What's the type of that 'green' space? You can keep that one if you think it contains data. Just delete the two orange partitions and proceed from there, using the available free space (weird white). Instructions are the same so you should be safe.

Kind regards,

Eric

What do you mean what's the type of that green space ?
It's just a color bar whose color is green in the middle.
Then beneath there's a legend saying what the green refers to. In that case, there's no name (the blue is named "windows" and the 2 oranges have names as well). But it is said /dev/sda2 and the disk space is mentioned as well.

If you're in the Prepare partitions window where you delete and add the partitions then in the list below the colored bar you have the partitions listed also. There's a column Type which indicates what type of file system the partition holds. That's what I was referring to. Just keep it for now, you can always check it out later, when installation was successful. Just delete the other partitions and recreate the primary and swap partition as I indicated in my previous post.

Kind regards,

Eric

Oh no I'm not there yet. I told you I was still on the prepare disk space window.
I think (according to my previous attempt) this is the next window.
Shall I select 'specifiy partitions manually (advanced)' and press forward then ?

Euh, yes! I thought you already did that!? Just go ahead and follow the steps indicated in post 149.

Kind regards,

Eric

No I didn't.
Now I'm on step 7 (of 8, another one has been added).

There's a graphical bar as well, with 4 colors : sda1 (ntfs), sda2 (ntfs - this is what you wanted to know i think), sda4 (ext4), sda5 (linux-swap).
The colors are green orange blue green.

Then there's a data grid.
device type mount point format? size used (format is never checked, and moint point is always empty)
/dev/sda
/dev/sda1 ntfs
/dev/sda2 ntfs 100G 3G (not empty, let's not delete it !)
/dev/sda4 ext4 20G 500MB (weird, maybe it's because the installation begun and didn't end)
/dev/sda5 swap 2G 0

options are :
new partition table (cannot click on that) add (cannot click on that) change delete revert
quit back forward
step 7 of 8.

Hi,

That's what I meant, right. Ok, so keep the sda1 and sda2 partitions and perform the steps as I indicated on sda4 and sda5 (click on them and then on the Delete button). And then follow as explained in post 149. Make sure to check the Format box on the ext4 partition you're going to create in the free space. That will take some more time but it'll 'clean up' the partition and hopefully will result in a correct installation.

Kind regards,

Eric

May I ask a quick question : what happens if the memory and swap are full ?
and also, would it be better to have a specific number for the swap space, (like 10^n or 2^n), or does it not matter ?
it is said that the partition sizes are in megabytes (10^6 bytes)

That's likely never to happen if your system is functioning correctly. The first thing you'll notice is that your system will become a lot slower because a lot more read/write operations will be performed to disk. How much RAM do you have?

Kind regards,

Eric

Normally it's advised to have a swap that is twice the amount of your RAM, so if you have 1Gb ram then a swap of 2Gb is advised. However most computers nowadays have 2Gb or more RAM so setting the swap to the same amount is more then enough. I only have 2Gb RAM and swap of 2Gb and haven't encountered problems yet.

Kind regards,

Eric

Ok, thanks. I already knew that the computer would slow down. What I'm wondering is what will actually happen if the swap is full (for example a memory leak would do it I guess ?)
Twice the ram, ok. But 2000 or 2048, or doesn't it matter ?

Wouldn't be able to tell you because haven't encountered that problem yet ;).

AFAIK it doesn't matter if you put 2000 or 2048.

Kind regards,

Eric

I'm going to have to leave for a while. I'll be back in some hours. I'm not touching the computer. Sorry about that. Thanks very much for your help so far, I'll post when I am back.

Ok, no problem, I'll 'see' you when you get back. And you're welcome.

Kind regards,

Eric

To discuss that topic, you should first understand the distinction between "committing" memory and using it. The system normally commits significantly more memory than it uses.

When any process requests use of memory, the kernel must decide whether to commit memory for that request, but it doesn't actually allocate any specific memory at that point. If too much memory has already been committed, the kernel will reject the request, which normally causes the process that made the request to fail.

For various reasons, processes typically use only a fraction of the memory they request. Actual memory is allocated (possibly forcing previously allocated memory out to swap space) only as the process actually uses each 4KB page of memory.

Most systems are configured to allow significant over commit of memory, so as processes use memory that they previously requested, the swap space might fill up and the system might need to push still more pages out to swap and be unable to do so. At that point the "Out of Memory Killer" component of the OS will select and kill some process in order to prevent the whole system from deadlocking.

So the common symptom of filling up ram plus swap is some process will get killed. This usually will not be the process whose recent increase in memory use pushed the system out of memory.

But sometimes the limiting factor will be the commit level, rather than the actual use of memory. So a process will fail when requesting memory, possibly when actual use of memory is far short of full.

In theory, a process could be coded defensively to deal with a failure when requesting memory. So in theory it is better to fail that way than to invoke the out of memory killer. But in practice programs don't deal well enough with memory request failures to show any real benefit. So failing a memory request is just as bad as invoking the out of memory killer.

Partitions are normally allocated in whole cylinders rather than in exactly the number of MB you request. Swap space is used in whole 4KiB blocks. So there is likely a little waste that you can't reasonably control. But disk space is normally cheap enough that you shouldn't care at all about that level of detail.

Deciding on swap partition size is usually a wild guess. The best size depends on the way you will use the system and almost no one knows that level of detail about their intended use of their computer.

The various common rules, such as "twice ram size" for small ram systems, or "2GB is usually enough" for large ram systems, have no real validity. I guess it is easier to follow such a rule than to make a wild guess yourself when you have no real basis for an informed decision.

The amount of swap space you need depends on the memory use of the processes you will be running. You don't know their memory use in advance, so you're stuck guessing.

I think the size and expected use of your disk space should be a bigger factor in making that guess:
If you have a 30GB drive, then selecting a 4GB swap partition when you only needed 1GB would be wasting 10% of your disk drive. If you have a 600GB drive, the same mistake would only be wasting half a percent of the disk drive. I would rather waste half a percent of the disk drive than even think about the question of whether 4GB is too much swap. But I'd rather risk killing some process and then needing to reconfigure the partitioning (once I understand memory use better) than wasting 10% of the disk.

I'm back.
johnsfine, thanks a lot for all this detailed information. Very instructive.

So I'm still in the prepare partitions window.
I made some changes so that it now looks that way :
device type mount point format? size used
/dev/sda
/dev/sda1 ntfs (nothing) (unselected) 50 GB 25 GB
/dev/sda2 ntfs (nothing) (unselected) 100 GB 3 GB
/dev/sda3 ext4 / (selected) 20 GB unknown
/dev/sda5 swap (nothing) (unselected) 4GB unknown

Can I press forward ?

Hello,

I'm almost sure you made a typing error but that's not important. You have all the partitions with sda1 which is impossible :D

Just click on the partition that says ext4 and then on the forward button.

Kind regards,

Eric

oh yes wrong copy/paste. Edited now.
I pressed forward. Back to the who are you window. Forward again ?

Hello and good morning,

If you filled in your details, yes, press Forward.

Kind regards,

Eric

Hello,
good morning :)

It was already filled in from the previous attempt.
I then got the migrate documents window, I pressed forward too.
Now the recapitulation window.

language, keyboard layout,name,login name, location, migration assistant are ok.
then :

if you continue, the changes listed below will be written to the disks.
otherwise, you will be able to make further changes manually

warning : this will destroy all data on any partitions you have removed as well as on the partitions that are going to be formatted.

the partition tables of the following devices are changed :
scsi1 (0,0,0) (sda)

the following partitions are going to be formatted :
partition #3 of scsi1 (0,0,0) sda as ext4
partition #5 of scsi1 (0,0,0) sda as swap


Can I press "install" now ?

Yes, press Install and keep your fingers crossed!

Kind regards,

Eric

Done !! thanks a lot Eric :).
I'm on the desktop.
What now ?

So it installed correctly this time? Great news, I'm pleased to hear that.

Now reboot the normal way, clicking your name top right of the screen and restart. See if you can boot normally and if Ubuntu starts up correctly without any errors.

Kind regards,

Eric

Yes it's starting normally.
I didn't notice any errors.
There are quite a lot of things that need to be installed now, I'm waiting for your instructions (you said yesterday that there were procedures to do once the installation is complete so that the next reinstallation would be easier).
There is no admin user at the moment, I'm not sure I have the admin rights but I think it's safer not to.
Maybe I can remake a packages.txt so that we can compare ?

Hi,

Good, the first thing to do is update your basic system to the latest version of the installed packages.

Normally your user is in the sudoers group which means you can do system maintenance. We'll know soon enough.

Go to System - Administration - Update Manager and start it. Click on Check to see if updates are available. Your system will prompt you for your password. Type it in and then OK.

When all is done, click on the button Install updates if any updates are listed in the window.

Kind regards,

Eric

Don't I need to set up my internet connection first ? :)
I know how to do that, but I have a small question. I'm using a secure one. I was wondering if there was a way to type the password in an encrypted way, because if I type it just like that it can be accessed in the internet options.

I thought you already were connected to the internet, sorry :D

Of course you need to be connected to the internet first in order to check for updates.

I'm not sure what you mean with 'type the password in an encrypted way'. And what do you mean by accessing the password in the internet options?

Normally you set up a connection using the network manager in Ubuntu. That one takes care of encrypting the password when communicating with your device. Can you tell me how you usually connect to the internet? Using wireless or cable? Do you have a DSL connection or other?

Kind regards,

Eric

wireless. There's an icon in the panel where I can choose my network. It then opens a window called wireless network authentification required.
I can type my password here.
If I do though, and then right click on the icon, then edit connections, then wireless, then the name of my connection, then a window appears intitled 'allow access' : allow application access to keyring ? The application 'nm-connection-editor (usr bin nm-connection editor) wants to acces the password for 'network secret for myconnection in the default keyring. If I (or someone else than me) then press 'allow once' and then go to 'wireless security' and 'show password', the password is visible, even though no admin password was asked during the whole procedure.

Hello,

I'm afraid someone else with more knowledge on Ubuntu has to kick in on that one. Normally I would say that your password is encrypted and only available to you. Of course if you leave your computer with a session open then anyone can get access to your password while you're away. If you lock your screen then they'd have to know your user password.

I'm not sure but I think that the connections are configured on per user basis, so if you create another user, he'll have to go through the same process to connect to your router. That new user will not have access to your data (unless if you put him in the sudoers group, then he can gain access).

Kind regards,

Eric

Ok nevermind let's proceed. I'm going to create a new thread because this one is becoming quite long, and the main problem has been fixed. Thanks a lot for your help Eric, and all the others too :).

Hi elishac,

OK, sounds like a good idea to keep the procedures separated. You're welcome, I'm glad to be of assistance.

Kind regards,

Eric

Don't forget to mark this thread as solved, since your Ubuntu starts up correctly again, I imagine this part is indeed solved.

Kind regards,

Eric