David Turner DaveCTurner

Keybase proof

I hereby claim:

I am davecturner on github.
I am dcturner (https://keybase.io/dcturner) on keybase.
I have a public key ASAZdCj2ryspkWzhpFttsuadl4bwlg4fgKtJ_oaaHRjzowo

To claim this, I am signing this object:

Linearisability vs Sequential Consistency

Linearisability is a really rather strong property on a distributed system. There is a good discussion in [1] with some much more precise definitions on which I'm going to base this article.

The setup is a distributed system with some client processes which can perform operations (think: RPCs) on some remote data objects (think: a single-value register). The operations, being remote, take some nonzero amount of time between the client invoking the operation and being notified of its

	#!/usr/bin/python

	import sys
	import tarfile
	import hashlib

	for filename in sys.argv[1:]:
	print filename
	with tarfile.open(filename, 'r') as tar:
	for tarinfo in tar:

	-- ClearBefore.hs

	module ClearBefore where

	import Data.Monoid

	data ClearBefore a = ClearBefore Bool a

	instance Monoid a => Monoid (ClearBefore a) where
	mempty = ClearBefore False mempty

	{-# LANGUAGE GeneralizedNewtypeDeriving #-}
	{-# LANGUAGE LambdaCase #-}
	{-# LANGUAGE RecordWildCards #-}

	module Main (main) where

	import Control.Applicative
	import Control.Monad
	import Control.Monad.RWS
	import Control.Monad.Trans.Either

	{- a simpler implementation -}

	module Main (main) where

	import Test.Hspec
	import Test.Hspec.QuickCheck
	import Data.List
	import qualified Data.Map as M

	main :: IO ()

	import Network.Socket
	import System.Log.Logger
	import System.Log.Handler.Syslog

	openUDP = generalOpen
	$ openlog_remote AF_INET "127.0.0.1" 514

	openDevLog = generalOpen
	$ openlog_local "/dev/log"

	{-# LANGUAGE TupleSections #-}

	import System.Random
	import Control.Monad
	import Data.List
	import Text.Printf

	main :: IO ()
	main = do
	let target = 4.7

	curl https://api.github.com/repos/vincenthz/hs-certificate/pulls \
	-XPOST --data-binary '{"issue":57,"head":"DaveCTurner:issue-57","base":"master"}' \
	-H"Content-type: application/json" -u DaveCTurner -H"X-GitHub-OTP: nnnnnn" # asks for password


	railwayPeriodStart :: Integer -> Integer -> Day
	railwayPeriodStart yr pd
	\| pd == 1 = fromGregorian (yr - 1) 4 1
	\| otherwise = addDays (28 * pd) (dayZero yr)

	railwayPeriodEnd :: Integer -> Integer -> Day
	railwayPeriodEnd yr pd = addDays (-1) $ railwayPeriodStart yr' (pd' + 1)
	where (yr', pd') = divMod (yr * 13 + pd) 13