Checks blog

FairUCE, a spam filter developed by IBM, stands for (”Fair use of Unsolicited Commercial Email”). It is an early form of Challenge-response spam filtering and shares its drawbacks.

As at 2007-05-28, FairUCE’s homepage hasn’t been updated since 2004-11-30.

Technically, well-known domain, IP address, whitelist blacklist database should be maintained for FairUCE to take action on the email. FairUCE tries to find a relationship connecting the envelope sender’s domain and the IP address of the client delivering the mail, using a series of cached DNS look-ups. If a relationship can be found, FairUCE checks the recipient’s whitelist and blacklist, as well as the domain’s reputation, to determine whether to accept, reject, challenge on reputation, or present the user with a set of whitelist/blacklist options.

Andre Comeau (born September 10, 1970) is a singer and songwriter who gained notoriety as one of the original cast members of television reality show The Real World.

He graduated from Clarence M. Kimball High School in Royal Oak, Michigan. His early musical influences were the Beatles, The Rolling Stones, and Bob Dylan.

His band, Reigndance, moved to the New York area in early 1990. During auditions for the Mtv show, Andre and his bandmates were excited as they felt that it would be a great way to showcase their band. After viewing the first few episodes, they discovered that it wasn’t what they had in mind.

After the season, the band felt overexposed and changed their name to Makeshift Gleam. They released their 3rd and final album after securing a publishing deal. Andre moved to Los Angeles and in 1999, formed a new band, MiLkWeeD. The band released one album “MiLkWeeD… For Breakfast”, and broke up shortly thereafter.

During the 10 year Real World reunion special, a protest of castmembers broke out. Andre participated in the protest on the basis that royalty checks for songs written by Reigndance wasn’t properly credited and that he wasn’t receiving royalty checks. During the original season, they would play music from Reigndance, but they would credit the songs’ writers as being “unknown”. After a lengthy discussion, Reigndance began receiving royalty checks for their music being played on The Real World.

Andre went solo in 2004. Going back to his musical influences, he now sings folk/bluegrass music with the Andre Comeau Band.

External links

• Andre Comeau Band Myspace

Checkless Chess (or prohibition chess) is a chess variant where neither player is allowed to give a check, with the exception of checkmate. All other rules are as in regular chess. This change has a profound impact on the way the game is played.

In regular chess, the king needs to be kept safe, since attacks on it need to be parried, and checks can be used to gain time or chase the king to an unsafe position. In checkless chess however, the king is immune from most attacks, as long as checkmates are avoided. In order to achieve checkmate the king must be encircled without checks.

Another impact of this rule is that the king, immune from attack, is now itself a powerful force. The king can defend pieces by placing itself so that capturing the piece would place the king in check. The king can advance into the enemy position, creating havoc in the enemy camp as they need to avoid squares where they would put the king under check. Such a plan may be risky however, since getting the king trapped in the enemy camp may subject it to an untimely checkmate.

References

• Entry on “Checkless chess” in

External links

• Checkless chess by Hans Bodlaender.

Gaylord Chemical Corporation is based in the New Orleans suburb of Slidell, Louisiana. The manufacturing facilities are in Bogalusa, Louisiana. The company makes DMSO and other sulfur chemicals.

In 1995 a railroad tank car imploded at their Bogalusa, Louisiana facility releasing nitrogen tetroxide and forced the evacuation of about 3,000 people within a one mile radius. Residents say “the sky turned orange” as a result. Emergency rooms filled with about 4,000 people who complained of burning eyes, skin, and lungs. Dozens of lawsuits were filed against Gaylord Chemical and were finally settled in May of 2005, with compensation checks issued to around 20,000 people involved in the accident.

External links

• Official website

In computer science, data validation is the process of ensuring that a program operates on clean, correct and useful data. It uses routines, often called validation rules, that check for correctness or meaningfulness of data that are input to the system.

The simplest data validation verifies that the characters provided come from a valid set. For example, telephone numbers should include the digits and possibly the characters +, -, ( and ) (plus, minus and the parentheses). A more sophisticated data validation routine would check to see the user has entered a valid country code; the number of digits entered matches the convention for the country or area specified, etc.

Incorrect data validation can lead to data corruption or a security vulnerability. Data validation checks that the data are valid and sensible/reasonable before they are processed.

Some methods used for validation are…

• Format or picture check

Checks that the data is in a specified format (template), e.g., dates have to be in the format DD/MM/YYYY.

• Data type checks

Check the data type of the input and give an error message if the input data does not match with the chosen data type, e.g., In an input box accepting numeric data, if the letter ‘O’ was typed instead of the number zero, an error message would appear.

• Range check

Checks that the data lie within a specified range of values, e.g., the month of a person’s date of birth should lie between 1 and 12.

• Limit check

Unlike range checks, data is checked for one limit only, upper OR lower, e.g., data should not be greater than 2 (>2).

• Presence check

Checks that important data are actually present and have not been missed out, e.g., customers may be required to have their telephone numbers listed.

• Check digits

Used for numerical data. An extra digit is added to a number which is calculated from the digits. The computer checks this calculation when data are entered, e.g., The ISBN for a book. The last digit is a check digit calculated using a modulus 11 method.

• Batch totals

Checks for missing records. Numerical fields may be added together for all records in a batch. The batch total is entered and the computer checks that the total is correct, e.g., add the ‘Total Cost’ field of a number of transactions together.

• Hash totals

This is just a batch total done on one or more numeric fields which appears in every record, e.g., add the Telephone Numbers together for a number of Customers.

• Spelling check

Looks for spelling and grammar errors.

• Consistency Checks

Checks fields to ensure data in these fields corresponds, e.g., If Title = “Mr.”, then Gender = “M”.

External links

• Data Validation

GHDL is a complete free software simulator for VHDL using GCC technology. The VHDL language is implemented according to the IEEE 1076-1987 or the IEEE 1076-1993 standard. It works by compiling VHDL files into a binary which simulates (or executes) the design. Some have already reported GHDL has (in a few cases) better implementation of standards than some commercial simulators. However, GHDL does not do synthesis and it cannot translate a design into a netlist.

Features

• GHDL implements the VHDL87 (common name for IEEE 1076-1987) standard, the VHDL93 standard (aka IEEE 1076-1993) and the protected types of VHDL00 (aka IEEE 1076a or IEEE 1076-2000). GHDL can also implement non-standard third party libraries such as those provided by Synopsys and Mentor Graphics, but this is discouraged [1].
• GHDL directly creates binaries or executable images, which is considered the best form for testbenches (autonomous self-checking VHDL designs which use assert). These binaries can also create a VCD file or a GHW file, which may be visually inspected with a waveform viewer such as GTKWave.
• GHDL can also be used to pretty print or to generate cross references in HTML.
• GHDL can generate a Makefile for any component in a design.

Shortcomings

• GHDL is only officially available on Linux systems, but some have had success compiling GHDL on Solaris Sparc, Mac OS X, and Microsoft Windows (using Cygwin).
• Overflow detection is not yet implemented.
• Some constraint checks are missing.
• VHDL-93 is not completely implemented.
• Partial support of VHDL-02.
• There are no checks for elaboration order.

External links

• Project home page

In UK aviation, BUMPH is a mnemonic for the pre-landing checks carried out by pilots of light aircraft when approaching an airport with intention to land. In aviation practice elsewhere, the GUMPS check is more commonly used.

BUMPH is an acronym for

• Brakes - unlocked so that wheels are free to rotate on touchdown
• Undercarriage - down and locked (or welded in the case of fixed-gear aircraft)
• Mixture - set full rich (or as appropriate to temperature and altitude)
• Propellor - set full fine pitch (when a variable pitch propellor is fitted)
• Hatches (and Harnesses) - secured.

These provide only the bare minimum of pre-landing checks, but a more complete list doesn’t provide a neat acronym. In this sense the mnemonic should probably be used only as a reminder rather than a complete set of checks.

A more complete check would include:

• Brakes
• Undercarriage
• Mixture
• Carb heat - apply and check for icing (This step is omitted in aircraft with fuel injection systems)
• Fuel - select correct tank and check there’s enough to perform a go around if necessary, fuel pump ON
• Flaps - select landing or descending flap
• Hatches and Harness
• Transponder - select as appropriate
• Landing Light - switch on

The word ‘bumph’ is also English slang for paper - of any sort. It is used on its own as in ‘there’s a whole pile of bumph on my desk, and also with some other words, eg ‘loo bumph’ is toilet paper.
‘Bumph’ or ‘Bumf’, when alluding to excessive paperwork was an RAF (Royal Air Force) acronym for Bum Fodder. This means toilet paper, which was hard to come by during WWII. Air Ministry paperwork was routinely ignored, hole-punched and hung on a string in the privvy (toilet).

See also

HASELL

In the preface of each of his books and on his websiteSee http://sunburn.stanford.edu/~knuth/books.html, computer scientist Donald Knuth offers to cheerfully pay a reward of “$2.56″ (USD) to the first finder of each error in one of his published books, whether it be technical, typographical, or historical. Knuth explains that $2.56, or 256 cents, correspond to one hexadecimal dollar.Frequently Asked Questions on Don Knuth’s webpage Valuable suggestions are worth 32¢.

These reward checks have been described as “among computerdom’s most prized trophies“.Steve Ditlea . Rewriting the Bible in 0’s and 1’s. MIT’s “Technology Review”, 11 January 2002. As of October 2001, Knuth reports having written more than 2,000 such checks, with an average value exceeding $8 per check.http://www.ams.org/notices/200203/fea-knuth.pdf As of March 2005, the total value of the checks signed by Knuth was over $20,000 (see NPR interview below).
Very few of these checks are actually cashed, however, even the largest ones; more often, they are framed, or kept as bragging rights.Kara Platoni, Love at First Byte. Stanford Magazine, May-June 2006The History of TeX

Intelligence: Finding an error in a Knuth text.

Stupidity: Cashing that $2.56 check you got.

Seen in a Slashdot signature, quoted by Edward O’Connorhttp://www.stgray.com/quotes/programming.html

The reward for coding errors found in Knuth’s TeX and METAFONT programs (as distinguished from errors in Knuth’s books) followed an audacious scheme inspired by the Wheat and Chessboard Problem . It started at $2.56, and doubled every year until it reached $327.68 http://www.ams.org/notices/200203/fea-knuth.pdf. Recipients of this “sweepstakes” reward include Chris Thompson (Cambridge) and Boguslaw Jackowski (Gdansk)http://www.uni-giessen.de/hrz/tex/more_info/info/mailarchiv/mutex.1995/msg00147.html; and also Peter Breitenlohner on 20 March 1995 http://www.tug.org/TUGboat/Articles/tb17-1/tb50knut.pdf and Ch 34 of Digital Typography.

Knuth is often not able to answer immediately when a reader finds a mistake in one of his books or programs; in some cases, the delay was several years long. For example, on 1 July 1996, Knuth sent out more than 250 letters, 125 of which contained checks, for errors reported in The Art of Computer Programming since the summer of 1981. A few of these remain unclaimed as of May 2006.What is your current mailing address? on Don Knuth’s website. When Knuth is not able to reply immediately, he adds a 5% interest, compounded continuously, to the reward.See http://www.math.rutgers.edu/~zeilberg/mamarim/mamarimPDF/king.pdf, and http://developers.slashdot.org/comments.pl?sid=29586&pid=3178058#3178872.

Each check’s memo field identifies the book and page number. 1.23 indicates an error on page 23 of Volume 1. (1.23) indicates a valuable suggestion on that page. The symbol Θ denotes the book Things a Computer Scientist Rarely Talks About, KLR denotes the book Mathematical Writing (by Knuth, Larrabee, and Roberts), GKP and CM denote the book Concrete Mathematics (by Graham, Knuth, and Patashnik), f1 denotes fascicle 1, CMT denotes the book Computer Modern Typefaces, and DT denotes the book Digital Typography.

Notes and references

External links

• Interview (RealVideo format) (or Transcript) with Knuth on National Public Radio

Software verification is a broad and complex discipline of software engineering whose goal is to assure that a software fully satisfies all the expected requirements.

There are two fundamental approaches to verification:

• Dynamic verification, also known as Test or Experimentation
• Static verification, also known as Analysis

Dynamic verification (Test, Experimentation)

Dynamic verification is performed during the execution of a software, and dynamically checks its behaviour; it is commonly known as Test phase.
Verification is a Review Process.
Depending on the scope of tests, we can categorize them in three families:

• Test in the small: a test that checks a single function or class (Unit test)
• Test in the large: a test that checks a group of classes, such as
  • Module test (a single module)
  • Integration test (more than one module)
  • System test (the entire system)
• Acceptance test: a formal test defined to check acceptance criteria for a software
  • Functional test
  • Non functional test (performance, stress test)

Software verification is often confused with software validation. The difference between ‘verification and validation:

• Software verification asks the question, “Are we building the product right?”; that is, does the software conform to its specification.
• Software validation asks the question, “Are we building the right product?”; that is, is the software doing what the user really requires.

The aim of software verification is to find the errors introduced by an activity, i.e. check if the product of the activity is as correct as it was at the beginning of the activity.

The aim of software validation is to declare whether the product of an activity is indeed what expected, i.e. the activity extended the product successfully.

Static verification (Analysis)

Static verification is a process to check some requirements of a software doing a physical inspection of it. For example:

• Code conventions verification
• Bad practices detection
• Software metrics calculation
• Formal verification

References

• IEEE: SWEBOK: Guide to the Software Engineering Body of Knowledge
• Carlo Ghezzi, Mehdi Jazayeri, Dino Mandrioli: Fundamentals of Software Engineering, Prentice Hall, ISBN 0-13-099183-X