The need for signed integer arithmetic is often misplaced as most
integers never represent negative values within a program. The
indexing of arrays and iteration count of a loop reflects this
concept as well. There should be a propensity to use unsigned
integers more often than signed, yet despite this, most code
incorrectly choses to use signed integers almost exclusively.
Fuzzing is a type of automated testing which continuously
manipulates inputs to a program to find bugs. Go fuzzing uses
coverage guidance to intelligently walk through the code being
fuzzed to find and report failures to the user. Since it can reach
edge cases which humans often miss, fuzz testing can be particularly
valuable for finding security exploits and vulnerabilities.
It's been a while since my last language
series on this blog, but I
figured I shouldn't let an entire calendar year go by without doing
some technical writing here. This time we'll be working on creating
a toy relational database in the vein of Tutorial
as described in Databases, Types, and The Relational Model: The
Third Manifesto by C.J. Date and Hugh Darwen. However, instead of
creating a full database language with a its own syntax, we're going
to embed the database language in Haskell. In particular, we're
going to try and get ghc to ensure that queries are well typed as
opposed to writing our own type checker.
I know what you are thinking, is this really another guide to OAuth 2.0?
Well, yes and no. This guide is different than most of the others
out there because it covers all of the ways that we actually use
OAuth. It also covers all of the details you need to be an OAuth
expert without reading all the specifications or writing your own
OAuth server. This document is based on hundreds of conversations
and client implementations as well as our experience building
FusionAuth, an OAuth server which has been downloaded over a million
Infix expressions are a common pain point for recursive descent
parsers, but there is a common solution that mostly preserves this
direct style: Pratt
or “top-down operator precedence.” My goal here is to take your
familiarity with recursive descent and Pratt parsing to build an
intuition for the more-general but often-mysterious LR
These are my personal notes on installing, setting up, and using
OpenBSD on two Thinkpads (an X220 and a T400). They’re applicable
to OpenBSD-current as at 2020-09-05 (somewhere between OpenBSD
versions 6.7 and 6.8) - please bear in mind that some things may
have changed if you’re using a different version.
Brad Whitaker is a radio host trying to get his stepchildren to love
him and call him Dad. But his plans turn upside down when their
biological father, Dusty Mayron, returns.
In the evening Adam, Alice and I watched Daddy's
Home. I liked the movie and
give it a 7 out of 10. I also liked the sound track: Here Comes Your
Man (Pixies), Self Esteem (The Offspring), and Hate to Say I Told
You So (The Hives).
There are nearly infinite options available for hosting software
today and more come come out every day. However, many articles and
guides you'll find online for this kind of thing are either from
public cloud providers or companies with massive infrastructure,
complex application needs, and huge amounts of traffic.
I wanted to write this up mostly to share the decisions I made for
the architecture and why I've done things the way I have. Although
my needs are much smaller-scale and I don't currently charge any
money for anything I'm running, I still want to provide the best
possible experience for my sites' users and protect all the work
I've put into my projects.
Making backups is important. You don’t want to lose all your
information because of a broken device or a stolen account. One
proposed solution is the 3–2–1
(3 copies, at least in 2 different devices, and 1 of them off-site)
and you should make at least one full backup every year (that could
match the World Backup
Day). What to back up is up to
you. You can backup your contacts, emails, messages, social networks
content… and your code.
Backing up code is a bit tricky question. Most of the people host
their code on their computer, probably with Git and maybe on
Github. But having one copy is having no
copies. You don’t want to depend on Github exclusively for your
code, and it is wise to have at least one extra copy. The question
is then, how to make that extra copy.
This post is not about importing
but instead imports that are themselves optional. Libraries often
have optional dependencies, and the code should work whether or not
the import is there.
If you were creating a web app from scratch today, what database
would you use? Probably the most frequent answer I see to this is
Postgres, although there are a wide range of common answers: MySQL,
MariaDB, Microsoft SQL Server, MongoDB, etc. Today I want you to
consider: what if SQLite would do just fine?
In the past years there’s been a lot of talk about category theory
in the functional programming community. This is because category
theory provides a general setting to speak about computation and it
gives us concepts such as Functor and Monad which allow us to
abstract of lot of interesting patterns (error handling,
I remember a brief time in the mid-2000s insisting on so-called
in my Perl. I would place constants to the left of equality
case I accidentally typed a single = instead of ==, the compiler
would catch it instead of blithely
Heap's thousands of customers can build queries in the Heap UI to
answer almost any question about how users are using their
product. Optimizing all of these queries across all our customers
presents special challenges you wouldn't typically encounter if you
were optimizing the performance of a small set of queries within a
This post is about why this scale requires us to conduct performance
experiments to optimize our SQL, and it details how we conduct those
Zsh is particularly powerful when you need some good old
expansions. It supports common ones used by Bash too, and add many
flags and modifiers on top. It comes in handy to manipulate quickly
your commands without writing boring shell scripts.
Because microprocessors are so fast, computer architecture design
has evolved towards adding various levels of caching between compute
units and the main memory, in order to hide the latency of bringing
the bits to the brains. However, the key insight here is that these
caches are partially shared among the CPUs, which means that perfect
performance isolation of co-hosted containers is not possible. If
the container running on the core next to your container suddenly
decides to fetch a lot of data from the RAM, it will inevitably
result in more cache misses for you (and hence a potential
In the last
of this series we introduced trying to model fire probability in
Northern California based on weather data. We showed how to use SQL
to do data shaping and preparation. We ended with a data set that
was ready with all the fire occurrences and weather data in a single
table almost prepped for logistic regression.
There is now one more step: sample the data. If you have worked with
logistic regression before you know you should try to balance the
number of occurrences (1) with absences (0). To do this we are going
to sample out from the non_fire_weather equal to the count in
fire_weather and then combine them into one table.