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hubs

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creating a swap-file on a computer - a stepwise HowTo

i have a very very old notebook a Thinkpad t530

and i need to do some clever steps to get a ubuntu (or other linux flavour ) up and running. Well i have heard that swap-files may help here.

so idid some digging into the topic. but to make sure i am doing right - have written down all the things i have read. So plz correct me if i have learned any thing wrong. I want you to give me hints and to correct me if i am doing wrong in creating a swap file.

and yes: this may be a help for others too. i hope so at least.
BTW: i am so happy about this awesome forum here:

A swap file is a type of swap memory for Computers.

Well a swap file is in the form of a computer file on an HDD or SSD that serves as an extension to physical memory (RAM). It is a good thing.
A machine uses a swap file to store data from RAM that is temporarily inactive - and we can also say - that is not used.
The so called swapping process frees lots of memory - so called up RAM space: How does this work?
Well frankly it works by moving infrequently used data in RAM to a so called swap file - and this is generally spoken a good thing.

Swap files are a special case of virtual memory management: i like this very much. Swap-files serve as a kind of - lemme say fallback mechanism in the computer.

we can say that the swap space has significantly less speed (some friends of myne say a so called slower access times) than RAM.

how to deal with swap-files - well thats the quesion: how to create one swap-file:

The free command with the -h tag shows us the total, available, and used swap space in our computer:

free -h

The /proc/meminfo file . it is another form to show the total, free, and used swap space in human readalbe format - here in kilobytes:

cat /proc/meminfo | grep Swap

explanation: The /proc/swaps file shows active swap devices:

cat /proc/swaps

but there is more: The swapon command is a very very cool command with the --show tag displays swap information:

swapon --show

well there is even more: We can use swap-investigations on a linux machine: I will show some more commmands on terminal

How to View a Swap File on Linux:
To view the contents of a swap file, use the strings command and save the contents to another file. For example:

sudo strings <some kind of a swap file path> > <some kind of a output file path>.txt

How can i create a new Swap File on my Linux notebook?

well i think that reating a swap file on Linux is a pretty simple process: That said i think i have to do like so: to make a new swap file on a Linux system.

1. i have to create some kind of Storage File
therefore i have to make use the dd tool to create a new storage file. For example:

like so

sudo dd if=/dev/zero of=/swapfile bs=2MB count=1024

note: we could have used every (!) other value. This is only a simple example. Yes it is.

The command contains the following parameters:

if=/dev/zero is the input file. The /dev/zero

file is a kind of a very special file that returns as many (awful many) null characters as a read operation requests.
of=/swapfile is the output swap storage file. The common practice is to place the file in the root directory.
The bs parameter is the block size.: it is damned important
The count parameter determines how many blocks to copy. I often use this command. The total data size is bs*count, which in this case is 2GB. But well, we could use every other value. Believe me. We could.

and now its pretty important to set the Swap Permissions; but how!? can i set the swap file permissions for the swap file to the user root read and write.

well can i do make use the following command:

sudo chmod 600 /swapfile

The command shows - afaik no output. Check the permissions with the following:

ls / | grep swapfile

swap file permissions - well this is pretty important. We need to do this extra step: but wait: how to do this!? well how to changing the permissions to root helps avoid accidental overwriting.

3. Set Up Swap Area

that said - we have to take care for the rest of the conditions: The swap file requires some kind of formatting the reserved file size into a so called swap area. This step is pretty important. Here we prefer to make use of the so called mkswap command to format the swap file:

sudo mkswap /swapfile

The command formats the swap file into a swap space and outputs the size, label, and UUID.

4. Enable Swap
To enable the swap area for use, run the following command:

sudo swapon /swapfile

Verify the swap is active with the following command:

swapon --show

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