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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 the apparatus for handling a
uniform data stream between various communicating processors participating
in the network.
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 distributed Feb. 16,
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 a 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 distributed
May 21, 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. However, distribution
systems problems arise when a document from a processor of higher
capabilities is communicated to a processor or work station of lower or
limited processing capabilities. This problem would be further complicated
when it is necessary to further transmit the same document to a subsequent
processor having greater or expanded data processing capabilities. This
type of interchange may arise in many situations. For example, assume that
a data stream containing relatively specific and sophisticated parameters
with respect to document display is transmitted to a processor in the
network which has very limited display capabilities and cannot process
these specific parameters. After this receiving terminal has completed its
processing requirements with respect to the document represented by the
data stream, e.g., printing the document, it may become necessary for the
data stream representative of the document to then be forwarded from this
less sophisticated receiving processor to a more sophisticated processor
which has the specific and complex display parameter processing
capability. There is a need for the processor to have the ability of
transmitting the original data stream intact to the final work station.
A similar need arises when a data stream representative of a document is to
be transmitted to a less sophisticated processor station which performs
some processing function and then onto the more sophisticated data
processor. Here again there is a need to pass the data stream intact
through the intermediate data processing station to the more sophisticated
file station.
SUMMARY OF THE INVENTION
The present invention is directed to an electronic document distribution
system having a network of communicating data processors and communication
linkages between these processors. Each of the processors has means for
receiving and means for transmitting a uniform data stream representative
of the content and format of the document as well as the processing to be
performed relative to that document. The network includes higher level
processors having a higher level of data processing capability with
respect to the data stream and one or more lower level processors which
have lower level of data processing capability with respect to the same
data stream. At least one of the lower level processors further includes
means for scanning a received data stream in order to select from the data
stream those parameters which this lower level processor is capable of
processing as well as means for storing the non-selected parameters which
the lower level processor cannot process so that after the lower level
processor has completed the processing of the selected parameters, it may
utilize means for merging the selected and the stored parameters into a
reconstituted data stream corresponding to the original received data
stream together with means for transmitting this reconstituted data stream
to another processor, particularly a more sophisticated processor which is
capable of processing parameters not selected and stored in the lower
level processor.
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 apparatus which is used in the
practice of the present invention.
FIG. 2 is a flow chart showing the general steps involved in receiving and
processing the data stream representative of a particular document by the
apparatus of FIG. 1.
FIG. 3 is a flow chart of the operations involved utilizing the apparatus
of FIG. 1 to reconstitute and transmit or send the original received
document data stream after processing has been completed.
FIG. 4 is a prior art diagrammatic representation of a data stream with its
units and sub-units broken down to the levels 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 be described. Let us assume that communicating
processor 10 is the data processor having a relatively high level of data
processing capability. This communicating processor will transmit over
linkage 11 the data stream to communicating processor 12 which is a
processor having a lower level of data capability with respect to the data
stream than does communicating processor 10. Communicating processor 12
will selectively process the received data stream and subsequently
transmit this received data stream intact to communicating processor 14
over linkage 13. Communicating processor 14 will for purposes of this
illustration be a processor having a higher level of processing capability
with respect to the data stream. 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 which is a
processor having relatively lower level of data processing capability than
processors 10 and 14.
For purposes of this example, let us assume that initially, communicating
processor 10 is transmitting or sending over linkage 11 a document to
communicating processor 12. Communicating processor 12 is to have the
contents of the document printed at a work station of which communicating
processor 12 forms a part. The printing operation involved with respect to
the contents of the document is not part of the present invention and will
not be shown or described. The document to be printed under the control of
processor 12 will be represented by a data stream communicated over
linkage 11 to processor 12. In addition to the content of the document
involved, the data stream will contain parameters related to processing
operations which are within the capabilities of communicating processors
10 and 14 but beyond the capability of processor 12. Let us assume for
example that these parameters relate to document length. In other words,
some more sophisticated processors like processors 10 or 14 have a
capability for utilizing information concerning document length in order
to anticipate and plan for the number of pages which the document will
require and consequently the number of lines on each particular page.
Since the data stream to be transmitted throughout the document
distribution network is preferably a uniform one, parameters related to
document size are included in the data stream transmitted to processor 12
even though processor 12 has no capability with respect to any document
sizing operations.
Since processing parameters such as those related to sizing of the document
and the partitioning of the document by number of pages are processing
parameters and do not relate to document content, they are customarily
included in that portion of the data stream which relates to document
distribution or document interchange architecture (DIA) rather than being
treated as part of the document content unit in 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. 4 of the Drawings which
is based upon a figure appearing at page 225 of the Schick et al article.
In any event, a data stream like that shown in FIG. 4 is transmitted over
linkage 11 and received by communications adapter 15 in processor 12. This
communication adapter may be any standard device having the capability, at
the receiving end for converting received serial data communicated over
linkage 11 to parallel form so that it may be handled in processor 12 and
if there is to be any subsequent transmission from processor 12 onto
linkage 13 then for reconverting the parallel data being handled in
processor 12 to a serial form so that it may be transmitted or sent over
linkage 13. The data stream received through communications adapter 15 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. 4 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 by the
communications control unit 19 through the buffer control program unit 20
which controls the buffer 16. If the data stream satisfies the
requirements of the SDLC and the SNA unit, the buffer control program unit
moves the data stream from buffer 16 to document distribution data storage
buffer 21. Then, the operations of the present invention to be described
with respect to the flow charts in FIGS. 2 and 3 will be carried out.
First, a determination is made by the document interchange architecture
(DIA) supervisory unit 35 as to whether the basic document interchange
unit (DIU) as shown in FIG. 4 is present in the data stream. This step is
shown in decision block 40 in the received document data stream processing
flow chart shown in FIG. 2 which will now be followed in considering the
processing operations involved when a document is received within
processor 12. If the basic DIU unit is not present, an error condition
will be indicated. If the DIU is present, then a determination is made,
decision block 41, as to whether the document profile unit is present in
the data stream. This document profile unit shown in the illustration of
the data stream in FIG. 4 is the basic unit in which various document
processing and distribution parameters are contained. Here again, if
document profile is not present, then an error condition will be signaled.
On the other hand, if the document profile is present, then, block 42, the
profile will then be scanned or examined under the control of DIU receive
controller 22.
Next, decision block 43 in FIG. 2, a determination is made as to whether a
base subprofile is present within the document profile. It is this base
subprofile that contains both mandatory and optional processing parameters
which are to be carried out with respect to the processing or interchange
of the particular document. Of course, whether these parameters are
carried out is dependent upon the processing capability of the particular
processor then handling the document. The presence of the base profile is
determined under the control of the DIU receive controller unit 22.
If this base subprofile is present, then the processor 12 enters an
operation involving steps 44, 45 and 46 wherein all of the parameters in
the base profile are examined in sequence and the determination is first
made, step 44 as to whether next parameter in the sequence is useable,
i.e., whether processor 12 is capable of using the information in the next
parameter. If processor 12 is capable, then, step 46, the parameter is
extracted from the data stream. If processor 12 is not capable of
processing that parameter, then, the process is looped back to step 44 and
the next parameter is examined for the same purpose. This procedure is
repeated until a determination is made, step 46, that the end of the base
profile has been reached. The whole sequence is carried out under the
control of profile validation unit 23 shown in the logic of FIG. 1. Upon
the completion of the examination of the base profile, a document label is
written, step 47, i.e., all of the parameters which have been extracted
from the base profile of the data stream as being utilizable are
transferred from data storage buffer 21 to a diskette storage means 25 in
processor 12 through a diskette access method. These stored parameters are
now available for the subsequent processing to be carried out on processor
12 with respect to the actual document content. For example, if the
parameters relate primarily to a printing operation which is to be carried
out on a printer not shown associated with processor 12, when the document
contents are subsequently received, parameters stored in the diskette
storage means on the document label will be utilized by the processor 12
in controlling the printing operation. As previously indicated, the actual
printing operation under the control of processor 12 is not considered to
be part of the present invention and will not be described. However, if
details are desired as to the operation of a typical text processing work
station including a processor 12 to print a document, they are provided in
co-pending application of D. G. Busch entitled "Data Ccmmunications System
with Receiving Terminal for Varying the Portions of Received Data Being
Displayed", Ser. No. 274,050, assigned to the assignee of the present
invention and filed on June 16, 1981. 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, that if the display is to be utilized it may be
accessed through the DIU receive controller 22 acting through session
summary logic 26 and display access method 27.
Next, and still under the control of the profile validation unit 23, a
determination is made as to whether there have been processing parameters
in the base subprofile which have not been extracted, i.e., these would be
processing parameters which had been previously passed over because
processor 12 was incapable of carrying them out. If there are such
processing parameters, then, step 49, a profile vector is written
including these parameters. Here again and still under the control of the
profile validation unit 23, the non-extracted parameters in the base
profile previously examined are removed from the data stream that is
stored in buffer 21 and then stored on a diskette 25 through diskette
access method 24 as previously described. Thus, this write profile vector
stored on a diskette in storage means 25 is representative of the
parameters which the processor 12 was incapable of executing.
Upon the completion of the storage of non-extracted parameters if there are
any, the operation proceeds to its next step 50 wherein a portion of the
data stream representative of the document content is received in storage
buffer 21 under the control of document processor unit 28. Then, in a
process involving steps 51 and 52 of FIG. 2 under the control of document
processor unit 28, document content vectors are written, i.e., that
portion of the data stream representative of document content is
transferred to diskette storage 25 via diskette access method 24 in
substantially the same manner as previously described with respect to the
transfer of processing parameters.
At this point, with the document content appropriately stored in diskette
storage 25 and the processing parameters carried out with respect to the
printing of the document, for example, under the control of processor 12
also stored in diskette storage 25 as a document label, the processor 12
is now ready to carry out such processing operations. While the processing
operations are carried out by processor 12, the processing parameters
which processor 12 is incapable of executing remain stored as the write
profile vector in diskette storage 25.
At some stage in subsequent operation either immediately after the
performance of the document processing such as printing by processor 12,
it may be necessary for processor 12 to transmit the original data stream
as received to another processor such as communicating processor 14.
Processor 12 has the capability of reconstituting the data stream so that
it is substantially identical to the data stream received from processor
10.
When the reconstituted data stream is to be transmitted to communicating
processor 14, an appropriate command is inserted in command queue manager
unit 29. In cases where the transmission upon completion of the processing
in processor 12 is predetermined, the appropriate command may be preset in
command queue manager 29. On the other hand, if there is a subsequent call
for the document at some subsequent time after processing, the command may
be inserted into command queue manager at the appropriate time either by
communication through the network itself or by an operator keying in the
request to the queue manager 29. At this point, the procedure set forth in
the flow chart in FIG. 3 is as follows. First, step 53, command queue
manager 29 activates DIU send controller unit 30 which will then control
reconstitution of the base subprofile portion of the document interchange
unit which was the portion previously separated into the document label
and profile vector. At this point, step 54, document label is read out of
storage in the diskette. This document label which contains the extracted
parameters from the base profile which processor 12 has carried out is
accessed from diskette storage means 25 through diskette access method 24
and stored in the appropriate sequence of the base profile being
reconstructed as a portion of a data stream in data storage buffer 21.
Similarly, step 55, and still under the control of the DIU send controller
30, the profile vector which contained the non-extracted parameters, i.e.,
those which processor 12 was incapable of executing is also read out of
diskette storage 25 through diskette access method 24 and stored in its
appropriate sequence in the profile of the data stream being reconstituted
in data storage buffer 21. The extracted and non-extracted parameters are
thus reformatted into the profile of the data stream in data storage
buffer 21, step 56. At this point, a sequence involving steps 57, 58 and
59 under the control of DIU send controller 30 is carried out which
involves reading the document content vector from diskette storage 25
through diskette access method 24 to the data storage buffer 21 and
inserting this document content vector as the document content portion of
the data stream being reconstituted in buffer 21.
Then, under the control of the communication control unit 19, the data
stream under the supervision of communication control unit 19 is moved
into send buffer 31. Then, coordinated by the communications control unit
19, the SNA unit 18 determines whether or not the reconstituted data
stream meets the network architecture requirements. This is carried out
through buffer control program 20 which controls the send buffer 31. Next,
in essentially the same manner as previously described with respect to the
received information, SDLC unit 17 determines that the data link control
elements in the data stream in send buffer 31 are proper. If the SDLC and
SNA requirements are met in the reconstituted data stream in buffer 31,
then, information in buffer 31 is transmitted through communication
adapter 15 which makes the parallel serial conversion over linkage 13 to
communicating processor 14.
Based upon the earlier assumption made in the present example,
communicating processor 14 has a higher level of data processing
capability than does processor 12 and particularly with respect to
parameters dealing with document sizing and distribution of the document
over a number of pages. Since the data stream being transmitted over link
13 from processor 12 is substantially the same as that originally
transmitted to processor 12 over link 11, all of the parameters which
processor 12 is incapable of handling have now been reconstituted into the
data stream and are available to communicating processor 14 which has the
capability for executing these parameters.
In example given above, we were dealing with communicating data processors
of relatively higher and lower data processing capability. It should be
noted that the present invention is also applicable to situations wherein
there are a specific class or category of processors which participate in
the distribution network which may not necessarily have a higher data
processing capability but do have certain specific or private data
processing procedures which they carry out with respect to the document
which no other processors in the distribution network specifically follow.
Such private or specific data processing parameters may also be included
in the uniform data stream. In such a case, any data processor in the
network not belonging to the specific class of processors will simply
extract and ignore these private parameters. The particular processor
receiving the data stream will store the parameters and then reconstitute
them into the data stream so that they may be available as private
parameters for any members of the particular class of processors requiring
such parameters.
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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