girish

What I Wish I'd Known About Equity Before Joining A Unicorn

Disclaimer: This piece is written anonymously. The names of a few particular companies are mentioned, but as common examples only.

This is a short write-up on things that I wish I'd known and considered before joining a private company (aka startup, aka unicorn in some cases). I'm not trying to make the case that you should never join a private company, but the power imbalance between founder and employee is extreme, and that potential candidates would

girish

import bisect

class NFA(object):
  EPSILON = object()
  ANY = object()
  
  def __init__(self, start_state):
    self.transitions = {}
    self.final_states = set()
    self._start_state = start_state

girish

#! /usr/bin/env python
import fileinput
import argparse
from operator import itemgetter

parser = argparse.ArgumentParser()
parser.add_argument('--target-mb', action = 'store', dest = 'target_mb', default = 61000, type = int)
parser.add_argument('vmtouch_output_file', action = 'store', nargs = '+')
args = parser.parse_args()

girish

Latency numbers every programmer should know

L1 cache reference ......................... 0.5 ns
Branch mispredict ............................ 5 ns                     on recent CPU
L2 cache reference ........................... 7 ns                     14x L1 cache
Mutex lock/unlock ........................... 25 ns
Main memory reference ...................... 100 ns                     20x L2 cache, 200x L1 cache
Compress 1K bytes with Zippy ............. 3,000 ns  =   3 µs
Send 2K bytes over 1 Gbps network ....... 20,000 ns  =  20 µs
SSD random read ........................ 150,000 ns  = 150 µs

Read 1 MB sequentially from memory ..... 250,000 ns = 250 µs 4X memory

girish

The introduction to Reactive Programming you've been missing

(by @andrestaltz)

So you're curious in learning this new thing called (Functional) Reactive Programming (FRP).

Learning it is hard, even harder by the lack of good material. When I started, I tried looking for tutorials. I found only a handful of practical guides, but they just scratched the surface and never tackled the challenge of building the whole architecture around it. Library documentations often don't help when you're trying to understand some function. I mean, honestly, look at this:

Rx.Observable.prototype.flatMapLatest(selector, [thisArg])

Projects each element of an observable sequence into a new sequence of observable sequences by incorporating the element's index and then transforms an observable sequence of observable sequences into an observable sequence producing values only from the most recent observable sequence.

girish

In order to use segtree class defined above, you will need to create a datatype(a struct most likely), which will implement the function merge(). It can also additionally implement split, if you need to define the split operation.
A sample is shown as "struct segtree_node" in the code above.

The segtree has to be instantiated with this defined data type. For example,as 
segtree<segtree_node> s;

You have to first call the init function of the class, which will take 
  int n=number of elements in your array,
  node[] = your inital array,
  identity = an element such that merge(y,identity) = merge(identity,y) = y for all y's.

girish

tmux shortcuts & cheatsheet

start new:

tmux

start new with session name:

tmux new -s myname

girish

#! /usr/bin/python

from sys import argv
from os.path import exists
from os import makedirs
from os import symlink
from os import system
import getopt

#

girish

# Simple, scrappy UDP DNS server in Ruby (with protocol annotations)
# By Peter Cooper
#
# MIT license
#
# * Not advised to use in your production environment! ;-)
# * Requires Ruby 1.9
# * Supports A and CNAME records
# * See http://www.ietf.org/rfc/rfc1035.txt for protocol guidance
# * All records get the same TTL

girish

#!/usr/bin/env ruby
# A quick and dirty implementation of an HTTP proxy server in Ruby
# because I did not want to install anything.
# 
# Copyright (C) 2009 Torsten Becker <torsten.becker@gmail.com>

require 'socket'
require 'uri'