Core metrics we need to know are: the power of 2, latency numbers, availability, storage..

The Power Of 2

Starting with the power of two, as it showcases the size of data we are working with.

1 byte is equal to 8 bits (each bit is either 1 or 0) hence we have the concept of ‘power of 2’. The table with rough estimations is:

• 2^10 = 1,000 bytes = 1 Kilobyte
• 2^20 = 1 Megabyte
• 2^30 = 1 Gigabyte
• 2^40 = 1 Terabyte
• 2^50 = 1 Petabyte

Latency

Next up we have latency. Some engineer from Google (forgot the name ☹️) calculated and came up with rough numbers on the core ops we do with the computer. It’s important to note that these numbers may have decreased since the initial calculations as computers in general have progressed a lot and processors are being optimized constantly.

The times we are working with are, in order:

• nanoseconds
• microseconds = 1,000 nanosecs
• milliseconds = 1,000 microsecs
• seconds = 1,000 millisecs

Here are the rough estimates:

• L1 Cache hit - 1 nanosecs
• L2 Cache hit - 10 nanosecs
• 1 MB read from memory - 250 microsecs