Re:Computer Latency at a Human Scale
by Yen on Wednesday March 20, 2019 @10:06PM
(#19448736)
I've been wanting to do a similar thing, but also bring memory/storage into the human scale as well.
A byte is approximately a single letter.
A 4kb page of memory is approximately a single-sided piece of paper.
A 32kb L1 cache is 16 pages, spread on the desk, though you may prefer to think of 512 64-byte post-it notes. You could probably find and read a note in ~2s.
A 256kb L2 cache is a 64-page binder on the desk. Plausible to find a page in ~7s.
A 8MB L3 cache is a filing cabinet or small bookshelf, with 32 binders. It might take a minute to walk over, identify the right book, pull it out, find a page, find a sentence.
8GB of RAM is a sizable library, though far from the largest ever - rows & rows of bookshelves, 512 large shelves in total, 64 books each. If you knew right where you were going, it might take a few minutes to fetch the right book.
A 1TB SSD is 4 million books, among the largest libraries today, or perhaps a warehouse.
If that 1TB is instead a HDD, you can't actually browse the stacks - instead, there's a staircase outside the building, and you can reach in through the window on any floor - the entire building rotates, at the blistering pace of a full rotation every 8 months.
A byte is approximately a single letter.
A 4kb page of memory is approximately a single-sided piece of paper.
A 32kb L1 cache is 16 pages, spread on the desk, though you may prefer to think of 512 64-byte post-it notes. You could probably find and read a note in ~2s.
A 256kb L2 cache is a 64-page binder on the desk. Plausible to find a page in ~7s.
A 8MB L3 cache is a filing cabinet or small bookshelf, with 32 binders. It might take a minute to walk over, identify the right book, pull it out, find a page, find a sentence.
8GB of RAM is a sizable library, though far from the largest ever - rows & rows of bookshelves, 512 large shelves in total, 64 books each. If you knew right where you were going, it might take a few minutes to fetch the right book.
A 1TB SSD is 4 million books, among the largest libraries today, or perhaps a warehouse.
If that 1TB is instead a HDD, you can't actually browse the stacks - instead, there's a staircase outside the building, and you can reach in through the window on any floor - the entire building rotates, at the blistering pace of a full rotation every 8 months.