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BACKGROUND OF THE INVENTION
The present invention relates to distributed processing and more
particularly to interchange of data in a communication system having one
or more host processors connected for cooperative interaction with a
plurality of intelligent terminals or work stations.
Cooperative processing is well known in the art, illustrative of which are
systems such as those depicted in FIG. 1 hereof, wherein a host processor
is operative in a purely reactive mode to requests for objects (data and
processing routines) requested by the connected terminal/work stations.
While such systems provide substantial economies of equipment by providing
for the sharing of selected computational features at a consolidated
level, (i.e. at a host processor) they nevertheless require two flows of
information for each item communicated from the host to a connected
terminal/work station:
(1) The initiation of a request at the work station communicated over a
data link to the host; and
(2) Data generated or otherwise produced at the host and communicated over
a data link back to the requesting terminal/work station.
When the host processor is busy, requests for information may await their
turn in a queue, thereby resulting in significant delays. Moreover, even
if there is no queue, and the request for data is responded to immediately
upon receipt, there nevertheless is a loss of time occasioned by the need
for the requesting terminal to transmit a request to the host together
with loss of time involved in production of requested data and their
communication by the host back to the terminal over the connecting link.
Moreover, it is desirable further to improve the efficiency of time and
equipment utilization in systems of the type described herein in order to
provide an anticipatory mode within the host computer whereby the host
anticipates the need at the work stations of certain types of data and or
processing information (hereinafter referred to as "objects") and to
voluntarily provide the same to the work stations so that objects are
available at the work stations for utilization (display/processing)
immediately upon request by the user, thereby substantially improving time
efficiency and equipment utilization.
OBJECTS AND FEATURES
It is one general object of this invention to improve distributed data
processing systems.
It is another object of this invention to improve time efficiency in
utilization of intelligent work stations.
It is another object of this invention to improve efficiency of equipment
utilization in distributed processing systems.
It is yet another object of this invention to facilitate utilization of the
equipment and attendant productivity of equipment user personnel.
Accordingly, in accordance with one feature of the invention, heuristics
are provided within the host processor to screen objects and anticipate
the need for such objects at work stations, thereby eliminating the
necessity, at least for thus selected objects, for the user or work
station to request them from the host.
In accordance with another feature of the invention, anticipatory data
(also referred to herein as prestaged data or objects) are transmitted
from the host to one or more selected terminals at optimal times, e.g.,
when the host processor is not otherwise engaged, thereby improving
efficiency of utilization.
In accordance with still another feature of the invention, several objects
may be selected for transmission from the host and transmitted as a group,
thereby eliminating the need for a plurality of data/overhead items (e.g.
re-starting transmission and identifying user), thereby further improving
efficiency of equipment use.
In accordance with yet another feature of the invention, selected objects
are retained in storage (e.g. memory or DASD) at the local terminal/work
stations until either: 1. a predetermined period of time has passed
without their being used; or 2. until the available storage at the
terminal/work station is full and a higher priority item seeks entry
thereto
These and other objects and features of the invention will be apparent from
the following detailed description, by way of preferred embodiment, with
reference to the drawings.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a flow chart illustrating operative principles embodied in the
prior art;
FIG. 2 is a flowchart illustrating the preferred embodiment of the
invention;
FIG. 3 is a diagram identifying two types of information for which the
principles of the invention are particularly useful; and
FIG. 4 is a diagram illustrating a block of information and the advantage
of communicating groups of data objects.
FIG. 5 is a block diagram of the system in accordance with the invention.
DETAILED DESCRIPTION OF THE INVENTION
Referring now to FIG. 1, a typical distributive processing system according
to the prior art is illustrated. Steps progress operatively in descending
order from top to bottom and represent, by vertical column, the host
processor, terminal/work station and user respectively. As will be
observed from the top of the host column, action begins with starting of
the host system and the terminal/work station(s) respectively. These
actions are represented by start symbols 10 and 20. In this connection, it
should be observed that reference to terminal and/or work station when
used in the singular is intended to include the plural and vice versa
unless the context requires otherwise.
Once the system is activated, objects are received at the host as
represented by the descriptor "object item arrives", symbol 12. This is
accomplished in accordance with heretofore generally known techniques in
equipment of the prior art. After arrival, the object item is stored at
the host for later retrieval when a request is subsequently received from
the user for such item.
When a user elects to view the object, e.g. object 1 as noted by symbol 40,
he or she makes an appropriate entry, normally by manipulation of a
keyboard or the like; and in response thereto, the work station develops
and sends to the host a request for the object as denoted by symbol 21.
Upon receiving such an input, the work station circuits transmit a request
for the object over communication link 22 to the host processor with a
request that the identified object be sent to the work station. This then
is accomplished as represented by communication link 23, and the work
station equipment accepts the requested object and then displays it to the
user as noted by symbol 24. The item may be temporarily retained at the
work station until the memory capacity is needed for the next item.
Ordinarily, however, the item is not retained in storage at the work
station and consequently must be recalled again from the host if it is to
be viewed subsequently. This is represented by the sequence beginning with
selection by the user to view the object as denoted by symbol 41. Circuits
in the work station are then activated as denoted by symbol 25 and act in
the manner similar to that denoted by symbol 21 to send a request to the
host over transmission path 26 to circuits in the host which responds as
noted by symbol 15 to send the requested object to the work station over
communication link 27. The object is then displayed to the user as denoted
by symbol 28.
Should the user desire to view a different object (e.g. object 2) a
procedure similar to the foregoing is employed, with the user electing to
view the object 2 as denoted by symbol 42 to send a request to the host
and receive the object as denoted by symbols 29, 30, 31 and 16. Other
similar sequences of operation are represented by symbols 17, 18 and 19 at
the host station and by symbols 32, 33 and 34 at the work station.
Completion of the foregoing sequences or deactivation are denoted by
symbols 20 and 35.
From the foregoing, it will be observed that in accordance with the prior
art, the system is entirely reactive; that is, the host does not take the
initiative to voluntarily or anticipatorily send objects to the work
stations but awaits receipt of a request before doing so. Moreover, it
will be observed that after display of the object or utilization thereof
by the work station, the object is not stored there but is retained at the
host, thereby requiring subsequent individual retrievals of the object
from the host for use or display.
Now turning to FIG. 2, it will be observed that the present invention is
illustrated therein. As with the prior art, the inventive system includes
a host and one or more work stations These are presented in a form similar
to that of FIG. 1 and are activated by start-up which is indicated by
symbols 50 and 70 respectively. As with the case of the prior art, objects
are received and are represented by "object item arrives", symbol 51. The
items are then stored in host storage 52. Next, without waiting for a
request from a work station, the heuristic logic circuits 53 identify the
item. However, after such identification, in contrast with the prior art
systems, heuristic logic circuits 53 then either determine that the item
is not to be voluntarily sent to a work station as noted by the word "no"
at the base of diamond 53, or that it is to be sent as noted by the word
"yes" which appears adjacent path 54. If the answer is "no", then the
object simply remains in storage 52 and is available for later retrieval
and transmission as noted by rectangle 56; if "yes", then the object is
sent to a work station as noted by link 54, rectangle 55 and link 58.
Thus, the system is effective to voluntarily send selected ones of the
objects to one or more predetermined work stations as represented by
symbol 71, without any request from a work station as represented by
symbol 55.
The host is conditioned to respond to a specific request from a work
station and to send the object to the work station as represented by
symbol 56. Communication between the circuits 53, 55 and 56 and the
corresponding work station circuits of 71 and 74 is effected over
communication links 58, 59 and 60. Deactivation of the host system is of
course, represented by "end" symbol 61.
As will be evident to those skilled in the art, link 54 is a logic path
rather than a communication path. However, path 54 may also be considered
to represent communication of data within the host so that it can be
transmitted over communication link 58 to one or more work stations.
As mentioned above, circuits at the work stations are equipped with
sufficient storage capacity to store and retain objects ordinarily desired
and/or used by the work station operators. Accordingly, after a item has
been received by circuits 71, it is stored in storage 77 (which is
symbolic of storage at each work station) where it remains until, because
of inactivity or need for replacement by an object of higher priority, it
is erased therefrom. Paths interonnecting circuits 71, 72, 73 and 74 with
storage 77 are identified by communication paths 68, 69, 78 and 79.
As shown in FIG. 2, displays of requested objects, e.g. mail, to the user
are identified by symbols 72, 73 and 75. Of course, it will be evident to
those skilled in the art that these are representative of a number of
different showings of the same or different objects.
Completion of a sequence of actions or eventual deactivation of the system
is denoted by symbols 61 and 76 in the conventional manner.
Again as evident from inspection of FIG. 2, a work station user may select
to view an object that is either currently resident within local storage
77 or which must be summoned from the host. Symbols 80 and 81 represent
selection by the work station user to view one or more objects resident in
storage 77, whereas, symbol 82 identifies selection by the user of viewing
an object which is currently not in work station storage 77, but which
must be summoned from the host processor. Thus, in accordance with a
feature of the invention, dual modes of operation are provided whereby the
user can select items that are currently either in the local storage and
host storage or in the storage of the host and wherein the local storage
memory normally contains objects which are most likely to be selected by
the user in accordance with the principles hereinafter described.
Communication link 79 is provided to show that when a user selects to view
a given object, he may not know whether it is in local storage 77 or must
be summoned from the host. Accordingly, before a request is made to the
host, local storage 77 is first checked via link 79. This link 79 is also
used to store the object once it has been obtained from the host.
FIG. 3 illustrates two categories of objects which many users would like to
maintain. These are electronic mail and calendar. Accordingly, at least a
portion of storage 77 is allocated for storing information of these two
categories. Other objects may also be included as, for example, those
which are described in co-pending U.S. Pat. application Ser. No.
07/312,222, filed on even date herewith by the inventors hereof for
"Asynchronous Staging of Objects Between Computer Systems in Cooperative
Processing Systems".
Electronic mail 90 is provided for storage of selected items of mail which
are newly arrived, designated by the users for retention, or are being
maintained at the work station for a predetermined or indeterminate
interval of time.
Calendar 91 designates information of a chronological nature such as
schedules for meetings, appointments, holidays, travel and the like which
the user finds necessary or useful in organizing, planning and conducting
his activities.
As described above, the electronic mail storage 90 is adapted to store for
a predetermined or indeterminate period of time such items as have been
selected for storage by the work station. In order to prevent overflow and
loss of desirable data, a system of priority hierachies is established
within the work station circuits in accordance with known techniques so as
to identify items which may be displaced to make room for newly arrived
information. Thus, when an item of information newly arrives, and there is
insufficient space to store the new item, the item furthest down in the
order of priority is bumped in order to make room for storage of the new
item, thus insuring at all times that the latest and highest priority
items are retained in the electronic mail storage 90.
In accordance with establishing the hierarchy of priorities, the most
recently arrived item is accorded first priority, provided that it does
not occupy more than a predetermined amount of storage. Should the item
exceed a permitted storage limitation, an indication may be provided to
the user; and, after displaying the item and its use within the memory of
the work station, the item is discarded from the work station. On the
other hand, if the item meets the storage requirements, it then is stored
in electronic mail storage segment 90 without displacing any other
information if sufficient unoccupied storage exists. However, if there is
insufficient unused storage, then one or more items of the greatest age
and lowest retention priority are displaced and erased from memory 90.
Returning now to the establishment of priorities, after newly arrived
items, there are those which are utilized on a frequent basis at the work
station. Following these, are those which are infrequently used, and last
of all are those which have not been utilized at all during a
predetermined interval.
As an optional alternative feature, the order of priorities may include the
feature by which when an item is used, it is advanced either to the head
of the queue or a predetermined higher position therewithin.
As mentioned above, the calendar section 93 is dedicated to the storage of
items that are forward looking and time dependant. Because the user is
more likely to look at the current week, and another week or two in
advance, the calendar is specially adapted for storing and updating
information covering that period. Thus, the calendar is adapted for the
establishment of a time priority which includes a sliding window of
predetermined duration, e.g. two to three weeks (or longer, at the
discretion of the user) into which calendar information is introduced and
retained, to which new items are added, and from which past items are
deleted. It also optionally includes a feature by which selected future
items lying outside of the window can be separately stored for capture
within the window when the window has advanced to that point
chronologically.
Turning to FIG. 4, another feature of the invention is illustrated. Here,
it will be observed there is identified a block of information 100 which,
for purposes of illustration, includes 3 objects, 101, 102, and 103, a
header packet 104 and a data check packet 105.
As mentioned above, one of the features hereof is the provision for
transmitting more than one object from a host to a terminal storage as
part of one incident in order to achieve increased efficiency through the
use of but one set of overhead items, (e.g. header 104 and data check
105).
As mentioned above, through the utilization of communication during times
when the host is otherwise unoccupied (or at other predetermined times at
the discretion of the host manager), batches of information, such as that
represented by symbol 100, can be transmitted and thus achieve the
efficiencies inherent in such batch communication.
In summary, through the anticipatory heuristics described herein, a
pre-staging system is provided which includes a host and plurality of work
stations that are substantially improved in efficiency by virtue of the
voluntary or anticipatory transmission of objects in accordance with the
prediction of the needs or desires of the user, thus substantially
increasing speed of operation and efficiency in use of time and equipment.
It will now be evident that what has been described herein is a distributed
processing system having substantially improved features. Although the
inventive concepts hereof have been illustrated by way of a preferred
embodiment, it will be evident to those skilled in the art that other
adaptations and modifications may be employed without departing from the
spirit and scope of the invention. Thus, for example, other types of
memory allocations could be identified and provided in addition to those
of electronic mail and calendar.
The terms and expressions herein employed are used as terms of description
and not of limitation, and there is no intent in the use thereof to
exclude equivalents, but on the contrary it is intended to include any and
all equivalents, adaptations and modifications that can be employed
without departing from the spirit and scope of the invention as described
in the specification and claims herein.
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