synchronous vs asynchronous socket

synchronous vs asynchronous socket calls.

Builds up slowly and explains nicely.
http://www.wangafu.net/~nickm/libevent-book/01_intro.html

vim tools

====================================
google CCTree vim plugin

Some commands :

:CCTreeLoadDB cscope.out

:CCTreeTraceForward main

:CCTreeTraceReverse

:CCTreeRecurseDepthMinus   //you can run this multiple times.. But It will reach a limit :)

:CCTreeRecurseDepthPlus   //you can run this multiple times.. But It will reach a limit :)


====================================
// for directory view
:NERDTree


// To see all functions in single file
:TlistToggle
====================================

Default OS after Fedora installation

First check current kernels in the system:
# sudo grubby --info=ALL | grep -E "^kernel|^index"
index=0
kernel="/boot/vmlinuz-6.XYZ
index=1
kernel="/boot/vmlinuz-6.ABC
index=2
kernel="/boot/vmlinuz-6.PQR
index=3
kernel="/boot/vmlinuz-0-rescue-ABCCD"

Set the default index:
# sudo grubby --set-default-index=0 
The default is /boot/loader/entries/86b961286bda43e580ff4adfd8da7d0e-6.11.10-200.fc40.x86_64.conf with index 0 and kernel /boot/vmlinuz-6.XYZ

Cross check the set kernel:
root@fedora:/home/saran# sudo grubby --default-kernel 
/boot/vmlinuz-6.XYZ

32GB restriction on microsd cards

Why there is a restriction on smartphone saying that it support microsd of size upto 32 GB.

Because specs says so::

Currently, microSD cards have a maximum capacity of 32GB as this is a limitation imposed by version 2 of the SD Specifications: “High Capacity SD Memory Card: More than 2GB (This version of specification limits capacity up to and including 32GB)”.

console access to VM

On the virtual machine, add ‘console=ttyS0‘ at the end of the kernel lines in the /boot/grub2/grub.cfg file(by executing the following grubby command):

# grubby --update-kernel=ALL --args="console=ttyS0"

NOTE: ssh to VM (or) use virt-manager and run the

above command. 

Now, reboot the virtual machine:

# reboot

Now,

virsh list --all 

virsh start <your vm name>

virsh start /etc/libvirt/qemu/YOUR_VM.xml

virsh list
// output
// say vm.example.com is the domain.

Now, connect to the virtual machine’s console (here vm.example.com):

# virsh console vm.example.com

(or)

#virsh console <ID number>