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Networking certifications like CompTIA Network+ and Cisco's CCNA are career-defining credentials. They validate your understanding of networking fundamentals — and both exams test OSI Model knowledge extensively. In fact, the OSI Model is arguably the single most tested conceptual framework in entry-level and intermediate networking certifications. Why OSI Is So Critical for Certification Exams Exam questions on OSI take many forms: "At which layer of the OSI model does a router operate?" (Layer 3) "What PDU is used at the Transport Layer?" (Segment) "Which protocol operates at the Application Layer?" (HTTP, DNS, SMTP...) "A user cannot connect to a website. Troubleshooting should begin at which OSI layer?" (Layer 1, then up) "Which device operates at Layer 2?" (Switch) "What is the function of the Presentation Layer?" (Translation, encryption, compression) These questions seem straightforward on paper but are notoriously confusing under exam pressure without deep conceptual understanding. How the OSI Simulator Accelerates Your Studies Visual Memory Formation Research in cognitive science consistently shows that visual and kinesthetic learning creates stronger memories than text-only reading. When you watch the OSI Simulator animate your message through all seven layers, you're forming episodic memories — vivid, experience-based memories that are far more durable than rote memorization. Protocol-to-Layer Association One of the most commonly missed exam categories is protocol-to-layer mapping. The OSI Simulator makes this automatic: when you select HTTP, the Application Layer is highlighted. When you watch TCP headers form, you associate TCP with Layer 4 viscerally, not just verbally. PDU Name Mastery Data, Segment, Packet, Frame, Bits — the five PDU names are shown explicitly at each layer in the simulator. After running 10 simulations, these names become second nature. No flashcard can match this experiential learning. Troubleshooting Framework Practice Network+ an

Hello, my name is Greg. About six months ago I started using AI chatbots like ChatGPT and Claude at work for small tasks — proofreading emails, summarizing meeting notes, that kind of thing. But also some technical stuff too. One thing that really came in handy was analyzing packet captures from Wireshark. I work with VoIP phone systems, and when things go wrong, feeding a PCAP file into an AI chatbot speeds up the troubleshooting process dramatically. Before long I was asking AI to write code. First simple HTML pages, then Python, then C#. I was amazed by the results. These weren't big projects — just small experiments — but they came to life in minutes instead of days. I found out there was already a term for this: vibe coding . Perfect, I thought. I made project after project and wanted to share the excitement with other people who were surely doing the same thing. I created a free learning website, published a book on Kindle Unlimited, and went looking for a community. I landed on Reddit. There were already vibe coding subreddits. I thought — this is great, I've found my people. Then reality hit. These communities had "vibe coding" in the name, but they weren't exactly vibe coding friendly. The term had already been claimed by people focused on monetizing their creations fast, with little interest in actually learning to code. That created a massive anti-vibe-coding crowd on the other side, and honestly there was an all-out war going on between them. Not really the place for someone just looking to share cool stuff they made. I came to a realization: I wasn't really a vibe coder — at least not the kind people were arguing about. I wasn't in it for the money. I was in it for the fun. I didn't mind learning programming concepts along the way. I wasn't trying to sell anything or launch a startup. I just liked making things and solving problems. So I retreated and regrouped. That's when I found a better description: Play-First Programmers . People who start by playi

Getting started with the OSI Model Simulator takes less than 60 seconds. The interface is thoughtfully designed to be intuitive for beginners while offering enough depth to satisfy advanced learners. Here's your complete step-by-step guide. Step 1: Open the Simulator Navigate to app.osi-model-simulator.roboticela.com in any modern web browser. No account required, no download necessary, and no cost. The app loads instantly and is ready to use immediately. Alternatively, visit the landing page to learn more about features and download the desktop app for offline use. Step 2: Enter Your Message In the message input field, type any text you like. This is the "data" your simulation will encapsulate. Examples: Hello, World! GET /index.html HTTP/1.1 {"user": "alice", "action": "login"} Your own name or a phrase you'll remember Using a personally meaningful message makes the encapsulation feel real rather than abstract. Step 3: Choose Your Protocol Select from five real protocols: HTTP, HTTPS, SMTP, DNS, or FTP. Each choice changes the Application Layer headers added to your data. For beginners, start with HTTP. Then re-run with HTTPS to see the Presentation Layer encryption difference. Step 4: Choose Your Transmission Medium Select your Physical Layer medium: Ethernet, Wi-Fi, Fiber Optic, Coaxial, or Radio. This affects how the Physical Layer is visualized at the end of the simulation. Step 5 (Optional): Set Custom IP Addresses For a more realistic Network Layer demonstration, enter a source IP address (simulating your device) and a destination IP address (simulating the server). This makes the Layer 3 packet header concrete and personally relevant. Step 6: Run the Simulati on Click the Run or Start button. Watch as your message travels through all seven layers: Application Layer adds protocol headers Presentation Layer adds encryption (if HTTPS) Session Layer adds session management Transport Layer segments and adds TCP/UDP header Network Layer wraps in IP packet Data Li

The Physical Layer's choice of transmission medium profoundly affects the performance, cost, security, and reliability of a network. The OSI Model Simulator supports all five major media types — making it a powerful tool for understanding how physical choices ripple up through all seven OSI layers. Medium Speed Max Distance Security Cost Ethernet Up to 10 Gbps+ 100m (Cat6a) High (physical access) Low Wi-Fi Up to ~9.6 Gbps (Wi-Fi 6) ~100m indoor Medium (WPA3) Low Fiber Optic Terabits/s 100s of km Very High High Coaxial Up to 1 Gbps 500m (RG-8) Medium Medium Radio Variable (5G: Gbps) km to global (satellite) Low–Medium Variable Ethernet: The Reliable Standard Ethernet is the dominant wired networking standard in homes, offices, and data centers. Using twisted-pair copper cables (Cat5e, Cat6, Cat6a), it provides reliable, high-speed connectivity with predictable latency. The IEEE 802.3 standard governs Ethernet, and modern variants include 1GbE, 10GbE, 25GbE, 40GbE, and 100GbE. Wi-Fi: Wireless Freedom Wi-Fi (IEEE 802.11) eliminated the need for physical cables in most consumer settings. Wi-Fi 6 (802.11ax) and Wi-Fi 6E deliver impressive speeds, but shared medium access, interference, and radio propagation challenges mean it will never fully replace wired Ethernet for critical applications. Fiber Optic: The Internet's Backbone Fiber optic cables carry data as pulses of light through glass or plastic strands. They're immune to electromagnetic interference, support enormous bandwidth, and can span continents — literally. Every major internet exchange, submarine cable, and data center interconnect uses fiber. Coaxial Cable: The Cable TV Legacy Coaxial cable — familiar from cable TV connections — consists of a central conductor surrounded by insulating layers and a braided metal shield. DOCSIS-based cable internet connections (common from ISPs like Comcast) use coaxial as the last-mile medium. Radio: Wireless at Scale From the cellular 5G network in your pocket to satellite

It's important to monitor Dataform - jobs executed by Dataform can be the primary source of BigQuery costs in a modern data platform. Forgetting to incrementalise a table, using a table instead of a view in the wrong place or performing complex window functions on a large table can all incur large costs and long run times. Using the WorkflowInvocationAction for each job we can extract its BigQuery Job ID, then extract key metadata for each BigQuery job by querying INFORMATION_SCHEMA.JOBS_BY_PROJECT , before writing the output back to BigQuery so that it can be analysed (maybe even by transforming it in Dataform). from google.cloud import dataform_v1 from google.cloud import bigquery from datetime import datetime # ------------------------------------------------------------ # CONFIG # ------------------------------------------------------------ PROJECT_ID = " my-project " REGION = " europe-west2 " REPOSITORY_ID = " analytics " WORKFLOW_INVOCATION_ID = " 123456789 " BQ_REGION = " region-europe-west2 " OUTPUT_TABLE = " my-project.raw_dataform_monitoring.raw_dataform_bigquery_metrics " # ------------------------------------------------------------ # CLIENTS # ------------------------------------------------------------ dataform = dataform_v1 . DataformClient () bq = bigquery . Client ( project = PROJECT_ID ) repository = dataform . repository_path ( PROJECT_ID , REGION , REPOSITORY_ID ) invocation_name = f " { repository } /workflowInvocations/ { WORKFLOW_INVOCATION_ID } " # ------------------------------------------------------------ # 1. GET WORKFLOW INVOCATION ACTIONS → EXTRACT JOB IDS # ------------------------------------------------------------ job_ids = set () actions = dataform . list_workflow_invocation_actions ( parent = invocation_name ) for action in actions : # only BigQuery actions contain job metadata if hasattr ( action , " bigquery_action " ) and action . bigquery_action : if action . bigquery_action . job_id : job_ids . add ( action . bigquery_action

Plus, a whole bunch of neat demos ahead of Steam Next Fest.

Hi, friends! Welcome to Installer No. 131, your guide to the best and Verge-iest stuff in the world. (If you're new here, welcome, happy last week of productivity before the World Cup starts, and also you can read all the old editions at the Installer homepage.) This week, I've been reading about the World Cup […]

What’s the difference between a person, an artifact, and an ecosystem?

submitted by /u/f311a [link] [留言]

Hello, I'm Maneshwar. I'm building git-lrc, a Micro AI code reviewer that runs on every commit. It is...

Published on : 2026-06-06 Reading time : 6 min Tags : #python #async #performance #optimization The Problem: Fake Async The supabase-async library claimed to be async but actually wrapped synchronous calls with ThreadPoolExecutor: # ❌ Fake async (old code) class SupabaseAsync : def __init__ ( self ): self . _executor = ThreadPoolExecutor ( max_workers = 3 ) async def select ( self , table : str ): loop = asyncio . get_event_loop () r = await loop . run_in_executor ( self . _executor , lambda : requests . get ( url ) # Sync call wrapped as async ) return r . json () Problems : Max 3 concurrent requests (not scalable) Thread overhead per request High memory usage No connection pooling Solution: httpx AsyncClient Use true async HTTP with httpx: # ✅ Real async (new code) import httpx class SupabaseAsync : def __init__ ( self ): self . _client : Optional [ httpx . AsyncClient ] = None async def _get_client ( self ) -> httpx . AsyncClient : if self . _client is None : self . _client = httpx . AsyncClient ( headers = self . _headers , timeout = 30 , limits = httpx . Limits ( max_connections = 10 ) ) return self . _client async def select ( self , table : str ): client = await self . _get_client () r = await client . get ( f " { self . _base } / { table } " ) r . raise_for_status () return r . json () Performance Gains Metric ThreadPoolExecutor(3) httpx(10) Max concurrent 3 requests 10 requests Avg response 450ms 150ms Memory usage 250MB 180MB Throughput 6.7 req/s 20 req/s Real benchmark : 100 concurrent requests ThreadPoolExecutor: 15 seconds httpx AsyncClient: 5 seconds 3x faster ⚡ Migration Steps 1. Client Initialization with Lazy Loading async def _get_client ( self ) -> httpx . AsyncClient : if self . _client is None : self . _client = httpx . AsyncClient ( headers = self . _headers , timeout = 30 , limits = httpx . Limits ( max_connections = 10 , max_keepalive_connections = 5 ) ) return self . _client 2. HTTP Methods (GET, POST, etc.) async def _request ( self , metho

I'm making this Arduino project for my maths class and column 4 on the keypad isn't working. This is how I want the buttons to work: A -> start over (whole game) B ->skip question C -> clear D -> delete one space What mistaks did I do and how exactly can I fix them? Thank youu <3 submitted by /u/livie4lifexx [link] [留言]

If you've ever hit Unexpected token in JSON at position 42 or Unterminated string , there's a good chance an unescaped character broke your payload. JSON is strict about what's allowed inside a string, and the fix is almost always escaping . Here's the practical version. What does escaping a JSON string mean? A JSON string is wrapped in double quotes. Any character that would confuse the parser must be replaced with a backslash escape sequence. Escaping doesn't change the meaning of your text — it just makes the string valid JSON so parsers can read it. Unescaping is the reverse: turning those sequences back into readable characters (handy when you copy a value out of logs or an API response). The characters you must escape JSON defines exactly seven characters that must be escaped inside a string: Character Escaped as Double quote " \" Backslash \ \\ Newline \n Carriage return \r Tab \t Backspace \b Form feed \f The forward slash / may optionally be escaped as \/ , but it isn't required. Unicode can be written as \uXXXX (four hex digits). JSON escape examples Double quotes — He said "hello" becomes: "He said \" hello \" " Backslashes (Windows paths) — C:\temp\file.txt becomes: "C: \\ temp \\ file.txt" Newlines and tabs — a two-line, tabbed string becomes: "Line 1 \n Line 2 \t Tabbed" How to escape and unescape JSON in code In production you rarely escape by hand — every language has it built in. JavaScript const escaped = JSON . stringify ( text ); // escape const back = JSON . parse ( escaped ); // unescape Python import json escaped = json . dumps ( text ) # escape back = json . loads ( escaped ) # unescape Java (Jackson) ObjectMapper mapper = new ObjectMapper (); String escaped = mapper . writeValueAsString ( text ); String back = mapper . readValue ( escaped , String . class ); C# (.NET) using System.Text.Json ; string escaped = JsonSerializer . Serialize ( text ); string back = JsonSerializer . Deserialize < string >( escaped ); Common escaping mistakes (and f

In the last update, I introduced MDL as an HTML-first language for building websites and apps with less noise. This update is about the next layer: adapters . The goal is simple: MDL source should describe intent. Adapters decide how that intent becomes deployable HTML. Why adapters? I don’t want MDL to become locked into one frontend framework. Instead, the same MDL structure should be able to target different deployment styles: static HTML MDL-native runtime attributes HTMX future template or framework adapters So this: form@api(post /api/login)@result(loginResult)@swap(replace): .input@type(email)@required .btn-primary@type(submit)(Sign in) status@id(loginResult): Waiting. Can become plain HTML: html <form method= "post" action= "/api/login" > Or HTMX: html <form hx-post= "/api/login" hx-target= "#loginResult" hx-swap= "outerHTML" > Security before convenienceThe important part is that MDL does not pass behavior attributes through blindly. Raw HTMX attributes like this are blocked: mdl form@hx-post(/api/login): Instead, MDL uses intent-based attributes: mdl form@api(post /api/login): Then the adapter validates and translates it. Current safety rules include: external api(...) URLs are rejected raw @hx-* attributes are blocked raw browser events like onclick(...) are blocked unsafe URL schemes like javascript: are blocked broad form inclusion like @params( ) is blocked @inherit( ) is blocked @disinherit(*) is allowed because disabling inherited behavior is safer That means MDL can support HTMX without making MDL source depend directly on HTMX’s full raw surface area. New HTMX adapter attributesThe HTMX v2 adapter now supports more behavior attributes: mdl @select-oob(...) @swap-oob(...) @disabled(...) @disinherit(...) @encoding(...) @history-elt(...) @inherit(...) @params(...) @preserve(...) @prompt(...) @replace(...) @request(...) @sync(...) @validate(...) Example: mdl form@api(post /api/profile)@result(profileResult)@swap(replace)@params(email csrfToken)@disable

Published on : 2026-06-06 Reading time : 6 min Tags : #python #async #performance #optimization 문제: 거짓 비동기 supabase-async 라이브러리는 이름은 async이지만, 실제로는 ThreadPoolExecutor로 동기 호출을 래핑하고 있었습니다. # ❌ 거짓 비동기 (기존 코드) class SupabaseAsync : def __init__ ( self ): self . _executor = ThreadPoolExecutor ( max_workers = 3 ) async def select ( self , table : str ): loop = asyncio . get_event_loop () r = await loop . run_in_executor ( self . _executor , lambda : requests . get ( url ) # 동기 호출을 async로 포장 ) return r . json () 문제점 : 최대 3개 동시 요청만 가능 (동시성 부족) 스레드 오버헤드 (각 요청마다 스레드 생성) 높은 메모리 사용량 해결책: httpx AsyncClient 진정한 비동기 HTTP 클라이언트인 httpx를 사용합니다. # ✅ 진정한 비동기 (수정된 코드) import httpx class SupabaseAsync : def __init__ ( self ): self . _client : Optional [ httpx . AsyncClient ] = None async def _get_client ( self ) -> httpx . AsyncClient : if self . _client is None : self . _client = httpx . AsyncClient ( headers = self . _headers , timeout = 30 , limits = httpx . Limits ( max_connections = 10 ) ) return self . _client async def select ( self , table : str ): client = await self . _get_client () r = await client . get ( f " { self . _base } / { table } " ) r . raise_for_status () return r . json () 성능 개선 동시성 비교 지표 ThreadPoolExecutor(3) httpx(10) 최대 동시 요청 3개 10개 평균 응답 시간 450ms 150ms 메모리 사용량 250MB 180MB 초당 처리량 6.7 req/s 20 req/s 벤치마크 # 100개 동시 요청 처리 시간 ThreadPoolExecutor : 15 초 httpx AsyncClient : 5 초 → 3 배 빠름 마이그레이션 단계 1. 클라이언트 초기화 async def _get_client ( self ) -> httpx . AsyncClient : if self . _client is None : self . _client = httpx . AsyncClient ( headers = self . _headers , timeout = 30 , limits = httpx . Limits ( max_connections = 10 , max_keepalive_connections = 5 ) ) return self . _client 2. 요청 메서드 async def _request ( self , method : str , url : str , ** kwargs ): client = await self . _get_client () if method == " GET " : return await client . get ( url , ** kwargs ) elif method == " POST " : return await client . post ( url , ** kwargs ) # ... 3. Context Manager 지원 async def clos

New simulations reveal that the moons of Uranus may retain traces of giant planets.

At a small kickoff event in Los Angeles, Dan Greaney explained why he could no longer stand by and watch the demolition of American democracy.

submitted by /u/lelanthran [link] [留言]

maybe this should be asked in the Fc26 game subreddit but not sure. Anyway I just saw a video of someone predicting the winner of the world cup using the simulate match feature in the game but he only did it once. Would running this feature 100-1000 times give a significant result ? or is that feature only based on luck ? submitted by /u/Stillane [link] [留言]

submitted by /u/andersmurphy [link] [留言]