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| | Semaphore |
 | | Semaphore is a means of line-of-sight communication dating from the early 1800s. | | | Semaphore has three teaching features: (I.) You can type a letter on the keyboard and see the flag code displayed; (2.) Beginners can test on random five-letter groups; (3.) Experienced readers can test on messages taken from memory at random. | | | The basic technique of semaphore is to hold each arm at one of eight possible angles--straight up, straight down, left, right, or one of the diagonals. |
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http://www.atarimagazines.com/v7n8/semaphore.html
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| | Semaphore - what is that? |
| | A succeeding task may not start until it has received the semaphores from all of it's predecessors; this is the order of communication in which a semaphore is used to 'talk' to all successors. | | | Semaphores are actually widely used in programming to share resources cleanly; BSD uses it for interprocess communication -- one of the reasons I dig BSD so much. | | | A semaphore is a lot like a locking mechanism, only smarter. |
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http://www.ozzu.com/ftopic42616.html
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| | Lab 5 – Inter-process Communication |
| | The kernel will block the process if the semaphore is zero or doesn't have a value high enough for the decrement. | | | When a process wants a resource, it checks the value of the semaphore, and if it is nonzero, it decrements the appropriate number from the semaphore in accordance to the amount of resources it wishes to use. | | | You have to submit all the source files and header files of all the three processes implementation. |
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http://www.cs.ucr.edu/~bagrawal/cs153/cs153_lab5.html
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| | Civilian Etiquette: Symbolic Communication |
| | There are a number of visual communications that may have been carried on with a lady’s fan that have been circulated in recent years, and if true, it would have behooved a gentleman to understand "fan language" if such was used. | | | Too, if that form of communication had been in widespread use, it stands to reason that publications of the day would have had cartoons or humorous accounts dealing with overheated young ladies sending out all sorts of outlandish or outrageous messages inadvertently. | | | As we’ve noted before about the "fan language", communication from one person to another during the period of the War Between the States through herbs is apocryphal, by and large. |
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http://www.geocities.com/heartland/woods/3501/civilian10.htm
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| | Semaphore - Wikipedia, the free encyclopedia |
| | Semaphore communication by means of flags or other positional indicators | | | Semaphores in computer science, in which only one part of a concurrent system may access a limited resource; this application of mutual exclusion in computing was invented by Edsger Dijkstra | | | Semaphore is a comprehensive integrating accounting software systems |
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http://en.wikipedia.org/wiki/Semaphore
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| | Inter-process communication (IPC) parameters |
| | NOTE: All memory and data structures for the semaphore IPC are dynamically allocated as needed. | | | The maximum number of shared memory segments that can be attached per process also is dependent on the available unused space the process has. | | | Specifies the maximum number of undo entries per process. |
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http://ou800doc.caldera.com/SM_perform/_Inter-Process_Communication_IPC.html
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| | Inter Process Communication. - System V IPC. |
| | There is one sem_undo structure associated with a process for each semaphore which was altered (with an undo request) by the process. | | | Processes waiting on the zero_queue or increment_queue are awakened if any of the semval's becomes zero or is incremented respectively. | | | EINTR : The process was interrupted on its way to a wait queue. |
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http://www.ugcs.caltech.edu/info/util/ipc_1.html
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| | The UNIX Forums - Inter Process Communication |
| | When reading and writing shared memory, you must wrap your opens, reads and writes in each process to check the a semaphore to see if it is set or clear. | | | Semaphores can be used with lots of things, however they are often used as you ask, with shared memory access. | | | The UNIX Forums > Network Computing Topics > C Programming in the UNIX Environment |
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http://www.unix.com/showthread.php?t=1584
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| | Java Interprocess Communication Server |
| | JIPC is library providing interprocess synchronization and communication capabilities for Java processes running in different JVMs at different computers. | | | This mode is useful to provide synchronization and communication between several Java processes at the same or different computers. | | | JIPC provides wide set of standard primitives: semaphore, event, FIFO queue, barrier, shared memory, shared and exclusive locks. |
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http://www.garret.ru/~knizhnik/jipc/jipc.html
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| | Inter-Process Communication - Part II LG #105 |
| | Exploring the use of sockets in an connectionless-oriented communication is left as an exercise to the readers. | | | Generally, sockets are associated with the concept of network communication in the form of client-server programming; a pair of processes of which one will be a client and one a server. | | | This is the administrator of the semaphore set. |
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http://linuxgazette.net/105/ramankutty.html
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| | NSPR Reference: Chapter 30 IPC Semaphores |
| | NSPR provides an interprocess communication mechanism using a counting semaphore model similar to that which is provided in Unix and Windows platforms. | | | This chapter describes the NSPR API for using interprocess communication semaphores. | | | If the value of the semaphore is 0, the function blocks until the value becomes > 0, then the semaphore is decremented and the function returns. |
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http://www.mozilla.org/projects/nspr/reference/html/pripcsem.html
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| | semaphore esources 2002 june brand semaphore |
| | (Semaphore is defined as a system of visual communication through the positioning of flags.) And although the only flags we use are in our own corporate branding design, we have created successful visual communication through branding and other marketing efforts for a wide variety of clients in more than 30 years in business. | | | As for the Semaphore brand, our name is literally a symbol for communication as our business is the practice of communication. | | | However, the latest incarnation is the first attempt to make full use of the literal definition of Semaphore and to incorporate flag imagery as part of the overall design. |
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http://www.semaphoreinc.com/esources/newsletters/2002_06_c.html
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| | Interprocess Communication APIs |
| | Once a semaphore is created and a pointer to the semaphore is obtained, the same operations are used to manipulate the values of both types of semaphores. | | | After the value of the semaphore is incremented, it may be decremented immediately by threads that have blocked trying to decrement the semaphore. | | | A thread waiting on a semaphore in a semaphore set appears to be in a semaphore wait state (SEMW) on the Work with Threads display (requested using the WRKJOB command and taking option 20). |
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http://www.redbooks.ibm.com/pubs/html/as400/v4r5/ic2924/info/apis/unix3.htm
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| | IOI'95 Task: Printing |
| | When the semaphore sends a message "Open" to the client, this client changes its state to SC and sends the print job with a message "S_Job" to the server related to the sending semaphore. | | | If the state of the semaphore is S1, then the state of the semaphore will change to S2 and the semaphore will send a message "Open" to the computer that sent the message "Are_you_open?". | | | In Documentation 3 you find in the `Communication Structure Diagram' all the message types that can be sent between the different object types. |
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http://olympiads.win.tue.nl/ioi95/task/print.html
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| | OOSC 2: 28.5 SYNCHRONIZATION ISSUES |
| | But if you devise a good communication mechanism you might very well have solved synchronization too: because two units cannot communicate unless the sender is ready to send and the receiver ready to receive, communication implies synchronization; pure synchronization may be viewed as the extreme case of communicating an empty message. | | | Communication mechanisms allow processes to exchange information, which in the object-oriented case will be in the form of objects or object structures. | | | A semaphore is an object on which two operations are available: reserve and free (traditionally called P and V, but more suggestive names are preferable). |
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http://archive.eiffel.com/doc/manuals/technology/concurrency/concurrency-05.html
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| | semctl(3): XSI semaphore control operations - Linux man page |
| | Set the value of semval for each semaphore in the semaphore set according to the array pointed to by arg.array, where arg is the fourth argument to semctl(). | | | Return the value of semval for each semaphore in the semaphore set and place into the array pointed to by arg.array, where arg is the fourth argument to semctl(). | | | The value of semid is not a valid semaphore identifier, or the value of semnum is less than 0 or greater than or equal to sem_nsems, or the value of cmd is not a valid command. |
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http://www.die.net/doc/linux/man/man3/semctl.3.html
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| | Learn Semaphore |
| | Semaphore is a communication medium by which a person signals with two hand flags, moving his arms through various positions to represent letters, numerals, and special signs. | | | Wigwag, a semaphore system of signal communication, was invented in the United States during the 19th century and used in the Civil War. | | | Semaphores also remain in use for maritime communications. |
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http://www.lpickard.com/sem.htm
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| | Assignment 1 |
| | A constructor Semaphore (int limit), where limit, signifies the number times the critical region can be entered before blocking, i.e., a value of 1 for limit would imply a binary semaphore. | | | Remember that in all the above methods, the distributed semaphore object simply sends a request to the server and waits for the reply and returns the status as in the reply. | | | In order to do the communication, the server will have to open a datagram socket specifying a port number and keep listening to it in an infinite loop. |
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http://www.cs.cornell.edu/Courses/cs414/2000su/asgn2.html
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| | Semaphore communication - Wikipedia, the free encyclopedia |
| | Look for Semaphore communication in the Commons, our repository for free images, music, sound, and video. | | | Check for Semaphore communication in the deletion log, or visit its deletion vote page if it exists. | | | Look for Semaphore communication in Wiktionary, our sister dictionary project. |
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http://www.sciencedaily.com/encyclopedia/semaphore__communication_
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| | semaphore esources july |
| | Semaphore Account Executive Marian Douglas Pearce, APR, recently earned recognition as a professional communicator in a national program offered by the Council of Rural Electric Communicators, which is affiliated with the National Rural Electric Cooperative Association (NRECA). | | | This is done through the establishment of professional development goals, identification of a body of knowledge and skills necessary to the practice of electric co-ops communication, and recognition of those individuals who have demonstrated a professional level of excellence. | | | Semaphore Inc. is proud to announce the hiring of Kevin Shelton as its Web Business Manager. |
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http://www.semaphoreinc.com/esources/newsletters/2003_07_esources.html
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| | ipc |
| | Interprocess communication in UNIX ================================================================================ Overview: When processes are coordinating their efforts to solve a problem or implement some application (like a distributed database, communica- tion system, etc.) they need to "talk" to each other. | | | P is the standard semaphore name for acquiring a semaphore, or waiting for it to become free. | | | C programmers might be tempted to use a file as a semaphore variable or a flag. |
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http://www-cs.canisius.edu/OLDSITE1997/PL_TUTORIALS/C/ADVANCED/ipc
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| | communication |
| | The term is most often used in describing electronic means of communication, but can also include methods such as smoke signals and semaphore. | | | Communication studies began to emerge as a distinct academic field in the mid-20th century. | | | The process of communication is what allows us to interact with other people; without it, we would be unable to share knowledge or experiences with anything outside of ourselves. |
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http://www.fact-library.com/communication.html
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| | Semaphores in System V UNIX |
| | The System V specification of the UNIX operating system introduces semaphores among the other facilities for Inter-Process Communication (IPC). | | | This system call returns an integer id for the semaphore (analogous to a file descriptor), or -1 in case of error. | | | Cooperating processes wishing to access the semaphore set must use the same key, much like a file name is used to store on disk shared data by cooperating processes. |
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http://www.cim.mcgill.ca/~franco/OpSys-304-427/lecture-notes/node31.html
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| | Semaphore - TheBestLinks.com - Computer science, Edsger Dijkstra, Mutual exclusion, Semaphore (communication), ... |
| | Semaphore - TheBestLinks.com - Computer science, Edsger Dijkstra, Mutual exclusion, Semaphore (communication),... | | | Semaphore (programming), invented by Edsger Dijkstra for computer science, where only one part of a concurrent system may access a limited resource. | | | Semaphore, Computer science, Edsger Dijkstra, Mutual exclusion, Semaphore... |
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http://www.thebestlinks.com/Semaphore.html
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| | File 97289 |
| | Semaphores are also used to control two-task communication between the user process and shadow process if the fast (shared memory) driver is used. | | | Semaphores are generally not used one at a time, so Unix uses the concept of semaphore sets to make it easier to allocate and refer to semaphores. | | | Since it's hard to tell which semaphore set belongs to which process, you may have to wait until everyone logs off the database (and perhaps for the database to be shut down) before you can tell which semaphore set you need to free. |
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http://www.uaex.edu/srea/osee/97289.htm
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| | How to Teach Semaphore - ScoutDocs |
| | And after all Semaphore is a "visual" form of communication. | | | The most important thing about both Semaphore and Morse Codes, is the ability to read, not to send. | | | These letters have special meaning and are used to assist the communication. |
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http://scoutdocs.ca/Documents/Semaphore.php
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| | More on 'Semaphore Communication'. |
| | Connected Earth is the place to continue your study of the term semaphore communication. | | | To progress your search for the term semaphore communication, a visit to the Connected Earth website is likely to help you. | | | It's a complete multi-media experience, where you can switch between clearly-written stories, more detailed study, images of exhibits in 3D, reminiscences in oral and written form from people who - in the past - worked in the telecommunications industry, film clips, and simple explanations or interactive animations of the way that things work. |
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http://www.connected-earth.com/content/semaphore_communication.html
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| | 2. The Electric Telegraph (1860-1914) |
| | Early communications development included a variety of semaphore telegraph lines, where spotters used visual signals to relay messages from one elevated location to the next. | | | A Semaphore Telegraph Station, from the April 20, 1895 issue of the Scientific American Supplement, described a French shoreline installation, which displayed meteorological signals, sent messages to passing ships, and also received commercial telegrams sent from the ships by semaphore flags. | | | However, radio's use in international communication meant that a single standard telegraphic code was needed in order to avoid confusion. |
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http://www.earlyradiohistory.us/sec002.htm
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| | System V IPC Parameters |
| | We are talking about the System V interprocess communication semaphores here. | | | Please note that System V semaphore cannot exist by themselves. | | | They are always grouped into a semaphore set, even if the set only contains a single semaphore. |
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http://www.sean.de/Solaris/sysvipc.html
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| | Semaphores in System V UNIX |
| | The System V specification of the UNIX operating system introduces semaphores among the other facilities for Inter-Process Communication (IPC). | | | This system call returns an integer id for the semaphore (analogous to a file descriptor), or -1 in case of error. | | | Cooperating processes wishing to access the semaphore set must use the same key, much like a file name is used to store on disk shared data by cooperating processes. |
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http://www.cim.mcgill.ca/~franco/OpSys-304-427/lecture-notes/node31.html
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