A Review of Modern Sail Theory (1981) [pdf] | Hacker News
Bruce Banks and Dick Kenny in their book “Looking at
Sails” (Reference 1) state that “it is essential to anyone
interested in sails, and indeed sailing, that the fundamen-
tal principles are thoroughly understood.” They then
follow with several pages of sail theory and repeat basic
ideas that have appeared in the sailing literature for many
years. Unfortunately, their explanations of the most
important aspects of sail theory (how a sail gives lift, the
interaction between the jib and main, the slot effect) are
completely wrong.
Virtually all of the sailing references contain similar, but
erroneous explanations when they discuss the aerody-
namics of sails. References 1 through 5 are typical. These
books and magazine articles were written by recognized
sailing authorities, class champions, Olympic sailors, and
famous sailmakers. How could these fundamental ideas
on sailing be wrong, and how could they persist for so
long? All of these people are certainly excellent sailors.
They have learned from practical experience what it takes
to make a boat go fast. But when they talk or write about
the aerodynamics of sails, they get into trouble.
As a research aerodynamicist, I was dumbfounded when I
first started reading the sailing literature as a beginning
sailor and saw what a confused state sail theory was in.
Even the basic explanations of how a sail generates lift
were wrong. This I could understand, since even the
popular aviation books were wrong in their attempts to
explain lift. It is difficult to explain the generation of lift for
laymen. The simplifications devised in attempts to do this
seemed logical but usually turned out to be wrong.
pdf  sailing 
13 days ago
A structured VHDL design method [pdf]
Description of 2 process (one async and one sync) design methodology for VHDL.
vhdl  pdf  work 
26 days ago
htop explained | peteris.rocks
For the longest time I did not know what everything meant in htop.

I thought that load average 1.0 on my two core machine means that the CPU usage is at 50%. That's not quite right. And also, why does it say 1.0?

I decided to look everything up and document it here.

They also say that the best way to learn something is to try to teach it.
performance  server  tools 
december 2016
Linux Device Drivers, Third Edition
Device drivers literally drive everything you're interested in--disks, monitors, keyboards, modems--everything outside the computer chip and memory. And writing device drivers is one of the few areas of programming for the Linux operating system that calls for unique, Linux-specific knowledge. For years now, programmers have relied on the classic Linux Device Drivers from O'Reilly to master this critical subject. Now in its third edition, this bestselling guide provides all the information you'll need to write drivers for a wide range of devices.Over the years the book has helped countless programmers learn:

how to support computer peripherals under the Linux operating system
how to develop and write software for new hardware under Linux
the basics of Linux operation even if they are not expecting to write a driver

The new edition of Linux Device Drivers is better than ever. The book covers all the significant changes to Version 2.6 of the Linux kernel, which simplifies many activities, and contains subtle new features that can make a driver both more efficient and more flexible. Readers will find new chapters on important types of drivers not covered previously, such as consoles, USB drivers, and more.Best of all, you don't have to be a kernel hacker to understand and enjoy this book. All you need is an understanding of the C programming language and some background in Unix system calls. And for maximum ease-of-use, the book uses full-featured examples that you can compile and run without special hardware.Today Linux holds fast as the most rapidly growing segment of the computer market and continues to win over enthusiastic adherents in many application areas. With this increasing support, Linux is now absolutely mainstream, and viewed as a solid platform for embedded systems. If you're writing device drivers, you'll want this book. In fact, you'll wonder how drivers are ever written without it.
Linux  work  kernel  C  pdf 
july 2016
Writing a Linux Kernel Module — Part 2: A Character Device | derekmolloy.ie
In this series of articles I describe how you can write a Linux loadable kernel module (LKM) for an embedded Linux device.
Linux  kernel  work  C 
july 2016
Timing Constraints - Altera Wiki
This page should help you understand what timing constraints are and how to apply them. This page will give you an overview of what synchronous and asynchronous signals are and the most important commands to constrain a design.
FPGA  timing 
may 2016
CTAN: tex-archive/graphics/pgf/contrib/tikz-timing
This package provides macros and an environment to generate timing diagrams
(digital waveforms) without much effort. The TikZ (pgf) package is used to
produce the graphics. The diagrams may be inserted into text (paragraphs,
\hbox, etc.) and into tikzpictures. A tabular-like environment is provided to
produce larger timing diagrams.
LaTeX  timing 
april 2016
Kanboard - Simple and open source visual task board
Kanboard is a project management software that uses the Kanban methodology
opensource  task_management  kanban 
march 2016
Comparison of 10 ACME / Let's Encrypt Clients | Chris Hager
This post is an overview and comparison of 10 popular Let’s Encrypt clients
server  encryption  letsencrypt 
march 2016
BetterExplained | Friendly lessons for lasting insight.
Math lessons that actually explain concepts.

Instead of memorizing procedures, learn why equations work. This site helps you overcome mental roadblocks and truly grasp new concepts.
education  learning  math  programming 
december 2015
suoto/vim-hdl · GitHub
Vim plugin to aid VHDL development
work  vim  vhdl 
december 2015
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