File Transfer Protocol Ftp Information Technology Essay

File Transfer Protocol Ftp Information Technology Essay File Transfer Protocol is a standard network protocol used mainly in transferring files from one computer to another through the internet, it can also be used to manipulate or exchange files over a TCP/IP based network such as a local area network (LAN) or via the internet. One general use of FTP is to make download and upload of files very easy without directly dealing with the client or server operating system. This means an authorised remote FTP user is able to carry out some extra tasks as editing a file, change a file name, move file from one directory to another and much more (Zadjali, 2010). In most cases, a vast majority of people or organizations who use FTP often have some shared large files which relate to a particular project stored on a file server, access to these remote files are mainly derived through authenticated FTP client or an anonymous user. FTP, without its flaws has proved to be very effective in file transfer (upload and download) and this feature is particularly vital to carry out some much needed tasks since there are tendencies that continuous communication with the satellite is unavoidable. FTP is as a result of an RFC (request for comment) first drafted in the 1970s and has only gone through some few changes. With this in mind, we can have further discussions on how FTP works, have a little discussion on its flaws, and finally see what can be done to avoid some of the well-known draw backs of FTP. FTP has evolved from its original purpose of just a file transferring protocol to a tool used for a far wider range of functions on the World Wide Web and in specialized application with some revision releases as the years passes by, therefore in our own case FTP can be used as a means of sending or manipulating a file containing critical code that is vital to the operation and or functioning of the satellite system whenever the need arises. How FTP Works Transmission Control Protocol (TCP) and Internet Protocol (IP) are the backbone of the internet; TCP is responsible for or manages data transfer while IP helps to direct traffics to internet addresses. FTP is an underling of TCP and shuttles files back and forth between FTP server and FTP client, for FTP to work properly it requires that two ports be opened; one is the listening port of the server usually on port 21, this port listens for an incoming connection from the client machine. A successful connection from the client to this port then forms the control stream through which commands from the client machine are passed to the server and in return replies are collected. The FTP server on the other hand then opens a corresponding port connection to the client usually on port 20 for data transfer, the separation of ports for commands and data transfer makes FTP more effective (Oxbridge Graduate, -). When using the normal active mode the FTP client relays to the server all the information needed for the server to communicate back; some of the basic information includes the port number and IP address upon which it will listen to receive corresponding information from the FTP server. This information sent from the client, that is the PORT and IP are sent as an argument to the FTP server in a format H1,H2,H3,H4,P1,P2. Each of the given field represents 8bits of the host IP, followed by the data port chosen by the client machine. For example a client that has an IP address 192.168.0.1 listening on port number 49154 for the data connection from the server will usually send a command PORT 192,168,0,1,192,2. The port field is then interpreted as P1*256+P2 of which in this example is calculated as 192*256+2=49154. Normally the in-built firewall on our systems prevents internet sites or external system from initiating file transfer to our computer (the computer behind the router), and this is the way passive mode of the FTP server works. To get around this obstacle one must make use of the PASV command which help to reverse the FTP process; this reverse process allows the computer behind the firewall initiate the transfer process by sending the PASV command to which the server in return would reply with a something like 299 Entering Passive Mode (127.0.0.1,192,52) (Oxbridge Graduate, -). PASV FTP can also be used as a security measure to prevent unwanted external files from being downloaded into the system. In the real sense, when using passive mode, the FTP server opens a dynamic port and sends the client machine all necessary information to facilitate the connection, these are the port number on which it is listening and the IP address to connect to (this information usually is a 16 bit value split into a high and low bites as described above) and wait for the client to initiate the connection. Connection in this case requires that the client binds the source port of the connection to a dynamic port. While data is either being uploaded or downloaded through the data stream, the control stream always remains idle and such scenario can cause some problem especially if the files being transmitted is large. A system firewall is designed to time out/terminate sessions after a lengthy period of idleness, meaning although the large file is expected to go through but may be terminated because of the time it will take for the transfer to be completed causing an error (Oxbridge Graduate, -). Effect of Latency on FTP Latency or network delay can be considered as the amount of time delay caused by every element involved in the transfer of data/packet through a particular network path beginning from the initiation point to the destination device. The time taken for each sent packet to be acknowledged is measured as Round Trip Time (RTT) or Round Trip Latency, and latency RTT causes FTP to slow down considering the time it will take for satellite communication to be established and file transfer to be acknowledged, this can be into hundreds or thousands of milliseconds of RTT depending on the bandwidth capacity and the orbiting distance of our satellite. TCP/IP is as of today the most widely deployed internet protocol in existence, consequently FTP being the protocol responsible for file transfer and operates underneath TCP has been found to inherit the drawbacks of TCP/IP. (Unlimi-Tech Software Inc., 2010) One way Latency R S SIN Round Trip Latency ACK Figure : A typical TCP session showing round trip latency Major Acting Elements of Latency Latency as a factor is mainly made up of three (3) major elements that can significantly impact the end-to-end latency, these elements include: Queuing delay Propagation delay Serialization delay Queuing delay is the total sum of all delays caused whenever packets are received, stored and transmitted using queues. This form of delay has been found to be the most variable form of delay in modern networks, and it also depends on the queue length and the number of queues in that particular route; for instance in a congested and heavily loaded network the queue will be long and the queuing delay will be directly proportional to the queue. In several cases this alone will contribute the greatest in the overall latency, but considering networks that are less congested this delay would often not have any meaningful impact (TCPing, 2007). Propagation delay is the time it will take a packet/signal to physically navigate a given path; this delay is linked directly with the distance between a sending and receiving device. Even on a high performing network, the overall latency is commonly affected by the propagation delay and hence cannot be considerably reduced. How consistent the propagation delay is can be greatly dependent on the route signals have to navigate. A direct connection (static route) would in most cases ensure an equally constant latency since no route changes is required but on the other hand a dynamic route will tend to result to more latency variation (TCPing, 2007). Serialization delay is the necessary delay required of a sender to transmit a packet or signal onto the outbound queue, for an available bandwidth and a given packet size serialization delay is a constant and can be calculated by dividing the packet size (in bits) by the available bandwidth (in bits per second) (TCPing, 2007). It is only reasonable to talk about jitter after analysing some of its contributing factors; jitter is the variation in packet transportation or variation in the time between packet arrival caused by queuing, propagation and serialization effect on the packet path through the network, another popular cause of jitter is the electromagnetic interference (EMI). Generally higher amount of jitter will tend to take place on heavily congested or slow network. To understand what jitter really means, one must remember that computer data be it in the form of pictures, text, video or audio are sent out in manageable packets with footers and headers that help to indicate the correct order of the packets when it gets to its destined system for playback. When a jitter occurs, the code to re-assemble the data packets may be lost or some data packets itself may Effect of Packet Loss on FTP A typical packet loss occurs when a packet travelling from one end of the network never made its way to the other due to

Kings Park Psychiatric Center :: essays research papers fc

The Kings Park Psychiatric Center has had a large effect on the social changes of Long Island. A small town grew larger and prosperous from the direct effect of this State hospital from the time of 1885 to the present. The history of the town, the patients and court cases held, and the concluding plans for the land after its closing have all had a significant mark on the social changes of the town. The first hospital was built in a quiet farming town later named Kings Park. In 1885, officials of what was then the city of Brooklyn established the Kings County Farm on more than 800 acres to care for the mentally ill. Kings Park was only a small part of what would later become a giant chain of connected mental hospitals on Long Island, each with over 2,500 patients at one time.(Bleyer,2) As new buildings went up at Kings Park, so did the patient population. At the turn of the century, Kings Park in just 15 years had grown to, 697 patients and a staff of 454. This dramatic increase had given the hospital a larger population than the rest of the Town of Smithtown. (Sarhaddi) The hospital was very equipped; therefore, not very dependant on the rest of Long Island. All the hospitals built around this time prided themselves on being self-sufficient farm communities. At Kings Park, the three wooden houses grew into more than 150 permanent buildings, including a bakery, Laundromat, amusement hall, bandstand, library, furniture repair shops, and nursing school. Most of the people who lived in Kings Park worked at the Psychiatric Center. Many of them were Irish immigrants brought from their native land more than 50 years ago by relatives who worked at the mental hospital on the Long Island Sound and who had promises of jobs for them too. (Bleyer) During World War II, when many employees joined the armed forces, Central Islip recruited black workers from the Carolinas, which led to cultural changes in the mix of the community. This developed distinct differences between certain areas of race such as African American, Hispanic, and white neighborhoods. Minority groups not allowed to fight in the war or not taken to fight were offered jobs to work at the hospitals. The Kings Park Psychiatric Hospital hadn’t really become very over-populated until the 1960’s. (Sarhaddi) The Kings Park Psychiatric Center was in its Heyday in the 1960’s.

Problems faced by the sugar industry Essay

Topic: Problems faced by the Sugar Industry in the British West Indies specifically Jamaica. Research Question: The problems faced by the Sugar Industry affected the British West Indies during the period of 1838-1876. In light of those problems to what extent did this result in the decline of sugar and the economic state of Jamaica. Rationale/ Aim It is believed that the problems faced by the sugar industry were caused due to the fact that the planters had a very negative and spiteful attitude towards the apprentices. Also these problems were caused due to the fact that now that the slaves became newly freed, they did not want to return to the estate work. Due to the abolition of slavery the sugar industry saw a rapid decline in the production of sugar. Reading and researching this topic sparked much interest in the researcher. To see that something so successful become unsuccessfully so quickly showed that anything is possible. The essay being done will hopefully give the researcher and society a better insight to the struggles in which the British Sugar Industry faced during the period of 1838-1876. Introduction Topic: Problems faced by the Sugar Industry in the British West Indies specifically Jamaica. Thesis statement: The problems that the sugar industry faced led to immense problems in the British West Indies. This essay examines the problems in which the sugar industry faced during the period of 1838-1876. The Planter’s in the British West Indies Acquired Large sums of money from the ever rowing and popular sugar industry. Due to the abolition of slavery in 1838; Labour that was needed for the production of  sugar decreased rapidly and so did the profitable income the planter’s once received. Soon because of the lack of labour estates became encumbered. There are specific factors that contributed to the problems that the sugar industry faced. These factors are; Capital, Labour, Technology and Free Trade. Labour:-Now that slavery was abolished, there was an increase in the price of slaves and this caused an uncompetitive rise in the price of sugar. Due to this labour became scarce and expensive. Some planter continued and hired ex-slaves to work for them and they had to pay them wages. These wages accounted for as much as two thirds of the total cost of production. Some slaves did not return back to the estate in which they worked on instead they got land for themselves and cultivated their own crops. This caused a number of territories to experience e a significant decline in the production of sugar in the first thirty (30) years of emancipation. These territories were:- Territories Percentage Reduction St. Vincent 25% British Guiana 40% Grenada 50% Jamaica Decreased three times the pre-emancipation level Capital: – The planters lacked capital in which they needed for wages and labour saving equipments and equipments. Up until the end of this period Majority of estates still used the same old techniques. The wage level was considerably high in territories where land was available and where peasantry was developing well. Two territories associated with this are: Trinidad and British Guiana who were in the expansion and establishment process. By 1854 a number of estates became encumbered due to the fact that the planter’s were filled with debt. The lack of capital forced them out of production because they could not repay their debts. Jamaica and Grenada had the highest amount of abandoned estates. The fact that these estates were encumbered their value fell tremendously. In some cases estates owed their taxes and because of this government workers could not be paid the salaries. Technology: – emancipation gave rise to the use of Machinery. Some of the planters tried items of machinery such as the centrifugal systems the plough, harrow and vacuum pans on their estates. Others introduced the railways. Trinidad, British Guiana and St. Kitts introduced steam mills. Also some planters being in debt could not be able to afford the machinery they needed for production. The enslaved also would abuse and destroy estate equipment which is known as industrial sabotage. Free Trade: – Before equalization there was no help to the West Indian interest. The price of sugar fell almost immediately from 33-25/10d per 50 kg. Due to the fact that the English would not lend money to any companies and banks that specialised in Caribbean issues, by 1847, 13 leading West Indian companies became bankrupt. The Planters Bank in Jamaica and the West Indian Bank both closed for good and because of these planters could not borrow money to cover their losses. Around 474 sugar and coffee plantations went out of business in Jamaica  between the years 1846 and 1852. By the year 1858 Grenada’s sugar production was half that of the last year of slavery and Montserrat, St Vincent and Tobago were two thirds. After the Equalization act was passed, Planters tried to reduce cost by cutting wages by half, to this the labourers did not sit still. Due to the many protests that were occurring on the planters’ estates they tried to compensate the workers for the loss of their earnings. CONCLUSION There were many problems in which the sugar industry faced and they had very negative effects on the Caribbean. These problems made the researcher realise that anything successful can really be unsuccessful and it doesn’t matter what time it is. Although the sugar went through a lot of problems after the year of 1876 and the planter’s were allowed to get immigrants to work for them on their estate, the sugar industry would try to make a comeback through this. BIBLIOGRAPHY www.notesmaster.com Caribbean Revision History for CxC- Peter Ashdown and Francis Humphreys Caribbean History: Foundations Bk1- Claypole, William and Robottom, John Caribbean History Theme Text Adjustments to Emancipation: 1838-1876- Veta Dawson

Comparing Gay Meets Bible Belt State - 825 Words

Gay Meets Bible Belt State The Portrayal of Homosexuality in the Laurel Leader-Call (1960-1979) On February 7, 2013, one of the two major news publications in Laurel Mississippi, printed a a story detailing the unofficial marriage of Jessica Powell to Crystal Craven, a lesbian couple whose desire to wed was intensified by the fact that Craven was dying of brain cancer. The article was titled â€Å"Historic Wedding† and claimed the ceremony was the first between two people of the same gender to take place in Jones County, Mississippi. In the short period between the publication of the article and Craven’s death a few weeks later, the small-town newspaper made a big wave. The Laurel Leader-Call story received national attention, receiving praise from liberals and upsetting conservatives. Well-known news sources such as The Huffington Post and The Christian Post picked up the story from Leader Call and referred to it in their publications. The responses to the Leader-Call article, which poured in from around the nation, ranged from agreement with and support for Powe ll and Craven, to condemning the Leader-Call for covering the ceremony. The impact of the Leader-Call article was tremendous, as the story went national and revealed conflicting political and moral ideologies in the traditionally conservative state of Mississippi. Although the February 2013 article might have become a national story, it was not the first time the Leader Call had dealt with the issue of homosexuality.Show MoreRelatedAnalysis on Conversation Features. Differenfes Between British and American English16034 Words   |  65 Pageset al. explain in their book: Longman Student Grammar of Spoken and Written English (1999). They classify the conversational features according to the social and situational characteristics of conversation they are associated with. As Biber et al. state, â€Å"conversation cannot be characterized in terms of communicative goals or social functions†. This does not occur in the other registers: academic prose, news, fiction. Conversation has a special set of features which cannot be found in the other registersRead MoreOne Significant Change That Has Occurred in the World Between 1900 and 2005. Explain the Impact This Change Has Made on Our Lives and Why It Is an Important Change.163893 Words   |  656 Pagespolitics—20th century. I. Adas, Michael, 1943– II. American Historical Association. D421.E77 2010 909.82—dc22 2009052961 The paper used in this publication meets the requirements of the American National Standard for Information Sciences—Permanence of Paper for Printed Library Materials, ANSI Z39.48-1992 Printed in the United States of America 2 4 6 8 9 7 5 3 1 C ONTENTS Introduction Michael Adas 1 1 World Migration in the Long Twentieth Century †¢ Jose C. Moya and Adam McKeown Read More_x000C_Introduction to Statistics and Data Analysis355457 Words   |  1422 Pagesintentionally left blank Introduction to Statistics and Data Analysis Third Edition Roxy Peck California Polytechnic State University, San Luis Obispo Chris Olsen George Washington High School, Cedar Rapids, IA Jay Devore California Polytechnic State University, San Luis Obispo Australia †¢ Brazil †¢ Canada †¢ Mexico †¢ Singapore †¢ Spain †¢ United Kingdom †¢ United States Introduction to Statistics and Data Analysis, Third Edition Roxy Peck, Chris Olsen, Jay Devore Acquisitions Editor:Read MoreStephen P. Robbins Timothy A. Judge (2011) Organizational Behaviour 15th Edition New Jersey: Prentice Hall393164 Words   |  1573 PagesOrganizational Behavior This page intentionally left blank Organizational Behavior EDITION 15 Stephen P. Robbins —San Diego State University Timothy A. Judge —University of Notre Dame i3iEi35Bj! Boston Columbus Indianapolis New York San Francisco Upper Saddle River Amsterdam Cape Town Dubai London Madrid Milan Munich Paris Montreal Toronto Delhi Mexico City Sao Paulo Sydney Hong Kong Seoul Singapore Taipei Tokyo Editorial Director: Sally Yagan Director of Editorial Services: