Three Questions Concerning Booting From USB

Question

(i) In order to be able to boot from USB, the USB has to be modified in advance, as I understand it. Also, all data will be erased from the USB drive. Therefore, I want to know: After being able to boot from USB flash drive, can I just use my USB flash drive as usual, if there is enough storage?

(ii) Is a USB flash drive with 1.85 GB enough? Online, I read about recommendations of 2 GB flash drives ... Please note that I would probably to experiment with Ubuntu 18.04 first.

EDIT: Thanks so far for your answers! After having searched, I now found my 500 GB external Intenso-hard-disk. Ca it be recommended making a ful install (not just a LIVE USB drive) with a 500 GB hard disk? I mean at some point in the future, I might still want to use it as usually.

(iii) If booting from USB, can I also save files in Ubuntu or will those be erased every time I restart my laptop?

Currently, I am still using Windows 10.

Thanks in advance!

If you're asking how to try Ubuntu before committing to installing it, you build a Ubuntu Live DVD/USB. Whatever was on the USB will be gone after you make it into a Live USB. You can't save files on a Live USB. I'd recommend at least a 4G USB drive. — heynnema, Mar 09 '20 at 22:10
Re Edit: I have a 4TB hard disk with a 100GB Ubuntu partition on it. The other partition on this disk is NTFS which I share with Windows which is on a SSD. Internal or external HDD makes little difference. — C.S.Cameron, Mar 10 '20 at 09:06
@user68186 How would that work? A link would be appreciated. — Anonymous5638, Mar 10 '20 at 18:06
Does this answer your question? How to make a live Ubuntu 18.04 USB with a persistent storage of more than 4GB — karel, Mar 11 '20 at 01:12

score 1 · Answer 1 · answered Mar 09 '20 at 22:19

(i) The Ubuntu LiveUSB houses a READ-ONLY filesystem. All changes you make will be lost at restart. An additional read-write partition for persistent data storage is fairly easy to create, but you will need a larger USB drive.

(ii) Some versions of Ubuntu will fit under 1.85GB, others will not. See http://cdimage.ubuntu.com for the options and sizes. Advice: Get a slightly larger USB stick, and try the 19.10 Ubuntu Desktop image (2.3GB).

(iii) See (i).

There are many convenient ways to try Ubuntu. If you are using older hardware, than a lighter flavor might be more appropriate. If you are using newer hardware, booting the .iso in a Virtual Machine might be simpler than mucking about with USB drives. Ubuntu, like Windows, rewards the resources that you let if have - more resources means a smoother experience.

Actually, I am right now writing this post from a VM with Ubuntu 18.04, the only thing that really distresses me is the window size ... — Anonymous5638, Mar 10 '20 at 07:52

score 1 · Answer 2 · answered Mar 10 '20 at 04:47

Full Install USB

A 1.85GB drive will not be large enough to experiment with and save from boot to boot. Last time I checked a 2GB flash drive was as expensive as some 16GB drives. A Full install will fit easily onto a 16GB drive and have plenty of room for saving downloaded programs, data and settings.

Comparison between Persistent and Full install USB

Advantages of a persistent install:

1) You can use the persistent pendrive to install Ubuntu to another computer.

2) A persistent install takes up less space on the pendrive.

3) You can reset the pendrive by overwriting the old casper-rw file with a new one.

4) The install to pendrive takes less time.

Advantages of a Full install:

1) You can update and upgrade.

2) If you have problems or wish to modify, the solution is the same as with an internal install, (You can ask for help in these forums).

3) No ugly startup / install screen.

4) Better security, you can use full encryption

5) You can use proprietary drivers.

6) Hibernation works.

7) A persistent install is limited to a 4GB casper-rw and a 4GB home-rw persistence file, to get more persistence requires persistence partitions. Once casper-rw is full, the drive will not boot.

8) Faster boot.

9) You can run VBox and use virtual machines.

Note that once booted, both methods run at about the same speed.

Full Install Methods

Here are two methods for creating Full install pendrives: How to make a live Ubuntu 18.04 USB with a persistent storage of more than 4GB and How to fully install Ubuntu on USB Flashdrive?

score 1 · Answer 3 · answered Mar 10 '20 at 08:09

(i) In order to be able to boot from USB, the USB has to be modified in advance, as I understand it. Also, all data will be erased from the USB drive. Therefore, I want to know: After being able to boot from USB flash drive, can I just use my USB flash drive as usual, if there is enough storage?

In Windows there are several good tools to create an Ubuntu USB boot drive. The officially recommended tool is Rufus.

It is probably best to restore the USB drive to a standard storage device after you have used it to [try and] install Ubuntu.

If you want something more advanced, you can also create a persistent live system or an installed system in the USB drive. This is more advanced and maybe not the first thing to do, if you have no previous experience of Ubuntu.

(ii) Is a USB flash drive with 1.85 GB enough? Online, I read about recommendations of 2 GB flash drives ... Please note that I would probably to experiment with Ubuntu 18.04 first.

No, you need a 4 GB USB drive for Ubuntu 18.04.x LTS. But you can use your small USB drive for the light-weight Ubuntu family flavours Lubuntu or Xubuntu 18.04.x LTS or 19.10.

(iii) If booting from USB, can I also save files in Ubuntu or will those be erased every time I restart my laptop?

You can not save files in a standard live (live-only) Ubuntu system, but you can save files in a persistent live system and an installed system (installed in a USB drive like into an internal drive as described in my link above and in the answer by C.S.Cameron).

Three Questions Concerning Booting From USB

3 Answers3

Full Install USB