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Saturday, June 25, 2016

Do we really need memory optimidation Apps such as Clean Master, SDMaid etc on Android based smartphone mobiles or tablets?

Recently I tried Clean Master and  SDMaid Apps on my Android based smartphones and tablets. Wanted to know whether these really helps or just pretends or simulate the things. Here are my findings.

1. Cache cleaning: Yes, the feature really works. However, you can also do it manually, by going to System Settings > Storage and selecting "Cached data" options.

2. Memory boosting: No, the feature is not really that helpful. Android intentionally keeps the Apps into memory (RAM) for better performance.  The Apps like Clean Master, claims cleaning memory and increasing performance by cleaning un-necessary Apps from memory. However, you will notice that the Android OS will again load those Apps into the  memory again, and this degrades performance even more., as the CPU cycles are wasted.

3. Other features: These Apps provide several other features, out of which App Lock feature is really cool.
The AppLock feature lets you password (or pattern)-protect apps. this means you can lock camera, Contacts, SMS, Video players...... really cool. However, the most irritating thing about this feature is that once you are online over internet, this starts shows Advertisements on your Security Lock screen, and many of these advertisements are about  too cheap things.

So, its up to you, you may like to go for feature 1 and 2 above.

Sunday, March 27, 2016

Black Screen of Death after upgrading ubuntu! How to roll back the upgrade?

If you get Black Screen of Death after upgrading ubuntu.
You may like to rollback or uninstall the upgrade.

To do so, first you need to run the computer in Recovery Mode:
  • Reboot the computer
  • At GRUB screen, select the line which starts with "Advanced options" and then line ending with "(recovery mode)"
  • It will ask for username and password.
  • On successful login, type following command:

        sudo apt-get remove –-auto-remove upgrade-system
 Note: if unable to run the above command, you may have to run following command before removing the upgrade:
 sudo dpkg --configure -a 
(If it doesn't try running sudo apt-get install -f (to fix broken packages) and then try running sudo dpkg --configure -a again )

Reboot the computer! 

Wednesday, February 17, 2016

Installing ClamAV from Ubuntu Linux.

          Most malware are written for Windows because of  its market share, however irrespective of OS platform (Windows or Linux or Android or ...), you need a good anti-malware application against viruses, worms, adware and other malware.

ClamAV is free and open source Anti-Virus, also available for Linux.

To install ClamAV,  open terminal and use below command line:

$ sudo apt-get install clamav clamtk

Once installed, you can access ClamAV from dashboard:



You may set some useful preferences:

 To update virus definitions, type:

$ sudo freshclam

Saturday, January 16, 2016

Extending hard disk volume of a VMware virtual machine. Solving error: Failed to expand the disk "C:\My Vurtual Machines\windows 8\Windows 8.vmdk": One of the parameters supplied is invalid (0x100003e80).

1. Delete all snapshots. (Make sure you have backups)
2. Shutdown the Virtual Machine and use VMWware-vdiskmanager utiltiy (comes with VMWare Workstation) to extend partition.
Example: if you want to increase OS drive of your Windows 8.0 virtual machine (located at "D:\My Vurtual Machines\windows 8\Windows 8.vmdk" ) by 15GB then use following commmand:
    C:\Program Files (x86)\VMware\VMware Workstation>vmware-vdiskmanager.exe -x 45Gb "C:\My Vurtual Machines\windows 8\Windows 8.vmdk"

3. If you are attempting to extend the OS drive, you can use some 3rd party partitioning software (such as Partition Magic or Paragon Partition Manager).  If you are increasing the size of a data-drive/partition,  you can use DISKPART commands in your Virtual Machine.
Example: for extending OS drive, use the 3rd party partitioning software, and allocate the unallocated space as “primary”: then merge it with ‘basic’ C-drive.

If you get error:
Failed to expand the disk  "C:\My Vurtual Machines\windows 8\Windows 8.vmdk": One of the parameters supplied is invalid (0x100003e80).

Possibly, you have not created the vmdk file as of fixed size, instead selected option that would let the hard disk volume grow when become larger. So, there might be multiple .vmdk files, and therefore the vmware-vdiskmanager causes the above error.
For this type of vmdk,
Select "Edit virtual machine settings" from VMWare Workstation. then, Hard disk > Utilities > Expand : now expand the hard disk to 45GB

After this, run the virtual machine. Right click the  Computer or My Computer: Select "Manage"
In "Computer Management": select "Disk Management": It will show 45GB as unallocatted volume.
Right click your OS-drive (C Drive) and select "Extend volume" and extend it ti complete 45GB.
That's  all!!

Saturday, January 09, 2016

Sometimes my Ubuntu laptop doesn't detect my ADSL Modem based WiFi Access Point

I am having dual OS (Windows & Ubuntu) in my Laptop, and a ADSL Modem based WiFi Access Point.
The WiFi Access Point always  works fine with Windows, however with Ubuntu sometimes (or infact most of the times) it is not being detected. Further, the Ubuntu always shows other surrounding WiFi networks.

Reason: The possible reason may be conflict of Channel or Frequency with other WiFi networks.

Try to change following settings in your WiFi Access Point:
1. Change Channel from Auto to a fixed channel number. (for example: 07)
2. Change Channel bandwidth to 20Mhz to 20/40Mhz.
3. Restart the Access Point.