1

The usb ubuntu bootable made from an ISO is also a live image if you click "try ubuntu". If I do some stuff in the terminal for example, does it get recorder in any way in the USB stick?

I think that it could mount some part of the USB as a temporary partition, I don't know. Or does it use RAM only for that?

Guerlando OCs
  • 863
  • 10
  • 51
  • 88
  • The live system is a RO squashfs image, where all writes are COW (copy on write) & stored in RAM. You've not given any specifics (architecture; ISO, release etc) nor details as to if persistence is involved (where it writes to a different partition on the media) but with rare exceptions (usually daily or dev images) no change is made to the RO media intentionally (exceptions I'm thinking of were bugs, which got reported, & fixed as boot process was altered during some cycles). – guiverc Nov 03 '21 at 02:15
  • The exception I mentioned in prior comment was specific dailies in specific dev cycles; where the daily ISO could only be booted a single time due to changes being written to media (you needed to re-write ISO to thumb-drive to boot it again)... I'm convinced that won't apply to any released ISO, but only alpha dailies during the testing phase of changes.. If you want to save changes; you can use persistence (which uses another part of your thumb-drive for the changes/additional packages you install etc). It's still not the same as an installed system though. – guiverc Nov 03 '21 at 02:19

1 Answers1

0

Live, Persistent or Full install to USB

A Live install to USB does not record any data to either the USB or internal disk. All new information for the session is temporarily recorded in RAM and deleted when the computer is shut down.

A Persistent Live install to USB includes a overlay layer in the form of Persistent file(s) or partition(s) (named writable, casper-rw or home-rw). These files or partitions store any changes to the filesystem or home directory between sessions. Persistent files or partitions can be located on the USB or on the internal drive.

A Full install to USB stores information to the USB the same as a Full install to the internal disk stores info to that disk.

Etcher, dd, Disks, and Startup Disk Creator create Live only systems. Unetbootin, YUMI, Universal and Ventoy use a file to store persistence. Rufus and mkusb will create persistent partitions.

A Live USB will use any swap file that it can find on the computer. this will temporarily store the data from RAM. Hibernation can be installed to a Persistent USB but not to a Live USB.

C.S.Cameron
  • 19,519
  • got confused with the last paragraph. What is a live install to usb? is it the dd thing? – Guerlando OCs Nov 03 '21 at 11:46
  • By live install to USB, I mean a live install without persistence. such as Etcher, dd, Disks or Startup Disk Creator makes. Sometimes this is called a clone. – C.S.Cameron Nov 03 '21 at 13:16
  • If the usage of the swap file on the harddrive bothers you, then you really need to reword your question as in: "Does the live stick leave any evidence on the swap-file of the system. If yes, how can I avoid that". Voting to leave it closed for now. – MadMike Nov 04 '21 at 07:29