Glossary

These are some technological words found throughout this site, placed here in case you need them!

56-bit encryption: The old, popular DES (Data Encryption Standard) key length. To decrypt a 56-bit encrypted document, one must implement the right combination of 56 0s and 1s. It was proved to be insecure after a number of distributed computing efforts — included distributed.net’s RC5 and the Electronic Frontier Foundation — cracked the encryption. See also: bit, 64-bit encryption, Electronic Frontier Foundation, encryption.

64-bit encryption: The new DES (Data Encryption Standard) key length. To decrypt a 64-bit encrypted document, one must implement the right combination of 64 0s and 1s. See also: bit, 56-bit encryption, encryption.

Anderson, David: Project director of SETI@home. He designed and implemented the scan of the sky for radio signals. See also: SETI@home.

application logic layer: the second layer of an application, which has three layers. It is the actual core of the application that interprets data, sends the appropriate output to the presentation layer, and communicates with the bottom layer. Mentioned in: Application Layers. See also: presentation layer, bottom layer. Pictures: Layers of an Application

application programming interface (API): in context, software that allows an application to communicate with the networking software. The API does the actual sending and receiving of raw data for the application, but leaves it up to the networking software and middleware to address the packet and take care of computer semantics (languages between different computer systems, like a Mac and a PC). Mentioned in: Network Software. See also: network operating system.

application server: server that handles the application logic layer of an application. See also: application logic layer.

architecture: The format in which clients and servers are set up. The RC5-64 project has a pyramid architecture, with a master keyserver at the top, many proxy keyservers in the middle and clients at the bottom. See also: client, server.

Arecibo: The world’s largest radio telescope, it records signals for the SETI@home project. It is located in Puerto Rico. See also: SETI@home.

Asimov: A SETI@home servers, Asimov runs a database server. All of the interesting signals that SETI@home clients find are sent back to the server and entered into the database. This server and Cyclops house over a half-billion signals. See also: Cyclops, Sagan.

asynchronous operation: a type of operation between two computers. A computer sends a message to the other and does not require a reply in order for it (the sender) to continue. Mentioned in: Network Communications. See also: synchronous operation.

authentication: the act of ensuring the validity of data transferred over the network or logged-in users.

background noise: Humans send out signals into space every day, via television transmissions and radio broadcasts. Military radar is the strongest type of background noise, and the earliest military radar signals are approximated to be fifty light years away from earth.

bit: In cryptography, binary digits; 0 or 1.

bottom layer: the third layer of an application, which has three layers. Takes care of basic services for the application, such as printing, communicating with other computers, writing and reading files and databases. Mentioned in: Application Layers. See also: presentation layer, application logic layer. Pictures: Layers of an Application

brute force: A method of searching that every piece of data must be blindly processed or tested until the solution is found. RC5-64 is an example of this; they must test every block in their search for the key block- all blocks have an equal chance of being the solution, and any user could, at any time, find the key block. See also: RC5-64.

bus network: also known as ethernet. Type of local-area network that sends a packet to all computers in the network, even if it is for one particular computer. The computers check to see if it's for them. If it isn't, they trash the message. Mentioned in: Network Communication. See also: token-ring network, star network.

business logic layer: Mentioned in: Application Layers. See application logic layer.

Caldwell, Chris: A college professor and mathematician who owns and operates “The Prime Pages”- a website dedicated to prime numbers, mathematicians, and formulas. See also: prime numbers.

Casino-21: A new distributed computing project that hopes to use thousands of peoples’ computer processing power to determine what the weather will be like in the latter half of the 21st century.

client: Most commonly in distributed computing, it is the software that a user runs. In commercial distributed computing, however, a client also refers to a person purchasing processing power. In client/server networks, the client controls the presentation layer of an application and requests services from the server, such as data.

client/server network: type of network in which particular computers — servers — are responsible for resources and providing these resources for other computers — clients. There can be many clients and one server, or vice versa. Servers can have one specific type of resource to control. Mentioned in: Types of Networks. See also: peer-to-peer network, file server, newsgroup server, print server, application server, file server.

clustering: a cross between parallel processing and distributed computing. Networked computers, on a local level, work together just like a parallel machine. Although the work is split across multiple computers, they behave in a parallel fashion. The same hurdles for parallel processing still exist. Mentioned in: DC Alternatives, Parallel Processing. See also: parallel processing.

Common Object Request Broker Architecture (CORBA): a set of standards by the Object Management Group (OMG) for distributed technologies and objects. It's platform-neutral and quite popular. Its ORB technology allows communication between distributed objects. Its equivalents are the Open Group's Distributed Computing Environment and Microsoft's Distributed COM system. Mentioned in: DC Communication. See also: Distributed Computing Environment, Microsoft Distributed Component Object Model.

Computing Minimum Equal Sums of Like Power: A distributed computing project that is searching for the best values of k, m, and n to plug into equations. K is the power, m is the number of digits on the left side of the equation, and n is the number of digits on the right side of the equation.

Cray: A supercomputer manufacturer, owned by Silicon Graphics, Inc.

cryptography: The science of using mathematics to make information secure. See also: encryption.

Cyclops: A SETI@home servers, Cyclops runs a database server. All of the interesting signals that SETI@home clients find are sent back to the server and entered into the database. This server and Asimov house over a half-billion signals. See also: Asimov, Sagan.

Distributed Component Object Model (Microsoft DCOM): a set of standards by Microsoft for the implementation of distributed technologies. Its equivalents are the Open Group's Distributed Computing Environment and OMG's Common Object Request Broker Architecture. Mentioned in: DC Communication. See also: Distributed Computing Environment, Common Object Request Broker Architecture.

distributed computing: a type of system that divides a workload to computers connected to a network. The network may be either be enclosed in a room or out in the open, like the Internet. Distributed computing is also referred to as distributed processing, cooperative computing, and collective computing. See the Introduction section for a major treatment. See also: render farms, parallel processing. Pictures: Regular Computing vs. Distributed Computing diagram.

Distributed Computing Environment (DCE): a set of standards by the Open Group for the implementation of distributed technologies. Its equivalents are the Microsoft Distributed Component Object Model and OMG's Common Object Request Broker Architecture. Mentioned in: DC Communication. See also: Microsoft Distributed Component Object Model, Common Object Request Broker Architecture.

distributed file system: files stored over several computers, whose actual location is given to the application by particular software. (TechEncyclopedia) Mentioned in: DC Communication.

distributed.net: An organization that provides clients for various distributed computing projects. Currently they are trying to break the RC5-64 encryption code and discover new Optimal Golomb Rulers. See also: RC5-64, OGR.

distributed object: objects independent of platform and application that contain their own data and functions for accessing the data. It's like a drive-in window at a fast-food restaurant: you tell the attendant at the window (or the window) what you want, and they retrieve the "data" food for you. Mentioned in: DC Communication. Pictures: distributed objects.

Electronic Frontier Foundation: An organization that, in their words, is “the leading global nonprofit organization linking technical architectures with legal frameworks to support the rights of individuals in an open society.” They are currently giving away cooperative computing awards for the first individual or group who finds certain prime numbers. They were also the first organization to break the 56-bit encryption standard in 39 days with only one machine. See also: 56-bit encryption, prime numbers.

encryption: The conversion of text into a less readable format via a mathematical process. This encrypted text can be read by anyone with the key that decrypts the encrypted text. For example, a 56-bit encrypted document could be read with someone with a code of 56 0s and 1s in the correct order. See also: 56-bit encryption.

Entropia: a commercial company using distributed computing to process projects. Mentioned in: Distributed Computing's Applications. Website: http://www.entropia.com/.

error-control: data in a packet that contains a mechanism for checking the validity and integrity of data. For example, let's say you send a five-word message. The error-control data would say that your message had five words total. If the data doesn't have five words, then the computer will know that the message is not valid. Mentioned in: Network Communication.

Evolution-at-home: A new distributed computing project that will attempt to simulate mutations and ways they can be stopped. See also: spontaneous mutation.

file server: type of network that handles the transfer of files. One particular type used on the Internet is the File Transfer Protocol (FTP) server. Mentioned in: Types of Networks.

function: a function or routine is a programmer's term for a process a program executes. Routines do different things; there's a routine for saving a file, displaying it on a screen, etc. Local routines are those that execute on the same computer, while remote procedural calls execute routines on other computers. See also: remote procedural call.

Fermat number: Numbers based on Mathematician Fermat’s conjecture that every number of the form 2^2^n + 1 is prime. Although his theory was wrong, it is true for some numbers, so in the formula Fn=2^2^n + 1 , the n is called the nth Fermat number. If it is prime, it is called a Fermat prime. See also: prime numbers.

Fermat’s Little Theorem: Mathematician Fermat proposed this theorem in 1640: “Let p be a prime which does not divide the integer a, then a^p^-1 = 1 (mod p)”. This theorem is used in the PrimeForm project, as with many other primality tests, since it is easy to calculate a^p^-1. See also: PrimeForm.

GARSP: The name of one of the original OGR clients. See also: OGR.

GIMPS: Also known as the Great Internet Mesenne Prime Search. A distributed computing project that began in January, 1996 to search for Mersenne primes. So far the project has discovered the 4 largest Mersenne primes. A person running the GIMPS software has a 1 in 60,000 chance of discovering a new prime. See also: Mersenne, Mersenne prime numbers.

Golomb, Dr. Solomon: A mathematician who discovered Golomb rulers in the 1960s. He was a contributor to the Scientific American "Mathematical Games" and had an interest in coding and number theory, both which led to this discovery. See also: Golomb Rulers.

Golomb Ruler: Numbers in a line in such a way that the distances between each number are different. See also: Optimal Golomb Rulers.

GVANT: The name of one of the original OGR clients. See also: OGR.

hub: device used to connect cables from more than two computers together. Can be used for peer-to-peer and local-area networks. Mentioned in: Types of Networks. See also: network. Pictures: Photo 1, Photo 2.

host: a computer that "hosts" a session on the Internet by acting as a "messenger" between the client computer and the Internet. Hosts are generally used with Internet Service Providers. Mentioned in: Network Communication. See also: Internet Service Provider. Pictures: messages over the Internet.

idle time: The time in which a user isn’t working on a computer and it is using very little of its processing power. When a computer runs a screensaver due to lack of activity, it is said to be idle.

Internet: a worldwide network of smaller networks with redundant connections. The Internet is particularly useful for distributed computing because of the vast numbers of computers that can aid in processing a workload. In fact, you are accessing the Internet right now! Pictures: Client/Server as it relates to the Internet, Internet communication between computers.

Internet Movie Project: The Internet Movie Project is a distributed computing project that will attempt to create a 3D movie using Persistence of Vision (POV) Ray Tracers. Users will either be actively involved in the project by designing scenes or graphics while others will donate their computer time as render farms. See also: POV Ray Tracers, render farms.

internet service provider (ISP): provides a connection to the Internet. Home computer clients dial into the host computer, which is connected directly to the Internet. Mentioned in: Network Communication. See also: host. Pictures: messages over the Internet.

key: Composed of bits, people can encrypt and decrypt data with keys. They are often used in cryptography. See also: bit, cryptography.

key length: The number of bits in an encryption mode. Increasing the key length causes an increase in key space- making information more secure and harder to decrypt. See also: key space, encryption, bit.

keyspace: All possible keys in a specific system. In the RC5-64 project, there are more than 68,000,000,000 blocks with even more keys. 30% of the keyspace has been exhausted, meaning that 30% of the keys have been tested. See also: RC5-64, key.

Lawson, Jeff: A distributed.net head who created the RC5 software. See also: distributed.net.

length: On a Golomb ruler, the total sum of the ruler. For example, a ruler with marks at 0-1-3-7 would have total length 7, found by subtracting the first and last number of the ruler. If written in the more conventional way with distances, 0-1-2-4, (the same ruler as the first example) one would find the length by adding up all the numbers. IE, 0+1+2+4=7. See also: Golomb rulers.

local distributed computing: distributed computing used on a local level, generally on a local-area network. "Local" refers to an enclosed space, building, or area, such as a university or an office. The Internet is not local.

local routine: a function or routine that executes on the same computer it is called from. Mentioned in: DC Communication.

Lucas-Lehmer: The primality test that GIMPS utilizes. The form is: For p odd, the Mersenne number 2p-1 is prime if and only if 2p-1 divides S(p-1) where S(n+1) = S(n)2-2, and S(1) = 4. It was a theory proposed by mathematician Lucas in the 1800s and then revised by Lehmer in the 1930s. See also: GIMPS, Mersenne Prime numbers.

mail server: type of server that sends and receives electronic mail messages as directed by the client. For those technical types, the Post Office Protocol version 3 (POP3) server receives mail and sends them to the client. The Simple Mail Transfer Protocol (SMTP) server sends off e-mails to other computers. An Internet Messaging Access Protocol version 4 (IMAP4) server controls large files or voice mail. (Derfler 194-195) This is why e-mail clients, like Eudora or Microsoft Outlook, require a POP3 and SMTP server information. Web-accessed e-mail, such as MSN Hotmail or Yahoo! Mail, automatically handle these protocols for you. Mentioned in: Network Communication. Pictures: Client/Server as it relates to the Internet.

mark: On a Golomb ruler, the number of numbers in the line. A ruler of 0-1-3-7 would have 4 marks. See also: Golomb Rulers.

master keyserver: In RC5-64’s architecture, the master keyserver is at the top of the “pyramid.” The master keyserver keeps track of the keyblocks: which keyblocks have been sent out, returned, and those that still need to be checked. See also: architecture, RC5-64, keyblock.

McNett, David: distributed.net head who manages the organization of distributed.net, he also created the statistics database on the site. See also: distributed.net.

Mersenne: A mathematician as well as a French Monk who lived in the 16th century, he investigated prime numbers, hoping to create a formula that would represent all primes. Although he did not find one, he did create the formula 2^P-1: if the answer to that equation is prime, then P must be prime. See also: GIMPS, Mersenne Prime numbers.

Mersenne Prime numbers: a prime number that has the form 2^P-1. 2^3-1= 7; 7 is a Mersenne prime. There have been only 38 Mersenne primes found. See also: GIMPS, Mersenne.

middleware: a layer of software between the network and the application. It encompasses everything from the client's API to the transmission of the message by the computer's hardware. Mentioned in: Middleware. See also: application programming interface, network operating system. Picture: Middleware.

Monte Carlo: A technique that is used especially in weather forecasting, in which simulations are performed and compared. Each simulation is like a different roll of dice. The simulations are compared, and if each states the same thing, like it’s going to be a hot day, then it probably will be. If the simulations come up different, the weather forecast isn’t quite so certain. A new distributed computing project, Casino-21, will be using this method. See also: Casino-21.

MRI scanner: Magnetic Resonance Imaging scanner. This type of scanner provides doctors a three-dimensional probe of your body without having to resort to surgery. Useful for diagnosing cancerous tumors. Mentioned in: Parallel Processing.

n-body simulation: simulation which calculates the effects of a force field on atoms in a gas or a fluid. This is an example of a problem using dependent variables. Mentioned in: DC Disadvantages.

network: a system in which one or more computers are connected to each other and sharing resources. Mentioned in: entire InsideDC section. See also: peer-to-peer network, client/server network, Internet.

network operating system (NOS): software that takes messages from the application programming interface, changes it into a packet by affixing proper addressing, and then sends it to the network communications driver, the interface card driver, and then the actual interface hardware. It's kind of confusing because of all the layers a message must go through, but it's like an assembly line. First comes the application, which sends the message to the API, then to the NOS for stamping, and then the proper drivers for transmission through the network. Mentioned in: Network Software. See also: application programming interface.

newsgroup server: type of server that handles newsgroup/Usenet messages. Newsgroups are message boards similar to the one on this site. Mentioned in: Types of Networks.

node: In the OGR project, a node is the smallest unit that is checked by the client. Each node represents a single Golomb ruler possibility. See also: OGR, Golomb Ruler.

Novell Netware: networking software that transfers messages from applications to the network card, to another computer. Mentioned in Network Software.

null: Nothing. Empty. Zero. A "null packet" is one that does not contain any information; it usually means that the network's transport layer is clear and ready for a new packet. Mentioned in: Network Communication.

Object Request Broker (ORB): allows communication to take place between two distributed objects. Its specifications are drawn by CORBA. Mentioned in: DC Communication. See also: Common Object Request Broker Architecture.

OGR: The OGR project, or Optimal Golomb Rulers, is another project by distributed.net. They are currently searching for both 24 and 25 mark optimal rulers. See also: distributed.net, Optimal Golomb Rulers.

OGR-21, 22, 23: The original OGR distributed computing project. It didn’t find new optimal rulers with 21, 22, or 23 marks, but proved that the existing rulers for those marks were optimal. See also: OGR.

Optimal Golomb Ruler: Golomb rulers that have the shortest length for a given number of marks. See also: length, marks.

packet: messages sent between computers, containing the actual message data, the data type, the data's length, the sender's computer, network, and socket, the destination's computer, network, and socket, and error-control information. (Derfler 88-89) As it relates to OGR, each packet represents a single stub. Thus, a client will be checking one ruler at a time for optimality. See also: stub, OGR. Mentioned in: Network Communication. Pictures: Packets.

parallel computing: Parallel Processing.

parallel machine: a computer which utilizes multiple processors working together — parallel processing.

parallel processing: type of distributed computing which, instead of distributing the workload across multiple computers, distributes the workload across multiple processors within one computer. Better speed and communication than distributed computing, but is not widely used due to the difficulty of programming for parallel machines. Mentioned in: DC Alternatives, Parallel Processing. See also: distributed computing. Pictures: Distributed Computing vs. Parallel Processing diagram

parallel virtual machine: refers to distributed computing over the Internet. A parallel machine uses parallel processing — or multiple processors. Mentioned in: Distributed Computing's Advantages, Parallel Processing. See also: parallel processing.

peer-to-peer network: type of network in which computers share resources — printers, scanners, file services, etc. Almost every computer has its own resources to share. Mentioned in: Types of Networks. See also: client/server network. Pictures: Peer-to-Peer network diagram

PiHex: A distributed computing project to calculate a bit of pi. The five trillionth bit and forty trillionth bit have been calculated already- they are both 0. Currently they are working on calculating the quadrillionth bit of pi. See also: bit.

Pixar Studios: computer-animation studio that created Disney's Toy Story, Toy Story 2, and A Bug's Life. They used distributed computing to render the frames for Toy Story. Mentioned in: Distributed Computing's Applications. Visit their website at <http://www.pixar.com>.

POV Ray Tracers: Persistence of Vision Ray Tracers are 3D-graphics applications. Using a programming language, one can create remarkable images. However, the pictures can take a long time to render, which is why render farms are useful in creating such types of 3D animations. See also: render farms. Website: http://www.povray.org/

presentation layer: the first layer of an application, which has three layers. Handles user interface — input and output. The presentation layer is always situated on the client computer. Mentioned in: Application Layers. See also: application logic layer, bottom layer. Pictures: Layers of an Application

Primality test: A test, with alterable levels of probabilities, that determines if a number is prime.

PrimeForm: A mathematical distributed computing project that lets users plug in their own equations and search for prime numbers. The client uses Fermat’s Little Theorem. See also: Fermat’s Little Theorem.

prime numbers: A number that is divisible only by itself and 1. Examples are 2, 3, 5, 7, and 11.

print server: type of server that handles the print jobs. Mentioned in: Network Communication.

proxy keyservers: In RC5-64’s architecture, the proxy keyserver is in the middle of the pyramid. The proxy keyservers are mediators between the master keyserver and clients. The proxy keyservers request large keyblocks (superblocks) from the master keyserver and break them down into smaller blocks. The proxies then distribute them to the clients. See also: RC5-64, master keyserver, keyblock.

queue: a place where data is stored until it can be processed by the computer. Message queues hold incoming transmissions, while print queues hold documents until the printer gets to them. (TechEncyclopedia) Think of an amusement park. In America, people "line up"; in Britain, Singapore, and other former British colonies, people "queue". Here, the data is lining up for their turn to be processed. Mentioned in: Middleware.

RC5-64: RC5-64 is distributed.net’s distributed computing project to break a 64-bit encrypted message. RSA Security provided the encrypted message and distributed.net created the client software to break it. The project was started in 1997 and has not been completed yet. More than 30% of the keyspace has been tested. See also: RSA Security, encryption, keyspace.

remote procedural call (RPC): calls to a function from an application on one computer and are executed on a different computer. The results from the latter computer are then sent back to the original computer. Mentioned in: DC Communication. See also: function. Picture: RPC diagram.

render farms: A group of computers working on rendering pieces of a picture at a time. An image could be split up into four pieces, and four computers could each work concurrently, rendering it, and then the finished image could be pieced back together. Render farms save time; it could take one computer a long time to process one picture by itself, but with many computers working, the time is cut drastically.

router: machine that controls the flow of data in a network. Mentioned in: Network Communication.

routine: a function or routine is a programmer's term for a process a program executes. Routines do different things; there's a routine for saving a file, displaying it on a screen, etc. Local routines are those that execute on the same computer, while remote procedural calls execute routines on other computers. See also: remote procedural call.

RSA Security: The biggest e-business encryption provider. They believe that US government encryption standards should be 128-bits. See also: encryption.

Sagan: A SETI@home servers, Sagan is in charge of sending out the work-units. See also: Cyclops, Asimov.

SETI: The Search for Extraterrestrial Intelligence group, located in Berkeley, CA. They have been searching for more than 40 years for other life. See also: SETI@home.

SETI@home: A distributed computing project named the Search for Extraterrestrial Intelligence at home. SETI@home uses the Arecibo Telescope to record signals and analyze them via the 2 million users running the SETI@home client.

shrink-wrapped software: software that you can buy off the store shelves. This is opposed to software "parts" that you must put together " sometimes even programming them yourself!

spontaneous mutation: In nature, when a species encounters a mutation that keeps spreading until the original species becomes a new species, and the old species is extinct.

star network: type of local-area network where packets from one computer are taken to their destination via a router. Mentioned in: Network Communication. See also: bus network, token-ring network.

stub: Stubs are groups of nodes that will be checked by the client. Stubs that have smaller sums (ie, when all the distances between each node - length - are added, the sum is fairly small) will take longer to process, because there is a greater chance that it is an optimal Golomb ruler. See also: node, Optimal Golomb Rulers.

supercomputer: The fastest computer. Supercomputers are expensive but run at a faster speed than a typical home computer. Pictures: Supercomputers at the Loma Linda University Hospital

synchronous operation: a type of operation between two computers. A computer sends a message to the other and requires a reply from the other computer — such as confirmation upon receiving the message — in order for it (the sender) to proceed with its tasks. Mentioned in: Network Communications. See also: asynchronous operation.

terminal: type of bare-bones "computer" which relies on a centralized server. A terminal has only a text-displaying monitor and keyboard to display the server's signals and to record the user's keystrokes, which are sent back to the server. Mentioned in: DC Alternatives, Types of Networks. Pictures: Dynix terminal, used at A.K. Smiley Public Library

time synchronization: the act of keeping the realtime clock on computers synchronized with each other or with clocks on other servers. (TechEncyclopedia) Mentioned in: Middleware.

token-ring network: type of local-area network that sends a packet around computers until the packet hits its destination. Each computer along the network checks to see if the message is for them. If it isn't, they send the message along its way. If it is, it takes the message. Mentioned in: Network Communication. See also: bus network, star network.

Woltman, George: Interested in number theory for most of his life, Woltman graduated from MIT with both a BS and MS in Computer Science. He created the Great Internet Mersenne Prime Search in 1996 and has been successful in co-discovering 4 primes with the software. See also: GIMPS.

work-units: The data that is sent by SETI@home servers to users running the software. The work-units are quarter megabyte pieces that a computer will process in its idle time and then send back to SETI@home. See also: SETI@home.

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