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Description  |
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TECHNICAL FIELD
This invention relates to electronic document distribution systems or
networks and is particularly directed to means for providing document
interchange protocols for handling the interchange of documents between
communicating processors in the network which vary in number and
particularly in data processing capability.
BACKGROUND ART
At the present time, one of the most rapidly expanding technologies in data
processing is that of electronic document distribution to produce an
automated office environment. This technology utilizes communication
networks in an office-information-interchange system or electronic mail.
Such a network is a complex interconnection of processing terminals or
work stations of varying capabilities performing an assortment of data
processing and text processing operations with respect to document
production and distribution. A major problem that such networks present is
the variety of interfaces and data forms which must be accommodated to
functionally interconnect the various participating work stations and
processors into an operational information-interchange system. In a
conventional document distribution, not only must the various processing
terminals be functionally interconnected but the system must provide the
basic capability to enter and edit information, distribute information and
print or display information. Irrespective of the network configuration,
the system must be easy to use if it is to be effective. Also, the
complexities of the various interface and data forms must be transparent
to the users. In other words, the system must handle and distribute the
documents with a minimum of operator intervention. To expect the sender of
information to know very much about processor and data form requirements
is unrealistic. The sender should be able to request that information be
distributed. He should not have to be concerned about the expedients used
in such a distribution.
To this end, the art has been developing uniform data streams which are
discernible by the various processor-work stations participating in the
document distribution network. Architectures have been defined which
specify data stream content as well as the rules involved in the
communication in the network. These data stream architectures specify the
form of the information by describing the syntax and meaning of allowable
elements in the data stream. Reference is made to the article entitled
"Electronic Information Interchange in an Office Environment" by M. R.
DeSousa, IBM Systems Journal, Vol. 20, No. 1, 1981, at page 4. This
article describes a typical document distribution or interchange
architecture which permits information to be carried from a sender to a
recipient in such a network without requiring that both be interactively
communicating during the distribution process. Further, it permits a
sender to send information such as a document to multiple recipients with
a single distribution request. Finally, the distribution architecture
provides for services such as security base storage during distribution
and confirmation of delivery.
In data distribution networks, a uniform data stream may be considered to
comprise two major components: the above described document interchange
architecture which relates to communication and processing of the document
and the document content architecture which is representative of the
content and format of a particular document.
The document interchange architecture involved in the distribution and
processing of documents in distribution networks is described in even
greater detail in the article entitled "The Document Interchange
Architecture: Member of a Family of Architectures in the SNA Environment",
by T. Schick et al, IBM Systems Journal, Vol. 21, No. 2, 1982, at page
220. Because of the wide variety of data processing equipment available in
the current office environment together with the need to make document
distribution network readily compatible with equipment which may be made
available in the future, document distribution networks must have the
capability of integrating into the system communicating processors of
varying levels of data processing capabilities. Existing document
distribution systems such as those described in the above mentioned
articles provide for a uniform data stream whereby data processing
stations or work stations with varying data processing capability may
communicate with each other by following the protocol of the document
interchange architecture. In my co-pending application entitled "An
Electronic Document Distribution Network with Uniform Data Stream", Ser.
No. 06/440,484 filed on the same day as the present application, now U.S.
Pat. No. 4,532,588, I provided for a document interchange architecture and
network for communications between and processing of data by terminals of
varying data processing capabilities. The communication is handled through
a uniform data stream which remained unaffected by the data processing
capabilities of any of the communicating data processors involved in the
processing.
The system of this co-pending application is of course based on the premise
that a given pair of communicating processors want to communicate with
each other in document exchange and processing, i.e., that the processor
having the greater data processing capabilities wants to communicate with
the processor having the lesser capabilities. In a document distribution
network, this may often not be the case. For example, let us assume that a
communicating processor work station in Dallas, Tex. wishes to communicate
with another communicating processor in Macon, Ga. In order for the work
station in Macon to be able to completely handle the document
communication and processing requirements with respect to the document
which the Dallas processor wishes to communicate, the work station in
Macon must have distribution, application processing and document library
services capability. However, in extensive document distribution networks,
communicating processor work stations are being continuously and
dynamically added to the system, removed from the system as well as having
their respective processing capabilities continually changed, either
upgraded or downgraded. For instance, on a given day the communicating
data processor work stations at a given location may have only document
library services capability but two or three days later capabilities of
the particular work station are enhanced so that it now includes
distribution services capabilites. In another instance, a given
communicating processor work station may provide library services only
during certain time periods because these library services may be
available to the processor on only a time shared basis. As a result, in
such a dynamically variable document distribution system or network, the
most that a given communicating processor work station is likely to know
or have available with respect to the capabilities of any other work
station is that communicating processor work station exist at a given
location.
Thus, there appears to be a need in document interchange networks having
data processing work stations or terminal with dynamically variable
capability for expedients whereby any linked processors may determine
their respective variable processing capabilities and determine whether
the document interchange between these two terminals is feasible based
upon these variable capabilities; the present invention is directed to
this need.
DISCLOSURE OF THE INVENTION
The present invention is directed to a document distribution system having
a network of communicating data processing stations which vary in number
and particularly vary dynamically in their respective processing
capabilities. The present invention provides improved means for
determining document interchange protocols between any two processors in
the network. The invention comprises means whereby any processor may
establish a communication linkage with any other processor in the network
and means whereby one of said two linked processors may present its data
processing capabilities to the other over said linkage. Means are then
provided wherein these presented data processing capabilities may be
compared between the two linked processors. Means are provided for then
determining document interchange protocols based upon capabilities common
to both of the processors and for generating dynamically variable
protocols based upon these common capabilites.
More particularly, the present invention is directed to document
distribution systems wherein communicating processor work stations each
have means for receiving and transmitting a data stream including a
document interchange architecture predefining fixed protocols common to
all of the communicating processors. The network further includes means
for defining variable protocols to be used in combination with said fixed
protocols. These variable protocols are determined and generated based
upon common data processing capabilities between any pair of linked
communicating processor work stations resulting from the above described
comparison.
BRIEF DESCRIPTION OF DRAWINGS
Referring now to the drawings, wherein a preferred embodiment of the
invention is illustrated, and wherein like reference numerals are used
throughout to designate like parts;
FIG. 1 is a logical block diagram showing the apparatus which may be used
in the practice of the present invention.
FIG. 2 is a very genealized flow chart showing the general steps involved
in a document distribution network to establish a linkage between selected
pair of communicating processors.
FIG. 3 is a flow chart of the operation utilizing the apparatus of FIG. 1
whereby a pair of linked communicating processors exchange the data stream
which is to be compared in order to establish whether there are any
varialbe data processing capabilities common to the pair of linked
processors.
FIG. 4 is a flow chart of the operations involved utilizing the apparatus
of FIG. 1 wherein one of a pair of linked processors which has received
the data stream indicative of the variable data processing capabilites of
the other processor conducts a comparison in order to determine whether
any of these varialbe capabilities are also common to the receiving
processor.
FIG. 5 is a diagrammatic representation of a data stream with its units and
subunits broken down to the level dealt with in the present invention.
BEST MODE FOR CARRYING OUT THE INVENTION
With reference to the generalized apparatus of FIG. 1, the system of the
present invention will now be described. Communicating processor 12 is
respectively linked to communicating processor 10 and communicating
processor 14 via linkages 11 and 13. For purposes of the present
illustration, logic equivalent to that shown in detail in communicating
processor 12 to be hereinafter described will also be considered to be
present in both communicating processors 10 and 14. Also, linkages 11 and
13 will be considered to represent potential linkages in a document
distribution network with the understanding that in order for any pair of
communicating processors in a network to communicate with each other, the
linkages between a pair of processors must be activated through
conventional systems network architecture and data link control protocols
to be hereinafter described. Processors 10, 12 and 14 and communication
linkages 13 and 11 are part of a document distribution network of the type
described in the above mentioned M. R. DeSousa and T. Schick et al
publications and particularly in the Schick et al publication.
For purposes of the present embodiment, the illustrative communications
network being here described will be considered to be a system in the
Systems Network Architecture (SNA) environment described in the Schick et
al publication. The present description will concern itself primarily with
the functioning of communicating processor 12 in any communications
sessions or linkages. These will be described with respect to
communication from processor 12 over linkage 11 to processor 10. For
purposes of this illustration, let us assume that communicating processor
12 is in Austin, Tex. and that communication linkage is to be established
with communicating processor 10 which is in Macon, Ga. In the description
which follows, we will discuss systems network architecture required to
support the proposed linkage between Austin and Macon as well as the data
link control which must be established for this linkage. We will then
consider the specifics of the data streams being communicated between
processors 12 and 10 over linkage 11. Since the comparison involved in the
present invention as well as the generation of exchange protocols relates
to document distribution or document interchange architecture (DIA), it
will be considered with respect to that portion of the data stream. The
arrangement of a typical data stream illustrated by the data streams
described in the above mentioned Schick et al article will be subsequently
discussed in greater detail with respect to FIG. 5 of the Drawings which
is based upon a figure appearing at page 225 of the Schick et al article.
In any event at the start, let us assume that a data stream like that shown
in FIG. 5 is transmitted over linkage 11 from communicating processor 10
and received by communications adapter 15 in processor 12. Communications
adapter may be any standard device having the capability of converting
received serial data communicated over linkage 11 to parallel form so that
it may be handled in processor 12. The establishment of the linkage will
be now described with respect to the apparatus of FIG. 1 using the flow
chart of operations shown in FIG. 2. The operation is initiated by the
operator at communicating processor 10. First, step 40, a data link
control session must be established. The data stream received through
communications adapter 15 (FIG. 1) is stored in a receive buffer 16 while
the synchronized data link control (SDLC) unit 17 determines that the data
link control elements in the received data stream as shown in FIG. 5 at
the SDLC level of the data stream are proper. If they are proper, then a
determination is made as to whether the data stream meets systems network
architecture requirements. This is done by the SNA unit 18 which
determines whether the transmission header of the basic transmission unit
(at the SNA level of FIG. 4) is correct. The activities of the SDLC unit
17 and the SNA unit 18 with respect to the received information in buffer
16 is synchronized through the communications control unit 19 through the
buffer control program unit 20 which controls the buffer 16.
In establishing SNA session the apparatus typically performs in the
following manner. First, (FIG. 2) decision step 41, a determination is
made as to whether it has been predetermined that Austin is to be the
primary communicating processor in the exchange with processor 10 in
Macon, Ga. If Austin is the primary processor, then, step 42, a bind
request is sent from communicating processor 12 to communicating processor
10 in Macon. In accordance with conventional systems network architecture
protocols, this bond request includes ID or logical name of communicating
processor 12 in the overall document interchange network, the type of
communication session proposed, as well as a variety of conventional
systems network architecture management details. In response,
communicating processor 12 receives from communicating processor 10 its
bind response, step 43. Conversely, if communicating processor 12 is not
the prime communicating processor but rather processor 10 is, then, step
44, processor 12 will receive the bind request from processor 10 and, step
45, then send its bind response to processor 10. In these operations,
communicating processor 10 will be assumed to have the same logical
apparatus shown in FIG. 1 with respect to processor 12 and that processor
10 will operate in substantially identical fashion.
Then, if the received and sent bind request are appropriate and acceptable,
step 46, the systems network architecture communication session between
processors 10 and 12 is commenced or activated. System network
architecture (SNA) protocols divide a session into two states a Contention
state wherein the communicating processor is awaiting information and a
Conversation state wherein actual transmission of information or data in
the form of a data stream is taking place. In commencing the SNA session,
the communication control unit 19 (FIG. 1) transfers that portion of the
data stream stored in receive buffer 16 into document distribution storage
buffer 21 and relinquishes control of the session to DIA supervisor unit
35. Now under the control of the DIA supervisor unit, the operation of the
present invention to be described with respect to the flow chart in FIG. 1
will be carried out. First, the DIA supervisor unit makes a determination
as to whether the basic document interchange unit (DIU) as shown in FIG. 5
is present in the data stream. If this basic DIU unit is not present, an
error condition will be indicated. If the DIU unit is present then the
command sequence portion of the data stream (FIG. 5) which is stored in
the document distribution buffer 21 is examined under the control of the
DIU supervisor unit 35 in FIG. 1.
The operations with respect to scanning of the command sequence in order to
determine whether there are any data processing capabilities common to
both communicating processors 10 and 12 will now be considered with
respect to the operational flow chart show in FIG. 3. For convenience in
explanation let us assume that communicating processor 12 has received the
data stream from communicating processor 10. First, decision step 47, a
determination is made by DIA supervisor 35 to whether the command sequence
stored in buffer 21 contains a Conversation request, i.e., communicating
processor 10 has requested a Conversation state indicating that it has
data to convey. If this Conversation request has been received, then step
48, the DIA session controller 30 (FIG. 1) will receive the sign-on
request commands in the command sequence of the data stream stored in
buffer 21. Then, under the control of DIA session controller 30, the
operation will go to the "Determine" process as set forth in the flow
chart of FIG. 4. First, step 49, the identifier in the receive command
sequence will be validated, after which the authorization in the command
sequence will be validated, step 50.
Next, step 51, the functional set of parameters which are indicative of the
functions which communicating processor 10 would like to have performed by
receiving processor 12 on the document being interchanged are extracted
and examined under the control of DIA session controller 30. For example,
let us assume that communicating processor 10 wishes to forward a document
to communicating processor 12, and communicating processor 10 further
wishes processing to be performed on this communicated document which
requires three functional capabilities in processor 12: (1) distribution
service capability, (2) application processing service capability and (3)
library service capability (the ability to store and retrieve information
related to the document from archival storage). A set of functional
parameters will be considered in the following operations still under the
control of the DIA session controller. First, decision step 52, a
determination is made as to whether the previous parameter processed was
the last parameter in the set of three. If it was not, then, step 53,
comparison is made as to whether processor 12 is capable of performing
this extracted functional parameter. If there is a match with a function
processor 12, decision step 54, the matched parameter is saved for sign-on
response which is to be made back to processor 10, step 55, and the
operation is returned to step 52. If there is no match, the operation is
directly returned to step 52.
Considering now how this comparison for matching parameters is made, the
operation is still carried out under the supervision and control of DIA
session controller 30 in processor 12. In making the comparison in step 53
with parameters which processor 12 is capable of performing these
functions may be stored at any convenient point within the memory of
processor 12. The storage may be in some sort of tabular or list form, and
when a comparison is made with respect to a particular requested function
the stored list is accessed. For purposes of the present description we
have not gone into details concerning the memory of processor 12. For this
embodiment let us consider processors 10 and 12 to be communicating
display processor of the type detailed in co-pending application of D. G.
Busch entitled "Data Communications System with Receiving Terminal for
Varying the Portions of the Received Data Being Displayed", Ser. No.
274,050 assigned to the assignee of the present invention and filed on
June 16, 1981 in the U.S. Patent Office, now U.S. Pat. No. 4,577,288.
While this co-pending application uses an asynchronous protocol for
communication and the present invention uses synchronous protocol, the
general operation of the terminal with respect to display and printing
operations will be substantially the same. It should be noted that since
communicating processor 12 is a display terminal processor, if the display
is to be utilized it may be accessed through session summary logic 26 and
display access method 27.
In any event, a list of functional parameters which processor 12 is capable
of performing may be stored in the memory of a display processor like that
of the D. G. Busch co-pending application. Likewise, any matched
functional parameters saved for the sign-on response in accordance with
step 55 may also be stored in the display processor memory.
When a determination is made in decision step 52 that last parameter in the
requested functional set has been compared, then a determination is made
in decision step 56 as to whether there have been any functional
parameters saved as a result of there having been a match in step 54. If
there has not been any, then step 57 the session request is rejected,
i.e., the processor 12 advises processor 10 that it cannot perform any of
the requested document function and thus rejects the session. On the other
hand, if a determination is made in decision step 56 that there have been
some saved parameters resulting from a match, then, the sign-on respond
from processor 12 back to processor 10 indicating that processor 12 can
perform some of the requested document handling functions is formatted and
the process is returned to point 59 in the flow chart of FIG. 3. Following
through with our example, let us assume that of the three requested
functions set forth above as having been communicated from processor 10 to
processor 12, processor 12 has the capability of performing (1) the
distribution function and (2) the application processing function.
However, processor 12 has no capability at the point in time that the
present communication is made for (3) library services or archival access
purposes. The situation may be the result of processor 12 not having any
present library services capability, or processor 12 may time-share such a
library sevices capability on a host processor, and at the time the
request is made processor 12 does not have any time available on the
library services program.
Thus, step 60 (FIG. 3), processor 12 sends a sign-on response back to
processor 10 indicating that of the three requested functions, processor
12 has the capability to only perform (1) distribution and (2) application
processing services.
Then, step 61, processor 12 goes on to establish a document interchange
session. Actually, processor 12 establishes its half of the DIA session,
i.e., a DIA-half session. Processor 12 sets up its half of document
interchange protocol so that if the sign-on response sent to processor 10
is acceptable, i.e., processor 10 will accept the performance by processor
12 for only the (1) distribution and (2) application processing functions,
processor 10 may then go on to establish its half of the DIA session thus
completing the establishment of the DIA session. Then, processor 10 may
commence the transmission of the document or documents to be transmitted
to processor 12.
Returning now to decision step 47 in flow chart of FIG. 3, if the
determination as previously made by the DIA supervisor 35 as to whether
the command sequence in the data stream received from processor 10 and
stored in buffer 21 of processor 12 contains a Conversation request is
negative, then a determination is made, decision step 62 as to whether
command sequence in the stored data stream contains a Contention request.
This represents an indication from processor 10 that processor 10 has no
data to transmit but is awaiting data if processor 12 has any documents to
transmit to processor 10. If there is no Contention request from processor
10, then, step 63, processor 10 requests its command queue status. The
operator on processor 12 has the capability of keying into processor 12
commands related to documents which processor 12 wishes to transmit to
processor 10 when a DIA session is established. These are stored in a
command queue 28 in processor 12. This command queue is under the control
of a command queue manager 29. In carrying out step 63, the DIA supervisor
35 has command queue manager 29 determine the status of command queue 28.
If, decision step 64, a determination is there made that the command queue
is empty, then, step 65, we have a situation wherein a systems network
architecture communication linkage has been established between processors
10 and 12 but neither has any documents to communicate. Accordingly, in
step 65, processor 12 establishes an SNA Contention state with processor
10 and proceeds to wait for any subsequent document communication between
these two processors which may be forthcoming.
On the other hand, if in decision step 64, a determination is made that
queue 28 is not empty, i.e., the operator of processor 12 has keyed in
documents and associated commands to be sent to processor 10, then, step
66, an SNA Conversation state is establshed with processor 10. Next, step
67, processor 12 determines what functions are to be performed on the
documents keyed into queue 28. These function requests may be keyed in by
the operator when the documents and commands are keyed in through command
queue 28 or they may be stored somewhere in processor 12 as predetermined
standard functions which processor 12 needs to have performed with respect
to particular documents. In any event, this determination is made by DIA
supervisor 35 (FIG. 1). After this determination, processor 12 then
proceeds to send a sign-on request, step 68, to processor 10. This sign-on
request is formulated in document distribution data storage buffer 21
under the control of DIA session controller 30 and transmitted from
processor 12 through send buffer 31 and communications adapter 15. This
sign-on request will be indicative of the documents and comands which are
in the command queue as well as the required functional set of parameters
which processor 12 requests processor 10 to perform.
This sign-on request sent from processor 12 will be received in processor
10 and treated as a received sign-on request in the manner previously
described in step 48. Processor 10 will then proceed with the "Determine"
process described in the flow chart of FIG. 4 wherein the functional
parameters which processor 10 is capable of performing are compared to the
functional set of parameters requested by processor 12 in the
communication. If processor 10 can perform none of the requested
functional parameters, it will issue a reject session request message 57
back to processor 12. On the other hand, it can perform some of the
parameters as determined by decision step 56 it will format a sign-on
response 58 which will be transmitted back to processor 12. This sign-on
response will be received, step 69, FIG. 3 by processor 12 where it will
be stored in document distribution data buffer 21 under the control of DIA
session controller 30.
Then, a determination will be made, decision step 70, as to whether the
matched functions, i.e., the combination of requested functions which
processor 10 can perform is acceptable to processor 12. This determination
will be made based upon either what the operator has keyed in to command
queue 28 or predetermined decision data previously stored in processor 12.
If the matched functions are not acceptable, then, step 71, processor 12
will communicate back to processor 10 that the communication session is
rejected. On the other hand, if the combination of functions which
processor 10 can perform is acceptable, then, step 72, processor 12 will
proceed to establish its half of the DIA session which thus provides for a
complete DIA session between processors 12 and 10.
At this point, we will return to decision step 62 in the flow chart of FIG.
3. An SNA session has alredy been established between communicating
processors 10 and 12. However, processor 12 has not received a
Conversation request from processor 10. If then, decision step 62, it is
determined that a Contention request has been received from processor 10
which indicates that processor 10 wishes to receive anything which is or
may become available from processor 12, the status of the keyed command
queue is requested, step 63', carried out in the same manner as previously
described step 63. If then, a determination is made, step 64', that there
is something in the queue, the process branches to step 66, and steps 66
through 72 are carried out in the manner described hereinabove. On the
other hand, if in step 64', the queue is empty, then a determination is
made, decision step 74, as to whether an automatic DIA session should be
established. For many applications, it may be customary to preset the
conditions within a communicating processor like processor 12 so that
whenever a Contention request is received from another processor to
automatically proceed to establish a document interchange session with
that processor even if the command queue is empty. If this is the present
status of processor 12, then, the positive decision from step 73 will
branch the process again to step 66 and the process will proceed through
steps 66 through 72 to attempt to establish a DIA session. On the other
hand, if the resulting decision is negative, then, the process will
proceed to step 74 to establish a Contention state as previously described
with respect to step 65.
When a DIA session is established, processors 10 and 12 will communicate
with each other using interchange protocols sufficient to handle the (1)
distribution and (2) application processing functions but not (3) library
services functions.
While the invention has been particularly shown and described with
reference to a preferred embodiment it will be understood by those skilled
in the art that various other changes in form and detail may be made
without departing from the spirit and scope of the invention.
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