Paulo AlmeidaTroubleshooting tales — How to connect two QEMU guests via a bridge interfaceRecently, I wanted to study how DRBD worked closely and to accomplish it I always thought that being able to set a break-point and…Feb 2Feb 2
Paulo AlmeidaWhy /usr/bin/echo works just the same as /////usr//bin//////echo?Recently, I received as a suggestion for a patch I sent to trace-cmd utility to change my implementation to something like thisJan 19, 2023Jan 19, 2023
Paulo AlmeidaKernel Locking —Deep Dive into Spinlocks — Part 1The Linux Kernel provides a variety of locking primitives. Each one of them behaves in a unique way that makes it more or less suitable to…Feb 21, 20222Feb 21, 20222
Paulo Almeidax86–64 Troubleshooting Tales: I can jump to ring 3 via IRETQ but not via SYSRET… Why? — Part 1I spent months writing mymemory allocation and paging and it’s the time for the the long awaited ‘jump to the user mode’. What can go…Dec 6, 2021Dec 6, 2021
Paulo Almeidax86-64 Troubleshooting Tales: Why only half of my interrupts work?The idea is very simple: I document internal monologues I had while pulling my hair out; you learn a thing or 2 and laugh at the situationJul 22, 2021Jul 22, 2021
Paulo AlmeidaCustom Kernel Debugging — Using GDB to debug dynamically loaded ELF filesDebugging applications seems to be an art lost and forgotten to time already so how to debug your a custom kernel when you find an issue?Jun 21, 2021Jun 21, 2021
Paulo Almeidax86–64 4Kbyte Page translation design — is this the reason why pages are 4096 bytes aligned?I lost 3 weeks of my life trying to wrap my head around the x86–64 manuals to try to implement 4-Kbyte Page translation for my hobbyist OSMay 13, 2021May 13, 2021
Paulo AlmeidaDigging into Linux schedulerOne may argue that task scheduling is one of the most challenging problems to solve. Whether this is true remains to be seen but in this…Mar 10, 20201Mar 10, 20201
Paulo AlmeidaHow much traffic from your machine goes to the cloud?Irrespective of your opinion in the cloud vs on-premise debate, this is a question that all of us at least wondered once, whether this is…Jan 30, 20201Jan 30, 20201
Paulo AlmeidaWhy does DynamoDB implement CRC32 if it uses GZIP algorithm on layer 7?Disclaimer: This is a post from an old blog of mine (2017) which I’m planning to remove.Jan 28, 20201Jan 28, 20201
