Thrashing (computer science)

In computer science, thrashing occurs when a computer's virtual memory subsystem is in a constant state of paging, rapidly exchanging data in memory for data on disk, to the exclusion of most application-level processing. This causes the performance of the computer to degrade or collapse. The situation may continue indefinitely until the underlying cause is addressed. The term is also used for various similar phenomena, particularly movement between other levels of the memory hierarchy, where a process progresses slowly because significant time is being spent acquiring resources.

Overview

If a process does not have enough pages, thrashing is a high paging activity, and the page fault rate is high. This leads to low CPU utilization. In modern computers, thrashing may occur in the paging system (if there is not sufficient physical memory or the disk access time is overly long), or in the communications system (especially in conflicts over internal bus access), etc. Depending on the configuration and algorithms involved, the throughput and latency of a system may degrade by multiple orders of magnitude. Thrashing is a state in which the CPU performs 'productive' work less and 'swapping' more. The CPU is busy in swapping pages, so much that it can not respond to users' programs as much as required. Thrashing occurs when there are too many pages in memory, and each page refers to another page. The real memory shortens in capacity to have all the pages in it, so it uses 'virtual memory'. When each page in execution demands that page that is not currently in real memory (RAM) it places some pages on virtual memory and adjusts the required page on RAM. If the CPU is too busy in doing this task, thrashing occurs.

Kings (U.S. TV series)

Kings is an American television drama series which aired on NBC. The series' narrative is loosely based on the Biblical story of King David, but set in a kingdom that culturally and technologically resembles the present-day United States.

Advance showings received mostly positive critical reviews. The Sunday March 15, 2009 premiere placed fourth in network television ratings for that evening. After four episodes aired, NBC moved it to a Saturday slot, but only showed one more episode before pulling the series until summer. The remaining seven episodes were aired on Saturdays in June and July; however, Kings was canceled after failing to find a sufficient audience.

Plot

Kings is set in the fictional Kingdom of Gilboa, a modern absolute monarchy. Gilboa is ruled by King Silas Benjamin, who originally formed the united kingdom two decades before from the three warring countries of Gilboa, Carmel, and Selah. He believes that he has been divinely anointed king, and he often cites the day when a swarm of Monarch butterflies once landed on his head in the form of "a living crown" which called upon him to form the Monarchy and Kingdom.

Kings (game)

Circle of Death (also Kings, king's cup, donut, jug, oval of fire, or ring of fire) is a drinking game that uses playing cards. The player must drink and dispense drinks based on cards drawn. Each card has a rule that is predetermined before the game starts. Many houses have their own variation of rules.

Equipment

Setup and common rules

In this game, players perform actions associated with each card. Sometimes, rules on the cards "reveal interesting things about the participants."

Usually, cards are shuffled and dealt into a circle around either an empty cup or a full can of beer (or a shot/cup of spirits or wine). Each player takes turn drawing cards, and the players must participate in the instructions corresponding to the drawn card.

This game is highly open ended and all of the cards can signify any mini-game, the rules and the card assignments are normally confirmed at the start of the game. Depending on house rules, the game either ends when the last rule card has been pulled, or when the king's cup has been consumed; or when the cards are placed on top of the king's cup the game is over when the cards fall off, the one that knocked them off must consume the king's cup. Alternatively, the game may be played using a beer can with cards placed between the top of the can and the opening tab. The game ends when the beer can opens from the leverage of the cards.

Kings (provincial electoral district)

Kings was a provincial electoral district in Nova Scotia, Canada, that elected one member of the Nova Scotia House of Assembly. It existed from 1867-1956

References

MDC

MDC may refer to:

1mdc

1mdc was a digital gold currency (DGC), originally founded in 2001. Similar to other DGCs, 1mdc allowed for the instant electronic transfer of gold between user accounts. Unlike other DGC providers, 1mdc was backed by the reserves of e-gold, rather than their own physical bullion reserves.

The website appeared to switch between various offshore hosting locations, and used software designed by Interesting Software Ltd, an Anguilla company.

As of April 27, 2007, a US court order has forced e-gold to liquidate a large number of e-gold accounts totalling some 10 to 20 million US dollars' worth of gold. A small part of this seizure was 1mdc's accounts and assets . If the court order in the USA is reversed, a user's e-gold grams remaining in 1mdc will "unbail" normally to the user's e-gold account. Ultimately e-gold is owned and operated by US citizens, so, 1mdc users must respect the decisions of US courts and the US authorities regarding the disposition of e-gold and the safety and security of US citizens. Even though 1mdc has no connection whatsoever to the USA, and most 1mdc users are non-USA, ultimately e-gold is operated from the USA.

MDC-2

In cryptography, MDC-2 (Modification Detection Code 2, sometimes called Meyer-Schilling) is a cryptographic hash function. MDC-2 is a hash function based on a block cipher with a proof of security in the ideal-cipher model. The length of the output hash depends on the underlying block cipher used.

Algorithm

For a given message to hash and a given block cipher encryption function , the MDC-2 algorithm proceeds as follows. Let be the block length, two different constants of size . If where each has size , then the hash of the message is given by:

for to :

• 
• 
• 
• 
• 
• 

return

MDC-2DES hashes

When MDC-2 uses the DES block cipher, the 128-bit (16-byte) MDC-2 hashes are typically represented as 32-digit hexadecimal numbers. The following demonstrates a 43-byte ASCII input and the corresponding MDC-2 hash:

Even a small change in the message will (with probability) result in a completely different hash, e.g. changing d to c:

The hash of the zero-length string is:

Patent issues

MDC-2 was covered by U.S. Patent 4,908,861, issued on March 13, 1990 but filed by IBM on August 28, 1987.
For this reason, support for MDC-2 has been disabled in OpenSSL on most Linux distributions and is not implemented by many other cryptographic libraries.