I’ve found a new great blog, Gustavo Duarte’s blog, where he talks about hardware, operating system kernerls, and other fun items.

I liked his comparison of how fast different types of memory is.

The first thing that jumps out is how absurdly fast our processors are. Most simple instructions on the Core 2 take one clock cycle to execute, hence a third of a nanosecond at 3.0Ghz. For reference, light only travels ~4 inches (10 cm) in the time taken by a clock cycle…

Normally when the CPU needs to touch the contents of a memory region they must either be in the L1/L2 caches already or be brought in from the main system memory … To put this into perspective, reading from L1 cache is like grabbing a piece of paper from your desk (3 seconds), L2 cache is picking up a book from a nearby shelf (14 seconds), and main system memory is taking a 4-minute walk down the hall to buy a Twix bar…

[...] Even main memory is blazing fast compared to hard drives. Keeping with the office analogy, waiting for a hard drive seek is like leaving the building to roam the earth for one year and three months. This is why so many workloads are dominated by disk I/O and why database performance can drive off a cliff once the in-memory buffers are exhausted …

Subscribed. :)