Luggage locks

In Databases and Transaction processing, Two phase locking, (2PL) is a concurrency control locking protocol, mechanism, that guarantees Serializability. It is also the name of a class (set) of transaction schedules. Using locks that block processes, 2PL is subject to deadlocks that result from the mutual blocking of two transactions or more.

Two phase locking

According to the Two phase locking protocol, locks are handled by a transaction in two distinct, consecutive phases during the transaction’s execution:

Phase 1: Locks are acquired and no locks are released.

Phase 2: Locks are released and no locks are acquired.

The serializability property is guaranteed for a schedule with transactions that obey the protocol. The 2PL schedule class is defined as the class of all the schedules comprising transactions with data access orders that could be generated by the 2PL protocol.

Strict two phase locking

The Strict two phase locking (S2PL) class of schedules is the intersection of the 2PL class with the class of schedules possessing the Strictness property.

To comply with the S2PL protocol a transaction needs to comply with 2PL, and release its write (exclusive) locks only after it has ended, i.e., being either committed or aborted.

S2PL is a special case of 2PL, i.e., the S2PL class is a proper subclass of 2PL.

Strong strict two phase locking

To comply with the Strong strict two phase locking (SS2PL) protocol a transaction needs to comply with 2PL, and release both its write (exclusive) and read (shared) locks only after it has ended, i.e., being either committed or aborted.
A transaction obeying SS2PL can be viewed as having Phase 1 that lasts its entire execution duration, and no Phase 2 (or degenerate Phase 2). Thus, only one phase is actually left, and “two-phase” in the name seems to be still utilized due to the historical development of the concept from 2PL. The SS2PL property of a schedule is also called Rigorousness, and an SS2PL schedule is also called a Rigorous schedule.

SS2PL is a special case of S2PL, i.e., the SS2PL class of schedules is a proper subclass of S2PL (every SS2PL schedule is also an S2PL schedule, but S2PL schedules exist that are not SS2PL).

SS2PL is the concurrency control protocol of choice for most database systems since it provides besides serializability also Strictness, which is instrumental for efficient database recovery, and also Commitment ordering (CO) for participating in environments where a CO based Global serializability solution is employed.

Monospace may refer to:

In typography

• Monospace font, fixed-width typefaces whose glyphs have the same width
• Monospace (font), a computer font which carries said characteristic

Other

• Monospace or one-box car, a style of automobile body, that doesn’t feature clearly distinguishable ‘boxes’ for the engine, passenger and luggage compartments, like a three-box design.

A tubular lock pick is a specialized lockpicking tool used for opening a tubular pin tumbler lock. Tubular lock picks are all very similar in design and come in sizes to fit all major tubular locks, including 6, 7, and 8-pin locks.

The tool is simply inserted into the lock and turned clockwise with medium tension. As the tool is pushed into the lock, each of the picks is slowly forced down until they stop, thus binding the driver pins behind the shear line of the lock. When the final pick is pushed down, the shear plane is clear and the lock opens. This can usually be accomplished in a matter of seconds.

Most tubular lock picks come with a “decoder” which lets the locksmith know at what depths the pins broke the shear plane. By using the decoding key after the lock has been picked, the locksmith can cut a tubular key to the correct pin depths and thus avoid having to replace the lock.

In 2004 it was widely publicized that the barrel of a cheap ballpoint pen would act as an effective lock pick for many brands of tubular lock.

The River Thames falls 234 feet from Lechlade to Sea Level. Over the centuries the flow of water and the danger of flooding has been controlled by a series of Weirs on the River Thames. Weirs, however, presented an obstacle to navigation and to solve this problem Locks on the Thames were built alongside the weirs enabling boats to be moved easily up to the next higher level.

Locks were often built adjacent to islands and so are often situated in remote locations. Those close to main roads and towns tended to become magnets for spectators, while others are very difficut to find. When the motive power was provided by horses, a towpath was needed on the bank side. This towpath has formed the basis for the Thames Path.

There are 45 locks on the Thames. In upstream to downstream order, from source to sea, they are:

• St John’s Lock — the highest lock on the river
• Buscot Lock
• Grafton Lock
• Radcot Lock
• Rushey Lock
• Shifford Lock
• Northmoor Lock
• Pinkhill Lock
• Eynsham Lock
• King’s Lock
• Godstow Lock
• Osney Lock
• Iffley Lock
• Sandford Lock
• Abingdon Lock
• Culham Lock
• Clifton Lock
• Day’s Lock
• Benson Lock
• Cleeve Lock
• Goring Lock
• Whitchurch Lock
• Mapledurham Lock
• Caversham Lock
• Sonning Lock
• Shiplake Lock
• Marsh Lock
• Hambleden Lock
• Hurley Lock
• Temple Lock
• Marlow Lock
• Cookham Lock
• Boulter’s Lock
• Bray Lock
• Boveney Lock
• Romney Lock
• Old Windsor Lock
• Bell Weir Lock
• Penton Hook Lock
• Chertsey Lock
• Shepperton Lock
• Sunbury Lock
• Molesey Lock
• Teddington Lock — the last lock before the river becomes tidal
• Richmond Lock — on the tidal Thames. Owned and operated by the Port of London Authority

Additionally, Blake’s Lock is located on a reach of the River Kennet that is administered as part of the River Thames, and is often counted as a Thames Lock.

All the locks on the Thames (including Blake’s Lock) are manned and, except for Richmond Lock, are owned and operated by the Environment Agency. The Environment Agency still has the two responsibilities of managing the flow of water to control flooding, and providing for navigation.

Bingley Three Rise Locks is a staircase of three locks on the Leeds and Liverpool Canal at Bingley. It opened in 1774 and was a major feat of engineering at the time along with the larger Five Rise (more details on construction and history here) opened at the same time just a few hundred meters further up. The lock comprises a ’staircase’ flight - the lower gate of one lock forms the upper gate of the next lock.

The Luggage is a fictional object that appears in several of the Discworld novels by Terry Pratchett. It is a large chest made of sapient pearwood (a magical, intelligent plant which is nearly extinct, impervious to magic, and only grows in a few places outside the Agatean Empire, generally on sites of very old magic). It can produce hundreds of little legs protruding from its underside and can move very fast if the need arises. It has been described as “half suitcase, half homicidal maniac”.

Its function is to act as both a luggage carrier and bodyguard for its owner, against whom no threatening motion should be made. The Luggage is fiercely defensive of its owner, and is generally homicidal in nature, killing or eating several people and monsters and destroying various ships, walls, doors, and other obstacles throughout the books. Its mouth, the feature often remarked upon by those it is about to consume, contains “lots of big square teeth, white as sycamore, and a pulsating tongue, red as mahogany.” The inside area of The Luggage does not appear to be constrained by its external dimensions, and contains many conveniences: even when it has just devoured a monster, the next time it opens the owner will find his underwear, neatly pressed and smelling slightly of lavender.

One of the greatest features of The Luggage is its ability to follow its current owner anywhere including such places as inside its owner’s mind, off the edge of the Disc, Death’s Domain, the Dungeon Dimensions, and even (literally) to Hell and back. Like all luggage, it’s constantly getting lost and having to track its owner down. It has only one way of overcoming obstacles, and that is by simply ignoring them and smashing a hole through them - including a wall to a magick shop that had since relocated.

The Luggage first appears as the property of Twoflower the tourist in The Colour of Magic. When Twoflower returns home in The Light Fantastic he gives the luggage to Rincewind, and it follows him through several sequels. Twoflower says he got it by asking for “travelling luggage” at the store (one of about a dozen magical shops which are not limited by the constraints of time and space, to their owners’ dismay. According to “The Light Fantastic”, this chain of stores was born when an impatient sourcerer was served rather poorly.) - which is exactly what he got. When Rincewind eventually visits the Counterweight Continent, Twoflower’s home, he finds many items similar to Luggage travelling with their masters.

Pratchett says (at the beginning of Sourcery) that he got the idea for the Luggage when he saw a tartan suitcase with dozens of little wheels moving as though it had a mind of its own while an American tourist pulled it along. However, he has also stated (in The Art of Discworld) that it was loosely based on an idea from a roleplaying game he had designed – that being of a similar item that would do only and exactly as it was told.

The Luggage later finds a female Luggage and has children with it in Interesting Times.

The Luggage savages passers-by in:

• The Colour of Magic
• The Light Fantastic
• Sourcery
• Eric
• Interesting Times
• The Last Continent
• The Last Hero

The Luggage also ‘ate’ the most powerful magical spell book on the Disc at the climax of The Light Fantastic. However, as it is made of sapient pearwood and is impervious to magic, the book is probably under tighter control than it was in the university where it had to be chained to a plinth.

The Luggage has consumed many remarkable things, including quite a few people. Regardless of what it consumes, only the owner’s neatly pressed packing is found inside, with any clothes laundered, ironed and folded, and smelling faintly of lavender.

Computer games

In The Colour of Magic computer game, it is mentioned as in the novel. Also, in Discworld and Discworld 2, it acts as an inventory and can fit an infinite amount of items in his trunk.

The Chubb Locks subsidiary of the Assa Abloy Group is a British manufacturer of high security locking systems for residential and commercial applications.

Chubb was started as a ship’s ironmonger by Charles Chubb in Winchester, England and then moved to Portsmouth, England in 1804.

Chubb moved the company into the locksmith business in 1818 in Wolverhampton. The company worked out of a number of premises in Wolverhampton including the purpose built factory on Railway Street now still known as the Chubb Building. His brother Jeremiah Chubb then joined the company and they sold Jeremiah’s patented detector lock

In 1823 the company was awarded a special license by George IV and later became the sole supplier of locks to the General Post Office and a supplier to His Majesty’s Prison Service.

In 1835 they received a patent for a burglar-resisting safe and opened a safe factory in London in 1837.

In 1851 they designed a special secure display case for the Koh-i-Noor diamond for its appearance at the Great Exhibition.

In 1984 the company was purchased by Racal, who sold it in 1997 to Williams Plc. In August 2000, they were sold to Assa Abloy.

The Göta Canal () is a Swedish canal constructed in the early 19th century. The canal stretche from Gothenburg on the west coast, combined with the river Göta älv and the Trollhätte canal, through the large lakes Vänern and Vättern, in parallel with Motala ström, and to Söderköping on the Baltic Sea.

The architect was Baltzar von Platen, working to plans earlier developed at the request of the Swedish king by the Scottish civil engineer Thomas Telford; he got permission to begin to work on April 11, 1810 and the canal was officially opened on September 26, 1832. Telford himself travelled to Sweden in 1810 to oversee some of the initial excavations on the project.

Built only decades before the advent of railways, the canal was soon outdated, and never upgraded. The canal is a tourist attraction, sometimes called Sveriges blå band (”Sweden’s Blue Ribbon”).

To support the building of the canal with mechanical works, a small engineering workshop was established in Motala called Motala Verkstad. This industry has sometimes been referred to as cradle of the Swedish engineering industry.

In fiction

Several movies depict the canal, most notably the 1981 comedy Göta Kanal, in which two competing yacht constructors race the canal in order to win a huge construction stock order. In 2006, Göta Kanal 2 was released.

Locks

From the east-coast of Sweden all the way to the west-coast the locks are as follows:
(with meters per locks)

• Mem, 3
• Tegelbruket, 2.3
• Söderköping, 2.4
• Duvkullen nedre, 2.3
• Duvkullen övre, 2.4
• Mariehov nedre, 2.1
• Mariehov övre, 2.6
• Carlsborg nedre, 5.1
• Carlsborg övre, 4.7
• Klämman, open
• Hulta, 3.2
• Bråttom, 2.3
• Norsholm, 0.8
• Carl Johans slussar (seven locks), 18.8
• Oskars slussar, 4.8
• Karl Ludvig Eugéns slussar, 5.5
• Brunnby, 5.3
• Heda, 5.2
• Borensberg, 0.2
• Borenshult, 15.3
• Motala, 0.1

Lake Vättern

• Forsvik, 3.5
• Tåtorp, 0.2
• Hajstorp övre, 5.0
• Hajstorp nedre, 5.1
• Riksberg, 7.5
• Godhögen, 5.1
• Norrkvarn övre, 2.9
• Norrkvarn nedre, 2.9
• Sjötorp 7-8, 4.6
• Sjötorp 6, 2.4
• Sjötorp 4-5, 4.8
• Sjötorp 2-3, 4.8
• Sjötorp 1, 2.9

Trivia

The canal is nicknamed “skilmässodiket” which translates to “divorce ditch”. The name refers to the stress endured by couples navigating the numerous locks in the canal.

Monospace may refer to:

In typography

• Monospace font, fixed-width typefaces whose glyphs have the same width
• Monospace (font), a computer font which carries said characteristic

Other

• Monospace or one-box car, a style of automobile body, that doesn’t feature clearly distinguishable ‘boxes’ for the engine, passenger and luggage compartments, like a three-box design.

The balance lock was a type of lock to transport boats up and down a hillside on a canal.

Boats were to ride in caissons, essentially bathtubs, of water which were to be hauled up and down the hillside by chain, being balanced by another tub of water. It was patented by James Fussell during his work on the Dorset and Somerset Canal.