ClassInBytes (@classinbytes)

Your USB drive can queue behind your SSD. Here is how chipset connections share one link to the CPU. The graphics card gets a direct path, while USB, storage and network go through the chipset. Check your board specs before you plug fast drives into every port. Which two ports do you use at the…

Paid once, charged twice: a lost ACK makes the queue redeliver the same payment event. One idempotency key makes the second run do nothing. Which task in your system would run twice today? Save it before your next payment flow. #idempotency #messagequeue #atleastonce #backend #payments

Two identical M.2 SSDs, and your slot may accept only one. M.2 SATA vs NVMe, explained in a minute. Check form factor, interface and link bandwidth before you buy. Which M.2 drive is in your PC right now, SATA or NVMe? Part 16 of 28. Send this to a friend about to order an M.2 drive. #pcbuilding…

You paid for 16 PCIe lanes, and your game loads no faster. 🎮 How PCIe lanes and generations set bandwidth, and why a long x16 slot may be wired for only 4 lanes. Which slot is your graphics card in right now? Part 15 of 28. Send this to the friend who is about to pay extra for a bigger slot. #pcie…

Three servers, one delete, three empty servers: redundancy is not a backup. Replicas keep your service running. Only a backup snapshot gets old data back. Which of your databases has a backup you have actually restored? Part 10 of 27. Save it for your next disaster recovery review. #redundancy…

Your new graphics card fits the slot and still does nothing. Motherboard connections decide what really works together. CPU socket, RAM slots, PCIe, M.2 and SATA, plus the power routes that run separately. Which slot is your graphics card in? Part 14 of 28. Send this to someone choosing parts for…

A copied session token logs in as you, which is why Instagram never asks for your password again. How a session cookie works, how session hijacking needs no password, and the three flags that protect it. Where does your app keep its session token: a cookie or localStorage? Send it to a web…

Claude wrote over 80% of the code that builds the next Claude. That is AI building AI, and models now arrive 1.9 times faster. People still steer the loop, but every lap leaves the safety checks less time. Which worries you more: the speed or the shorter checks? #ai #anthropic #claude #aisafety…

More VRAM won't give you more FPS. VRAM capacity says how much fits, not how fast the GPU runs. Why two graphics cards with the same VRAM can run the same game at different speeds. Which number do you check first when you compare graphics cards? Part 13 of 28. Send this to a friend who is about to…

30,000 changes a day broke Git, so Anthropic moved its main repository to Scion. GitHub stayed for public projects. Why Git struggles with AI agents, and the difference between Git and GitHub. Which tool should we look at next: the code review that has to keep up? Send it to the one who thinks AI…

All that Scrum jargon fits on one screen. Scrum explained as one loop. The backlog, three roles, quality gates, gauges, and your own one-week sprint. Which Scrum piece is still fuzzy for you? Part 24 of 24. Send this to someone starting their first sprint. #agile #scrum #scrumframework…

Password plus PIN is not two-factor: one phishing page steals both. Here is what multi-factor authentication really needs. Know, have, are: three categories, and a thief with your password still stops at the second gate. Which two factors guard your main email right now? Part 8 of 27. Send it to…

Becoming a Scrum Master: your Scrum certificate takes an afternoon, but getting hired doesn't. PSM I vs CSM, how to prepare, and the stories that win the job. Which would you show first: a certificate or a retro you ran? Part 23 of 24. Send this to a friend who wants to be a Scrum Master. AI…

No lock broke on 29 October 2026: a LinkedIn job offer led to about 6.3 billion dollars leaving Binance, says Bloomberg. The Binance hack explained. How a fake job offer scam and one unchecked download reached a work laptop, and the 3 rules that protect you in any interview. #cybersecurity…

Your team hits 50 people and suddenly nothing ships. Scaling Scrum, explained. Ten people have 45 communication lines, fifty have 1,225. The fix: small teams, one backlog, a Scrum of Scrums. How many people work on your product? Part 22 of 24. AI voice. #agile #scrum #scalingscrum #scrumofscrums

Eight cores, and your export took exactly as long. Cores vs threads, explained. Why a chain of tasks leaves seven cores idle, and why 16 threads are not 16 cores. How many cores and threads does your PC list? Part 11 of 28. Send this to a friend who is about to buy a processor. AI voice. #cpu…

You added eight servers and the site got no faster. A load balancer helps throughput, not one slow request. Why you measure the bottleneck before you scale: throughput vs latency in about a minute. Which bottleneck should we break down next? Comment your pick. Part 6. Save it for your next System…

Amdahl's law explained: make 90% of your code instant, and it's still only 10x faster. Speed up 36 seconds of a 40-second run 9 times, and the whole run is just 5x faster. Here's why. Which part of your code refuses to get faster? Part 11 of 16. AI voice. #programming #computerarchitecture…

Your 16 GB of RAM can have twice the bandwidth. Here is how RAM bandwidth and dual channel work. Capacity is size, bandwidth is speed, and the notch keeps DDR4 and DDR5 apart. Which slots are your RAM sticks in right now? Part 10 of 28. Send this to a friend about to buy RAM. AI voice. #ram…

Your work is outside IT, but Scrum might still fit it. Scrum outside IT: marketing, hardware, research, and the one kind of work where it doesn't belong. Which bin is your work in: checklist or Scrum? Part 21 of 24. Send this to a friend who works outside IT. AI voice. #agile #scrum…

The padlock does not mean the site is honest. What does the padlock mean in your browser? HTTPS hides and seals the road, but a scam site can wear the same lock. Which site did you last trust just because of the padlock? Part 5 of 27. Send it to someone who trusts the padlock alone. AI voice…

Your 5 GHz processor can lose to a 4 GHz one. Clock speed vs performance, in one race. Same job: 8 seconds for 5 GHz, 5 seconds for 4 GHz. Work per tick decides. Which number do you check first when you compare processors? Part 9 of 28. Send this to anyone choosing a computer by gigahertz alone…

You retried the 429 instantly, and the API got worse. A retry is more load, not a fix. How a 429 Too Many Requests turns into a retry storm, and how exponential backoff with jitter spreads it out. Do you add jitter to your retries, or just a fixed sleep? Part 4 of 27. Send it to whoever writes…

Server utilization and power: your idle servers still eat about half their power. Pack the work onto fewer machines and energy per job drops, but leave no headroom and the next burst fills the queues. Which of your servers sits mostly idle right now? Part 15 of 16. AI voice. #serverutilization…

A sharper picture can make the same game run slower: more pixels means more GPU work per frame. Why does higher resolution lower FPS? 1080p to 1440p is 78% more pixels, and your monitor's hertz stays fixed. Which resolution do you play at? Part 8 of 28. Send this to the friend who cranks every…

One leaked table can show your password to everyone, unless it is hashed. Why hashing beats encryption for passwords, and how login still works without the original. Which one did your last project use: plain text, encrypted or hashed? Part 3 of 27. Save it for your next backend project. AI voice…

Your site loads for you but not for your customer. A wrong DNS record can do that: A record, AAAA record or CNAME? A number, a longer number, or "see another name", and what a proxy hides. Which record does your www use right now? Part 3 of the DNS test. Send this to the junior dev who just got a…

Your faster chip can make your small job slower. Hardware accelerator overhead, explained with one example: 10 items take 31 ms instead of 10 ms. At about 34 items the accelerator breaks even, and by 1000 items it wins. Have you ever moved a job to a faster tool and found it slower? Part 14 of 16…

Scrum for remote teams: your morning standup is midnight for a teammate 9 hours away. Here's the fix. 1 shared hour, one online board, and every decision written down. What time is your standup for your furthest teammate? Part 19 of 24. AI voice. #agile #scrum #remotework #remoteteams #dailystandup

VPN is on, but the site still knows you. Does a VPN make you anonymous? Not from everyone. Your ISP sees a tunnel, the VPN provider sees the sites, the website sees your cookies. Which observer are you hiding from? Part 2 of 27. Save it as a mini threat model for anyone who thinks VPN equals…