Internet Basics

1. HOW TO DOWNLOAD A FILE FTP - File Transfer Protocol
The Usage of Anonymous FTP'ing.

Downloading Amiga files from the 'net' is commonly carried out in two ways depending on which network you have access to. For Internet users, FTP is available. FTP uses TCP/IP protocol which allows different types of machines to communicate directly with each other. With FTP you have limited access, mainly for getting and sending files. Pure remote login capability is achieved using TELNET but file transfer is not available this way. Also not many organisations will allow the public full access to their machines. Those of you with Bitnet access will need to use an FTP server, this is a machine that will do an automatic FTP connection and use commands that you build into a piece of mail. As these are the two most common networks used by Amiga fans we will leave the other networks out (most other networks have some form of gateway to Internet or the FTP server so if you can read this document in electronic form you will be able to use one method or another). Note that the FTP server is available to Internet users, so even if you do not have FTP software you can still download files.

You may hear the phrase "anonymous FTP Sites" These are the Public Domain machines dotted around the world. They store a variety of data, obviously here we are interested in Amiga files.

The following is a brief description on how to use FTP to obtain Amiga files.

You will find various 'flavours' of FTP depending on the machine you are using, also some of the command modifiers will be different depending on the OS you are logging into. Check your own system for syntax, try FTP HELP as a starter.

How do I log onto a site (computer) and get some software?

There are several methods you can use:

1. ftp <site_name> (from your user prompt)

eg: ftp mathsun17.utk.edu

 2. ftp <Internet address(number)> (from your user prompt)

eg: ftp

128.169.200.117

You will, from time to time see machines reference thus:-

mathsun17.utk.edu (128.169.200.117 - referred to as the Internet address or IP address). This allows both methods of access. If you use a machine name and get an error of "unknown host" or similar, use the numbers (there is a lookup file on each system that matches names to numbers, FTP needs the number to operate, so it just means there is no match in your machine's file). Every machine on Internet has a unique number and is registered thus. If you have the name and no number, try the command

nslookup cs.mcgill.ca
Server:  server.af.mil
Address:  26.28.0.13

Non-authoritative answer:
Name:    cs.mcgill.ca
Address:  132.206.2.1

nslookup is certainly a unix command, I can't speak for other OS's. Look at the section on 'archie' for further info on Internet numbers.

3. While in ftp type: open/connect site_name (or number)

Once you are "Connected." you will be prompted to enter a name, you must use "anonymous" and a password of "your Email ID."

Here are some of the FTP commands and what they do for you:-

ls             List directory you are in.
ls (dir)       List directory below you.

ls -R          List recursively Some OS's will take the -R as redirection file
               name. Warning - This file can be *very* large.

ls a*          The * is a usual wildcard - be careful of redirection
dir            } These generally provide more detailed listings than ls,
list           } but this depends on the system you are using.
cd             Change directory
cwd            Change directory
set def        Change directory for logging into VAX machines
cd /           Return to top level
cd ..          Move up one directory
cdup           Move up one directory
hash           Put hash sign up when each 1024 bytes are transferred (useful
               for large files to show you it's still working)
pwd            Comfirm which directory you are currently in

OK, so now you have found the file you want, how do you transfer it.

First, you must decide if it is a text file or a binary (anything except text file). The FTP session must be set to the correct transfer mode otherwise you could end up with a corrupted file

BEWARE IT IS A VERY COMMON MISTAKE NOT TO SET BINARY MODE BEFORE TRANSFERRING. YOU WILL END UP WITH WHAT LOOKS LIKE A CORRUPT FILE

binary         Prepare for binary file transfer
set type i     same as binary

Once you set your file type, then proceed with the 'get' command. 'get' has a syntax of : get file nfile

file = the actual file you want

nfile = alternate filename (incase you want to call it
        something else when 'get'ting it, useful on long
        names or naming clash between systems - not
        mandatory). Also be aware of case sensitivity.
        It's not so bad when you are doing this
        interactively but what a waste of time if you
        have a program doing it for you or you are using
        the ftpmail facility.

On some systems you could use

mget A*

This would retrieve all files starting with a capital A.

Other systems have the bget command which automatically selects binary mode transfer.

How do I know if it's finished transferring the file? Basically it will tell you it's opening the connection and what type of file it is sending (file type is what you set it as being). You can however watch the progress of the file coming. Just type hash - this will toggle the printing of hash marks ('#', 1 hash equals 1024k = 1k). This is not available on all flavours of FTP , check your documentation. How do I get out of ftp?

At the 'ftp>' prompt type:

UNIX,IBM     bye (or exit, ^D or quit)
Vax/Vms      exit (or ^Z)

On some systems you can also use the command close to terminate the current ftp session but stay in ftp mode. How do I get the file to my Amiga?

If your Amiga is connected to a modem (That's a device that links your computer to the telephone line) get ZModem or maybe kermit and transfer via the phone. Zmodem is available on IBM/UNIX/VAX/AMIGA/etc.. machines. You will need the same software running at both ends (both Zmodem and kermit for the Amiga will be on the Utility Disk) If you have an IBM PC, clone or emulator(eg OPENPC on SPARCstations that is connected to internet, you can download to ibm formatted disks (720k format). After you download to an ibm formatted disk, you can use MSH (PD) or CrossDOS, to transfer them to your Amiga.(See section 4).

Many of the more popular and larger ftp sites (like wuarchive or uunet) run a more advanced ftpd. This ftpd will automatically create files which have been requested from it via get by following some simple rules i.e. if you request foobar.Z, but there is no foobar.Z file in the directory but there is a foobar, it will compress foobar on the fly and transfer the resulting file as foobar.Z instead of failing. This ftpd includes a rule to generate tar.Z files i.e. if you request foobar.tar.Z and there is just a directory foobar, this directory will automatically be tarzed'ed for you. Add to this the ability to specify a filter with get and you have the ability to transfer complete directory trees while preserving file attributes, access times, soft links and (possibly) ownerships. If you want to create a copy of the directory foobar and all its subdirectories on your local machine you type:

get foobar.tar.Z |Untarz

where Untarz is a simple shell script e.g. like this:

#!/bin/sh
zcat | tar xf -

If you are on BITNET you will not be able to use any TCP/IP protocol, in this case you will need to use the services of an FTP server. To receive files from an FTP server you will need to send mail with your FTP commands built into the message. For an explanation send mail with a subject line of help to:-

BITFTP@PUCC

A typical request to BITFTP would look something like this:-

ftp name.of.machine (or Internet number) uuencoded
        user anonymous
        cd incoming/amiga
        BINARY
        get SoundZAPv2.1.lha SoundZAP.lha
        get amos1.34_upgrade.zom amos1.34.zom
        quit

Notice the "uuencoded" on the first line. This tells bitftp to send all files uuencoded. This way, you need only to uudecode the file. They will probably be sent in fixed blocks of 512 bytes. Most compression programs ignore extra bytes at the end. DMS does not. It gives an error - something like "Header identification error" or some such thing. Dispite the error message, dms'ed files seem to work fine. Executables are a problem. The extra bytes at the end make it impossible to run. This is where ChopIt comes to play. You can use it to chop off those extra trailing bytes so that the file is back to its original length. You may also do this with dms files to get rid of the error message (but it's not necessary).

You would send this as a piece of mail to BITFTP@PUCC with no subject. The results may take a couple of days to be returned to you. (The HELP file did tell you this - you have got the help file before trying anything haven't you)

If you work on a VAX, the file may arrive as a NETDATA file. this type of file may well have problems. If this is the case use the NETFIX.COM program as listed in part 3.

All other receipts from BITFTP will arrive as mail, UUEncoded. UUEncoding is a method of turning a binary file into text so that it can be sent as mail. If you've ordered a large file it may well arrive in pieces. These pieces have to be concatenated (remember to remove mail headers) and then run through a UUDecoder. (Utility Disk)

A UUEncoded file can be recognised by the first line, it will start with

Here is a procedure for all you Amiga people using BITFTP to get ZOO files into a VAX/VMS system. The basic problem is that RECEIVE/BINARY puts the wrong carriage control attribute on the file. If you then try to use ZOO on it ZOO will complain.

To fix the carriage control attribute:

  1)  analyze/rms/fdl  xyz.zoo

  2)  ed/fdl  xyz.fdl

        You are now in the full-screen file definition languge editor.
        You want to MODIFY the RECORD attribute CARRIAGE-CONTROL
        by setting it to NONE (the menus are fairly strightforward).
        Exit from the FDL editor - a new version of xyz.fdl will be written.

  3)  convert/fdl=xyz.fdl  xyz.zoo  xyz2.zoo

VAX VMS uses a (file) record management system called RMS. RMS has many different file formats. This seems to cause people problems when moving files to machines of different architectures (Amiga,Unix boxes,...). Binary files can have various "layouts" but one common one (as show by DIR/FULL) looks like:

File organization:  Sequential
File attributes:    Allocation: 105, Extend: 0, Global buffer count: 0
Record format:      Fixed length 512 byte records   <---TAKE NOTE

To transfer files such as this under KERMIT you --MUST-- use SET FILE TYPE FIXED not SET FILE TYPE BINARY for the VAX end (use the standard BINARY mode on the Amiga end).

For Internet users who only have e-mail access, or don`t have an aminet mirror close to them may prefer to use FTPMail. This is basically a scripted ftp service where any files you request are sent to you enclosed in a e-mail. Some FTPMail servers are:

ftpmail@decwrl.dec.com
ftpmail@grasp.insa-lyon.fr (European users only please)
ftpmail@doc.ic.ac.uk
ftpmail@ftp.luth.se

The last two contain a full aminet mirror. You can use FTPMail to perform FTP from sites which do not have an ftpmail feature, but requests for files from the host server are given preference. To obtain help on this feature, simply send a message to one of the above sites with the body containing simply HELP.

An example of a ftpmail request is:

Open                        ; Opens an ftp session at the current server.
cd pub/aminet/game/think    ; Change directory
dir                         ; Get a directory listing
get ChinaTiles.lha          ; Get a file
size 50k                    ; Limit the part size to 50k
uuencode                    ; Select uuencoded format
quit                        ; Finish the session

This can be very handy if the link to an archive is very slow, or an archive is so busy that you have trouble gaining access to it.

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