Author: Brandon Dunson

52 Articles

The IBM 1401’s Unique Qui-Binary Arithmetic

November 5, 2015 by 12 Comments

Old mainframe computers are interesting, especially to those of us who weren’t around to see them in action. We sit with old-timers and listen to their stories of the good ol’ days. They tell us about loading paper tape or giving instructions one at a time with toggle switches and LED output indicators. We hang on every word because its interesting to know how we got to this point in the tech-timeline and we appreciate the patience and insanity it must have taken to soldier on through the “good ol’ days”.

[Ken Shirriff] is making those good ol’ days come alive with a series of articles relating to his work with hardware at the Computer History Museum. His latest installment is an article describing the strange implementation of the IBM 1401’s qui-binary arithmetic. Full disclosure: It has not been confirmed that [Ken] is an “old-timer” however his article doesn’t help the argument that he isn’t.

Ken describes in thorough detail how the IBM 1401 — which was first introduced in 1959 — takes a decimal number as an input and operates on it one BCD digit at a time. Before performing the instruction the BCD number is converted to qui-binary. Qui-binary is represented by 7 bits, 5 qui bits and 2 binary bits: 0000000. The qui portion represents the largest even number contained in the BCD value and the binary portion represents a 1 if the BCD value is odd or a 0 for even. For example if the BCD number is 9 then the Q8 bit and the B1 bit are set resulting in: 1000010.

The qui-binary representation makes for easy error checking since only one qui bit should be set and only one binary bit should be set. [Ken] goes on to explain more complex arithmetic and circuitry within the IBM 1401 in his post.

If you aren’t familiar with [Ken], we covered his reverse engineering of the Sinclair Scientific Calculator, his explanation of the TL431, and of course the core memory repair that is part of his Computer History Museum work.

Thanks for the tip [bobomb].

Hack The Steam Controller?

November 2, 2015 by 22 Comments

[willrandship] sent in a conversation from Reddit discussing the programming ports inside the Steam controller and their potential for hacking. From the posts and the pictures it seems the radio/SoC and the MCU can be programmed on the board, or at least they both have JTAG headers. The JTAG headers are in the form of “Tag-Connect” pads on the board so it will require the dedicated cable or soldering some hardware to the board temporarily.

From the pictures we can see a NXP LPC11U37F ARM Cortex-M0 and a Nordic nRF51822 ARM Cortex-M0 SoC with integrated Bluetooth low energy. There are only a limited number of Steam Controllers in the wild at this time so we don’t expect much in the way of hacking them thus far. There is a Steam Controller hackaday.io project just started for anyone who would like to contribute to the Steam Controller hacking.

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Lithium-Air Might Be The Better Battery

November 2, 2015 by 50 Comments

Researchers at Cambridge University demonstrated their latest version of what is being called the Lithium-Air battery. It can be more accurately referred to as a Lithium-Oxygen but Air sounds cooler.

The early estimates look pretty impressive with the energy density being 93% efficient which could be up to 10 times the energy density of Lithium-Ion and claims to be rechargeable up to 2,000 times.  Recent improvements toward Lithium-Air batteries include a graphene contact and using lithium hydroxide in place of lithium peroxide which increased both stability and efficiency.

Here’s the rub: Lithium-Air batteries are still years away from being ready for commercial use. There are still problems with the battery’s ability to charge and discharge (kind of a deal breaker if the battery won’t charge or discharge right?) There are still issues with safety, performance, efficiency, and the all too apparent need for pure oxygen.

Do batteries get you all charged up? Check out our coverage of MIT’s solid state battery research, or have a look at the Nissan Leaf and/or Tesla battery packs.

Thanks to [Jimmy] for the tip.

[Quinn] Uses “Forsooth” To Win The Internet! –Also Fixes Apple IIc+ Beep

October 30, 2015 by 3 Comments

By this point we are all familiar with [Quinn Dunki] and her awesome engineering and retro hacking. [Quinn] aims her latest blog post at the Apple IIc Plus and its tone deaf bleeping beep. You can hear it for yourself in her beep comparison video after the break.

[Quinn] gets straight into the source code as expected and works through a logical process that she explains quite nicely while looking for the origin of the problem. There are some interesting and hard to follow moves in the source as control jumps around the ROM(s) all in the name of minimizing RAM. In proper form [Quinn] uses the ROM bank switching ability to her advantage as she see’s [the Woz’s] efficiency and raises him some fancy footwork of her own along with a beep that doesn’t make our skin crawl.

Continue reading “[Quinn] Uses “Forsooth” To Win The Internet! –Also Fixes Apple IIc+ Beep” →

Don’t Look Now, Nothing Will Happen –Zeno Of Elea

October 26, 2015 by 53 Comments

The Greek philosopher [Zeno of Elea] proposed that an arrow in flight was in fact not in motion and its visible movement is only an illusion. A simple example of this is to glance at an arrow in flight, doing this causes our mind to store a snapshot of a motionless arrow. [Zeno] further defended this argument by stating that if an object has to travel a finite distance to reach a destination then the finite distance can be divided in half and the object must first reach this halfway point before arriving at the destination. This process can be repeated an infinite number of times, creating an infinite number of points that the object must occupy before reaching the destination thus it can never arrive at the destination.

Whoa, that’s a bit heavy. Let’s take a second here to think about this and never arrive at the conclusion, shall we?

So what does a fancy mathematics parlor trick have to do with the fact that we have all seen an arrow arrive at its destination? Recent experiments conducted at Cornell University have in fact verified the Zeno Effect. Researchers were able to achieve this by having atoms suspended between lasers in temperatures ~1 nano degree above absolute zero so that the atoms arrange themselves in a lattice formation. As per usual in quantum mechanics when observed, the atoms had an equal possibility of being anywhere within the space of the lattice. However, when they were observed at high enough frequencies the atoms remain motionless, bringing the quantum evolution to a halt.

An Improvised Synthetic Aperture Radar

October 25, 2015 by 14 Comments

[Henrik] is at it again. Another thoroughly detailed radar project has shown up on his blog. This time [Henrik] is making some significant improvements to his previous homemade radar with the addition of Synthetic Aperture Radar (SAR) to his previous Frequency Modulated Continuous Wave (FMCW) system.

[Henrik’s] new design uses an NXP LPC4320 which uniquely combines an ARM Cortex-M4 MCU along with a Cortex-M0 co-processor. The HackRF also uses this micro as it has some specific features that can be taken advantage of here like the Serial GPIO (SGPIO) which can be tediously configured and high-speed USB all for ~$8 in single quantity. The mixed signal design is done in two boards, a 4 layer RF board and 2 layer digital board.

Like the gentleman he is, [Henrik] has included schematics, board files, and his modified source from the HackRF project in his github repo. There is simply too much information in his post to attempt to summarize here, if you need instant gratification check out the pictures after the break.

The write-up on his personal blog is impressive and worth look if you didn’t catch our coverage of his single board Linux computer, or his previous radar design.

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An Internet Connected Earth

October 24, 2015 by 28 Comments

It shouldn’t come as much of a surprise that more than half of the world’s population doesn’t have an Internet connection. It’s tricky to get an exact figure on this, however the number of people without connection is commonly agreed to be somewhere around 2/3rds of the population of the planet. There are some heavy hitters working on this problem with some pretty interesting solutions.

OneWeb is an outfit with [Richard Branson] as the front-man who plan to launch low orbit satellites to communicate with ground terminals. The ground terminals would rebroadcast the communication signals from the satellites resulting in 2G, 3G, LTE, and WiFi signals for those near a ground terminal.

SpaceX is throwing its hat in the ring with a little helpful funding from Google and Fidelity to the tune of $1 Billion.

Perhaps the most surprising is [Zuckerberg’s] solar-powered internet laser beaming drones. The idea is that these laser birds will circle over an Internet dead-zone like buzzard over a dying buffalo (reaching?) and provide connectivity to those below. The solar drones will fly at an altitude of 20km which is a pretty good ways up there, and they are believed to be able to stay in flight for months at a time. There’s a Facebook PhD explaining this in a video after the break, thanks Dr. Facebook.

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