6.11. FTP File Information Resources

Lecture



The FTP system is a repository of files of various types (spreadsheets, programs, data, graphics, sound) that are stored on FTP servers. These servers are built by almost all large companies. The most common type of DNS name is: ftp. <Firm_name> .com.

By accessibility, information on FTP servers is divided into three categories:

1) freeware files (Freeshare), in case their use is non-commercial;

2) protected information, access to which is granted to a special circle of registered users for an additional fee;

3) files with shareware status. The user is able to test them for free for a certain time. After this time, to continue operation, you must register on the server and pay the cost of the file.

When logging in to the FTP server, you need to register, specifying your ID and password. If there is no special registration system on the server, then it is recommended to specify the word Anonymous as an identifier, and your E-mail address as the password. When accessing files of the Freeshare or Shareware category, this type of registration is used by the server developers for recording and statistical analysis of the number of users.

The information on the FTP server is located in the form of traditional directories. Directory names are compiled in random order. Files on FTP servers are divided into text (in ASCII codes) and binary (documents prepared by Windows editors). These files are sent to the network in a different way. In the file copy program, you must specify the type of the file being sent or set the Auto Detect mode. In the latter mode, in some programs it is considered that only files with the TXT extension are text files, while in other programs it is possible to specify a list of text files. Sending a binary file as a text file can lead to loss of information and its distortion during transfer. If it is not known what type the file belongs to, it must be sent as a binary file, which, in turn, may increase the transfer time. Binary type files are converted into “pseudo-text” to shorten the transfer time. To do this, use the program Uuencode.

It is possible to copy a file from an FTP server using a browser, but it is more convenient to do this using special programs (WSFTP or CuteFTP). Both programs have two types of windows:

1) some analogue of the address book, in which the conditional meaningful names of FTP servers, their URLs, the login name and password of the user to enter, as well as other information common to the server are formed;

2) working window for direct work with the server.

When using these programs from the address book, first select the desired server. Then a connection is automatically established with it, after which a working window opens, including two panels. One of them corresponds to the user's computer, and the other to the server. Both panels contain a directory tree with files. Movement through the tree and activation of the directories on both panels takes place in the usual way. The selected files are marked and copied by command (click on the corresponding button) to the current directory of the local computer. When the connection is broken, these programs allow you to continue sending the file from the interrupted place.

In order to find a file by its name or a fragment of a name, you must use the Archie search engine, which is hosted on numerous servers. A permanent updated list of Archie servers is present on the Internet.

created: 2014-09-13
updated: 2021-03-13
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