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junker-town · 8 years ago

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The Georgia Dome got the farewell it deserved

Monster Jam was the last memorable event in a stadium that begged to be forgotten.

Monster Jam fills up enough of the Georgia Dome — most of the bottom bowl, and a good chunk of the mezzanines and upper deck. There is competition in town — but there also probably isn’t a lot of Sunday night overlap between the monster truck crowd and the people across town at Georgia Tech’s Bobby Dodd Stadium watching Atlanta United lose its first game ever to New York Red Bulls.

There are mostly dads, myself included, towing kids there with the promise of monster trucks and multiple concession stand runs.

One of these runs: for a $20 Monster Jam official Grave Digger sno-cone with commemorative Grave Digger cup with molded grinning skeleton face and flashing lights triggered via a button in its plastic forehead. I bought it; one $15 commemorative non-truck-specific Monster Jam sno-cone; a $15 pair of headphones/ear protectors, with rubber tires mounted around the ear cups for one child; a $20 pair of less-elaborate ear protection for the other kid, who could not be persuaded to get the cheaper ones because, “I need different daddy”; at least $30 worth of bribes in the form of food and drink to keep them in the stands for half the show; $0 in alcohol, somehow, because two children at a monster truck show keep you so busy and running that you cannot find the time to get drunk enough to deal with the children.

While waiting, a towheaded 3-year-old behind us pointed to the beer man selling $12 oil cans of Busch Light.

“Daddy, you could get a beer.”

“You know Daddy only drinks crown.”

The Omni

The first thing I can remember about going to a live sports event involves DeBarge, and the memory is wrong. Wrong may not be the right word, actually. Better put, I misremembered because I was probably 6 years old, and 6-year-olds can’t be counted on to provide accurate testimony in a court of law or in a recollection involving the Atlanta Hawks and Philadelphia 76ers.

My dad took me to a Hawks game at the Omni. The Omni was the least-lovable building ever constructed, a black cube with tented pyramids of black sheet metal jutting from the roof, weird angular corner windows, and the street presence of a giant, menacing blast furnace. I thought it looked cool because it reminded me of the doomed spaceship in Disney’s The Black Hole. Kids have bad memories and deplorable taste in architecture.

The Omni was built to rust, to be an uncherished memory before it ever happened.

The first claim there is literal. By rusting, the steel elements of the building would become even more fused to each other. In its later years, it started to look like an overturned running shoe or waffle iron left outside to the elements. The designers reportedly did not factor in Atlanta’s subtropical climate, and the Omni kept rusting and rusting until the entire building had an incurable form of architectural arthritis. Holes appeared in the building’s frame, holes big enough for people to pass through without tickets or permission. Rather than fix the gaping holes in the building designed to rust in one of the United States’ most humid places, management instead put up chain-link fences along them.

The second claim, that the Omni was designed to be an uncherished memory, is a guess. The Hawks played there either way. My dad drove me down into the city with the radio on — never the rock station, but always the R&B station with Switch, Brick, Earth, Wind & Fire, The Gap Band, Roger and Zapp, or Kool and the Gang on. I knew the Hawks had a player named “Tree Rollins.” This was enough all by itself, but I would also get to go to Burger King for a kids meal, which, for a kid who was avowedly not into sports, was a low, low bribe bar to clear.

Tree Rollins totally looked like someone named Tree. I remember the Omni very much looking like the inside of a doomed spaceship, and that everyone was very excited that someone called Dr. J was there, even though he was evidently some off-brand version of Dr. J not equal to a previous version. There were men there with giant Jheri curls and Magnum, P.I. sunglasses and mustaches indicating that they were serious, wealthy, and just dangerous enough to wear a mustache. I remember the hair across all races and genders being massive and more carefully constructed than the arena they were standing in; I remember being one of the few kids in the building, and thinking that maybe, sometimes, my dad might just be taking me to stuff he liked in order to get out of the house and have a few too many beers by himself.

Photo by Streeter Lecka/Getty Images

On the way home, I remember passing the few super-distinct pieces of the Atlanta skyline: the Peachtree Westin that Dar Robinson jumped out of for a Burt Reynolds stunt, the UFO-shaped alien cake of Fulton County Stadium where the Braves played and where my dad would later take us to sit in empty seats and pick up fiendish sunburns, the Georgia Capital that always seemed completely out of place in all that retro-futurism and brutalist forestry around it. That’s the kind of place Atlanta was and still is — a place where the past is what seems unnecessary, not the future.

The music had changed. My dad drove in silence and smoked Vantage cigarettes with the window cracked even though it was winter, I think, and cold enough to have the heat cranking. It was Quiet Storm time on the radio, and that meant Jeffrey Osborne, Marvin Gaye, Rita Coolidge, and Gladys Knight, Stevie Wonder, Teddy Pendergrass. DeBarge’s “All This Love” came on and the nylon string guitar solo played and I looked up and thought how the streetlights were on but still looked so dark against the streets and the houses of what I now know was a decimated Techwood.

I’m pretty sure since that song came out in 1982 that we’d already moved to Tennessee by then, but at a certain point emotional memories are immune to fact-checking. The fadeout and ride in the song is endless over the background singers going say you really love me baby/ say you really love me darling/for I really love you baby/sure enough love you darlin’

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At the Georgia Dome, there is some of exactly what you think should be at a Monster Jam show in the South.

There was, for example, a terrifying man in the sleeveless Confederate flag shirt eight rows below our seats. I asked him if he knew where I could get ear protection before the race. He looked at me for about five seconds before responding because he:

comes from someplace where there is a daily quota on words for interpersonal communication

thought I was a godless bearded urbanite hitting on him

or was very drunk and hearing me talking on a built-in beer-induced tape delay.

I hope he was drunk, and also that he thought I was hitting on him.

The trucks have names ranging from the super-uninspiring and corporate — the FS1 Cleatus Truck! the Team Hot Wheels Firestorm! — to the classic and menacing (Bounty Hunter and El Toro Loco). There is a truck called Obsession and its unimaginatively named partner, Obsessed. One is called Ice Cream Man, easily the least-intimidating monster truck of all time because it comes out to tinkly ice cream van chimes, or the most unsettling because it plays a song synonymous with the sketchiest non-related regular cast member of most people’s childhoods — the neighborhood ice cream man who might have lived in the van he worked in.

There is a Monster Energy truck with green neon lights built into the undercarriage. I am here to report against my will that it looks absolutely and positively sick. It is called “the Monster Energy Truck” because there are two good monster truck names in the universe, and both are taken. (Grave Digger and Bigfoot, to be specific.)

The anthem is sung while a bald eagle flaps in slow motion on the end-zone video boards.

The Georgia Dome was built in 1992, and it will be imploded in the summer of 2017. It will never see its 30th birthday, and it will not be missed because it, too, was built to be forgotten. The last event in the dome will be Monster Jam. If you are from outside of the state, you will think it is appropriate because LOL REDNECKS; if you are from here, you will probably also think it is appropriate because LOL REDNECKS, but will get mad when anyone else says it.

For the record, the Dome didn’t even try to be interesting on the level of the Omni or Fulton County Stadium. It was fine but unmemorable as something you drove past, sat in, or saw in shots of the city skyline. Take a hotel bathtub, preferably one of the cheap ones, too shallow to do anything in but sit unhappily for five minutes before giving up and draining the water. Cover it with a large golf umbrella blown inside out by the wind. Solder the two together. Paint it first teal and maroon, because someone in 1991 thought putting the bedroom color scheme from a Florida vacation rental on the outside of a stadium in Atlanta was a good idea.

When you remember the Atlanta Falcons play football there, paint it in a new scheme with red and black in it to remind everyone of their existence. Don’t do this until 16 years after you open the stadium, and only nine years before its eventual demolition.

Photo by Doug Benc/Getty Images

Monster Jam is the last event here. Other things happened before that. The Atlanta Falcons played mostly forgettable football here, unless you take out the Vick years, which you might want to given how they ended. If there were some way to keep the part where all the mostly African-American fans in the upper deck went bonkers the minute they started playing “Bring ’Em Out” for those teams, you should do that. That may be the most excited single concentration of minutes you could salvage from the team’s history at the Georgia Dome: Before the team played, but after they remembered they were going to watch the fastest player in the NFL touch the ball on every play. This is a happy memory. There aren’t a lot of those there.

It hosted a lot of college football, including the annual SEC Championship game. Tim Tebow cried on the sideline there after Alabama clipped Florida’s undefeated streak short in 2009; Les Miles in 2007 used his backup quarterback to win an SEC title there, and then a national title LSU somehow got with two losses later in New Orleans. Before that game he hustled every reporter in reach to a press conference where he denied Kirk Herbstreit’s report that he was going to take the Michigan job, and then with his chest at full inflation demanded that the room “have a great day.” I was there for that and, yes, it was just as confusing in person as it was on television.

Photo by A. Messerschmidt/Getty Images

LSU coach Les Miles after defeating the University of Miami, 40-3, in the 2005 Chick-fil-A Peach Bowl.

There was Wrestlemania in 2011, when the Rock returned and I nearly flipped my laptop off a table when the glass broke and Stone Cold Steve Austin ripped down the entry ramp on an ATV like the Pope of All Shitkicking Rednecks. In 1994, Deion Sanders and Andre Rison punched each other while wearing helmets in fight during a football game, an event that easily clears the hurdle to being one of the top 25 most memorable moments in Atlanta history, and was also incredibly dumb. Those two circles overlap a lot here.

There were two Super Bowls in the Dome. The first was a forgettable one in 1994 where the Cowboys beat the Bills. This beating was different from the seven other Bills/Cowboys Super Bowls in the 1990s because the pregame show featured Kriss Kross, Charlie Daniels, the Georgia Satellites, and the Morehouse Marching Band doing a tribute to “Georgia Music Makers.” Charlie Daniels is from North Carolina but did a song about an unenforceable contract between the Devil and a mentally ill violin player, so by any standard he counted.

The second is best remembered for an unseasonably brutal ice storm and Ray Lewis picking up two murder charges from the Fulton County District Attorney after a very bad night out on the town with his friends. The Tennessee Titans came up a yard short in Atlanta, but most Nashville things measured in Atlanta terms fail by much, much more than that. Feel better thinking about it in those terms, Nashville.

There was also the time the tornado struck the Georgia Dome while I was inside it during the 2008 SEC basketball tournament, rippling the ceiling like water and throwing the scoreboard around like a weight on a fishing lure. That happened, too.

Other than all that, there’s not much else. Monster Jam will close out the building’s life, if you like to anthropomorphize a stadium no one ever thought to give a personality or memory. The seats will be auctioned off or sold to high schools for repurposing. The innards will be sold in stages, right down to a yard sale of whatever’s left in the building getting gutted and gaveled out right on the sidewalk outside the Dome on Northside Drive.

Sometime during the summer it will be imploded and become a parking lot for the new stadium. It’s a corporate-sponsored metallic oculus someone will probably remember as looking like a very old future. The Falcons and Atlanta United will call it home, and the Georgia Dome will be gone and not mourned. That’s fine, and I don’t want you to think for a second it isn’t. Some things are built to be forgotten, and the Georgia Dome is one of them.

Photo by Chris Graythen/Getty Images

The trucks spend the first half of the show racing by pairs in heats. They can sort of drift a corner — sort of, as much as a 10,000-pound truck can slide on dirt. The drivers don’t hammer the gas so much as they get up to speed, and then feather the throttle to keep the trucks moving with careful blasts of the engine. It’s like watching extremely short rallycross races run by farting whales in track shoes.

Finishing fast is interesting. Finishing sideways doing something reckless and badass is better, but finishing first and flying sideways across the finish line is best. This is particularly true if you can roll the truck over, hit the throttle, catch one enormous tire in the dirt on the end of the roll, and flip the entire vehicle back onto all four tires for a save, a round of WOOOOS and applause, and a pass to the next round of racing.

This happens twice in the racing segment of the show, which is two more times than anyone should be able to pull that off in the aforementioned 10,000-pound trucks. Grave Digger sacrificed itself for the crowd’s pleasure early — it hit a massive jump while trying to speed across the finish line, bouncing sideways, blowing out one enormous tire and a mess of important-looking metal stuff in the chassis on impact, and then rolling to stop on its ceiling while soaking up the applause. Grave Digger left the arena with three good wheels, one completely destroyed tire, and the limp of a champion who’d given their all. If I had been drinking, I might have teared up a little.

The second half is the freestyle, the more entertaining part where Monster Jam ditches the entire concept of racing, and just lets drivers try to tear apart their cars for the crowd. The drivers have two minutes to run through their routine. The most popular runs don’t even make it that long, though. They end abruptly and satisfactorily when the driver rolls their truck onto its roof off an ill-advised but spectacular jump, breaks an axle or blows out a tire, or cripples the thing trying to land a backflip.

The Monster Energy truck — the one with the absolutely sick neon — whipped itself around during the freestyle event with such force that its flimsy body panels sheared off in every direction. One truck just did donuts for the last 20 seconds of their routine. If a monster truck rips donuts on dirt, there is an involuntary response from the body. “WOOOOOOOO” leaps from the diaphragm. You can’t fight it, and wouldn’t want to if you could.

The MCs yell out this or something like it repeatedly.

“DOIN’ IT ONE LAST TIME FOR THE GEORGIA DOME.”

It doesn’t have much effect, not even when a local DJ yells it out during a bike race between three audience members racing on children’s bikes. But then, the Georgia Dome is used to quiet echoing off its cavernous walls, or having fan noise piped in to ricochet between its empty seats. There is nothing more to give from this afternoon’s audience, for one: Being at Monster Jam is getting blasted in the face for three hours with engine noise, and then coated with a gentle drizzle of dirt floating down between runs. Maximum audience participation is clapping and yelling just loudly enough to be heard over engines that burn a gallon of fuel a minute. There is no 11, or giving it up any harder than one is already giving it up.

Very few people seemed to realize this was the end, or at least attached any significance to it, or cared whether anyone would begin gutting the building the instant the last earth-mover carried out the dirt.

We had to leave three trucks into the freestyle when both of their attention spans wore out, and were unrecoverable. We left before the Georgia Dome paid one last tribute to itself: A grease fire broke out in a concession stand, which was quickly put out only after filling a concourse with smoke and scaring the hell out of a few patrons. Remember that on the way out: that the building tried to save everyone the trouble of demolition by burning itself down.

Photo by Chris Graythen/Getty Images

A tear in the ceiling of the Georgia Dome is visible after severe weather passed over the building during the SEC Men's Basketball Tournament on March 14, 2008.

Walking out with my kids, they were about the same age I was when I left the Omni with my dad at the Omni in 1982, or 1983, or whenever it was in fuzzy kid-time. They saw the new stadium next door and thought it looked pretty much like a spaceship, or like someplace where Skylanders would live.

That is exactly what the Omni and Fulton County Stadium looked like to me as a kid —so much so that later, when my dad and another dad would awkwardly hang out for the benefit of their sons’ juvenile need to socialize with other dudes, my friend Jim and I would sit in the backseat as they drove and point out the buildings we would own in the future. He’d take the Westin, and keep all his Legos there. I’d take Fulton County Stadium, and reserve it exclusively for my collection of helicopters. A city was a place to be had, a thing to be purchased for your convenience.

Kids, weirdly enough, understand that a city is just something to be bought and sold.

Later, weirder, less-tenable ideas creep into your head: That it could be home, that the buildings you can name mean something beyond the names, that there might be some kind of resonant harmony between you and this random system of properties and spaces. Sometime someone might superimpose a sports team into that imaginary relationship, making this city not just a place, but a place for you, and people like you, and that all of you can thrive here. It is special. You are special, and the team, its players, and all the spaces they pass through and live in are special and remarkable and unlike anything else in the world.

There is a magic you can believe about a place as an adult that children do not even begin to believe or accept. A 7-year-old would laugh you out of the room, probably while telling you that the new place was much better, both because it looked like a place where Skylanders would live, and also because it was new. New things are better, and you should always take the new thing.

Photo by Streeter Lecka/Getty Images

That shouldn’t be hard to accept. Take the new thing, even if the nagging, haunting feeling of living somewhere boils down to a problem with you, with that thing where you’re looking for something in tangible space to consider a landmark, a guidepost. To consider something significant, if only so that you, in relation to it, can have a bit of that significance. The city I live in makes that hard to do, though there’s an honesty in that constant self-digestion and auto-demolition. Do not get attached. It, and everything in it, will eventually move, just like the teams and the people who call it home.

That’s the rational, reasonable thing to think, yet even with an intentionally blank, mostly unmemorable empty space like the Georgia Dome I want something to be there, to definitively have happened there. There should be a definite something there, thinks some deeply schizophrenic part of my brain that doesn’t want so much as a garden shed to collapse around me without some memory attached to it. Otherwise it’s just a thing — and by extension, so is the city, and the very personally important me I’ve attached to it.

I have a definite thing to attach myself to here. After all, I thought for a few seconds on March 14, 2008 that I was going to die on the floor of the Georgia Dome on press row at the SEC men’s basketball tournament.

I thought Kentucky fans were stomping their feet in unison on the bleachers at first, but the noise swelled, and swelled more, and grew so loud and limitless all at once. It felt limitless in the sense of being infinitely powerful with no range or end to the noise, so loud and yet so obviously just getting started on the way to a theoretical full volume. What do you think a tornado at pace is? It’s actually just clearing its throat and warming up, volume-wise. It’s whispering, holding back. You just hear it as a roar.

There wasn’t even a shudder from impact. There was just the sensation that the entire building was next to an immense floor buffer, spinning and vibrating at thousands of RPM. When that vibration turned into waves the roof flapped like a subwoofer, the air vents started spitting out pieces of insulating foam, and for one second I weighed the options of dying standing up and being crushed by the falling roof and lighting, or taking my chances ducking under a table, only to be crushed by all that plus one flimsy plywood table. The lights swayed 10 to 15 feet in either direction. The waves got stronger, and the entire overturned bathtub of the stadium was now being thumped by a very pissed off janitor pushing that giant floor buffer into the side of the Georgia Dome.

I was sitting next to Verne Lundquist and Bill Raftery. That would have been memorable for me, at least, getting crushed next to a legendary announcer, in the few seconds I had to have a last memory. If I’d heard Verne say “oh my” as it collapsed, it would have been my last tweet, and the RTs and favs would be infinite.

Instead of bearing down at full speed and colliding with the Dome, though, the tornado drunkenly staggered into the Georgia Congress Center next door, then down Marietta Street and into Cabbagetown before dissipating into the night. Not knowing what else to do, I walked out and took pictures of holes in the walls of the Congress Center, and thought about how great I felt about not dying in the Georgia Dome that night.

Leaving the last event at a building that was designed to be forgotten, I didn’t even really think about the one thing I should remember and attach to the spot.

Instead I thought about the only song I think about when I think about the irrational need for a place to give me something only a human can — especially this place, the first place I did so many things, like leaning my head against the window listening to DeBarge after a Hawks game. That need will never make sense, no matter how many games you watch there, or how many moments you spend there. It won’t make sense, not even after years of silently asking a place to just talk back to you once after you spend years monologuing to it. To look at a place that eats its own every day, and buries its stadiums and buildings and places under like daisies beneath a plow, and ask it, as if you were some exception to the rule, to sing the outro to you:

say you really love me baby

say you really love me darling

for I really love you baby

sure enough love you darlin’

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tulagibtc-blog · 8 years ago

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Blockchain Terminology - a developer perspective

One of the discussions I had with SCC's committee on "Blockchain and electronic distributed ledger technologies" was about the various terminologies used by the Bitcoin / blockchain community. In light of that, I figured I would put together some of my interpretations of those terms as they might be viewed by a developer working in the field. The following list is by no means exhaustive and it could be further refined, but I hope at least some of the examples and nuances in meaning would be helpful in expanding some of the definitions of more rigorous dictionaries.

Address

A string of characters representing the destination of a funds transfer on a Blockchain. For example, "1PiachuEVn6sh52Ez7o6Fymvw54qvQ4RBm" is a Bitcoin address, "0xcd234a471b72ba2f1ccf0a70fcaba648a5eecd8d" is an Ethereum address. Addresses are usually a human-readible representations of a Public Key composed using a fixed scheme, but they can also represent concepts that don't correspond to Keys, like Ethereum's contract addresses.

In most blockchain systems, every entity can own many addresses. Some blockchains like Bitcoin focus on creating a lot of addresses, while others, like Ripple, focus on reusing the same address many times over.

Addresses are analogous to bank account numbers.

Altcoin

A term that originated early in the Bitcoin history, an Altcoin refers to "an alternative coin implementation", usually being an alternative to Bitcoin. It has often been used dismissively and sometimes even derogatorily, especially when referring to a lot of "copycat coins" that are a carbon copy of Bitcoin with minor tweaks. Most well known Altcoins include Litecoin and Dogecoin.

A lot of Altcoins mostly focus on tweaking small parameters of Bitcoin while preserving how the system operates on a higher level. The tweaks most often focus on the Hashing Algorithm, Block creation time, Coin distribution, name and branding.

When an Altcoin is created solely to be speculated on and then abandoned, it's usually referred to as a "pump and dump" or a "ScamCoin".

Some part of the community refers to every non-Bitcoin cryptocurrency as an Altcoin, while others shy away from this term when talking about more sophisticated projects that differ greatly from Bitcoin, such as Ripple or Ethereum.

Block

A Block is a cryptographically secured collection of Transactions along with some extra information stored in the Block Header. That extra information usually states the Hash of the previous Block, the current time, and the Merkle Root of the transactions, among other information.

There is usually some limitation to how many and how often Blocks are created in a given Blockchain project. In Bitcoin, the Blocks require a Proof of Work to be valid. Ripple Blocks require a consensus to be reached.

Blocks are usually referred to by their Hash. Due to how their Hash is computed, the Block cannot be altered without creating a completely different Hash.

Blockchain

A Blockchain is a collection of Blocks refering to one another in a linear sequence all the way to a Genesis Block. Because of how the chain is created, any change to any Block in the sequence would invalidate all of the Blocks that came afterwards. This is one of the core features of a Blockchain known as Immutability.

If two or more Blocks refer to the same previous Block Hash, this is known as a Fork. In most systems, only one of those Blocks will be considered valid, usually the one that will end up in the longest branch.

The term "Blockchain" is also used to refer to the projects that use Blockchains. Bitcoin is a Blockchain project that contains the Bitcoin Blockchain. This term was popularized in mid-2015 by large enterprises such as Overstock and NASDAQ wanting to use the then called "Bitcoin technology" without using the term "Bitcoin" due to its various connotations.

Colored Coins

A Colored Coin is an idea of "earmarking" particular outputs of a given Transaction and assigning some extrinsic value to them, usually representing some real world assets or currencies. This is the most basic implementation of a Crypto 2.0 system, allowing simple Blockchains such as Bitcoin to track non-native currencies.

There are specific rules governing how a perticular implementation of Colored Coins handles transaction mixing and other related features.

CryptoCurrency

A CryptoCurrency is a cryptographically secured currency. The authorisation of transfers of CryptoCurrency between Addresses is handled either by public-key cryptography, or Smart Contracts.

Most Blockchain projects contain at least one form of Native CryptoCurrency, often referred to as a Coin or a Token. Bitcoin the project is used to transact in bitcoin the currency, Litecoin - litecoins, etc. Some projects have multiple native tokens (such as Factom with its Factoids and EntryCredits), while a few projects (usually Permissioned Blockchains) have none (such as Hyperledger or Eris).

Some Blockchain projects, sometimes referred to as "Crypto 2.0", can also support user-created CryptoCurrencies. Those usually take a form of an IOU for a real-world asset, such as BitstampUSD on Ripple, or TetherUSD on Omni. A few projects also create currencies based on derivatives from the Native Tokens, such as BitUSD. Some of the Crypto 2.0 projects that support Smart Contract allow for complex script to manage how the currency behaves.

Decentralized Autonomous Organizations

A Decentralized Autonomous Organization (or DAO) is a computer software that is able to manage money without being reliant on third parties. They usually take a form of an automated Smart Contract, but the definition can also include some Blockchain Projects as a whole, such as BitShares.

DAOs are created with a set of rules governing how it will handle its money (usually in a form of the Native Cryptocurrency). Once put in place those rules are usually immutable.

DAOs can exist in a legal gray area due to their distributed nature. One of the first concepts for a DAO is that of a decentralized casino. While operating an online casino might be illegal in some jurisdictions, it is hard to say whether a DAO casino is legal or not.

The most well-known example of a DAO was called "The DAO".

Distributed Ledger Technology

Distributed Ledger Technology is a term used to describe a superset of the Blockchain Technology and ledgerless crypto suites (such as Corda or Open Transactions).

The term is relatively new as of February 2017 and it may be seen as a way for governments and big companies to further move away from the terms "Bitcoin" and "Blockchain".

Fork

There are multiple different concepts in the Blockchain space that are referred to as "forks".

The simplest Fork is a Repository Fork - a term originating from software development where a developer copies a repository of a given project to create their own version of the software. This is most often used to create Altcoins - most of them are Forks of the Bitcoin repository, or other forked repositories.

Another type of Fork is a Blockchain Fork. It is an event in which there are multiple competing blocks of the same height. Those Forks may occur naturally due to multiple Miners creating a Block each at a similar time, or they can be malicious, for example - a result of a 51% Attack.

The last type of Fork is a Blockchain Fork caused by changes in the software operating the Blockchain (such as bitcoind). Those Forks may be incidental (such as the March 2013 Bitcoin fork), or deliberate (Ethereum's DAO fork). The latter are generally split into two kinds - Soft Forks and Hard Forks.

Soft Forks are less invasive and mainly require the Miners to upgrade their software. Old software will still recognize new blocks created after the Soft Fork as valid. An example of a Soft Fork could be the bugfix for Value Overflow Incident.

Hard Forks are more invasive and require everyone to upgrade their software. Old software will not recognize new blocks or transactions as valid after the Hard Fork. The Ethereum DAO Fork is perhaps the most famous example of a Hard Fork.

Contentious Hard Forks can sometimes lead to network splits, where a part of the network and community decide not to opt into the Forked code and Blockchain, and instead decide to take a different approach. Ethereum Classic is a network split that resulted from the DAO Fork.

Hash

A Hash is a cryptographic digest of a piece of data. Hashes are most often used to refer to a given Transaction or a Block, as each of them would have a unique Hash, and the length of that Hash is short enough to be easy to use.

Most Blockchain Projects use the SHA256 hashing algorithm dominantly, with ocasional use of other algorithms (such as RIPEMD-160 being used by Bitcoin for creating its Addresses).

The Block Hash is also an integral part of the Proof of Work Mining algorithm.

Merkle Tree

Merkle Tree is a tree build out of Hashes. Each node in the tree is a hash of its child nodes. The final hash in the Merkle Tree is called a Merkle Root.

Merkle Trees are used to create a single Hash that represents a collection of Hashes. It can be used in Simplified Payment Verification or Proof of Existence to prove a given Transaction was part of a Block by specifying only log2(n) hashes, rather than n hashes it would take to list all of the Transaction Hashes. SPV is an important part of Light Nodes / Wallets.

Miner

Miner is an entity involved in the Mining process of a Proof of Work Blockchain, such as Bitcoin. Other Block generation schemas use different terminology for similar functions - Validators, Farmers, etc.

The term Miner can refer to:

The machine doing the computations

The business owner running said machines

Less frequently, to the piece of software performing the computations

Miners often use Mining Pools to pool their computation resources and create Blocks together to reduce the variance of their income.

Mining

Mining is the process by which Miners create a Proof of Work Block in Blockchains such as Bitcoin. It is a process of iterating through many possible Blocks (often iterating using the Nonce) until the Block satisfied the PoW criteria. This involves the Hash of the Block being a number smaller than the Target for a given block (see: Difficulty).

The Miners are rewarded for creating a valid Block by the Block Reward and any Fees spent by Transactions included in the Block.

There are also a handful of minor activities similar to Block Mining that serve a different purpose. As Addresses are essentially random numbers, some people iterate over them in a process of Vanity Address Mining to create a desirable looking Address (similar to vanity plates for cars). One can also mine for different Transaction Hashes, but it's a fringe activity used only in special cases.

Node

A Node is a computer running the specialized software used to communicate directly with a Blockchain Network. A Node is often a Wallet, but it doesn't need to be.

Generally, there are two types of Nodes - a Full Node and a Light Node.

A Full Node downloads and stores all of the Blockchain information. It can provide the data to other Nodes in the network as needed. Distributed Blockchain Networks require a web of Full Nodes to be operating at all times to maintain the network.

A Light Node only downloads the core data it needs to validate the current Blockchain status (most often - Block Headers) and any information relating to the Addresses it cares about. It has a much lower memory and network footprint than a Full Node, but it cannot provide all of the information a Full Node might. A set of Full Nodes is till required to maintain the network.

Nonce

A nonce is a random number used to easily create a different input. It is most notably used in a Block Header to create a different Block Hash without changing any important information stored in a Block. This is most often used in Proof of Work Blockchains that need to iterate over many block hashes. Due to the avalanche effect, changing even a single bit in the nonce creates a completely different Hash.

Permissioned Blockchain

A Permissioned Blockchain is a Blockchain Project that restricts access to its Blockchain in some way to the users. It could require user authentication before they can connect their nodes to the network, or even download their Clients.

In constract, Permissionless Blockchains, such as Bitcoin, are inclusive by nature, allowing anyone to join and transact on the network.

Permissioned Blockchains are still in early phases of adoption as of February 2017. For their time being, their target market consists of banks, governments and other large entities that want to exert some form of control over their Blockchain network. This could be done due to regulatory, KYC or other reasons.

Some Permissionless Blockchains do offer some features for their users to restrict access to some of their financial assets. Ripple allows explicit white- and blacklists of Addresses, while Smart Contract scripts give even finer control over how a given asset can be used.

Proof of Existence

Proof of Existence is a cryptographics-based proof that a given piece of data existed, unchanged, at a given point in time. It can be used as a replacement for a notary service. Proof of Existence relies on a public Blockchain, such as Bitcoin's. The data in question is hashes and embedded into a Transaction or a Block. Given that a Block contains a timestamp and it is impossible to rewrite old Blocks without invalidating the proceeding Blocks, it is possible to prove the data existed in its current form no later than when that Block was created. Factom is one Blockchain project that focuses on providing Proof of Existence "as a service". It maintains its own Blockchain that is itself "anchored" into the Bitcoin Blockchain, extending the Proof of Existence to a bigger amount of data.

Proof of Stake

Proof of Stake is an alternative Block creation algorithm to Proof of Work. Instead of relying on a lot of computational power to create a Block, one instead relies on a large supply of Coins. The reasoning behind Proof of Stake is that an attacker trying to subvert the network would be risking a lot of their wealth in the attempt, therefore they would be disincentivised to attack the network to preserve the value of their Coins. Similarly, users with a lot of Coins have a high stake in keeping the Blockchain operating properly to increase the value of their Coins.