UNIX HOSTS Most of the systems available on the Internet are running the unix operating system. While you don't have to learn unix in order to use FTP, you will have to deal with unix file names and directories. These are handled a little differently than DOS file names and directories. The major differences between unix and DOS files are: 1) unix file names can be much longer than DOS file names. This is particularly important when getting a file from the unix host. If the file name is longer than eight characters before the first period in the name (if there *is* a period), or longer than three characters after the period, the name will be truncated to a DOS file name. 2) unix file names are case sensitive. That is, "README" is a different file name from "readme" or "Readme". It's important to type the file name in exactly." Note that the "*" character is a wildcard in unix, just as in DOS. For example, the command: dir wp* will return a list of all of the files with names beginning with "wp" in the current directory of the remote computer. Fortunately, the basic unix directory structure is much like that of DOS. Directories may have subdirectories, which may have subdirectories... just like DOS. Of course, unix directory names follow the same rules as unix file names. In addition, there is one important difference between unix directory specifications and those of DOS: unix directories are separated by "/" rather than "\" characters. For example: /pub/hamradio/filename is a legal unix file specification, while: \pub\hamradio\filename is *not* legal in unix. When you get a list of files from a unix host, it looks like this: drwxr-xr-x 2 root 1 240 Dec 21 08:09 ArchieSeeThis -rw-r--r-- 1 98 1 371 Sep 11 1991 NOTICE -rw-r--r-- 1 98 ftp 496 Sep 4 1991 README drwxr-xr-x 2 root 1 80 Apr 30 20:08 bin drwxr-xr-x 2 root ftp 112 Apr 30 20:06 bin_mc drwxr-xr-x 2 root 1 48 Apr 30 20:14 dev drwxr-xr-x 2 root 1 64 Apr 30 20:07 etc drwxr-xr-x 2 root ftp 64 Apr 30 20:06 etc_mc lrwxrwxrwx 1 root 1 9 Feb 28 1991 in -> incomming drwxrwxrwx 3 98 ftp 576 Apr 30 20:05 incomming drwxr-xr-x 13 98 ftp 256 Mar 13 04:09 pub drwxr-xr-x 3 root 1 48 Apr 30 20:12 usr The leftmost character on the line is interpreted as follows: d = directory (the entry is a subdirectory) - = file (the entry is a file) l = link (the entry points to another entry) In the above example, the only files in the listing are "NOTICE" and "README". Everything else is a directory, except for "in" which points to "incoming". (Thus, for example, the command "cd in" would be exactly equivalent to "cd incoming".) The size, date/time and file name are at the right of each line. Most unix systems keep their public files in a directory called "/pub" as shown above. One other difference between DOS and unix (and most other systems) is in the way they store text files. Because of this, FTP provides a mechanism to specify that a text file is being transferred. But *you* have to specify. We haven't used this mechanism on the LAN because all of the machines on the LAN are DOS machines. But if you are retrieving a text file from a remote Internet host, it's a very good idea to issue the "type a" command first to make the transfer in "ASCII" (text) mode. A FEW GOOD HOSTS There are literally thousands of computers connected to the Internet. Of them, most have nothing of interest to the casual browser. But there are a few that have much to offer. Among them: simtel20.army.mil Repository of thousands of public-domain and shareware software files. Of most interest are those files in the MSDOS area. This machine uses an unusual operating system that does not have the usual directory structure. Get and read the ASCII files, 00-README.TXT and HOW-TO-CD.DOC first. wuarchive.wustl.edu A unix system that mirrors the archives of other systems. In particular, it contains most of what's available on simtel20. Try the directory, /mirrors/msdos, which has *lots* of subdirectories containing over 7000 files. Each directory contains a file called "00-index.txt" that describes the files contained in that directory. ftp.cs.buffalo.edu The "standard" ham-radio archive host. Look in the /pub/ham-radio directory for the files. world.std.com Yet another good ham radio archive site. Many subdirectories, including an FTP area of the ARRL's Automated Information Server Files - /pub/hamradio/arrl/Server-files. ucsd.edu Where a lot of the ham radio "techies" hang out, including the TCP/IP developers. See the /hamradio directory. The members and HQ staff would like to thank the following people for their contributions to this information file: KE3Z Send any additional information or changes to mtracy@arrl.org. 73 from ARRL HQ.