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-   -   linux doesn't start. (https://www.linuxquestions.org/questions/linux-newbie-8/linux-doesnt-start-787581/)

EricTRA 02-27-2010 10:13 AM

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

elishac 02-27-2010 10:24 AM

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.

EricTRA 02-27-2010 10:27 AM

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

elishac 02-27-2010 10:32 AM

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 ?

EricTRA 02-27-2010 10:34 AM

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

Kind regards,

Eric

elishac 02-27-2010 10:43 AM

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.

EricTRA 02-27-2010 10:47 AM

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

elishac 02-27-2010 10:51 AM

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)

EricTRA 02-27-2010 10:54 AM

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

EricTRA 02-27-2010 10:56 AM

Quote:

Originally Posted by elishac (Post 3879063)
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 ?

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

elishac 02-27-2010 11:01 AM

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 ?

EricTRA 02-27-2010 11:10 AM

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

elishac 02-27-2010 11:11 AM

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.

EricTRA 02-27-2010 11:15 AM

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

Kind regards,

Eric

johnsfine 02-27-2010 11:31 AM

Quote:

Originally Posted by elishac (Post 3879063)
May I ask a quick question : what happens if the memory and swap are full ?

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.

Quote:

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)
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.


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