This NES ROM Is A ZIP Of Its Source

February 6, 2018 by Eric Evenchick 12 Comments

Polyglots, in computing terms, are files have multiple valid meanings. We’ve seen some amazing examples of polyglot files in releases of The International Journal of PoC||GTFO. One example: a PDF that is also a ZIP, HTML file, and BPG image.

[Vi Grey] was inspired by PoC||GTFO’s release of a PDF/ZIP/NES ROM hybrid file for issue 0x14. Using a different method, [Vi] created a file which is both an NES ROM and ZIP, where the full contents of the ZIP are stored in the NES ROM.

When PoC||GTFO created their NES ROM polyglot, they stuck most the information outside the bounds of the NES ROM. While the file is valid, you’d lose the ZIP archive if it was burnt to a cartridge.

[Vi]’s polyglot is different. Rip it from a real NES cartridge and you get a ZIP file. Unzip it, and you get the source. Compile that source, and you get a valid ZIP file containing the source. Burn that to a cartridge and… hopefully you grok the recursion at this point.

The source and scripts to mangle the polyglot together are up on Github.

3D Printering: Printing Sticks For A PLA Hot Glue Gun

February 5, 2018 by Donald Papp 85 Comments

When is a hot glue stick not a hot glue stick? When it’s PLA, of course! A glue gun that dispenses molten PLA instead of hot glue turned out to be a handy tool for joining 3D-printed objects together, once I had figured out how to print my own “glue” sticks out of PLA. The result is a bit like a plus-sized 3D-printing pen, but much simpler and capable of much heavier extrusion. But it wasn’t quite as simple as shoving scrap PLA into a hot glue gun and mashing the trigger; a few glitches needed to be ironed out.

Why Use a Glue Gun for PLA?

Some solutions come from no more than looking at two dissimilar things while in the right mindset, and realizing they can be mashed together. In this case I had recently segmented a large, hollow, 3D model into smaller 3D-printer-sized pieces and printed them all out, but found myself with a problem. I now had a large number of curved, thin-walled pieces that needed to be connected flush with one another. These were essentially butt joints on all sides — the weakest kind of joint — offering very little surface for gluing. On top of it all, the curved surfaces meant clamping was impractical, and any movement of the pieces while gluing would result in other pieces not lining up.

An advantage was that only the outside of my hollow model was a presentation surface; the inside could be ugly. A hot glue gun is worth considering for a job like this. The idea would be to hold two pieces with the presentation sides lined up properly with each other, then anchor the seams together by applying melted glue on the inside (non-presentation) side of the joint. Let the hot glue cool and harden, and repeat. It’s a workable process, but I felt that hot glue just wasn’t the right thing to use in this case. Hot glue can be slow to cool completely, and will always have a bit of flexibility to it. I wanted to work fast, and I wanted the joints to be hard and stiff. What I really wanted was melted PLA instead of glue, but I had no way to do it. Friction welding the 3D-printed pieces was a possibility but I doubted how maneuverable my rotary tool would be in awkward orientations. I was considering ordering a 3D-printing pen to use as a small PLA spot welder when I laid eyes on my cheap desktop glue gun.

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Black Holes And The Elusive Mystery That Lies Within An Equation

February 5, 2018 by Will Sweatman 83 Comments

“If I have seen further than others, it is by standing upon the shoulders of giants.” This famous quote by Isaac Newton points to an axiom that lies at the heart of The Sciences — knowledge precedes knowledge.

What we know today is entirely based upon what we learned in the past. This general pattern is echoed throughout recorded history by the revelation of one scientific mystery leading to other mysteries… other more compounding questions. In the vast majority of cases these mysteries and other questions are sprung from the source of an experiment with an unexpected outcome sparking the question: “why the hell did it do that?” This leads to more experiments which creates even more questions and next thing you know we go from moving around on horse-drawn carriages to landing drones on Mars in a few generations.

The observant of you will have noticed that I preceded a statement above with “the vast majority of cases.” Apart from particle physics, almost all scientific discovery throughout recorded history has been made via experiment and observation. There are a few, however, that have been discovered hidden within the confines of an equation, only later to be confirmed with observation. One such discovery is the Black Hole, and how it was stumbled upon on a dusty chalkboard in the early 1900s will be the focal point of today’s article.

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Mechanisms: The Screw Thread

February 1, 2018 by Dan Maloney 65 Comments

They hold together everything from the most delicate watch to the largest bridge. The world is literally kept from coming apart by screws and bolts, and yet we don’t often give a thought to these mechanisms. Part of that is probably because we’ve gotten so good at making them that they’re seen as cheap commodities, but the physics and engineering behind the screw thread is interesting stuff.

We all likely remember an early science lesson wherein the basic building blocks of all mechanisms laid out. The simple machines are mechanisms that use an applied force to do work, such as the inclined plane, the lever, and the pulley. For instance, an inclined plane, in the form of a splitting wedge, directs the force of blows against its flat face into a chunk of wood, forcing the wood apart.

Screw threads are another simple machine, and can be thought of as a long, gently sloped inclined plane wrapped around a cylinder. Cut a long right triangle out of paper, wrap it around a pencil starting at the big end, and the hypotenuse forms a helical ramp that looks just like a thread. Of course, for a screw thread to do any work, it has to project out more than the thickness of a piece of paper, and the shape of the projection determines the mechanical properties of the screw.

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The Hard-Learned Lessons Of The Columbia Disaster

February 1, 2018 by Tom Nardi 136 Comments

On February 1st, 2003 at eighteen seconds past 9:00 AM Eastern Standard Time, the Space Shuttle Columbia broke up during atmospheric entry over Texas. Still traveling at approximately Mach 18.3, the disintegration of Columbia was complete and nearly instantaneous. According to the official accident investigation, the crew had at most one minute from realizing they were in a desperate situation to complete destruction of the spacecraft. Due to the design of the Space Shuttle, no contingency plan or emergency procedure could have saved the crew at this point in the mission: all seven crew members were lost in this tragedy.

While the Space Shuttle, officially known as the Space Transportation System (STS) would fly again after the Columbia disaster, even the program’s most ardent supporters had to admit fundamental design of the Shuttle was flawed. Steps needed to be taken to ensure no future astronauts would be lost, and ultimately, the decision was made to retire the Shuttle fleet after primary construction of the International Space Station (ISS) was complete. There was simply too much invested in the ISS at this point to cancel the only spacecraft capable of helping to assemble it, so the STS had to continue despite the crushing loss of human life it had already incurred.

Between the loss of Challenger and Columbia, the STS program claimed fourteen lives in its thirty year run. Having only flown 135 missions in that time, the STS is far and away the most deadly spacecraft to ever fly. A grim record that, with any luck, is never to be broken.

The real tragedy was, like Challenger, the loss of Columbia could have been prevented. Ground Control knew that the Shuttle had sustained damage during launch, but no procedures were in place to investigate or repair damage to the spacecraft while in orbit. Changes to the standard Shuttle mission profile gave future crews a chance of survival that the men and women aboard Columbia never had.

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Global Resistor Shortage, Economics, And Consumer Behavior

January 31, 2018 by Brian Benchoff 78 Comments

The passive component industry — the manufacturers who make the boring but vital resistors, capacitors, and diodes found in every single electronic device — is on the cusp of a shortage. You’ll always be able to buy a 220 Ω, 0805 resistor, but instead of buying two for a penny like you can today, you may only get one in the very near future.

Yageo, one of the largest manufacturers of surface mount (SMD) resistors and multilayer ceramic capacitors, announced in December they were not taking new chip resistor orders. Yageo was cutting production of cheap chip resistors to focus on higher-margin niche-market components for automotive, IoT, and other industrial uses, as reported by Digitimes. Earlier this month, Yaego resumed taking orders for chip resistors, but with 15-20% higher quotes (article behind paywall, try clicking through via this Tweet).

As a result, there are rumors of runs on passive components at the Shenzhen electronics market, and several tweets from members of the electronics community have said the price of some components have doubled. Because every electronic device uses these ‘jellybean’ parts, a decrease in supply or increase in price means some products won’t ship on time, margins will be lower, or prices on the newest electronic gadget will increase.

The question remains: are we on the brink of a resistor shortage, and what are the implications of manufacturers that don’t have the parts they need?

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Inventing The Microprocessor: The Intel 4004

January 29, 2018 by Steven Dufresne 66 Comments

We recently looked at the origins of the integrated circuit (IC) and the calculator, which was the IC’s first killer app, but a surprise twist is that the calculator played a big part in the invention of the next world-changing marvel, the microprocessor.

There is some dispute as to which company invented the microprocessor, and we’ll talk about that further down. But who invented the first commercially available microprocessor? That honor goes to Intel for the 4004.

Path To The 4004

Busicom calculator motherboard based on 4004 (center) and the calculator (right)

We pick up the tale with Robert Noyce, who had co-invented the IC while at Fairchild Semiconductor. In July 1968 he left Fairchild to co-found Intel for the purpose of manufacturing semiconductor memory chips.

While Intel was still a new startup living off of their initial $3 million in financing, and before they had a semiconductor memory product, as many start-ups do to survive they took on custom work. In April 1969, Japanese company Busicom hired them to do LSI (Large-Scale Integration) work for a family of calculators.

Busicom’s design, consisting of twelve interlinked chips, was considered a complicated one. For example, it included shift-register memory, a serial type of memory which complicates the control logic. It also used Binary Coded Decimal (BCD) arithmetic. Marcian Edward Hoff Jr — known as “Ted”, head of the Intel’s Application Research Department, felt that the design was even more complicated than a general purpose computer like the PDP-8, which had a fairly simple architecture. He felt they may not be able to meet the cost targets and so Noyce gave Hoff the go-ahead to look for ways to simplify it.

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