Paulo
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paulocuambe.bsky.social
Paulo
@paulocuambe.bsky.social
57 followers 280 following 170 posts
Platform Engineer | AWS Solutions Architect Professional | Chess enjoyer.

I think computers are the coolest beasts in the world. Studying them is so fun.

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paulocuambe.bsky.social
On X you will sometimes see people complaining about Rust binaries being large compared to the C ones.

This is not new. When Unix was re-written to C in 1973 its size increase by about 1/3, but the authors claimed that the benefits far outweighed this increase in size.
The size of the new system was about one-third greater than that of the old. Since the new system not only became much easier to understand and to modify but also included many functional improvements, including multiprogramming and the ability to share reentrant code among several user programs, we consider this increase in size quite acceptable.
May 9, 2025 at 2:42 AM
paulocuambe.bsky.social
CPUs are so cool
One way to increase the utilization of processor superscalar capabilities is to issue instructions from more than one thread on each clock cycle. This is called simultaneous multithreading. By simultaneously executing instructions from different threads, there is a greater likelihood that the instruction sequences will depend on disparate functional capabilities within the processor, thereby allowing increased execution parallelism.
February 6, 2025 at 11:53 AM
paulocuambe.bsky.social
I'm having so many aha moments reading this book.

I have been trying to write an operating system from scratch without getting in the Get Things Done mode, which is to ignore the details.

Now I'm being intentional about learning everything I need before proceeding. This answers so many doubts.
Depending on the system configuration, either the BIOS or the operating system manages the initialization of PCI devices during system startup. At the completion of a successful configuration process, all PCI devices have been assigned compatible I/O port ranges, memory-mapped I/O ranges, and interrupt numbers.
January 19, 2025 at 5:14 PM
paulocuambe.bsky.social
I feel strongly about a comment he makes earlier about “People basically just accept that software has a ton of bugs and that it’s normal to run into hundreds or thousands of software bugs in any given week”.

but I wouldn't call people using Go amateurs.

lobste.rs/s/eld5cs/go_...
I feel like we live in a tech dystopia and I’m mad about it. Borrowing Dan Luu’s words: “People basically just accept that software has a ton of bugs and that it’s normal to run into hundreds or thousands of software bugs in any given week” “widely used software is frequently 100000x slower than it could be if it were highly optimized” Arguably it’s mainly societal pressures that create this incentive structure, however, the widespread use of a programming language as undisciplined as Go certainly factors into it. And I’m happy to send a stray shot at Google any time for all the evil & advertisements they inflict on us.
January 17, 2025 at 3:42 PM
paulocuambe.bsky.social
Andrew Kelley ⎯ Zig's creator, made a comment about Go comparable to the infamous Linus comment about C++.

lobste.rs/s/eld5cs/go_...

harmful.cat-v.org/software/c++...
the faq entry about assertions boldly betrays a fundamental lack of understanding about control flow and data invariants defer is function-scoped and heap allocates the double return value system is undisciplined, clunky, and buggy, you can easily miss an error when refactoring lack of basic type safety for example with enums channels are an awful, buggy concurrency primitive, especially with the way they implemented them making zero meaningful hides bugs for example by making all pointers optional that was just 30 seconds off the top of my head. go is great if you are an amateur with no taste, like 99% of google employees. On Tue, 20 Jan 2004, Robin Rosenberg wrote: > > This is the "We've always used COBOL^H^H^H^H" argument. In fact, in Linux we did try C++ once already, back in 1992. It sucks. Trust me - writing kernel code in C++ is a BLOODY STUPID IDEA. The fact is, C++ compilers are not trustworthy. They were even worse in 1992, but some fundamental facts haven't changed: - the whole C++ exception handling thing is fundamentally broken. It's _especially_ broken for kernels. - any compiler or language that likes to hide things like memory allocations behind your back just isn't a good choice for a kernel. - you can write object-oriented code (useful for filesystems etc) in C, _without_ the crap that is C++. In general, I'd say that anybody who designs his kernel modules for C++ is either (a) looking for problems (b) a C++ bigot that can't see what he is writing is really just C anyway (c) was given an assignment in CS class to do so. Feel free to make up (d). Linus
January 17, 2025 at 3:34 PM
paulocuambe.bsky.social
you are really not that fast
Because the bandwidth requirements for human interaction are so low, some computer motherboards provide a slower USB 2.0 port for keyboard connection while offering higher-performance USB 3.0 or better interfaces for high-speed peripherals. This results in a small cost reduction for the motherboard components
January 16, 2025 at 2:23 PM
paulocuambe.bsky.social
this goes against my belief. I expected the keyboard and mouse to have the highest requirements for bandwidth, as when you type of move the mouse you expect an immediate feedback, but it seems like humans are slow creatures, at least when compared to the speed at which computers react to events.
Compared to the high-speed device interfaces discussed earlier in this chapter, the bandwidth requirements for a keyboard and mouse are quite modest. These devices are the sole input methods used by the human operator in most computer configurations, and thus are only required to operate at the speed of human actions. Even the fastest typist can only press one or two dozen keys per second.
January 16, 2025 at 1:45 PM
paulocuambe.bsky.social
Computers are so smart.
We do wonders in the software land, but the hardware does so much heavy lifting for us.

Knowing about Prefetching implement by DRAM, allows us to plan how we store our data in memory, so that the hits are more accurate and the software is faster.

I really like computers.
The idea behind prefetching is to exploit the fact that whenever a particular memory location is being accessed by a processor, it is likely that access will soon be needed to a location close to the first location. Prefetching consists of reading a larger block of memory than the single location a processor instruction references and passing the entire block from the DRAM device to the processor. In the context of a DDR4 memory module, the block size is normally 64 bytes.
January 16, 2025 at 9:26 AM
paulocuambe.bsky.social
I have close to zero knowledge about digital electronics, but this is cool. This makes me want to study digital electronics.

MOSFET is cool.
Since then, the MOSFET has been by far the most common type of transistor used in integrated circuits. As of 2018, it is estimated that 13 sextillion (a sextillion is one followed by 21 zeros) transistors had been manufactured, 99.9 percent of which were MOS transistors. The MOSFET is the most frequently manufactured device in human history.
January 15, 2025 at 2:30 PM
paulocuambe.bsky.social
I like Go in general, but this point about DateTime is so so so so real. You have to use a specific day of some random year to format your dates in Go. Like why, why do I have to do that?
January 13, 2025 at 9:13 AM
paulocuambe.bsky.social
iPhone was really a leap of innovation at the time.
Computers are amazing. People who build computers are the real wizards.
The iPhone 1 had a 3.5" screen with a resolution of 320x480 pixels. It was 0.46 inches thick (thinner than other smartphones), had a 2-megapixel camera built in, and weighed 4.8 oz. A proximity sensor detected when the phone was held to the user's ear and turned off screen illumination and touchscreen sensing during calls. It had an ambient light sensor to automatically set the screen brightness and an accelerometer detected whether the screen was being held in portrait or landscape orientation.
January 13, 2025 at 8:42 AM
paulocuambe.bsky.social
How debugging was like back in the day.
From the book: Modern Computer Architecture and Organizational by Jim Ledin.
ENIAC programs consisted of plugboard wiring and switch-based function tables. Programming the system was an arduous process that often took the team of talented female programmers weeks to complete. Highleted section starts here: Reliability was a problem, as vacuum tubes failed regularly, requiring troubleshooting on a day-to-day basis to isolate and replace failed tubes.
January 13, 2025 at 7:34 AM
paulocuambe.bsky.social
a fine chess game. the engine says i was playing like a 2000 ELO player. My opponent was playing at the 1800s. www.chess.com/live/game/13...
I’m playing with the black pieces. check mate on the middle of the board. King on g3, mated by a queen on g4 and another queen on e2.
January 8, 2025 at 11:56 AM
paulocuambe.bsky.social
I’m proud of this game. A forced mate after some good decisions by yours truly.

www.chess.com/live/game/13...
The chess game ends in a the oponent with the black pieces giving up after two consecutive checks by the white queen on d7, and later on e8. The king was on d8, scapes the check to b8, but is met with another check by the queen on e8. The game would end in a forced mate if the Knight on c6 defended on d8.
January 7, 2025 at 4:20 PM
paulocuambe.bsky.social
I won a chess game that I barely held on to for most of the game.

www.chess.com/live/game/12...
Game ends with a queen check on f4 to the king on c1. I’m playing with the black pieces.
January 6, 2025 at 4:02 PM
paulocuambe.bsky.social
String is just a struct wrapping a Vec<u8> 🤯
/// [Deref]: core::ops::Deref "ops::Deref" /// [`Deref`]: core::ops::Deref "ops::Deref" /// [`as_str()`]: String::as_str #[derive(PartialEq, PartialOrd, Eq, Ord)] #[stable(feature = "rust1", since = "1.0.0")] #[cfg_attr(not(test), lang = "String")] pub struct String { vec: Vec<u8>, }
January 3, 2025 at 7:16 PM
paulocuambe.bsky.social
this motivated me again wiki.osdev.org/Getting_Star...
First of all, developing an operating system is probably one of the most challenging things you can do on a computer (next to killing the final boss in Doom on Nightmare difficulty level). Composing an operating system requires a lot of knowledge about several complex areas within computer science. You need to understand how hardware works and be able to read and write the complex assembly language as well as a higher-level language (such as C, C++, or Pascal). Your mind has to be able to wrap itself around abstract theory and hold a myriad of thoughts. Feel discouraged yet? Don't fear! Because all of these things are also the things that makes OS programming fun and entertaining.
November 20, 2024 at 6:15 PM