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# ![@popovicu94 Avatar](https://lunarcrush.com/gi/w:26/cr:twitter::1402325461.png) @popovicu94 Uros Popovic

Uros Popovic posts on X about if you, scratch, vm, virtual the most. They currently have XXXXXX followers and XX posts still getting attention that total XXXXX engagements in the last XX hours.

### Engagements: XXXXX [#](/creator/twitter::1402325461/interactions)
![Engagements Line Chart](https://lunarcrush.com/gi/w:600/cr:twitter::1402325461/c:line/m:interactions.svg)

- X Week XXXXXXX -XXXX%
- X Month XXXXXXXXX +431%
- X Months XXXXXXXXX +504,378%
- X Year XXXXXXXXX +2,772,583%

### Mentions: XX [#](/creator/twitter::1402325461/posts_active)
![Mentions Line Chart](https://lunarcrush.com/gi/w:600/cr:twitter::1402325461/c:line/m:posts_active.svg)

- X Month XXX +120%
- X Months XXX +6,100%
- X Year XXX +12,450%

### Followers: XXXXXX [#](/creator/twitter::1402325461/followers)
![Followers Line Chart](https://lunarcrush.com/gi/w:600/cr:twitter::1402325461/c:line/m:followers.svg)

- X Week XXXXXX +5.70%
- X Month XXXXXX +231%
- X Months XXXXXX +2,601%
- X Year XXXXXX +3,038%

### CreatorRank: XXXXXXX [#](/creator/twitter::1402325461/influencer_rank)
![CreatorRank Line Chart](https://lunarcrush.com/gi/w:600/cr:twitter::1402325461/c:line/m:influencer_rank.svg)

### Social Influence

**Social category influence**
[technology brands](/list/technology-brands)  XXXX% [stocks](/list/stocks)  XXXX%

**Social topic influence**
[if you](/topic/if-you) 4.94%, [scratch](/topic/scratch) #65, [vm](/topic/vm) 2.47%, [virtual](/topic/virtual) 2.47%, [$googl](/topic/$googl) 2.47%, [core](/topic/core) 2.47%, [lenovo](/topic/lenovo) #58, [shell](/topic/shell) #838, [hosted](/topic/hosted) 1.23%, [pi](/topic/pi) XXXX%

**Top accounts mentioned or mentioned by**
[@tmikov](/creator/undefined) [@unix2mars](/creator/undefined) [@jamonholmgren](/creator/undefined) [@advancedlong](/creator/undefined) [@vermaden](/creator/undefined) [@makakmayumjava](/creator/undefined) [@okasion2012](/creator/undefined) [@dhh](/creator/undefined) [@arunkumar9t2](/creator/undefined) [@456c6f727269](/creator/undefined) [@alive_nishant](/creator/undefined) [@8bitmoaner](/creator/undefined) [@r0b0tsp1der](/creator/undefined) [@monsterlieeeee](/creator/undefined) [@saltmineranch](/creator/undefined) [@tejasfoo](/creator/undefined) [@cgtwts](/creator/undefined) [@marcosnils](/creator/undefined) [@milanmilanovic](/creator/undefined) [@droogstoppel13](/creator/undefined)

**Top assets mentioned**
[Alphabet Inc Class A (GOOGL)](/topic/$googl)
### Top Social Posts
Top posts by engagements in the last XX hours

"Resizing a 1GB buffer sounds expensive. X. Allocate new 1GB X. Copy 1GB of data X. Free old 1GB This burns CPU cycles and trashes your cache. But Linux has a shortcut that makes this lighter. mremap (#25 on x86_64): the syscall that resizes memory without copying bytes. 🧵👇"  
[X Link](https://x.com/popovicu94/status/1994973654753710488)  2025-11-30T03:35Z 11.3K followers, 40.5K engagements


"Now this What are they hosting these on Raspberry Pi"  
[X Link](https://x.com/popovicu94/status/1995066727361925190)  2025-11-30T09:45Z 11.3K followers, 8395 engagements


"Quick experiment: I built a Linux distribution from scratch. I call it "Home Cooked Linux." 🍳 No Buildroot no Yocto. Those tools are powerful but they hide the magic. I wanted to own the process end to end. My "build system" was just standard tools on a Debian VM: gcc make tar and other traditional utils. That's it. I cross-compiled the GNU coreutils against musl libc (to avoid glibc complexity) added a few more tools and wrapped it all in runit. In the screenshot below you can see the result: a clean boot a custom environment (linked to musl) and a graceful shutdown sequence. It proves that"  
[X Link](https://x.com/popovicu94/status/1995319844305317967)  2025-12-01T02:31Z 11.3K followers, 17.3K engagements


"Virtual memory in Linux is a comfortable lie. When you mmap a file Linux gives you memory addresses but often doesn't load the data. It waits until you touch it. That "wait" causes a page fault pausing your app while the disk spins. How do you avoid that pause mincore (#27 on x86_64). 🧵👇"  
[X Link](https://x.com/popovicu94/status/1995709487127429365)  2025-12-02T04:19Z 11.3K followers, 30.2K engagements


"I spent years at Google working on various teams including the TPU chips. The biggest bottleneck usually isn't writing the code. It's the tooling. If you can't move fast you can't iterate. For my custom CPU (Mrav) I didn't just write a core. I wrote a software ecosystem around it using Bazel and got the full build system for free. I wrote custom Bazel rules (mrav_binary) that treat my custom Assembly language just like C++ or Go. Here is what happens when I run a single build command: Bazel bootstraps the Go toolchain. It compiles my custom simulator (written in Go). It assembles the Mrav"  
[X Link](https://x.com/popovicu94/status/1996417655704780863)  2025-12-04T03:13Z 11.3K followers, 40.4K engagements


"Who uses this Database software like Oracle has historically used System V shared memory (via shmget) for its System Global Area (SGA) a region shared by all database processes. When microseconds count you can't afford kernel copy overhead. You need direct memory access"  
[X Link](https://x.com/popovicu94/status/1996436453405209034)  2025-12-04T04:28Z 11.3K followers, XXX engagements


"Under the hood shmat (Shared Memory Attach) manipulates the Page Tables. It takes a shared segment (created via shmget) and plugs it directly into your process's virtual address space"  
[X Link](https://x.com/popovicu94/status/1996785202316865879)  2025-12-05T03:34Z 11.3K followers, 1347 engagements


"@cgtwts Good riddance. People were really rude. I hated the experience every time I posted a question"  
[X Link](https://x.com/popovicu94/status/1997175739742106013)  2025-12-06T05:26Z 11.3K followers, 4234 engagements


"Lots of tutorials on using Linux: download a distro how to install it. But how about: - Build the latest kernel from source - Adapt it to run on custom hardware ($5 hardware) - Make your own Linux board - Create USB gadgets with Linux - Hack your car Follow me to learn"  
[X Link](https://x.com/popovicu94/status/1982476631836180852)  2025-10-26T15:57Z 11.3K followers, 109.3K engagements


"Stop downloading 4GB ISOs to create Linux VMs. You don't need an installer a GUI or a "Next Next Finish" wizard. You just need a directory of files. Here is how I build custom hacky bootable Debian VMs in XX seconds using debootstrap. Your distro is just a kernel and a collection of user-space binaries. If you can place those files correctly on a disk the kernel will work with it. X. The "Secret" Tool: We usually treat VM images (.qcow2) as black boxes. But qemu-nbd lets you map that virtual disk to a real device node (/dev/nbd0) on your host. This allows you to format and mount a virtual"  
[X Link](https://x.com/popovicu94/status/1993165606997156077)  2025-11-25T03:51Z 11.3K followers, 147.8K engagements


"Network servers handle traffic in two main ways: X. Thread-per-client (Classic textbook approach) X. The Event Loop (Node.js Nginx .) The Event Loop is the secret sauce of modern scalability. It relies on a specific kernel power: I/O Multiplexing. The syscall that started it all is select (#23 on x86_64). It's the grandfather of I/O multiplexing. Let's look at the code. 🧵👇"  
[X Link](https://x.com/popovicu94/status/1994251613196935606)  2025-11-28T03:46Z 11.3K followers, 46.1K engagements


"I applied the lessons I learned at Google about high-velocity automation to a personal challenge: building a custom CPU core from scratch as a proof of concept. But silicon is nothing without software. To make my CPU (Mrav) useful I needed an assembler to turn text into binary. I initially fell into the trap of over-engineering. I tried using complex parser generators and formal grammar frameworks. I thought I needed to build a "proper" compiler. Instead I ended up with a headache of dependencies and heavy tooling. So I threw it all out. I realized that for a custom CPU with XX instructions I"  
[X Link](https://x.com/popovicu94/status/1994612859263975439)  2025-11-29T03:42Z 11.3K followers, 28.2K engagements


"Your music software has X milliseconds to process an audio buffer. Miss that deadline You hear a crackle. This is why Linux has real-time scheduling. And syscall sched_yield (#24 on x86_64) is how real-time threads politely share the CPU. Let's talk about it. 🧵👇"  
[X Link](https://x.com/popovicu94/status/1994614163461869914)  2025-11-29T03:47Z 11.3K followers, 39.1K engagements


"I'm not a huge fan of the noise happening in projects we've been seeing lately but Zig seems to be just an amazing project. How often do you see the tools so nicely packaged liked in this case Just one clean statically linked binary and bundled libraries"  
[X Link](https://x.com/popovicu94/status/1995424111800271094)  2025-12-01T09:25Z 11.3K followers, 8886 engagements


"Its one thing to boot a custom Linux distro in QEMU. Its a completely different beast to get it running on real hardware. Update on "Home Cooked Linux": It is now alive on my Lenovo ThinkPad. This isn't a stripped-down Debian. This is: - My compiled Kernel - My cross-compiled userland (musl libc bash GCC) - My init scripts (runit) No heavy installer. No systemd. Just the kernel handing off to init and the system flying. The feeling of knowing exactly what every process is doing Unbeatable. Who is ready to compile their own OS 🐧"  
[X Link](https://x.com/popovicu94/status/1995686615893901588)  2025-12-02T02:49Z 11.3K followers, 36.1K engagements


"@arunkumar_9t2 Its great right People just hate on it without even understanding it"  
[X Link](https://x.com/popovicu94/status/1996709930871804267)  2025-12-04T22:35Z 11.3K followers, 17K engagements


"How to run Linux inside Linux without VM software: Most people use QEMU or VirtualBox. But there is a lighter "native" way. It's called User-Mode Linux (UML) and the architecture is brilliant: The kernel is a process: The guest kernel runs in userspace just like bash or vim. Resources are mapped: It doesn't need real drivers. It maps a host file to guest disk and your terminal to the guest console. Because it's just a process you can boot and kill it instantly. It's a forgotten superpower for testing and development. I wrote a full guide on setting this up from scratch:"  
[X Link](https://x.com/popovicu94/status/1996781890205110747)  2025-12-05T03:21Z 11.3K followers, 50.9K engagements


"First remember that every Linux process starts with three standard open streams: 0: stdin (input) 1: stdout (output) 2: stderr (error output) The dup(old_fd) syscall creates a copy of an existing file descriptor. But it follows one strict kernel rule: It always returns the *lowest available* descriptor number"  
[X Link](https://x.com/popovicu94/status/1997497525738394088)  2025-12-07T02:44Z 11.3K followers, XXX engagements


"To redirect output the shell performs a clever switcheroo before running your command: X. It opens your target file (getting say ID/fd 3). X. It closes stdout (fd 1). 🚫 X. It immediately calls dup(3). Because fd X is now the "lowest available" slot the kernel forces the file connection into fd 1"  
[X Link](https://x.com/popovicu94/status/1997497527218971049)  2025-12-07T02:44Z 11.3K followers, XXX engagements


"While dup demonstrates the logic production code often uses its sibling dup2(old new). dup2 allows you to specify exactly which number you want (e.g. "put this file at 1"). It performs the close-and-copy atomically preventing race conditions where another thread might steal ID X in between steps"  
[X Link](https://x.com/popovicu94/status/1997497531673223428)  2025-12-07T02:44Z 11.3K followers, XXX engagements


"This mechanism is the heart of the Unix philosophy. Programs don't need complex code to write to files pipes or sockets. They just write to fd X. The shell decides where fd X goes before the program even starts. It's the ultimate separation of concerns"  
[X Link](https://x.com/popovicu94/status/1997497533007048957)  2025-12-07T02:44Z 11.3K followers, 1002 engagements


"Throwback #1 spot orange site flex. My article on building a custom OS kernel from scratch was at the very top. Check it out if you want to see how a super simplified kernel is built for RISC-V. For added color the project is in Zig. Full text 🔗:"  
[X Link](https://x.com/popovicu94/status/1997790448648364108)  2025-12-07T22:08Z 11.3K followers, 6507 engagements


"@marcosnils I was having a similar thought for my Garmin watch. Can't it automatically figure out when I'm starting my workout or do I really need to press it every time I start"  
[X Link](https://x.com/popovicu94/status/1997852717386240158)  2025-12-08T02:16Z 11.3K followers, XXX engagements


"I'm sure you folks know about the CC flag when running 'make' on Linux. But how about CC_FOR_BUILD I'm currently hacking away on something like LFS and some packages get tripped when CC_FOR_BUILD isn't configured properly. Let me know if you know what I'm talking about. 🐧👇"  
[X Link](https://x.com/popovicu94/status/1998264491948319166)  2025-12-09T05:32Z 11.3K followers, 1796 engagements


"@456c6f727269 C and Unix/Linux are inseparable More important than understanding C itself is what is its position with regards to the kernel and OS in general. Keep following and reposting and I think you'll learn fast"  
[X Link](https://x.com/popovicu94/status/1998294564374032704)  2025-12-09T07:32Z 11.3K followers, XX engagements


"@milan_milanovic The most interesting stacks I've seen are the ones that just stupidly simple yet scale quite well beyond all odds. I've seen people give up on a proper database setups only to hardcode data in their server binary and only to realize. it's good enough"  
[X Link](https://x.com/popovicu94/status/1998295830554652732)  2025-12-09T07:37Z 11.3K followers, XXX engagements