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Showing posts from June, 2006

Same problems again !!

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Recently a group of fresh engineers joined our team. These young people are bubbling with so much excitement and enthusiasm, it is such a pleasure to welcome a new group in. But with all the hurly-burly come those typical problems that people bring to me (or whosoever they find free, I must be the laziest guy around :-) ).
A regular feature when new people are put on to work in Java is the problem of their code not being able to find corresponding jar files in the CLASSPATH. Now they swear that their path settings are correct and that they have put in correct libraries at the right places. YES, most of the times they are right !! What they fail to check is that at times their libraries are corrupted and that is a good reason for javac not being able to find the required classes.

More often then not the problem boils down to downloading libraries using ftp in ASCII mode (ftp is not extensively used in colleges so people are not used to it).

I am blogging this because today some one cam…

Boot Process

Lately lot of people have been asking about how a system boots at reall…llly low levels, I have no idea why the sudden interest in this topic. May be it's just that I read about the subject few weeks back, and it's me who is unintentionally :) prodding them to ask this question. Whatever is the reason here is my two cents’ worth on this topic.

We will talk about boot process of x86 system running Linux/Windows, though booting sequence in most of the architectures is more or less similar.

Steps to Boot a machine.

- Well as soon as machine is powered on BIOS code is copied from EPROM onto system memory, CPU looks for BIOS code at the end of system memory and executes it.

- POST (Power On Self Test) is run, initiated by the CPU and BIOS.

- BIOS looks for all the valid devices it can use to boot, it uses the boot configuration data to decide which device to check first for bootable code. A device is 'bootable' if it carries a boot sector with the byte sequence 0x55, 0xAA in byt…