Tech-Reader.blog

  The Immutable Exhibition: Why Tuples Never Change Timothy had mastered lists for organizing books, but one afternoon Margaret led him to a restricted section of the library: The Locked Display Cases. Here, collections were sealed behind glass—visible but permanently unchangeable. The Permanent Collections "These are tuples," Margaret explained, gesturing to the display cases. "They look similar to lists but with one crucial difference: once created, they can never be modified." Timothy examined a case containing coordinate pairs for mapping the library: main_entrance = ( 42 , 15 ) # x, y coordinates rare_books_section = ( 108 , 73 ) # Can read the values x_position = main_entrance [ 0 ] # 42 y_position = main_entrance [ 1 ] # 15 # Cannot modify them main_entrance [ 0 ] = 50 # TypeError: tuple doesn't support item assignment The parentheses instead of square brackets signaled this permanent nature. Once the coordinates were set, they rema...

  Error: 404 Not Found — When Missing Keys Look Like Outages # aws # s3 # devops # cloud Subtitle: Why absent objects masquerade as broken buckets. Problem It’s mid-shift, traffic is steady, and suddenly your app starts failing with: <Error> <Code>NoSuchKey</Code> <Message>The specified key does not exist.</Message> </Error> To the business, this looks like an outage — the bucket appears broken, customer data appears missing. But the truth? The bucket is fine. It’s the  key  (object path) that doesn’t exist. Clarifying the Issue The  404 Not Found / NoSuchKey  error means the object you’re trying to access isn’t present at that path. Common causes include: Typos in object keys ( Invoice-2023.pdf  vs.  invoice-2023.pdf ). Case sensitivity mismatches — S3 object keys are strictly case-sensitive. Misconfigured prefixes or folder paths. Lifecycle rules expiring or transitioning objects to Glacier. Applications assumi...

  The Code We Leave Behind # python # coding # programming # softwaredevelopment Grace Hopper's keynote at AWS re:Invent 2025 Rear Admiral Grace Hopper (1906-1992) pioneered compiler theory and made programming accessible to everyone. She believed that the most dangerous phrase in any language was "we've always done it this way." This is Part 3 of an ongoing series imagining Grace Hopper reviewing modern Python code. What would she say to 10,000 developers at the world's largest cloud computing conference? The stage at AWS re:Invent is enormous. Ten thousand developers fill the convention hall, laptops glowing in the dimmed lights. The screen behind me—a wall of pure light—displays a single line of code in stark white text on a black background. I'm 119 years old, technically. My knees protest every time I stand, but my mind is as sharp as it was in 1952. And I have things to say. "Good morning," I begin. "I'm Grace Hopper, and I'm here ...