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Longform articles, the best of what the Hackaday writing crew has to offer.

This Is Not Your Father’s FORTRAN

October 26, 2015 by 111 Comments

I learned to program FORTRAN IV in the spring of 1968 while working as an engineering technician in water resources. One of the engineers knew of my interest in computers and asked if I would like to learn FORTRAN. He needed to calculate the biological oxygen demand in streams but didn’t have any interest in programming. I jumped at the chance.

415I2ZfVyqL._SX258_BO1,204,203,200_This was the days of big iron when the term computer meant a room full of heavily air-conditioned equipment. The State University of New York at Buffalo had an IBM 704 but they soon upgraded to a CDC 6400. To help pay for it they were inviting people to attend a seminar on FORTRAN so they could use the system. My job was with a small State of NY office and getting approval for me to attend was surprisingly easy.

Off I went for 6 weeks of training on one night a week. I still have my black “A Guide to Fortran IV Programming” by [Daniel McCracken]. For years, this was the FORTRAN bible, commonly referred to as just “McCracken”.

The programming went well and somewhere out there is a very old paper with a reference to the results it generated about the Chadakoin River flowing through Jamestown, NY.

This is FORTRAN’s strength – scientific calculations. It’s name says it: FORmula TRANslation.

Origins and FORTRAN IV

[John W. Backus] suggested to IBM a language to replace assembly language. Development began in 1953 for the IBM 704 and the project reached fruition in 1957. Not only was it the first general purpose high-level language, just beating out COBOL and LISP, but its compiler optimized the code since it needed to compete head-on with assembly language. It was the C compiler of its day in that regard.

That was not the only reason it attained success. Reducing the number of punched cards needed for a program by a factor of 20 over assembly helped considerably.

In those days, you needed to use a key punch to create a deck of punch cards. To be really good you had to know how to create a programming card that would let you skip through the fields on a FORTRAN card, or how to edit a card by duplicating it and holding one of the cards in place while you typed in new characters. Because of my fascination with computers I’d taken a key punching and automation machines class in high school so I was all set.

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Killed By A Machine: The Therac-25

October 26, 2015 by 158 Comments

The Therac-25 was not a device anyone was happy to see. It was a radiation therapy machine. In layman’s terms it was a “cancer zapper”; a linear accelerator with a human as its target. Using X-rays or a beam of electrons, radiation therapy machines kill cancerous tissue, even deep inside the body. These room-sized medical devices would always cause some collateral damage to healthy tissue around the tumors. As with chemotherapy, the hope is that the net effect heals the patient more than it harms them. For six unfortunate patients in 1986 and 1987, the Therac-25 did the unthinkable: it exposed them to massive overdoses of radiation, killing four and leaving two others with lifelong injuries. During the investigation, it was determined that the root cause of the problem was twofold. Firstly, the software controlling the machine contained bugs which proved to be fatal. Secondly, the design of the machine relied on the controlling computer alone for safety. There were no hardware interlocks or supervisory circuits to ensure that software bugs couldn’t result in catastrophic failures.

The case of the Therac-25 has become one of the most well-known killer software bugs in history. Several universities use the case as a cautionary tale of what can go wrong, and how investigations can be lead astray. Much of this is due to the work of [Nancy Leveson], a software safety expert who exhaustively researched the incidents and resulting lawsuits. Much of the information published about the Therac (including this article) is based upon her research and 1993 paper with [Clark Turner] entitled “An Investigation of the Therac-25 Accidents”. [Nancy] has since published updated information in a second paper which is also included in her book.

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The FAA Wants Your Input On Upcoming Drone Regs

October 22, 2015 by 106 Comments

Earlier this week, the US Department of Transportation announced registration would be required for unmanned aerial systems. Yes, drones will be regulated, and right now representatives from the Academy of Model Aircraft, the Air Line Pilots Association, the Consumer Electronics Association and others are deciding which quadcopters, planes, and other aircraft should be exempt from registration.

Now, the US DOT and FAA are looking for consumer’s input. The US DOT is asking the public such questions as:

  • Should registration happen at point-of-sale, or after the box is opened?
  • Should registration be dependant on serial numbers? If so, how will kits be registered?
  • Should certain drones/UAS be excluded from registration? Should weight, speed, maximum altitude, or flight times be taken into account?
  • Should registration require a fee?
  • Are there any additional ways of encouraging accountability of drone/UAS use?

Comments will be taken until November 6, with the task force assembled by the US DOT providing its regulations by November 20. The hope for all involved parties is that this system of regulation will be in place for the holiday season. One million UAS are expected to be sold by Christmas.

Nomograms: Complex Analog Calculators Simple For Everyone

October 21, 2015 by 29 Comments

In the late 1800s, a railway engineer named Philbert Maurice d’Ocagne was part of a group of men faced with the task of expanding the French rail system. Before a single rail could be laid, the intended path had to be laid out and the terrain made level. This type of engineering involves a lot of cut and fill calculations, which determine where dirt must be added or removed. The goal of earthwork is to create a gentle grade and to minimize the work needed to create embankments.

In the course of the project, d’Ocagne came up with an elegant, reusable solution to quickly  solve these critical calculations. Most impressively, he did it with little more than a pen, some paper, and a straightedge. By developing and using a method which he called nomography, d’Ocagne was able to perform all the necessary calculations that made the gentle curves and slopes of the French railway possible.

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Why You Need To Be At The Hackaday SuperConference

October 20, 2015 by 18 Comments

Hackaday’s first ever SuperConference is November 14th and 15th. Imagine a hardware conference that’s actually about hardware creation, packed with the most talented people – both as attendees and presenters. We are taking over Dogpatch Studios in San Francisco for the event that’s sure to change your engineering life. Apply Now for your tickets.

This isn’t hype. Our excitement is well founded, and especially so in this case. Here’s why:

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Ultrasonic Power Transfer: UBeam’s Curious Engineering

October 20, 2015 by 96 Comments

The future is wireless power, or so say a thousand press releases in my spam folder, and with very few exceptions every single system of wireless power delivery has fallen flat on its face. Except for a few niche cases – RFID tags, Wacom tablets and the S Pen, and the Qi inductive power mats for cell phones – the future of wireless power hardly looks bright, and in some cases seems downright dangerous. No one seems to grasp that wireless power transfer is much more inefficient than using a wire, and the inverse square law only makes everything worse.

Now there’s a new wireless power technology that’s a strange mix of running in stealth mode and sending press releases to every tech outlet on the planet. It’s called uBeam. This company says it will deliver wireless power to the world, but it’s not doing it with giant Tesla-inspired towers of power, radios beamed directly at devices, induction, magnetic resonance, or even light. uBeam transmits power via sound, specifically high intensity ultrasound. uBeam has never demonstrated a prototype, has never released any technical specs, and even some high-profile investors that include [Mark Cuban] have not seen the uBeam working. Despite running in a ‘stealth mode’, it has garnered a lot of press, and has been featured on TechCrunch dozens of times. This may just be a consequence of CrunchFunds’s investment in uBeam, but there’s still more Google News results for a technology that hasn’t even been demonstrated than a reasonable person would expect.

In what is perhaps the greatest breakdown ever posted on the EEVForums, [georgesmith] goes over what uBeam is, how the technology doesn’t make sense, and how far you can take a business before engineers start to say, ‘put up or shut up.’ [georgesmith]’s research goes over just some of what makes uBeam impractical, but digging even further reveals how insane uBeam actually is.

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Breaking: Drone Registration Will Be Required Says US DoT

October 19, 2015 by 77 Comments

Today, the US Department of Transportation announced that unmanned aerial systems (UAS) will require registration in the future.

The announcement is not that UAS, quadcopters, or drones would be required to be registered immediately. This announcement is merely that a task force of representatives from the UAS industry, drone manufacturers, and manned aviation industries would provide recommendations to the Department of Transportation for what types of aircraft would require registration. The task force is expected to develop these recommendations and deliver a report by November 20.

A Short History of FAA Model Aircraft Regulation

Introduced in 1981, AC 91-57 was the model aircraft operating standards for more than 30 years. This standard suggested that model pilots not fly higher than 400 feet, and to notify a flight service station or control tower when flying within three miles of an airport.

The FAA Modernization And Reform Act Of 2012 (PDF) required the FAA to create a set of rules for unmanned aerial systems, however the FAA is expressly forbidden from, ‘promulgating any rule or regulation regarding model aircraft.’ The key term being, ‘model aircraft’. This term was defined by the FAA as being, “an unmanned aircraft that is capable of sustained flight in the atmosphere; flown within visual line of sight of the person operating the aircraft; and flown for hobby or recreational purposes.” Anything outside of this definition was an unmanned aerial system, and subject to FAA regulations.

While this definition of model aircraft would have been fine for the 1980s, technology has advanced since then. FPV flying, or putting a camera and video transmitter on a quadcopter, is an extraordinarily popular hobby now, and because it is not ‘line of sight’, it is outside the definition of ‘model aircraft’.

This interpretation has not seen a great deal of countenance from the model aircraft community; FPV flying is seen as a legitimate hobby and even a sport. The entire domain of model aircraft aviation is expanding, and the hobby has never been as popular as it is now.

The Safety of Model Aviation

The issue of drone regulation focuses nearly entirely on the safety of airways in the United States; model aviators flying within five miles of an airport must ask the airport or control tower for permission to fly. To that end, the FAA created the B4UFLY app that takes the trouble out of reading sectional charts and checking up on the latest NOTAMs and TFRs.

However, the FAA is increasingly concerned with drones, multicopters, and model aircraft. In a report issued last summer, the FAA cited a marked increase in the number of ‘close calls’ between manned aircraft and model aircraft. The Academy of Model Aeronautics went over this data and found a different story: only 3.5% of sightings were ‘close calls’ or ‘near misses’. The FAA data is questionable – the reports cited include a drone flying at 51,000 feet over Washington DC. Not only is this higher than any civilian passenger aircraft capable of flying, the ability for any civilian remote-controlled aircraft to operate at this altitude is questionable at best.

Nevertheless, the requirement for registration has been greatly influenced by the perceived concerns of regulators for mid-air collisions.

What exactly will require registration?

The group of industry representatives responsible for delivering the recommendations to the Department of Transportation will take into account what aircraft should be exempt from registration due to a low safety risk. Most likely, small toy quadcopters will be exempt from registration; it’s difficult to fly a small Cheerson quadcopter outside anyway. Whether this will affect larger quadcopters and drones such as the DJI Phantom, or 250 class FPV racing quadcopters remains to be seen.