add instructions for VM raw image

Author: fedelibre

README.md

@@ -1,16 +1,61 @@
 # LilyDevOS
 
-This repository is meant to *become* an alternative to
+This repository is meant to be an alternative to
 [LilyDev](https://github.com/fedelibre/LilyDev).
 
-Currently it provides just a container which can be run only on Linux hosts.
-Next step will be building images which include a desktop environment and
-can be loaded on virtual machine software on Mac and Windows.
+It provides two different options: a lightweight container for Linux hosts
+only and a full VM image for all operating systems.
 
 
-## How to use the images released
+## How to use the images
 
-Requirements: Linux host, systemd-nspawn.
+### Full virtual machine
+
+Runs on: any OS with a Virtual Machine software.
+
+Download the latest [release](https://github.com/fedelibre/LilyDevOS/releases).
+The image built for being emulated on VM software has a `-vm` suffix.
+
+You must first decompress the zip archive.  Then you can verify the integrity
+of the data comparing the hash in the SHA256SUMS file with the output of
+this command (in Linux):
+
+    sha256sum lilydevos-vm-VERSION.raw
+
+In Linux there are several VM GUI managers, like Virt Manager or Gnome Boxes.
+But you can also use the command line.  Something like this should work (tested
+on Fedora):
+
+    qemu-kvm -m 512 -smp 2 -bios /usr/share/edk2/ovmf/OVMF_CODE.fd -drive format=raw,file=lilydevos-vm-VERSION.raw
+
+512M of RAM *should* be enough, as the image contains also a swap partition
+of 2G.  If you can assign 1024M, even better.
+In case you see some weird error while compiling lilypond, your guest might be
+running out of memory (check the RAM available with the command `free -m`)
+and you should try assigning more RAM to the virtual machine.
+
+You'll log in as `dev` user (the password is `lilypond`).
+
+Desktop preferences suggestions:
+
+- Disable the screensaver: click on the menu icon on the bottom left, then
+on *Preferences»Monitor settings*; in the Mode dropdown menu choose
+*Disable Screen Saver*.
+
+- Change keybord layout from default US (american) to your national layout in
+*Preferences»Keyboard and Mouse»Keyboard Layout*; add your layout and
+then move it up to the list so it will be the default.
+
+
+### Container
+
+Runs on: Linux only.
+Requirements: systemd.
+
+It's the best choice if you want to run LilyDevOS in a Linux host: lightweight,
+full access to host system resource (including RAM), easy access from host
+to guest file system through the file manager (so no need to set up shared
+folders).
 
 Download the latest [release](https://github.com/fedelibre/LilyDevOS/releases).
 You need root privileges to extract the content, so you'd better do it on
@@ -32,7 +77,7 @@ the regular user `dev`, go to the home directory and run the setup.sh script:
 You are now ready to start contributing to LilyPond.
 
 Remember that `dev` user can get root privileges with `sudo` (even if you
-should not need it).
+should not need it). The password is `lilypond`.
 
 There's a good chance that your user in the Linux host and the `dev` user
 in the container have the same uid (probably 1000, use the command `id`
@@ -57,5 +102,5 @@ Usage is printed with this command:
 
     mkosi --help
 
-The command used to build LilyDevOS is in the Makefile.
+The commands used to build the images are in the Makefile.