this post was submitted on 27 Dec 2023
144 points (69.6% liked)

Technology

59671 readers
3627 users here now

This is a most excellent place for technology news and articles.


Our Rules


  1. Follow the lemmy.world rules.
  2. Only tech related content.
  3. Be excellent to each another!
  4. Mod approved content bots can post up to 10 articles per day.
  5. Threads asking for personal tech support may be deleted.
  6. Politics threads may be removed.
  7. No memes allowed as posts, OK to post as comments.
  8. Only approved bots from the list below, to ask if your bot can be added please contact us.
  9. Check for duplicates before posting, duplicates may be removed

Approved Bots


founded 1 year ago
MODERATORS
 

I often find myself explaining the same things in real life and online, so I recently started writing technical blog posts.

This one is about why it was a mistake to call 1024 bytes a kilobyte. It's about a 20min read so thank you very much in advance if you find the time to read it.

Feedback is very much welcome. Thank you.

you are viewing a single comment's thread
view the rest of the comments
[–] wischi@programming.dev 1 points 11 months ago (1 children)

Not even SSDs are. Do you have an SSD? You should lookup the exact drive size in bytes, it's very likely not an exact power of two.

[–] gens@programming.dev 1 points 11 months ago (1 children)

Checked and true. 500107862016 bytes.

Still, ssds are made of n^2 chips.

[–] wischi@programming.dev 1 points 11 months ago* (last edited 11 months ago) (1 children)

The underlying chips certainly are exact powers of two but the drive size you get as a consumer is practically never an exact power of two, that's why it doesn't really make sense to divide by 1024.

The size you provided would be 500107862016 / 1024 / 1024 / 1024 = 465.76174163818359375 GiB

Divided by 1000³ it would be 500.107862016 GB, so both numbers are not "pretty" and would've to be rounded. That's why there is no benefit in using 1024 for storage devices, even SSDs.

The situation is a bit different with RAM. 16 "gig" modules are exactly 17179869184 bytes. https://www.wolframalpha.com/input?i=prime+factors+of+17179869184

So you could say 17.179869184 GB or 16 GiB. Note that those 16 GiB are not rounded and the exact number of bytes for that RAM module. So for memory like caches, RAM, etc. it definitely makes sense to use binary prefixes with 1024 conversion but for storage devices it wouldn't make a difference because you'd have to round anyway.

[–] gens@programming.dev 1 points 11 months ago (1 children)

It's the size in bytes as the os sees it (and in SMART). And i do know how to use a calculator, thank you.

There is also no benefit to using 1000. Except to hdd makers.

[–] wischi@programming.dev 1 points 11 months ago* (last edited 11 months ago) (1 children)

There is a benefit in using 1000 because it's consistent with all the other 1000 conversions from kg to gramm, km to meter, etc. And you can do it in your head because we use a base 10 number system.

36826639 bytes are 36.826639 MB. But how many MiB? I don't know, I couldn't tell you without a calculator.

[–] gens@programming.dev 1 points 11 months ago* (last edited 11 months ago)

You don't have to know. It does not matter because your 8GB stick can't fit 16 512MB files anyway. Funny enough it might fit 500MB files if it is FAT32.

Being consistent with base10 systems does not matter in real world usage. Literally nobody cared before the asshats changed it.

Edit: i also understand si, down to its history. I don't live in an inch country. Computing is different then physical measurements. In computing 1024 is more "correct".