hemenkapadia

# MultiPlot - Arrange multiple R plots in a single grid type layout
# 
# Reference - http://www.cookbook-r.com/Graphs/Multiple_graphs_on_one_page_%28ggplot2%29/
#
# ggplot objects can be passed in ..., or to plotlist (as a list of ggplot objects)
# - cols:   Number of columns in layout
# - layout: A matrix specifying the layout. If present, 'cols' is ignored.
#
# If the layout is something like matrix(c(1,2,3,3), nrow=2, byrow=TRUE),
# then plot 1 will go in the upper left, 2 will go in the upper right, and

hemenkapadia

# Important - if the device shows as unauthorized in adb devices -l command. Then go into recovery mode and try adb shell. It will drop to you the shell as root.

# All the below steps needs to be performed in recovery mode.


The fix for the space limitation with yaffs /datadata partion is causing the phone to display low memory error when i enable corporate email on my Samsung Infuse.

The workaround i have is to move some of the data intensive applications to /data/data2 directory which is ext4 based - so far i have not noticed any challanges with performance.

These steps are to be performed in recovery mode. Use CWM to mount /datadata and /data partitions if you notice they are empty.

hemenkapadia

So this Keepawake problem had been plauging me a lot, a dirty workaround i found was to go to google play services in titanium backup, open system details and then clear the data for the same. This would crash the google play service without any noticable impact to the phone functionality, but would take care of the keep awake problem

But the issue was that after a couple of days the problem would return back and then the cycle repeats.

I needed a better solution and found the below to be working so far

Get the Disable Services App from play store
then in System > Google Play Service disable the three services below

GoogleLocationManagerService

hemenkapadia

# Many times we need to delete number of columsn in a data frame, in feature engineering process.
# Deleting the same with column numbers is possible, but is not a good idea from a maintenance standpoint.
# Using column names is a safer option.
# Use below code.

removeCols <- c("colA", "colB")
data.frame <- data.frame[, -which(names(data.frame) %in% removeCols]

hemenkapadia

#### Note about kernel versions ####
Between kernel versions 4.2 and 4.4 there are different options that need to bet set
to get this working. The same is highlighted below when necessary. I have not tested 
version 4.3 so not sure which of the two settings work, in which case try either one.


#### GRUB settings during install and first restart ####

Add the follwoing kernel options just before `quiet splash` in the GRUB boot 
menu while trying to install using a live USB and the very first start of the

hemenkapadia

###  NOTE  ###

The below gist is converted to a blog post and available at below link. Refer that instead.

http://hemenkapadia.github.io/blog/2016/11/11/Ubuntu-with-Nvidia-CUDA-Bumblebee.html


#### Note about kernel versions ####
Between kernel versions 4.2 and 4.4 there are different options that need to bet set
to get this working. The same is highlighted below when necessary. I have not tested 

hemenkapadia

# add the below scriptlet to your ~/.bashrc

# File to store the SSH Agent environment
SSH_ENV=$HOME/.ssh/environment

# start the ssh-agent
function start_agent {
    echo "Initializing new SSH agent..."
    /usr/bin/ssh-agent | sed 's/^echo/#echo/' > "${SSH_ENV}"
    echo "Agent started...."

hemenkapadia

Git Fundamentals

---

• Traditional VCS, like Subversion, CVS etc. are Centralized VCS based on where they store data
• They are also Delta Version Control Systems (VCS) based on how they store data.
  • base version of the file is created when it was added to VCS for tracking
  • changes are stored as a list of changes (i.e. diffs or deltas) per tracked file.

• Git is a Snapshot VCS

hemenkapadia

We use netcat to stream video capture from Raspberry Pi to the Linux machine and play the same in mplayer. Moreover we want to do it in such a way that the Linux server and mplayer should continue listening for the video stream and should start the video play back as soon as it is available

For this Open three terminals on your linux box
in terminal 1 make a fifo file using command mkfifo somefile
in the same terminal we start netcat to listen for incoming connections on port 54321 and redirect this stream to the fifo file we created. Moreover it does not disconnect when the stream ends- it continues listening for the next stream to start

nc -lk 54321 > somefile

in terminal 2 start mplayer to play the stream coming in the fifo file we created

hemenkapadia

#TODO - convert this into an installation script to help quickly setup the machine post installation


0. Time in Windows gets corrupted when dual boot with Ubuntu. (Note needed on 18.04 LTS)
  First adjust hardware time in BIOS to UTC time
  Windows will automatically recognise it and will display appropriate local time
  For Ubuntu, update /etc/default/rcS and change line with UTC=no to UTC=yes, indicating that BOIS time is UTC.
  Reboot - and check both systems.
  
  - Follow this method too - https://www.howtogeek.com/323390/how-to-fix-windows-and-linux-showing-different-times-when-dual-booting/