
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.

oak.oakland.edu          Yet another good ham radio archive site.  Many 
                         subdirectories, including an FTP area of the 
                         ARRL's Automated Information Server Files - 
                         /pub/hamradio/arrl/infoserver.

ftp.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.

