FreeBSD libretro cores

, 23/01/2020 | Source: Daniel Menelkir

I've made a gitlab repository with libretro cores to be used with retroarch (no, don't use the ancient one in ports, use at least this one from here). All you need to do is point core_updater_buildbot_cores_url in your ~/.config/retroarch/retroarch.cfg to "".

BTRFS filesystem full, now what?

, 28/12/2019 | Source: Daniel Menelkir

The mileage may vary, but I try to update this post.

Is your filesystem really full? Mis-balanced metadata and/or data chunks

Below, you'll see how to rebalance data blocks and metadata, and you are unlucky enough to get a filesystem full error before you balance, try running this first:
# btrfs balance start -musage=0 /path
# btrfs balance start -dusage=0 /path
A null rebalance will help in some cases, if not read on.
Also, if you are really unlucky, you might get in a no more space error that requires adding a temporary block device to your filesystem to allow balance to run. See below for details.

Pre-emptively rebalancing your filesystem

In an ideal world, btrfs would do this for you, but it does not. I personally recommend you do a rebalance weekly or nightly as part of of a btrfs scrub cron job. See the btrfs-scrub script.

Is your filesystem really full? Misbalanced metadata

Unfortunately btrfs has another failure case where the metadata space can fill up. When this happens, even though you have data space left, no new files will be writeable.
In the example below, you can see Metadata DUP 9.5GB out of 10GB. Btrfs keeps 0.5GB for itself, so in the case above, metadata is full and prevents new writes.
One suggested way is to force a full rebalance, and in the example below you can see metadata goes back down to 7.39GB after it's done. Yes, there again, it would be nice if btrfs did this on its own. It will one day (some if it is now in 3.18).
Sometimes, just using -dusage=0 is enough to rebalance metadata (this is now done automatically in 3.18 and above), but if it's not enough, you'll have to increase the number.
# btrfs fi df .
Data, single: total=800.42GiB, used=636.91GiB
System, DUP: total=8.00MiB, used=92.00KiB
System, single: total=4.00MiB, used=0.00
Metadata, DUP: total=10.00GiB, used=9.50GiB
Metadata, single: total=8.00MiB, used=0.00

legolas:/mnt/btrfs_pool2# btrfs balance start -v -dusage=0 /mnt/btrfs_pool2
Dumping filters: flags 0x1, state 0x0, force is off
DATA (flags 0x2): balancing, usage=0
Done, had to relocate 91 out of 823 chunks

legolas:/mnt/btrfs_pool2# btrfs fi df .
Data, single: total=709.01GiB, used=603.85GiB
System, DUP: total=8.00MiB, used=88.00KiB
System, single: total=4.00MiB, used=0.00
Metadata, DUP: total=10.00GiB, used=7.39GiB
Metadata, single: total=8.00MiB, used=0.00

Are you using space_cache?

Probably you've maded a massive copy like a Tb copy with features like space_cache enabled. While space_cache is nice and accelerate things up, you'll probably need to empty this cache. It's easier than you think:

# mount -o remount,clear_cache
# sync
# reboot 

Porteus Linux: A portable Linux with a difference

, 22/11/2019 | Source: Fitzcarraldo's Blog

I’m writing this in Porteus Linux v5.0rc1 for x86_64, a Live Linux distribution booted from a USB pendrive. It is fast, good-looking and has a good range of applications and utilities. I stumbled upon Porteus recently while looking for a compact Live Linux distribution to install on a couple of spare SD cards. It seemed […]

Installing and using NeXT OPENSTEP in VirtualBox for Linux

, 12/11/2019 | Source: Fitzcarraldo's Blog

Introduction and some history My first micro computer was an Apple II+, which I used extensively both for work and leisure. In fact I liked it so much that I bought a //e when Apple Computer, Inc. released that model. I was not tempted by the Apple /// or Lisa when they were released, although […]

Replacing the KDE Plasma widget ‘Thermal Monitor’ with ‘Kargos’ in Gentoo Linux

, 01/11/2019 | Source: Fitzcarraldo's Blog

The KDE Plasma widget Thermal Monitor has not been working correctly in my Gentoo Linux installations for quite some time. I notice Thermal Monitor’s repository has not been updated for a couple of years, despite several new versions of KDE Plasma having been released. Perhaps that is the reason. On my laptop running the Stable […]

How to enable a Windows application in WINE to access a Samba share on a NAS (continued)

, 26/10/2019 | Source: Fitzcarraldo's Blog

In a 2016 post ‘How to enable a Windows application in WINE to access a Samba share on a NAS‘ I explained how to mount in Linux a networked SMB shared folder so that a Windows application running via WINE could access the folder as Drive Y: in order to open and save files in […]

Make the Macbook touchpad works like MacOS (a modern and definitive guide)

, 26/10/2019 | Source: Daniel Menelkir

There's a lot of tutorials about that on the internet, I'll try to be as much distribution-agnostic as possible. If your distribution doesn't the package that I'm talking about, you should search elsewhere or compile yourself.


A working Xorg (not sure if works with wayland) and a working DE/WM
mtrack driver


Uninstall whatever the touchpad driver you're using, like synaptics, and install mtrack. And use the following configuration for that (in /etc/X11/xorg.conf or /etc/X11/xorg.conf.d/10-mtrack.conf):

Section "InputClass"
        MatchIsTouchpad "on"
        Identifier      "Touchpads"
        MatchDevicePath "/dev/input/event*"
        Driver          "mtrack"
        # The faster you move, the more distance pointer will travel, using "polynomial" profile
        Option          "AccelerationProfile" "2"
        # Tweak cursor movement speed with this
        Option          "Sensitivity" "0.08"
        # Pressure at which a finger is detected as a touch
        Option          "FingerHigh" "5"
        # Pressure at which a finger is detected as a release
        Option          "FingerLow" "5"
        # I often use thumb to press down the physical button, so let's not ignore it
        Option          "IgnoreThumb" "true"
        Option          "ThumbRatio" "70"
        Option          "ThumbSize" "25"
        # Ignore palm, with palm takes up to 30% of your touch pad
        Option          "IgnorePalm" "true"
        Option          "PalmSize" "30"
        # Trigger mouse button when tap: 1 finger - left click, 2 finger - right click, 3 - middle click
        Option          "TapButton1" "1"
        Option          "TapButton2" "3"
        Option          "TapButton3" "2"
        Option          "TapButton4" "0"
        Option          "ClickTime" "25"
        # Disable tap-to-drag, we're using three finger drag instead
        Option          "TapDragEnable" "false"
        # While touching the touch pad with # fingers, press the touchpad physical click button
        Option          "ClickFinger1" "1"
        Option          "ClickFinger2" "3"
        Option          "ClickFinger3" "2"
        Option          "ButtonMoveEmulate" "false"
        Option          "ButtonIntegrated" "true"
        # The momentum after scroll fingers released
        Option          "ScrollCoastDuration" "300"
        Option          "ScrollCoastEnableSpeed" ".1"
        # Natural scrolling with two fingers
        Option          "ScrollSmooth" "true"
        Option          "ScrollUpButton" "5"
        Option          "ScrollDownButton" "4"
        Option          "ScrollLeftButton" "6"
        Option          "ScrollRightButton" "7"
        # Tweak scroll sensitivity with ScrollDistance, don't touch ScrollSensitivity
        Option          "ScrollDistance" "250"
        Option          "ScrollClickTime" "10"
        # Three finger drag
        Option          "SwipeDistance" "1"
        Option          "SwipeLeftButton" "1"
        Option          "SwipeRightButton" "1"
        Option          "SwipeUpButton" "1"
        Option          "SwipeDownButton" "1"
        Option          "SwipeClickTime" "0"
        Option          "SwipeSensitivity" "1500"
        # Four finger swipe, 8 & 9 are for browsers navigating back and forth respectively
        Option          "Swipe4LeftButton" "9"
        Option          "Swipe4RightButton" "8"
        # Mouse button >= 10 are not used by Xorg, so we'll map them with xbindkeys and xdotool later
        Option          "Swipe4UpButton" "11"
        Option          "Swipe4DownButton" "10"
        # Mouse buttons triggered by 2-finger pinching gesture
        Option          "ScaleDistance" "300"
        Option          "ScaleUpButton" "12"
        Option          "ScaleDownButton" "13"
        # Mouse buttons trigger by 2-finger rotating gesture, disabled to enhance the pinch gesture
        Option          "RotateLeftButton" "0"
        Option          "RotateRightButton" "0"

By now, your trackpad will be working with a lot better. Pay attention to the comments if you need to customize. Now we'll create a map for what we still need. You can adjust the modifiers to fit your needs, or just remap then in your DE/WM. Create a $HOME/.xbindkeysrc with this:

# Next Workspace (Swipe4Left)
"xdotool key --clearmodifiers Control_L+Alt_L+Left"
# Previous Workspace (Swipe4Right)
"xdotool key --clearmodifiers Control_L+Alt_L+Right"
# Desktop Grid (Swipe4Down)(F4 key)
"xdotool key --clearmodifiers XF86LaunchA"
# Toggle Present Windows (Current Desktop) (Swipe4Up)(F5 key)
"xdotool key --clearmodifiers XF86LaunchB"
# Zoom in
"xdotool key ctrl+21"
# Zoom out
"xdotool key ctrl+20"

Dispad have a better touchpad-ignore than mtrack, so we're using it. Create this configuration at $HOME/.dispad (I know, it could be .dispadrc but the default is .dispad so I'll keep it):

# name of the property used to enable/disable the trackpad
property = "Trackpad Disable Input"
# the value used to enable the trackpad
enable = 0
# the value used to disable the trackpad
disable = 1
# whether or not modifier keys disable the trackpad
modifiers = false
# how long (in ms) to sleep between keyboard polls
poll = 48
# how long (in ms) to disable the trackpad after a keystroke
delay = 500

With the files in place, now we need to create a $HOME/.xprofile:

xbindkeys -f $HOME/.xbindkeysrc
dispad -c $HOME/.dispad


Sources used:

Creating a RAID of USB pendrives in Linux

, 17/10/2019 | Source: Fitzcarraldo's Blog

If you’re not familiar with the RAID (Redundant Array of Inexpensive Disks) concept and the different types of array, the article ‘RAID 0, RAID 1, RAID 5, RAID 10 Explained with Diagrams‘ gives a quick summary (and links to another article ‘RAID 2, RAID 3, RAID 4, RAID 6 Explained with Diagram‘). Another helpful article […]

Firewall zones (profiles) in Linux, and how to switch them automatically if you use UFW

, 04/10/2019 | Source: Fitzcarraldo's Blog

Firstly, a note on terminology: UFW (Uncomplicated Firewall) and its two GUI front-ends Gufw and UFW Frontends use the term ‘application profile’ to refer to a pre-configured set of rules specified in a file. Files containing UFW application profiles are placed in the directory /etc/ufw/applications.d/. An application profile for SMB, for example, enables the root […]

Paul Gideon Dann’s patchset for Poppler to enable Okular (Qt5) to use Cairo rather than Splash to render PDF files

, 27/09/2019 | Source: Fitzcarraldo's Blog

If you view the same PDF file in Okular (KDE) and Evince (GNOME), you may notice that fonts and lines are rendered better in Evince. Both applications use Poppler to render text and graphics in PDF files, but Poppler uses a different rendering backend in the two applications. For Evince Poppler uses the Cairo library, […]