Category: Linux and UNIX

So far in our detailed tour of the Linux boot sequence (which started here) we have seen how the UEFI firmware on modern hardware can call a “shim” program to support Secure Boot, which in turn runs the GRUB boot loader to find, load, and start the kernel. The kernel has loaded device drivers for […]

Last week our detailed tour of the Linux boot sequence (which started here) got as far as the “shim” component handling Secure Boot in the UEFI environment and then calling the next program in the chain, probably grubx64.efi. We found that grubx64.efi is part of the grub2-efi package and it references the file grub.cfg, also […]

Two weeks ago I started explaining how Linux boots.  Last week I got as far as the UEFI firmware finding a running a “shim” program named shim.efi to satisfy the Secure Boot security policy with its digital signature from a trusted signing authority (which, to further discourage the conspiracy theories, is not Microsoft or somehow […]

It’s amazing that the early 1980s IBM PC design lasted as long as it did. Into the 2000s people relied on its very limited BIOS firmware and MBR partition tables. But now it’s the 2010s and things have finally moved forward. I gave you an overview of how Linux boots. The first steps involve the […]

With Linux, you can just turn it on, wait a few moments, and start doing powerful things! But if you are going to be responsible for critical systems, you need to know how they are supposed to work so you can recognize and fix problems. At its very simplest, we’re looking at this sequence: Firmware […]