Getting Through Ubuntu & Windows Boot Loader


Ubuntu is a Debian based Operating System and is Open Source whereas on the other hand Windows being Closed Source.

 Bootloader contains the set of instructions which loads an Operating System or some other System Software.

 Windows bootloader named NTLDR shorted for NT LoaDeR where NT is the series of Operating Systems by Windows.
Windows NT is a family of OS by Microsoft where it's first version being Windows NT 3.1 and the latest version is Windows 10 Technical Preview and Windows 10 release is on 29th of July 2015.

 Ubuntu bootloader is Grub2 since 9.10 (karmic koala), all the earlier versions of Ubuntu uses Grub.

What actually happens when you install Ubuntu and Windows in dual boot is:

   Suppose you have Windows Installed on your system and then you try to Install Ubuntu in it in Dual Boot mode.
So what actually happens in the NTLDR is pre-written and when you are installing Ubuntu the Grub2 or Grub bootloader depending upon which version you are using writes over NTLDR and makes entry of Windows as well as Ubuntu in the bootloader enrtyand then in booting process both options i.e. Windows as well as Ubuntu are available and you can boot into any one of them.

 Deleting Ubuntu (In case you want)

People when want to delete Ubuntu what they generally do is they delete the partition in which Ubuntu is installed via Windows Partition Manager and then when you'll restart you'll get this screen.

<------------------------------------------------------------------------------------------------->
error : no such partition.

grub rescue> _
<------------------------------------------------------------------------------------------------->
The Reason behind this error is that when you delete the partition what you do is like you delete the drive but you forget to remove the bootloader which reads content from that specific drive only.

So to resolve this error we have two ways:

  1. First is to recover the partition if only the boot loader is corrupted while making some changes to it and that way is when you see this error try the following command:
  • Type command grub rescue> ls
    • To list all the partitions
  • Set boot option to a partition say msdos6
    • grub rescue> set boot = ( hd0, msdos6 )
  • Now Set the prefix to that same partition to locate grub where hd0 states your systems hard-drive 
    • grub rescue> set prefix = ( hd0, msdos6 )/boot/grub
  • To start the in normal mode we use
    • grub rescue> insmod normal
  • Normal command reads the config file /boot/grub/grub.cfg if 'grub.cfg' is found in the mentioned partition then system will run correctly
    • grub rescue> normal
If system doesn't run correctly then try it on other partitions and if none of them works then try the second option.

     2. For this you need a bootable device with Windows OS

  • Grab a pen-drive or DVD with bootable Windows OS and then boot using the bootable device and run Windows Setup
  • Select language and all and Click Next.
  • Click Repair your system
  • Open Command Prompt and Type
    • Bootrec.exe to start boot recovery program
    • They type
      • > fixMBR
      • > fixBoot
  • Reboot the System and you are good to go.
That is how boot loader works and you must get through this before going for Dual Boot option.

Next tutorial on: How to Install Ubuntu :: coming soon

Till then
Adios Lactores
Happy Blogging!!!

Comments

Post a Comment

Popular posts from this blog

A Brief about RDMA, RoCE v1 vs RoCE v2 vs iWARP

Hello folks, Today we'll see what RDMA is and how different kind of network solutions work over Ethernet. For those who are wondering what these words are, this is a post about Networking and an overview can be, how to increase your network speed without adding new servers or IB over your network, wherein IB stands for InfiniBand which is basically a networking communication standard majorly used in HPC  that features very high  throughput  and very low  latency , for what HPC is, refer to my previous blog. This is how a Mellanox IB cable looks like In order, not to use IB, increasing the speed for Ethernet-based solutions is a better and cost-effective solution in many cases which is implemented using RDMA, thus saving cost and technology shift overhead for every admin out there. So let's see what RDMA is, RDMA stands for Remote Direct Memory Access  is a  direct memory access  from the  memory  of one computer into that of another without involving either one'
Read more

Cryptocurrency & Blockchain

Today we have a look at what is a cryptocurrency, what blockchain is, how does it link to a cryptocurrency! So let's dive straight into cryptocurrency and see what it is! Very well defined at Wikipedia " A  cryptocurrency  is a digital asset designed to work as a medium of exchange that uses strong cryptography to secure financial transactions, control the creation of additional units, and verify the transfer of assets.", but is it actually is in even simpler language "A cryptocurrency is a digital currency that is created and managed through the use of advanced encryption techniques." A few keywords that you might need to know when talking about cryptocurrency are as follows:  Wallet - a place to store your cryptocurrency credentials: namely your private key  Private key - a 256-bit number, expressed as a hexadecimal  Eg: 9873D79C6D87DC0FB6A5778633389F4453213303DA61F20BD67FC233AA3326  When people say that they have lost their cryptocurrency(say Bi
Read more

Repairing your Ubuntu or Linux Dist. manually

If you are a regular user of any Linux based operating System then it is for sure that you have faced the error of "Broken Packages". When you are installing something new to your OS, it says Package cannot be installed because Package A depends on Package B, but Package B cannot be installed because of broken packages and this issue might occur while updating your system using Software Updater. If you have faced this error then trust me, you have a really good hand in that Linux Based OS because you have worked enough to corrupt it once. Now making this post a little brief lets jump directly to the solution!! There are more then one solution for it and different in OS using different packaging system, if your system is using dpkg , thus implying you'll be using apt to keep everything in tandem. So here is a list of solutions you can try for Ubuntu and few Others: This is the most easy solution if you hate CLI, but is not recommended at all. Use Synaptic Package
Read more