computer startup time

Computer Startup Time – Current Problems, Future Advancements, and Solutions You Can Consider For Now


Computer Startup Time – Current Problems, Future Advancements, and Solutions You Can Consider For Now
By Neon Zidaneneon.zidane@gmail.com

Please report any errors or suggestions for improvement. Thank you!


Table of Contents

Introduction – Booting Process

Current Startup Issues

Future Innovations and Advancements

What You Can Do For Now

End Notes and Conclusion

Introduction – Booting Process

First of all let’s familiarize ourselves with how the computer boots up. It’s a very simple to understand process. When you first press out the power button, the computer goes through an initialization process. Firstly, it’s important to check if a CPU is present and functional. If there is an error related to the CPU, depending on your motherboard model, it your motherboard might make a beeping sound, flash the power light, start to smoke, or burst into flames (no biggie 😉 ). Usually, after this, if you have a multiple CPU configuration system, one CPU (CPU 0) is selected to run the BIOS and initialize the kernel (a central component of your operating system which will “turn on” the remaining CPUs). At startup, a CPU can only address 1MB of memory, but some Intel processors have a special configuration where they use the last 16 bytes of the memory.

Then the computer starts executing the BIOS code, and starts checking for present hardware (Power on self test). Usually when there is a hardware error, it will display a message on the screen and make a beeping sound. Most motherboards make a beeping sound because if your video card turns out to be not functional, how else can they convey the message to you? Many of the modern (post 1996) BIOSs can use Advanced Power Configuration and Power Interface (ACPI) to list devices the computer has, and then the kernel uses this information.

After the POST, the BIOS wants to find an operating system to boot. It will search through a list of devices in a user-configurable order (CD, Hard Drive, Floppy, USB flash drives, memory cards, etc.) otherwise it will present you an error that says “Non System Disk or Disk Error” which could indicate that the disk could not be boot from. This could mean the disk is not functioning (broken hard drive, scratched/bad CD, etc.) or a configuration error you have made. If a bootable device is found though, the BIOS will read sector 0, the first 512 byte sector of the disk (remember that sector n-1 is the last sector of the hard drive where n is the total amount of sectors on the drive). Important data is in there: a boot sector. It also contains a partition table, 64 bytes – 16 bytes per partition (That’s why you can’t create more than 4 partitions on a hard drive, you will have to use a logical partition).

Since the boot sector is so small (460 bytes of usable space), it will either 1) launch another boot sector, 2) launch a second stage boot loader (could be DOS loader, NTLDR, BCD, GRUB, Lilo, maybe some strange virus you got off some website you shouldn’t be visiting anyways, etc.), or 3) Directly launch the kernel and start the operating system. Either way, if configured correctly, your computer will be told where an operating system is located and a file that will start the kernel. Your operating system splash screen will appear and in a few moments you are ready to use your computer system!

Current Startup Issues

How many things can you do in the time it takes your computer to start up? This means from turning on, operating system loading, then to a point where everything is ready, and you’re ready to start your favourite application (If your login is password protected, don’t count that!). Make a coffee? Make your entire breakfast? Go to school/work and then come home to find out your computer has FINALLY started up? Computers, unlike some other electronics, aren’t in a ready state the moment you turn them on. For example, a television would be ready within a few seconds of you turning it on, a phone would be ready the instant you turn it on. Even your CD player, DVD player, or Blu-ray player would be almost instantly ready when you turn it on. Usually you’re only waiting for it to spin up the disc.

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