Libris Britannia 4/science library(b).zip/science library(b)/COMMUNIC/BULLETIN/0597.ZIP/PROTOCOL.HLP

Text File | 1985-10-19 | 9KB | 179 lines

=============== COLOSSUS FILE SYSTEM TUTORIAL ==================

The files area allows users to move files between your system and
COLOSSUS. Downloading is the process of moving files from COLOSSUS
to your computer, and uploading is moving files from your computer
to COLOSSUS.

Data transfer can be done in a number of ways in COLOSSUS.  New
error checking protocols are being added on a regular basis, but
the most common transfer methods are XMODEM and standard ASCII.
XMODEM protocol was originally developed by Ward Christensen, a
pioneer in micro communications.  XMODEM is included in many
communications programs including PC-TALK III, QMODEM, CROSSTALK,
SMARTCOM and many more.  Before talking any more about specific
protocols, lets review the general method of locating a file or
program to download in a COLOSSUS system.

The explaination which follows assumes the SYSOP has adopted the
standard COLOSSUS FILES SYSTEM MENU, and is using the reccommended
prompts. Since every COLOSSUS system has the option of changing the
wording of this MENU, you may find some slight variation of the
menu prompts which will perform the same functions.

COLOSSUS allows storing files in separate subdirectories or areas,
each of which is devoted to different types of files or programs.
The status line directly above the Files Menu Prompt Line tells you
which file area or subdirectory is active.  File areas usually have
names like GAMES, UTILITIES, etc., and likewise contain that type
of file.  To list the specific programs available IN THE ACTIVE
FILE AREA, select the LIST command, usually displayed as <L>IST on
the menu.  The complete names of the files will be listed along
with file size, date added to the system, and a short description
of each file.

After reviewing the files in the CURRENT FILE AREA, you may change
to another area using the CHANGE FILE AREA command, usually
displayed as <C>HANGE FILE AREA on the menu.  Pressing C will bring
up a prompt asking which file area you wish to change to.  If you
are familiar with the particular system you are calling you can
enter the NUMBER corresponding to the area you want.  If you don't
know the areas available you may simply press <ENTER> or carriage
return for a complete list.  After indicating the change you wish
to make you may again use the <L>IST command to display the files
available in the new area.

XMODEM FILE TRANSFER

COLOSSUS supports two variations of the XMODEM protocol called
XMODEM and XMODEM/CRC respectively.  One of these two protocols is
required if you intend to transfer files with extensions of EXE,
OBJ, COM, ARC, LBR, xQx, as well as tokenized BASIC programs.
Files containing the IBM PC special ASCII characters (ones with
ASCII values above 128) must also be transferred with XMODEM,
including Wordstar files.  These files cannot be transferred in
ASCII mode since ASCII transfer is only 7 bit and these types of
files require the full 8 bit transfer of the data with no
translation of the contents of the file.

XMODEM also offers the advantage of error checking on a block by
block basis to assure that the data sent contains no errors.  It
does this by adding a checksum byte to the end of each block of
data; the receiver calculates its own checksum and compares it to
the one received.  If an error is detected in the transmission,
XMODEM will request that COLOSSUS retransmit the block of data.

In addition to the above checksum comparison, XMODEM/CRC adds
another level of error detection using a complex CYCLICAL
REDUNDANCY CHECK algorithm.

Please be certain to select and use matching protocol types for
accurate data interchange.  QMODEM, a product of John Friel and the
FORBIN PROJECT supports both XMODEM and XMODEM/CRC, and will
usually contain additional protocolls added to COLOSSUS.

To perform an XMODEM file download, first select a file by using
the <L>IST command in the appropriate file area.  NOTE:  THE FILE
YOU WISH TO DOWNLOAD MUST BE IN THE CURRENT FILE AREA!  <C>HANGE TO
THE CORRECT AREA PRIOR TO STARTING THE DOWNLOAD.

1.  Select <D>OWNLOAD from the FILES MENU

2.  Select the transfer protocol you want to use by entering the
    number which corresponds to it, ie 3 for XMODEM/CRC.

3.  Enter the COMPLETE file name; remember, if the file is not
    found it is probably because you are in a different FILE AREA.

4.  COLOSSUS will indicate how many blocks are to be sent and wait
    for you to begin you transfer procedure.  You should then open
    your recieve or capture file (QMODEM & PC-TALK.III Alt-R
    command) and start the XMODEM receive process.  PC-TALK.III
    starts XMODEM for you ONLY IF you put '=X' at the end of the
    download filename.  QMODEM will ask for the protocol type much
    the same way as COLOSSUS

5.  The file will be transferred automatically block by block under
    XMODEM until the entire file has been sent. You may abnormally
    abort the transfer by sending COLOSSUS an ASCII CAN code (CTRL-
    X). PC-TALK.III & QMODEM will do this for you if you enter an
    Alt-R during the file transfer, or it can be entered from the
    keyboard.

7.  When the file transfer is finished, XMODEM automatically closes
    your capture file for you. XMODEM also ensures that no garbage
    gets into your file; binary files and text files are sent to
    you with 99.6% error free transmission with XMODEM and better
    than 99.9% with XMODEM/CRC.

ASCII DATA CAPTURE

ASCII transfer is simply the sending of information as characters,
and is limited to 7 bit information.  The transfer of files in
ASCII mode can be done if your system is capable of any type of
data capture.  To download a file using the ASCII method, follow
the same sequence of steps listed above for XMODEM, but select
protocol type 1, ASCII.

4.  COLOSSUS will ask which type of ASCII transfer you want,
         1.  PROMPTED
         2.  TIME DELAY
         3.  NO DELAY

NO DELAY is the simplest and will cause COLOSSUS to send the file
full speed to your system with no pauses.  If it is a long file and
your system has only a small communications buffer, you may find
your computer is unable to keep up with receiving & writing the file
without losing some characters.  If so, change to a TIME DELAY as
indicated below.

TIME DELAY will allow you to specify the amount of time between each
transmitted character in hundredths of a second.  For example you
could specify 10 as the time delay and COLOSSUS would wait 10/100 of
a second (one tenth) between each character sent.  A delay between
10 and 50 will allow almost any system to successfully receive ASCII
even if a buffer problem has been found.

PROMPTED transmission allows receiving the file line by line with a
pause between each line until a specified character has been
received by COLOSSUS.  You must tell COLOSSUS what character will be
sent by your system to signal that it is ready for the next line.

5.  Open your capture or receive file as indicated by COLOSSUS
    (Opening your capture file is done by using the Alt-R command in
    PC-TALK & QMODEM)  After setting up to receive the file on your
    end, you have to send COLOSSUS one carriage return so that it
    knows you are ready to start.

6.  The file will be sent a line at a time until the entire file is
    sent.  You will see the lines of ASCII code (readable text and
    numbers) on your screen as they flow to your system.  A Ctrl-X
    (ASCII CAN) can be sent anytime to abort the transmission of the
    data.

7.  When the file transfer is finished, COLOSSUS will send you an
    End Of File Marker (Ctrl-Z) and tell you to close your capture
    file (PC-TALK & QMODEM Alt-R)

FILE UPLOADING

File uploading to COLOSSUS is very similar to downloading.

Uploading of ASCII files can be done without interruption between
lines.  COLOSSUS can handle data uploading at up to 2400 baud
without any problem.

Before sending a file be sure COLOSSUS has enough disk space to take
the file. When you select <U>PLOAD at the File menu, the system will
tell you how much disk space is free on the upload drive.

UPLOAD GROUND RULES

You are encouraged to donate programs to the library on this system.
Any type of program or document is welcome, however, a few ground
rules are in order.  The files donated must contain only information
that is in the public domain.  No private or commercial information
should be placed on this system.  The SYSOP is not responsible for
any of the data that is shared on this system.