Then I tested, with Ubuntu, the iOS apnote that I'm writing, and I figured
out that we really don't need "ifuse" or "libmobiledevice-utils" anymore,
as far as I can tell, unless we desperately want thumbnails when the iOS
device is mounted.

If we don't install ifuse & libimobiledevice-utils (I like to keep things
native, if I can), we have to know a manual trick though, which is to press
"Control+L" while viewing the default iOS mount points, and then we edit
the resulting path (afc://ios-serial-number/DCIM), such that we can then
instantly gain read/write access to the DCIM and Downloads directories on
the iOS device - but I'll write all that up separately.

This note is basically my response to your kind help, which is I decided to
give up and not mess with the dual boot on PC1, and instead, simply set up
dual boot on PC2.

Of course, it's just my luck that something screwed up the dual boot on PC2
such that Grub is locked and will not respond to the keyboard, but that's a
separate issue (as is the apnote on iOS).

This note is to tell you THANK YOU for your help, and to tell you I decided
NOT to try to mess with the PC1 dual boot, and instead, I installed dual
boot on PC2 (which should have been a piece of cake). Sigh.

The PC2 Grub issue is here:
<https://groups.google.com/forum/#!topic/alt.os.linux/yQmtemiHcVk>
Have you ever seen a Grub that wouldn't respond to the keyboard?

[Arlen Holder]

On 2 Jul 2018 03:23:14 GMT, Arlen Holder wrote:

> Then I tested, with Ubuntu, the iOS apnote that I'm writing, and I figured
> out that we really don't need "ifuse" or "libmobiledevice-utils" anymore,
> as far as I can tell, unless we desperately want thumbnails when the iOS
> device is mounted.
>
> If we don't install ifuse & libimobiledevice-utils (I like to keep things
> native, if I can), we have to know a manual trick though, which is to press
> "Control+L" while viewing the default iOS mount points, and then we edit
> the resulting path (afc://ios-serial-number/DCIM), such that we can then
> instantly gain read/write access to the DCIM and Downloads directories on
> the iOS device - but I'll write all that up separately.

I posted the apnote that I have been writing to here for others to benefit.
How to read/write access iOS file systems on Ubuntu/Windows over USB cable
https://groups.google.com/forum/#!topic/alt.os.linux/z_KXY4IHLe0

The one odd thing is that I had to turn off Windows 10 fast startup in
order for Ubuntu to automount Windows 10 in read/write mode. If faststartup
was enabled on Windows 10, Ubuntu automounted the Windows file system as
read only.

[Paul]

Fast Startup uses Hiberfil.sys just like Hibernate does.

https://helpdeskgeek.com/help-desk/hdg-explains-swapfile-sys-hiberfil-sys-and-pagefile-sys-in-windows-8/

The main fear with full "Hibernate" state, is that files are still
open from the session that is Hibernated. That's why mounting the
file system while it is in that state, is not considered to be a
good idea.

If just the kernel is hibernated via Fast Startup, then there's
no state info from a session present. The file system itself
would be put away in a safe state.

Paul

[Arlen Holder]

On 3 Jul 2018 11:58:11 GMT, Paul wrote:

> Fast Startup uses Hiberfil.sys just like Hibernate does.
>
> https://helpdeskgeek.com/help-desk/hdg-explains-swapfile-sys-hiberfil-sys-and-pagefile-sys-in-windows-8/
>
> The main fear with full "Hibernate" state, is that files are still
> open from the session that is Hibernated. That's why mounting the
> file system while it is in that state, is not considered to be a
> good idea.
>
> If just the kernel is hibernated via Fast Startup, then there's
> no state info from a session present. The file system itself
> would be put away in a safe state.

Hi Paul,

Thanks for that inforamtion as it's not intuitive that you have to turn off
the Microsoft fast-startup default in order for Ubuntu to automount Windows
partitions read/write.

It's just strange, in fact.
It took me while to figure this out since there is no error message.

One one of my systems, Ubuntu had automounted Windows read/write.
On the other, Ubuntu had authomounted Windows read only.

I was like, huh? WTF?
Sometimes these things are just not intuitive.

It was the same as with the "Control+L" trick I figured out to change the
automounting of the iOS file system from read only to read/write.

Regarding the hibernation of Windows, it's interesting that Ubuntu can tell
since we boot to Ubuntu, and not to Windows, in Grub. So how the heck does
Ubuntu even *know* that the Windows file system is in a semi hibernation
mode?

------ < Below is a personal message to Paul > -----
BTW, thanks Paul for all your kind help, where, you'll note, I took your
advice to stop trying to shame the trolls in the Q&A threads I care about
coming to an answer (e.g., Lewis, whos is a classic iOS troll just said we
couldn't do exactly what the apnote proves we can do - but I will ignore
him - as per your advice).

The Lewis iOS troll ... about 10 minutes ago:
<https://groups.google.com/d/msg/alt.os.linux/z_KXY4IHLe0/mDW1rzC1CAAJ>

Your advice ... about two days ago:
<http://www.pcbanter.net/showpost.php?p=3759795&postcount=2>

You need to always keep in mind that my Usenet model is different than
most, in that I ask a question and work the thread until the question is
resolved, where the trolls are detrimental to that eventual goal of
arriving at a solution.

In the chit-chat model which many people use, they don't care about a
successful resolution to the thread topic - so trolls aren't as much a
problem in that you can simply not feed them because you don't care if they
ruin a thread.

In the Q&A model, the trolls are more dangerous because they will prevent
you from arriving at a solution if they can - so what you want is to
proactively make it expensive for their egos - which is why I name them -
and you want them to be known - which is why I list their actions.

In the end, as you noted, it's hard to combat the trolls, where, sometimes,
even in a Q&A thread, ignoring them may still be the best solution
(although it's like ignoring melanoma.

[Aragorn]

On Wednesday 04 July 2018 23:17, Arlen Holder conveyed the following to
alt.os.linux...

> On 3 Jul 2018 11:58:11 GMT, Paul wrote:
>
>> Fast Startup uses Hiberfil.sys just like Hibernate does.
>>

>> The main fear with full "Hibernate" state, is that files are still
>> open from the session that is Hibernated. That's why mounting the
>> file system while it is in that state, is not considered to be a
>> good idea.
>>
>> If just the kernel is hibernated via Fast Startup, then there's
>> no state info from a session present. The file system itself
>> would be put away in a safe state.
>

> Regarding the hibernation of Windows, it's interesting that Ubuntu can
> tell since we boot to Ubuntu, and not to Windows, in Grub. So how the
> heck does Ubuntu even *know* that the Windows file system is in a semi
> hibernation mode?

The kernel always checks the integrity of the filesystem that is to be
mounted ─ either at boot time if that was specified in /etc/fstab, or at
mount time if it's not.

If the kernel detects that the filesystem is in an incoherent state,
then it is automatically mounted read-only so as to prevent further
damage. That is, if it can even be mounted at all, of course.
Sometimes the filesystem itself is damaged beyond repair, and then the
kernel will refuse to mount it.

--
With respect,
= Aragorn =

[Arlen Holder]

On 4 Jul 2018 23:05:33 GMT, Aragorn wrote:

> If the kernel detects that the filesystem is in an incoherent state,
> then it is automatically mounted read-only so as to prevent further
> damage.

I think I just ran into this on PC2! :)

Have you ever seen a Grub that wouldn't respond to the keyboard?

<https://groups.google.com/forum/#!topic/alt.os.linux/yQmtemiHcVk>

Thanks for that clarification, as it's pretty "smart" of Ubuntu to check if
the Windows 10 file system is set to "fast start" (which is, as Paul noted,
essentially a hibernated state as noted by the existence of a specific
"hiberfil.sys" file).

> That is, if it can even be mounted at all, of course.
> Sometimes the filesystem itself is damaged beyond repair, and then the
> kernel will refuse to mount it.

Just a few weeks ago, I ran into this on PC1! :)

For example, I think that's why the Ubuntu installation process ignores
disks that have "RAID dung" on them, thinking that it's a "degraded RAID"
when it wasn't RAID at all. :)
Why doesn't Ubuntu 18.04 ask to install next to Windows 10 Pro single HDD as a dual boot?
<https://groups.google.com/forum/#!topic/alt.os.linux/D7E7FQ1NLNk[1-25]>

It's just my luck to run into *both* issues, within weeks of each other!
:)