documentation/specification/protocols.txt

i-scream Protocols
==================

Contents
--------
 - Conventions

 - Host Connection Protocol
 - Host Heartbeat Protocol
 - Host Data Protocol

 - Client Control Protocol
 - Client Data Protocol


Conventions
-----------
All protocols in this document assume a valid connection of
the appropriate type has been made, and that data streams
are already available.  All strings should, and will be,
terminated with a \n (newline character) to indicate the end
of the message.  All messages are sent as ASCII Strings.

Fixed protocol messages will appear in [] brackets, if there
is a variety of options they will be separated with the |
character.  For example:

    [OK|ERROR]
   
Indicates that the message "OK" OR the message "ERROR" will
be sent depending on the result of the last action.

Data messages will appear in {} brackets, where the name in
the brackets indicates the type (as in kind, not data type)
of data that will be returned.  For example:

    {lastmodified}

Indicates that data for use as 'last modified' will be 
returned.   

If [ERROR] is sent back at any time, this indicates that all 
communication is over. EXCEPT where otherwise specified!


Host Connection Protocol
------------------------
The initial connection of a host to the i-scream server is
through the FilterManager.  A Host gets its configuration
and then gets assigned a Filter to connect to and start
sending data.

The port number of the FilterManager is fully configurable,
however the default at this time is 4567.

Host         (direction) Server         Comment
------------------------------------------------------------
[STARTCONFIG]---------->                Requests to start
                                        receiving config
                                        information
            
             <---------- [OK|ERROR]     If the server ok's
                                        the request or not

[LASTMODIFIED]---------->               Asks when the config
                                        was last modified
                                        (used when checking
                                        if the config has
                                        changed)
            
             <---------- [{lastmodified}Returns a long int
                         |ERROR]        time since epoch
                                        eg, 123456789
                                        To indicate what
                                        format this is in,
                                        I quote from the
                                        Java 1.3 JDK API
                                        "measured in milli
                                        -seconds since the
                                        epoch"
                                        
[FILELIST]   ---------->                Asks the server for
                                        the list of files
                                        that were used to
                                        build the config
                                        (used when checking
                                        if the config has
                                        changed)
       
             <---------- [{filelist}    Returns a semi-colon
                         |ERROR]        separated list of
                                        filenames
                                        eg,
                                        a.conf;b.conf;c.conf

             ********** LOOP START **********
             This loop reads configuration
             properties from the config

[{property}] ---------->                Sends the name of a
                                        property to be
                                        retrieved from the
                                        config file
                                        eg, UDPUpdateTime
            
             <---------- [{value}|ERROR]Returns the value of
                                        the requested config
                                        property
                                        eg, 120
                                        If it is unable to
                                        find the requested
                                        property it returns
                                        ERROR to indicate
                                        that fact, but 
                                        communication still 
                                        proceeds
                                       
             ********** LOOP UNTIL **********
             The loop continues until the host
             sends the following message
            
[ENDCONFIG]  ---------->                Indicates that the
                                        host requires no
                                        more config
            
             ********** LOOP  END **********
             Communication continues
            
             <---------- [OK]           Indicates that the
                                        server is ready to
                                        proceed
                                       
[FILTER]     ---------->                Asks the server to
                                        send it the host
                                        information of a
                                        filter that it
                                        should connect to
                                       
             <---------- {filter}       Returns a semi-colon
                                        separated list of
                                        FQDN hostname, UDP
                                        port number and TCP
                                        port number that a
                                        configured Filter is
                                        running on and
                                        assigned to the
                                        calling host
                                        eg,
                                        raptor.ukc.ac.uk;
                                        1234;5678

[END]        ---------->                Indicates to the
                                        server that the host
                                        has finished an will
                                        disconnect
            
             <---------- [OK|ERROR]     Indicates that the
                                        server is either ok
                                        or that it thought
                                        there was an error
------------------------------------------------------------
       
Host Heartbeat Protocol
-----------------------
When a host is configured after it has connected it should
obtain a property TCPUpdateTime.  This indicates how often
a host should send a "Heart Beat", which is a pro-active
connection to the server by the host to indicate that it is
still alive.  This "Heart Beat" also allows a host to see
its configuration has changed and act accordingly.  In a
well written host this should just be a case of dropping out
of a loop and heading back to the start (connecting to the
filter manager).

Host            (direction) Server      Comment
------------------------------------------------------------
[HEARTBEAT]     ---------->             Starts the
                                        heartbeat protocol
                                        off
                                       
                <---------- [OK|ERROR]  Indicates that the
                                        server is ok or not

[CONFIG]        ---------->             Indicates that the
                                        host wants to check
                                        its config

                <---------- [OK|ERROR]  Indicates that the
                                        server is ok or not

[{filelist}]    ---------->             Send a semi-colon
                                        separated list of
                                        filenames
                                        eg,
                                        a.conf;b.conf;c.conf
                                        This should be
                                        identical to the one
                                        received in the
                                        connection protocol

                <---------- [OK]        Indicates that the
                                        server is ok

[{lastmodified}]---------->             Returns a long int
                                        time since epoch
                                        eg, 123456789
                                        This should be
                                        identical to the one
                                        received in the
                                        connection protocol
                                        To indicate what
                                        format this is in,
                                        I quote from the
                                        Java 1.3 JDK API
                                        "measured in milli
                                        -seconds since the
                                        epoch"

                <---------- [OK|ERROR]  The server then
                                        checks all the files
                                        in the file list to
                                        see if they have
                                        been modified more
                                        recently than the
                                        lastmodified value.
                                        If they HAVE that
                                        indicates that the
                                        configuration has
                                        changed and the host
                                        should re-configure,
                                        thus it sends ERROR.
                                        If the files remain
                                        unchanged the server
                                        will return OK to
                                        indicate the host
                                        should continue as
                                        before

[ENDHEARTBEAT]  ---------->             Indicates to the
                                        server that the host
                                        has finished an will
                                        disconnect
               
                <---------- [OK|ERROR]  Indicates that the
                                        server is either ok
                                        or that it thought
                                        there was an error
------------------------------------------------------------

Host Data Protocol
------------------
The UDP data packets that are sent by the host contain
simply XML data.  For information on the format of this
data see the XML via UDP specification document at:

http://www.i-scream.org.uk/cgi-bin/docs.cgi?doc=specification/xml_via_udp.txt

Client Control Protocol
-----------------------

The client control protocol channel is opened by the client
and allows a variety of actions to be carried out by the
client at anytime.  Unlike previous protocols, this is NOT
sequential, all of the requests can be carried out in 
any order.

All client protocols are backwards compatible, and the
version is shown by the protocol identifier.

There are three sections to this protocol.

1) Initialise (sent only at start)
2) Send command(s) - unlimited number in any order
3) Disconnect (sent only at end)

If at anytime the client sends something the server does
not understand, an [ERROR] will be sent

All are indicated with <> brackets.

v1.0 - Protocol identifier: "PROTOCOL 1.0" (without quotes)
       Supported commands:
            STARTCONFIG
            STARTDATA
            STOPDATA

Host         (direction) Server         Comment
------------------------------------------------------------
<initialise>
[CONNECT]    ---------->                Starts off the 
                                        client protocol
             
             <---------- [{protocol}]   The server sends the
                                        protocol identifier
                                        
[{name}]     ---------->                The client sends its
                                        "name".  This name
                                        is used to identify
                                        the type of client
                                        to the system and
                                        obtain its config
                                        eg, Conient
             
             <---------- [OK]           Indicates the server
                                        is ok to proceed
                        

<command #1> (allows client to obtain its configuration)
[STARTCONFIG]---------->                Tell the server we
                                        want to start this
                                        command
             
             <---------- [OK]           Indicates the server
                                        is ok to proceed
             
             ********** LOOP START **********
             This loop reads configuration
             properties from the config

[{property}] ---------->                Sends the name of a
                                        property to be
                                        retrieved from the
                                        config file
                                        Clients can obtain
                                        host information
                                        eg, 
                                        Host.UDPUpdateTime
                                        Otherwise it must
                                        prefix requests
                                        with "Client."
                                        All other requests
                                        will be ignored as
                                        if it was unable to
                                        retieve the property
                                        
             <---------- [{value}|ERROR]Returns the value of
                                        the requested config
                                        property
                                        eg, 120
                                        If it is unable to
                                        find the requested 
                                        property it returns
                                        ERROR to indicate
                                        that fact
                                        
             ********** LOOP UNTIL **********
             The loop continues until the client
             sends the following message
             
[ENDCONFIG]  ---------->                Indicates that the 
                                        client requires no
                                        more config
             
             ********** LOOP  END **********
             Communication continues
             
             <---------- [OK]           Indicates that the
                                        server is ready to
                                        proceed

<command #2> (tells the server to start the data link)
[STARTDATA]  ---------->                Tell the server we
                                        want to start this
                                        command
            
             <---------- [{portnumber}  The server then sets
                         |ERROR]        itself listening for
                                        a connection on its
                                        data link socket for
                                        this client.  It
                                        returns the port no.
                                        that it is listening
                                        on eg, 12367
                                        If the data link is
                                        yet to be started
                                        the server will
                                        return ERROR
             
             <---------- [OK]           Indicates the server
                                        is ok to proceed and
                                        the client can 
                                        then connect its
                                        data link

<command #3> (tells the server to stop the data link)
[STOPDATA]   ---------->                Tell the server we
                                        want to start this
                                        command
                                        The server then
                                        shuts down the 
                                        data link to the
                                        client

             <---------- [OK|ERROR]     Returns OK is the
                                        server is ready to
                                        proceed, or ERROR
                                        if the data link
                                        was not open in the
                                        first place

<disconnect>
[DISCONNECT] ---------->                Tells the server the
                                        client wants to
                                        close the control
                                        link
                                        
             <---------- [OK]           The last word from
                                        the server, it will
                                        disappear after this
------------------------------------------------------------

v1.1 - Protocol identifier: "PROTOCOL 1.1" (without quotes)
       Supported commands:
            SETHOSTLIST

Host         (direction) Server         Comment
------------------------------------------------------------
<command #4> (indicates to the server which hosts the client
              wants data from)
[SETHOSTLIST]---------->                Tell the server we
                                        want to start this
                                        command
             
             <---------- [OK|ERROR]     The server will
                                        return an ERROR if
                                        the data link is
                                        open, as a host list
                                        must ONLY be set 
                                        if the data link is
                                        closed
                                        If the server is
                                        ok to proceed with
                                        the command it says
                                        [OK]

[{hostlist}] ---------->                This is a semi-colon
                                        seperated list of
                                        FQDN hostnames that
                                        the client wishes to
                                        recieve data from
                                        eg,
        raptor.ukc.ac.uk;killigrew.ukc.ac.uk;chalk.ukc.ac.uk
                                        
                                        If the list is sent
                                        blank (or if no list
                                        is set at all) then
                                        data from ALL hosts
                                        will be sent to the
                                        client
                                        
             <---------- [OK]           Indicates the server
                                        is ok to proceed and
                                        the host list has 
                                        been accepted
------------------------------------------------------------

Client Data Protocol
--------------------
Once the data link has been opened by the control link, the
server will send XML formated data packets seperated by the 
\n (newline) character.  For information on the format of 
this data see the XML via UDP specification document at:

http://www.i-scream.org.uk/cgi-bin/docs.cgi?doc=specification/xml_via_udp.txt

About
-----
This document was written by AJ Moore [ajm4@ukc.ac.uk] for
use by the team working on a 3rd year Computer Science
project called "i-scream". More details can be found on the
project website;

http://www.i-scream.org.uk
Revision:	1.5
Committed:	Sun Jan 28 20:29:32 2001 UTC (23 years, 10 months ago) by ajm
Content type:	text/plain
Branch:	MAIN
Changes since 1.4:	+15 -5 lines
Log Message:	added definition of the format of time since epoch...
#	User	Rev	Content
1	ajm	1.1	i-scream Protocols
2			==================
3
4			Contents
5			--------
6			- Conventions
7
8			- Host Connection Protocol
9			- Host Heartbeat Protocol
10			- Host Data Protocol
11
12			- Client Control Protocol
13			- Client Data Protocol
14
15	tdb	1.2
16	ajm	1.1	Conventions
17			-----------
18			All protocols in this document assume a valid connection of
19			the appropriate type has been made, and that data streams
20	tdb	1.2	are already available. All strings should, and will be,
21	ajm	1.1	terminated with a \n (newline character) to indicate the end
22			of the message. All messages are sent as ASCII Strings.
23
24			Fixed protocol messages will appear in [] brackets, if there
25	tdb	1.2	is a variety of options they will be separated with the \|
26	ajm	1.1	character. For example:
27
28			[OK\|ERROR]
29	tdb	1.2
30	ajm	1.1	Indicates that the message "OK" OR the message "ERROR" will
31			be sent depending on the result of the last action.
32
33			Data messages will appear in {} brackets, where the name in
34			the brackets indicates the type (as in kind, not data type)
35			of data that will be returned. For example:
36
37			{lastmodified}
38
39	tdb	1.2	Indicates that data for use as 'last modified' will be
40			returned.
41
42			If [ERROR] is sent back at any time, this indicates that all
43			communication is over. EXCEPT where otherwise specified!
44	ajm	1.1
45
46			Host Connection Protocol
47			------------------------
48			The initial connection of a host to the i-scream server is
49			through the FilterManager. A Host gets its configuration
50	tdb	1.2	and then gets assigned a Filter to connect to and start
51	ajm	1.1	sending data.
52
53	tdb	1.2	The port number of the FilterManager is fully configurable,
54	ajm	1.1	however the default at this time is 4567.
55
56			Host (direction) Server Comment
57			------------------------------------------------------------
58			[STARTCONFIG]----------> Requests to start
59			receiving config
60			information
61	tdb	1.2
62	ajm	1.1	<---------- [OK\|ERROR] If the server ok's
63			the request or not
64
65			[LASTMODIFIED]----------> Asks when the config
66			was last modified
67			(used when checking
68	tdb	1.2	if the config has
69	ajm	1.1	changed)
70	tdb	1.2
71	ajm	1.1	<---------- [{lastmodified}Returns a long int
72	tdb	1.2	\|ERROR] time since epoch
73	ajm	1.1	eg, 123456789
74	ajm	1.5	To indicate what
75			format this is in,
76			I quote from the
77			Java 1.3 JDK API
78			"measured in milli
79			-seconds since the
80			epoch"
81
82	ajm	1.1	[FILELIST] ----------> Asks the server for
83			the list of files
84			that were used to
85			build the config
86			(used when checking
87			if the config has
88			changed)
89	tdb	1.2
90	ajm	1.1	<---------- [{filelist} Returns a semi-colon
91	tdb	1.2	\|ERROR] separated list of
92	ajm	1.1	filenames
93			eg,
94			a.conf;b.conf;c.conf
95
96			******** LOOP START ********
97			This loop reads configuration
98			properties from the config
99
100			[{property}] ----------> Sends the name of a
101			property to be
102			retrieved from the
103			config file
104			eg, UDPUpdateTime
105	tdb	1.2
106	ajm	1.1	<---------- [{value}\|ERROR]Returns the value of
107			the requested config
108			property
109			eg, 120
110			If it is unable to
111	tdb	1.2	find the requested
112	ajm	1.1	property it returns
113			ERROR to indicate
114	tdb	1.2	that fact, but
115			communication still
116			proceeds
117
118	ajm	1.1	******** LOOP UNTIL ********
119			The loop continues until the host
120			sends the following message
121	tdb	1.2
122			[ENDCONFIG] ----------> Indicates that the
123	ajm	1.1	host requires no
124			more config
125	tdb	1.2
126	ajm	1.1	******** LOOP END ********
127			Communication continues
128	tdb	1.2
129	ajm	1.1	<---------- [OK] Indicates that the
130			server is ready to
131			proceed
132	tdb	1.2
133	ajm	1.1	[FILTER] ----------> Asks the server to
134			send it the host
135	tdb	1.2	information of a
136	ajm	1.1	filter that it
137			should connect to
138	tdb	1.2
139	ajm	1.1	<---------- {filter} Returns a semi-colon
140	tdb	1.2	separated list of
141	ajm	1.1	FQDN hostname, UDP
142			port number and TCP
143	tdb	1.2	port number that a
144	ajm	1.1	configured Filter is
145			running on and
146	tdb	1.2	assigned to the
147	ajm	1.1	calling host
148			eg,
149			raptor.ukc.ac.uk;
150			1234;5678
151
152			[END] ----------> Indicates to the
153			server that the host
154			has finished an will
155			disconnect
156	tdb	1.2
157	ajm	1.1	<---------- [OK\|ERROR] Indicates that the
158			server is either ok
159			or that it thought
160			there was an error
161	ajm	1.3	------------------------------------------------------------
162	tdb	1.2
163	ajm	1.1	Host Heartbeat Protocol
164			-----------------------
165			When a host is configured after it has connected it should
166			obtain a property TCPUpdateTime. This indicates how often
167	tdb	1.2	a host should send a "Heart Beat", which is a pro-active
168	ajm	1.1	connection to the server by the host to indicate that it is
169			still alive. This "Heart Beat" also allows a host to see
170	tdb	1.2	its configuration has changed and act accordingly. In a
171	ajm	1.1	well written host this should just be a case of dropping out
172			of a loop and heading back to the start (connecting to the
173			filter manager).
174
175			Host (direction) Server Comment
176			------------------------------------------------------------
177			[HEARTBEAT] ----------> Starts the
178			heartbeat protocol
179			off
180	tdb	1.2
181	ajm	1.1	<---------- [OK\|ERROR] Indicates that the
182			server is ok or not
183
184			[CONFIG] ----------> Indicates that the
185			host wants to check
186			its config
187
188			<---------- [OK\|ERROR] Indicates that the
189			server is ok or not
190
191			[{filelist}] ----------> Send a semi-colon
192	tdb	1.2	separated list of
193	ajm	1.1	filenames
194			eg,
195			a.conf;b.conf;c.conf
196			This should be
197			identical to the one
198	tdb	1.2	received in the
199	ajm	1.1	connection protocol
200
201			<---------- [OK] Indicates that the
202			server is ok
203
204			[{lastmodified}]----------> Returns a long int
205	tdb	1.2	time since epoch
206	ajm	1.1	eg, 123456789
207			This should be
208			identical to the one
209	tdb	1.2	received in the
210	ajm	1.1	connection protocol
211	ajm	1.5	To indicate what
212			format this is in,
213			I quote from the
214			Java 1.3 JDK API
215			"measured in milli
216			-seconds since the
217			epoch"
218	ajm	1.1
219			<---------- [OK\|ERROR] The server then
220			checks all the files
221			in the file list to
222			see if they have
223			been modified more
224			recently than the
225	tdb	1.2	lastmodified value.
226			If they HAVE that
227	ajm	1.1	indicates that the
228			configuration has
229			changed and the host
230			should re-configure,
231			thus it sends ERROR.
232			If the files remain
233			unchanged the server
234			will return OK to
235			indicate the host
236			should continue as
237			before
238
239			[ENDHEARTBEAT] ----------> Indicates to the
240			server that the host
241			has finished an will
242			disconnect
243	tdb	1.2
244	ajm	1.1	<---------- [OK\|ERROR] Indicates that the
245			server is either ok
246			or that it thought
247			there was an error
248	ajm	1.3	------------------------------------------------------------
249	ajm	1.1
250			Host Data Protocol
251			------------------
252			The UDP data packets that are sent by the host contain
253			simply XML data. For information on the format of this
254			data see the XML via UDP specification document at:
255
256	ajm	1.4	http://www.i-scream.org.uk/cgi-bin/docs.cgi?doc=specification/xml_via_udp.txt
257	ajm	1.1
258			Client Control Protocol
259			-----------------------
260
261	ajm	1.3	The client control protocol channel is opened by the client
262			and allows a variety of actions to be carried out by the
263			client at anytime. Unlike previous protocols, this is NOT
264			sequential, all of the requests can be carried out in
265			any order.
266
267			All client protocols are backwards compatible, and the
268			version is shown by the protocol identifier.
269
270			There are three sections to this protocol.
271
272			1) Initialise (sent only at start)
273			2) Send command(s) - unlimited number in any order
274			3) Disconnect (sent only at end)
275
276			If at anytime the client sends something the server does
277			not understand, an [ERROR] will be sent
278
279			All are indicated with <> brackets.
280
281			v1.0 - Protocol identifier: "PROTOCOL 1.0" (without quotes)
282			Supported commands:
283			STARTCONFIG
284			STARTDATA
285			STOPDATA
286
287			Host (direction) Server Comment
288			------------------------------------------------------------
289			<initialise>
290			[CONNECT] ----------> Starts off the
291			client protocol
292
293			<---------- [{protocol}] The server sends the
294			protocol identifier
295
296			[{name}] ----------> The client sends its
297			"name". This name
298			is used to identify
299			the type of client
300			to the system and
301			obtain its config
302			eg, Conient
303
304			<---------- [OK] Indicates the server
305			is ok to proceed
306
307
308			<command #1> (allows client to obtain its configuration)
309			[STARTCONFIG]----------> Tell the server we
310			want to start this
311			command
312
313			<---------- [OK] Indicates the server
314			is ok to proceed
315
316			******** LOOP START ********
317			This loop reads configuration
318			properties from the config
319
320			[{property}] ----------> Sends the name of a
321			property to be
322			retrieved from the
323			config file
324			Clients can obtain
325			host information
326			eg,
327			Host.UDPUpdateTime
328			Otherwise it must
329			prefix requests
330			with "Client."
331			All other requests
332			will be ignored as
333			if it was unable to
334			retieve the property
335
336			<---------- [{value}\|ERROR]Returns the value of
337			the requested config
338			property
339			eg, 120
340			If it is unable to
341			find the requested
342			property it returns
343			ERROR to indicate
344			that fact
345
346			******** LOOP UNTIL ********
347			The loop continues until the client
348			sends the following message
349
350			[ENDCONFIG] ----------> Indicates that the
351			client requires no
352			more config
353
354			******** LOOP END ********
355			Communication continues
356
357			<---------- [OK] Indicates that the
358			server is ready to
359			proceed
360
361			<command #2> (tells the server to start the data link)
362			[STARTDATA] ----------> Tell the server we
363			want to start this
364			command
365
366			<---------- [{portnumber} The server then sets
367			\|ERROR] itself listening for
368			a connection on its
369			data link socket for
370			this client. It
371			returns the port no.
372			that it is listening
373			on eg, 12367
374			If the data link is
375			yet to be started
376			the server will
377			return ERROR
378
379			<---------- [OK] Indicates the server
380			is ok to proceed and
381			the client can
382			then connect its
383			data link
384
385			<command #3> (tells the server to stop the data link)
386			[STOPDATA] ----------> Tell the server we
387			want to start this
388			command
389			The server then
390			shuts down the
391			data link to the
392			client
393
394			<---------- [OK\|ERROR] Returns OK is the
395			server is ready to
396			proceed, or ERROR
397			if the data link
398			was not open in the
399			first place
400
401			<disconnect>
402			[DISCONNECT] ----------> Tells the server the
403			client wants to
404			close the control
405			link
406
407			<---------- [OK] The last word from
408			the server, it will
409			disappear after this
410			------------------------------------------------------------
411
412			v1.1 - Protocol identifier: "PROTOCOL 1.1" (without quotes)
413			Supported commands:
414			SETHOSTLIST
415
416			Host (direction) Server Comment
417			------------------------------------------------------------
418			<command #4> (indicates to the server which hosts the client
419			wants data from)
420			[SETHOSTLIST]----------> Tell the server we
421			want to start this
422			command
423
424			<---------- [OK\|ERROR] The server will
425			return an ERROR if
426			the data link is
427			open, as a host list
428			must ONLY be set
429			if the data link is
430			closed
431			If the server is
432			ok to proceed with
433			the command it says
434			[OK]
435
436			[{hostlist}] ----------> This is a semi-colon
437			seperated list of
438			FQDN hostnames that
439			the client wishes to
440			recieve data from
441			eg,
442			raptor.ukc.ac.uk;killigrew.ukc.ac.uk;chalk.ukc.ac.uk
443
444			If the list is sent
445			blank (or if no list
446			is set at all) then
447			data from ALL hosts
448			will be sent to the
449			client
450
451			<---------- [OK] Indicates the server
452			is ok to proceed and
453			the host list has
454			been accepted
455			------------------------------------------------------------
456	ajm	1.1
457			Client Data Protocol
458			--------------------
459	ajm	1.3	Once the data link has been opened by the control link, the
460			server will send XML formated data packets seperated by the
461			\n (newline) character. For information on the format of
462			this data see the XML via UDP specification document at:
463	ajm	1.1
464	ajm	1.4	http://www.i-scream.org.uk/cgi-bin/docs.cgi?doc=specification/xml_via_udp.txt
465	ajm	1.1
466			About
467			-----
468			This document was written by AJ Moore [ajm4@ukc.ac.uk] for
469			use by the team working on a 3rd year Computer Science
470			project called "i-scream". More details can be found on the
471			project website;
472
473			http://www.i-scream.org.uk