The BOOT Process ( Intermediate level ) Class 4.

Hi Friends,

Now, that we are ready : We have gone through Basics of Computer/hardware and software lets now begin the interesting journey.

The First STEP ( Once you press the power button ) We will see how the computer starts.
After the power button is pressed, it performs 'power on self test' POST.

POST checks a computer's internal hardware for compatibility and working status before starting the boot process. If the computer passes the POST, the computer may give a single beep and it starts to continue to boot.

However, if the computer fails the POST, the computer will generate a beep code that tells the user the source of the problem.

Any errors here can be identified by beep sounds ( as display drivers are not loaded yet and there is no display formed )
However, because of the wide variety of different computer manufacturers with this BIOS, the beep codes may vary.

For a DELL motherboard below are the codes.
1 beep - BIOS ROM corruption or failure
2 beeps - Memory (RAM) not detected
3 beeps - Motherboard failure
4 beeps - Memory (RAM) failure
5 beeps - CMOS Battery failure
6 beeps - Video card failure
7 beeps - Bad processor (CPU)

After POST, the BIOS ( Basic Input/Output system ) locates and reads the configuration settings that are stored in the CMOS memory. The boot device priority, is the order in which devices are checked to locate the operating system.



The boot device priority is set in the BIOS and can be arranged in any order. The BIOS boots the computer using the first drive that contains an operating system.
Hard drives, network drives, USB drives, and even removable magnetic media, such as CompactFlash or Secure Digital (SD) cards can be used in the boot order, depending on the capabilities of the motherboard.

Some BIOS also have a boot device priority menu that is accessed with a special key combination while the computer is starting but before the boot sequence begins. You can use this menu to select the device to boot.

At this point, the NT kernel takes over. The NT kernel is the heart of all Windows operating systems. The name of this file is NTOSKRNL.EXE. It starts the login file called WINLOGON.EXE and displays the Windows Welcome screen.
All the above mentioned files can be found in C:\Windows\System32.



Now, that we know how the Computer is started, Lets get more into it!
In the next blog - We will learn the differences between Operating systems.




Thank you for reading!
-Omair Sharif.

If you have any questions, please put in the comments box below and submit, I will response at the earliest. Thank you again.


Comments

Post a Comment

Popular posts from this blog

What is a Firmware? ( Intermediate level )

Image
Hi Friends, Today we will learn about Firmware! ( the lesser known part of a Computer ) We only hear and see more of software and hardware/ But there is another very important part of any computer or an electronic device... This is a Firmware. To make is simple  : I would say " Firmware is a combination of hardware and software" Let dig into it, and find more details: There are a lot of devices that contain firmware, to name a few Computer peripherals, Embedded systems, consumer appliances and Computers. A very important point to note for a firmware is that it always resides on Non Volatile memory devices such as Flash memory or a ROM, also, these could never be changed in their lifetime ( major cases ) some manufactures also release updates to the Firmware to fix bugs and  some issues if reported major. These updates have to be FLASHED into the firmware. We will go into the flashing in another blog. For now, just remember flashing is the way any firmware is ...
Read more

Get to know your Computer. ( Very Basic ) Class 1.

Hello Friends, Let do the first Step... Lets get to know what a Computer is. I am not explaining a text book formula here, I will try to explain as clear and as neutral that everyone should be able to understand the fundamentals. A Computer is just another machine, similar to a mobile. Most of us are using Mobile phones, very similar to it is a computer. ( I would say a Computer is more friendly and interesting than a mobile. ) The first STEP is to make this very clear that a Computer is a very simple machine. With this in your mind, lets proceed and see what a Computer has. 01. Keyboard & Mouse 02. Monitor 03. CPU Now we will learn all the above 3 and see how they are related to each other. 01. Keyboard and Mouse: These are your hands that will make computer work. Whatever you want to communicate to the Computer you will do by them. Its not wrong, If I say these are your ( hand / tongue ) and these are the only two things that can communicate to the Computer. A...
Read more

What's Inside the Computer. ( Basics ) Class 2.

Image
Hello Friends, Welcome to the Second Blog as promised! What's Inside the Computer! Now that we know, what a Computer is. Lets dive in to find few more facts and insights of what is happening in a Computer. I will be concentrating more on the CPU part here. As the Other parts are pretty much easy and self explanatory,  01. Keyboard/mouse - This is our Hand/Tongue ( this is the way, how we request a task from the computer ) 02. Monitor - This is where our request is shown of what has been requested. ALSO : the results are displayed here. All the processing is happening inside the CPU that we will discuss here. The CPU: Central Processing Unit The CPU is the heart and brain of a computer. It receives data input/ executes instructions/ and processes the information and then displays the result on the output screen. The CPU contains at least one processor for it to work, which is the actual chip inside the CPU that performs calculations. For long time, most CPU's o...
Read more

How to set Chrome to not save history.

Image
Dear Readers, Lets learn how to avoid Chrome to save history. ( I have seen many requests regarding this on various forums, hence thought of sharing an Idea to accomplish this. )   Google Chrome has recently become the Default Web browser of choice for many Mac and PC users ( including me ). It’s fast, flexible, smart, user friendly, and relatively secure Etc Etc. But it has an issue / a flaw: unlike most browsers, Chrome has no user setting to prevent or automatically clear the browser history. We can though always manually clear the history, but doing that takes a few clicks through a few menus; not ideal. Luckily, there’s a trick we can use to prevent browsing history from being recorded in Chrome. See below for the trick. Chrome stores the browser history in a file on your computer’s drive. If we limit Chrome’s ability to modify that file, it won’t be able to record any web addresses. To start, first go into Chrome and manually clear your history by pressin...
Read more