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Claims  |
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What is claimed is:
1. An interactive electronic classroom system, comprising:
a central computer, including a central processor, a monitor, and
associated peripheral hardware, for running individual classroom programs,
including programs which accept sequences of input associated with student
tasks to which students provide responses, said central computer storing
said programs and said responses and providing analyses of said responses,
under control of the teacher, via said programs for display on said
monitor;
a plurality of student terminals, each including a microprocessor, input
means for inputting information, and a display, for receiving said student
tasks from said central computer, for executing said student tasks by
students to provide said responses, for transmitting said responses to
said central computer, and for providing feedback to the students;
network means for transmitting data between said central computer and said
plurality of student terminals, said data including said student tasks and
said responses;
a communication protocol, associated with said central computer, said
network means, and said plurality of student terminals, for transmitting
said data between said central computer and said plurality of student
terminals, for downloading of ones of said student tasks from said central
computer to said plurality of student terminals, and for transmitting said
responses from said plurality of student terminals to said central
computer;
activation means, associated with said central computer, said plurality of
student terminals, said network means, said communication protocol, and
said individual classroom programs, for allowing the teacher to initiate
and terminate said student tasks on said interactive electronic classroom
system, such that each of said plurality of student terminals provides
said responses to said student tasks at a pace that is under the control
of the teacher, with said responses being transmitted to and monitored by
said central computer;
viewing and analyzing means for viewing and analyzing said responses; and
electronic display means for displaying information, by the teacher to the
students.
2. A system as claimed in claim 1, wherein said activation means further
comprises means for pacing said student tasks at a pace that is under the
control of both the teacher and each of the students.
3. A system as claimed in claim 1, wherein said activation means further
comprises means for enabling a teacher to specify a time duration for
provision of said responses to ones of said student tasks.
4. A system as claimed in claim 1, wherein ones of said classroom programs
comprise means for enabling the teacher, during a class, to select,
retrieve, and use said sequences of input.
5. A system as claimed in claim 4, wherein said ones of said classroom
programs comprise means for enabling selection, retrieval, and use of a
subset of any of said sequences of input.
6. A system as claimed in claim 1, wherein said ones of said classroom
programs further comprise means for enabling the teacher, during a class,
to enter, in real time, a new sequence of input.
7. A system as claimed in claim 1, wherein said viewing and analyzing means
further comprises means for viewing and analyzing said responses to said
student tasks which were previously executed.
8. A system as claimed in claim 1, wherein said communication protocol
allows transmission of said data between said central computer and said
plurality of student terminals, both selectively and collectively, and
among said plurality of student terminals themselves, both selectively and
collectively.
9. A system as claimed in claim 1, further comprising database means for
storing class records and said responses in accordance with a selectable
format.
10. A system as claimed in claim 9, wherein said database means includes
means for storing class rolls, student attendance records, and said
sequences of input.
11. A system as claimed in claim 1, wherein said viewing and analyzing
means includes means for viewing and analyzing said responses both during
and after a classroom session.
12. A system as claimed in claim 1, wherein said viewing and analyzing
means includes means for viewing and analyzing responses to said student
tasks in accordance with the type of student task.
13. A system as claimed in claim 1, further comprising preparation means
for enabling preparation of said sequences of input for use during a
class, and for storing said sequences of input for later use.
14. A system as claimed in claim 13, wherein said preparation means
comprises means for displaying teacher choices in a menu format.
15. A system as claimed in claim 13, wherein said preparation means
comprises language means, selected from the group consisting of high level
programming languages, low level programming languages, and
computer-responsive languages, for enabling preparation of said sequences
of input.
16. A system as claimed in claim 15, further comprising a subroutine
library, callable by said language means, for preparing said sequences of
input.
17. A system as claimed in claim 1, wherein said activation means comprises
means for displaying teacher choices in a menu format.
18. A system as claimed in claim 1, further comprising grading means for
enabling a teacher to assign grades to said responses.
19. A system as claimed in claim 1, further comprising logon means for
identifying the students individually to the system by personal identity
and by location in the classroom.
20. A system as claimed in claim 1, wherein said central computer comprises
one of a personal computer and a workstation.
21. A system as claimed in claim 1, further comprising means for
transmitting prerecorded video information to said electronic display
means under control of the teacher for viewing by said students.
22. A system as claimed in claim 1, wherein said network means comprises a
local area network (LAN).
23. A system as claimed in claim 1, wherein said student tasks are compiled
from the group consisting of questions, quizzes, tests, classroom
exercises, didactic programs, instructional games, simulations, and
homework.
24. A system as claimed in claim 1, wherein said network means comprises at
least one network controller.
25. A system as claimed in claim 1, wherein said communication protocol
allows transmission of said data from said central computer to only one of
said plurality of student terminals at a time.
26. A system as claimed in claim 1, wherein said communication protocol
allows transmission of said data from said central computer simultaneously
to a selected subset consisting of fewer than all of said plurality of
student terminals.
27. A system as claimed in claim 1, wherein said communication protocol
allows transmission of said data from said central computing unit
simultaneously to a plurality of selected subsets each consisting of fewer
than all of said plurality of student terminals.
28. A system as claimed in claim 1, wherein said activation means allows
each of said plurality of student terminals to receive and respond to said
student tasks at each student's own pace.
29. A system as claimed in claim 1, wherein said activation means allows
all said plurality of student terminals to receive and respond to said
student tasks within time limits set by the teacher.
30. A system as claimed in claim 1, wherein said activation means allows
all of said plurality of student terminals within a selected subset,
consisting of fewer than all of said plurality of student terminals, to
receive and respond to said student tasks within time limits set by the
teacher.
31. A system as claimed in claim 1, wherein said activation means allows
selected subsets of said plurality of student terminals, each of said
selected subsets consisting of fewer than all of said plurality of student
terminals, to receive and respond to said student tasks within time limits
set by the teacher.
32. A system as claimed in claim 1, wherein said electronic display means
comprises a display selected from the group consisting of a liquid crystal
display a color television, and a color television projector.
33. A system as claimed in claim 3, wherein said activation means further
comprises means for changing said time duration.
34. A system as claimed in claim 1, wherein said sequences of input include
at least one predetermined time duration for provision of said responses.
35. A system as claimed in claim 1, wherein said sequences of input are
input to said central computer via devices compiled from the group
consisting of a keyboard, pointing device, floppy disk, hard disk, optical
disk, modem, and computer network.
36. A system as claimed in claim 1, wherein said sequences of input are
compiled from the group consisting of said student tasks, student task
descriptions, student task time limits, computer programs, enhanced
viewing and analyzing tools for specific student tasks, graphic images,
and video and audio sequences.
37. A system as claimed in claim 1, wherein at least one of said student
terminals includes means for providing narrative responses to said student
tasks.
38. A system as claimed in claim 1, wherein said viewing and analyzing
means includes means for viewing and analyzing responses to said student
tasks outside class on a separate computer that is separate from remaining
elements of said interactive electronic classroom system.
39. A system as claimed in claim 38, further comprising additional
networking means for networking said separate computer to said central
computer.
40. A system as claimed in claim 1, wherein at least one of said student
terminals is portable and comprises means for performing at least one
function selected from the group consisting of computer, calculator,
organizer, appointment diary, typewriter, phone directory, alarm clock,
thesaurus, and dictionary.
41. A system as claimed in claim 1, wherein ones of said student tasks
include programs, executing on said student terminals, for providing local
analyses of said responses and for providing individual instructions and
feedback to the students.
42. A system as claimed in claim 1, wherein said data transmitted by said
network means under said communication protocol includes said information
for display by said electronic display means.
43. A system as claimed in claim 1, wherein said network means includes
means for transmitting said data by electromagnetic waves.
44. A system as claimed in claim 30, wherein said activation means allows
ones of said plurality of student terminals, other than those in said
selected subset, to receive and respond to said student tasks at each
respective student's own pace.
45. A system as claimed in claim 31, wherein said activation means allows
ones of said plurality of student terminals other than those in said
selected subsets to receive and respond to said student tasks at each
respective student's own pace.
46. A system as claimed in claim 1, wherein said electronic display means
comprises means for enabling display of said information, by the teacher
to the students, at the display at each of said plurality of student
terminals.
47. A system as claimed in claim 1, wherein said electronic display means
comprises means for playing segments of prerecorded video and audio
information under control of said central computer, said segments being
selected in accordance with said sequences of input and said responses.
48. A system as claimed in claim 24, further comprising means for enabling
at least one microprocessor from said plurality of student terminals to
act as a microcontroller with said network controller.
49. A system as claimed in claim 1, wherein said electronic display means
comprises means for displaying analyses of said responses to said student
tasks. |
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Claims |
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Description |
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BACKGROUND OF THE INVENTION
The present invention relates to a computer-based teaching system employing
networking and computer assisted interactive techniques for enhancing a
teacher's efficiency and effectiveness in a classroom. As will be
discussed below, among its various attributes, the inventive system
enables a teacher: (1) to monitor progress of a class more closely during
each classroom session, and over each section of a course, than has been
possible in the past; (2) to stimulate active participation by all
students in a class; (3) to automate rollkeeping and the giving and
grading of quizzes and homework; and (4) to utilize instructional videos
and associated peripheral hardware interactively with the system. The
invention thus integrates computers into the mainstream of the learning
and grading process at educational institutions, with significant benefit
to the classroom environment, including facilitated knowledge of student
performance, and associated savings in routine paperwork.
There have been numerous techniques devised for enabling a teacher more
easily to convey information and understanding to a class, and ultimately
to relieve the teacher, to the greatest extent possible, of a number of
the burdens associated with conveying that information to the class.
Various electronically-based techniques have been implemented, but these
have proved to be quite limiting or otherwise disadvantageous. In one
sense, the techniques have been limiting in that interaction between the
student and the teacher may be limited to responses to multiple-choice
type questions, or to questions requiring only numerical answers. Examples
of such systems include those described in U.S. Pat. Nos. 3,656,243;
3,694,935; 3,716,929; and 4,004,354. Such systems have been further
limiting in that they have not provided any way of keeping accurate,
detailed records for individual students for the duration of a given
class.
Other more recently-proposed systems have taken advantage of advances in
technology to interconnect a number of students in the same classroom, or
in different classrooms, for purposes of gathering information, or
facilitating access to instructional programs. One example is U.S. Pat.
No. 4,636,174, which enables students to download instructional programs
from a central computer, which acts as a sort of file server. In this
system, the student, rather than the teacher, has control over system
access and operation.
Another example is U.S. Pat. No. 4,759,717, which discloses detailed
networking structure for connecting conventional personal computers.
However, there is at most only limited teacher-student interaction
contemplated. Rather, this system is directed more toward providing, at a
central location, an instructional program which may be downloaded locally
so that students can learn various types of computer programs.
Yet another example of a conventional student response system is U.S. Pat.
No. 4,764,120. This system is intended to collect data of a limited nature
(e.g. responses to multiple-choice questions) from a number of classrooms.
There is no provision of statistical analysis to inform the teacher of how
well a class is learning the concepts being conveyed. This feature also is
absent from the other two just-mentioned U.S. patents.
One of the important services an electronically-based classroom teaching
system can provide is to enable a teacher to monitor progress of the class
and of individual students, and to focus effort in areas where students
seem to have the most trouble understanding the concepts being taught. A
electronic classroom teaching aid also should assist a teacher in breaking
through the reluctance that students have to participating actively in
class. Some of this reluctance derives from basic shyness, or fear of
seeming different, or fear of seeming superior (or less intelligent, for
that matter). Enabling students to respond individually and confidentially
by electronic means to questions posed by the teacher can help to break
through some of the shyness or reluctance a student otherwise may exhibit.
However, this confidentiality by itself does not suffice to satisfy all
students, at all levels, in all teaching situations. Sometimes active
participation and motivation can be encouraged better by combining
students in small teams (by twos or threes) and requiring that they
respond to questions as a team. In this way, students can learn from the
insights and difficulties of their peers. The teacher can infer class
progress from the responses of the teams.
In still other situations it is important to enable students to proceed, if
possible, in a self-paced manner, to learn concepts conveyed in the
classroom, while still having the teacher present to monitor the situation
and to concentrate in areas where the class seems to be having difficulty.
Here, it is important that the interactive electronic classroom system
advise the teacher, as soon as possible, what percentage of the class
grasps the concepts being taught.
Certain of the above-mentioned U.S. patents, such as U.S. Pat. No.
4,004,354, describe systems which provide the teacher with a readout of
the percentage of students answering a question correctly. However, the
types of questions still are limited to multiple choice, and do not
provide a vehicle for further discussion and exploration of concepts which
appear to be difficult to grasp.
It would be desirable to have a system in which students could respond to a
wider range of questions, with different types of responses required (for
example, a narrative response of limited length). It also would be
desirable to enable a student to take a quiz at his or her own pace, with
questions requiring answers other than multiple choice or simple numerical
answers. Further, it is desirable for students to be able to run short
didactic programs which are designed to enable students to experiment
immediately and actively with the concepts which are being taught in that
class, and which simultaneously give feedback to the teacher. Those
students who have succeeded in a task may be assigned more advanced work
while others may receive remedial instruction. It follows that different
portions of a class should be able to work at one time, on different
tasks, under control and supervision of the teacher. Such a system would
be in complete contrast to conventional computer-based instruction which
has tended to have the effect of replacing, rather than assisting
teachers.
In summary, it is desirable to have a system which simply enables a teacher
to teach better by encouraging active learning in the classroom, by
providing rapid feedback on students' understanding, and which
simultaneously relieves a teacher of certain burdens in routine paperwork
that otherwise would have to be assumed, and which otherwise would take
important time away from the teacher. It further would be desirable for
such a system to be combinable with various electronic devices (such as
video or educational resource materials stored on optical discs) to
provide information to students through additional media which again do
not replace a teacher, but rather which augment what a teacher can offer
alone.
SUMMARY OF THE INVENTION
In view of the foregoing, it is an object of the present invention to
provide a computer-based, networked electronic classroom system in which
the teacher can monitor class progress, ask questions including those
requiring narrative or other more complicated responses, and generally
focus efforts in areas where more instruction appears to be needed.
It also is an object of the invention to provide classroom facilities for
students to perform computer based instructional exercises, run didactic
software and simulations, and compete as groups in games or other computer
based instructional activities under the close direction and supervision
of the teacher, while retaining the benefits of individual feedback
associated with single user stand-alone systems.
It is another object of the invention to provide facilities for fully or
partially automating the giving and grading of quizzes, class attendance
rollkeeping, grading of homework, and other routine paperwork associated
with monitoring student progress and recordkeeping.
To accomplish these and other goals, the novel, inventive electronic
classroom herein described includes a central computer and display at the
teacher's desk, a plurality of terminals at desks of individual students,
and network connection between the central computer and the terminals. The
terminals may range in complexity from a simple dedicated keypad with
rudimentary display, to a hybrid version of a calculator/terminal with
numeric and function keys, to a rudimentary hand-held computer with a full
keyboard and single or multi-line display, having a number of other
possible functions such as those of calculator, typewriter, organizer,
appointment diary, phone directory, thesaurus, and dictionary, up to a
full-fledged personal computer capable of operating in a stand-alone mode.
The student terminals may be fixed in the classroom, or may be carried by
students as portable devices with numerous possible ranges of applications
outside a classroom context.
Thus, the inventive system encompasses a range of possible hardware and
software embodiments, enabling a range of cost and functionality in its
possible implementations. This range also is evident for permissible
connections between the central computer and the student terminals.
The network connection between the central computer and student terminals
may consist of a full local area network (LAN), enabling equal
connectivity among all stations and any industry accepted physical
topology, or (in the preferred embodiment) may consist of one of many
possible lower cost network options with unequal connectivity where a
special higher level protocol ensures that all messages from student
terminals pass through the central computer or through a special network
server connected directly to it.
Another component of the inventive system is an electronic display for
displaying textual and graphic information for instructional purposes by a
teacher to a class. As with other components, this display may take
several forms. It may be a liquid crystal display which lies on top of an
overhead projector and is driven by the display output from the central
computer; it may be a projection video device which also is driven by a
display output from the central computer: it may consist of either of the
preceding physical display devices driven by a special graphics computer
using display commands from the central computer in a language such as the
"Display Postscript" (tm); language if student terminals have sufficiently
powerful displays, these may be used as the necessary display by sending
the information to be displayed down the network from the central computer
to the student terminals.
The information to be displayed may be divided into two categories. The
first category consists of any instructional material, such as normally is
displayed by teachers in conventional classrooms, and includes questions,
directions, or activities. The second category includes student responses
and statistical or graphic analyses (or other orderings, sortings or
summaries) of the same. The display of all such information in both
categories is under control of the teacher, who may view selectively such
information privately on the central computer monitor before sending it
out for viewing by the students.
The inventive system also involves a combination of software and hardware
to accomplish the following:
a communication protocol, associated with the central computer, the
network, and the plurality of student terminals, for allowing the
transmission of command data from the central computer to one or more of
the student terminals (selectively or collectively), for allowing the
downloading of programs from the central computer to one or more of the
student terminals in similar fashion, and for allowing the transmission of
student responses or other data from the student terminals to the central
computer;
a timing environment, associated with the central computer software, the
student terminals, and software operating on both the central computer and
the student terminals, for allowing each of the terminals to proceed
through a sequence of student tasks (those tasks consisting of one or a
combination of questions, quizzes, tests, classroom exercises, didactic
programs, instructional games, simulations, homework, and other
instructional activities) either at each student's own pace, or in
lockstep with all other students in the class. If the teacher assigns
different tasks to different groups of students in the class, then
students within each group may proceed either individually or in lockstep
with others in that group, at the selection of the teacher. In all cases
the responses would be transmitted and monitored by the central computer,
with the teacher retaining control of the pacing of student tasks via the
central computer;
a command language, with an optional associated menu driven command
language generator, for enabling an instructor to prepare a series of
student tasks (as described above) prior to a classroom session, and for
storing this information for subsequent retrieval and use, for example
using non-volatile memory or removable media such as floppy discs;
a control program, optionally utilizing menu driven facilities, for
enabling a teacher during a class to enter a new student task, or to
retrieve and view previously prepared student tasks which then may be
executed;
a log-on facility for students to identify themselves personally, and by
classroom location, to the system;
a database facility for storing information input to the system. This
information may be input by the teacher directly via the central computer,
by the students via student terminals, by reading from removable storage
media (such as floppy disks) or by other means (such as networking between
a teacher's private computer and the electronic classroom system). The
types of information which might be stored in the database would include
class records, student rolls, questions, tests, or other tasks asked
during each class, and student responses transmitted to the central
computer. The actual repository may be fixed media within the central
computer of the electronic classroom system, or it may be removable
storage media which may be transferred between the classroom system and
another computer outside the classroom (possibly the teacher's private
computer). This transferral also may take place via a local area network
between the central computer and other computers;
presentation and analysis facilities to enable a teacher to view and
analyze information gathered by the system. During a classroom session,
these facilities would allow a teacher to view and analyze student data
and responses. They also would permit the teacher selectively to show
certain of these responses and analyses of such responses to the class via
the electronic display. Outside a classroom session, probably on a
separate computer (possibly, one located in a teacher's office), these
facilities would allow a teacher to examine student responses further for
a variety of purposes. Such purposes might include a search for
weaknesses, or strengths, in areas of understanding for individual
students, or for the class as a whole. They might include the tracking of
progress of individual students, or the grouping of students with
particular weaknesses or strengths. They may include assessments of
attendance, class performance, homework performance, or the assignment of
grades, possibly with automatic facilities for grading the various
components of student performance to a selectable curve. They also may
include facilities for directly transmitting student grades to
administrative databases via a network.
The range of overall contexts in which the present invention may be
installed and used is almost unlimited. However, emphasis on particular
features of the system may vary from one context to another. For example,
at the primary level there is likely to be more emphasis on the additional
variety in activities provided by the system and its capability for
instructional feedback to students and teacher. In addition to these
factors, at the high school level automatic testing and record keeping
become more important, since one teacher teaches many more students. Also,
the diagnostic and early warning features become more significant. At the
college level, with huge classes, all these features are important, and a
professor is likely to have his or her own computer outside the classroom
to assist with the preparation of materials and with data management.
BRIEF DESCRIPTION OF THE DRAWINGS
The foregoing and other features and objects of the present invention will
be described in detail herein with reference to the accompanying drawings,
in which:
FIG. 1 is a simple block diagram showing basic components according to one
embodiment of the present invention;
FIGS. 2A-2B are flow charts describing a simple procedurally driven
implementation sequence of operation of certain of the features of the
present invention, and possible sequences of events in classroom sessions;
FIGS. 3A-3B are pictorial flow charts illustrating in greater detail
classroom session flow in accordance with the present invention;
FIGS. 4A-4EE illustrate sequentially an event driven implementation of the
invention by providing a series of views from the teacher's display, these
Figures representing a windowing environment with pull-down menus; and
FIGS. 5A-5B are exemplary histograms showing results of a
student-interactive classroom session.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT
Referring to FIG. 1, the inventive system herein described includes a
central computer 10 which is capable of acting as a host for teacher
interaction with the system. This computer, which also acts as coordinator
for the entire system, would be used by the teacher to administer lessons
and programs for different classroom sessions, as will be described below.
Such a machine might be an IBM PC-XT (tm) computer or PC-AT, or an XT- or
AT-compatible machine; an IBM-compatible machine employing one of the
Intel 80386 family of microprocessors an Apple MacIntosh (tm) computer or
other similarly capable computer; an IBM PS/2 (tm) computer, such as a
Model 70 or Model 80 (tm) computer or other computer employing the IBM
Microchannel (tm) architecture; a Sun, Apollo or Digital Equipment
Corporation (DEC) computer or workstation; a NeXT computer; or any other
computer capable of performing this function. Notwithstanding the
foregoing list of suitable hardware, the invention is not to be considered
as limited to specifically listed items.
The operation of the present invention is not dependent on the type of
operating system under which the computers employed run. Thus, the MS-DOS
(tm) operating system, PC-DOS the (tm) operating system, Apple's operating
system, any of the UNIX (tm) family of operating systems, the OS/2 (tm)
operating system, or any other general-purpose operating system supported
by the processor employed in the central computer 10 may be used. The
range of computers enumerated above should be considered to be expanded as
appropriate to encompass all those which are compatible with or otherwise
run under one or more of these listed operating systems.
The computer should include whatever storage peripheral(s) (such as a
floppy disk drive, a hard disk drive, or an optical drive such as a
write-once read-many (WORM) type drive) is (are) necessary to enable the
computer to run its programs; to store and access necessary information;
and to store results for subsequent access by the teacher. The speed,
storage, and display capabilities of the central computer 10 ideally
should be matched to the classroom in which the computer is installed. For
example, an IBM-XT (tm) compatible computer with a ten-inch screen may be
adequate for most applications in a class of thirty students, while a
class of three hundred students would benefit greatly from a Sun model
(tm) workstation with a 19-inch monitor.
In one embodiment under development by the present inventors, an
AT-compatible machine is being used, with one floppy disk drive, a 20 MB
hard disk drive, and an IBM Monochrome monitor driven by a "Hercules"
compatible graphics card. Other graphic display formats are available and
may be used, such as those employing a color graphics adaptor (CGA).
enhanced graphics adaptor (EGA). or video graphics adaptor (VGA).
The system also includes an electronic projection display 20, for example
an overhead projector with a liquid crystal display (LCD). The electronic
projection display 20 may be driven by an IBM compatible CGA unit inside
the central computer. Depending on the degree of resolution desired, other
types of adaptors, such as EGA. VGA or Hercules, also may be used (subject
to the capability of the operating system and hardware to accept two
displays of different formats). Also, monochrome displays, providing gray
scale formatting of color shadings, may be used. By connecting the display
20 with the computer 10, displays created by programs run by the computer
10 may be shown to the class. The projection display also may allow the
teacher to display handwritten information for discussion by the class, in
lieu of a chalkboard. The display 20 also may be used in association with
a video retrieval system, such as a videocassette recorder (VCR) or
videodisk player (VDP) 30, which may be used to show videos (possibly
under computer control) to the class.
In another embodiment, an Apple MacIntosh II (tm) computer is used, with an
internal hard disk drive and a color monitor for the teacher's display.
The projection display is driven by a second standard display interface.
Another structural element of the present invention is the necessary
connection between the central computer and student terminals. The
International Standards Organization Open Systems Interconnection Model
(ISO 7498-1984) describes the communication process as a hierarchy of
seven layers, each dependent on the layer directly beneath it and with
each layer possessing defined interfaces with the layers immediately above
and below. These seven layers are 1. Physical, 2. Data Link, 3. Network,
4. Transport, 5. Session, 6. Presentation, and 7. Application. It is not
contemplated that the invention, in its preferred embodiment or otherwise,
would require any particular implementation of any layer or any particular
interface between layers. Rather, the networking process may be defined by
the functional requirements of the system.
For example, the Physical Layer in the ISO document just mentioned refers
to the physical connections between the computer and the network,
including the mechanical aspects of the connection (cables or connectors)
and the electrical aspects (voltage, current levels, and the techniques
used to modulate the signal). This layer also defines the network
topology. Thus, for this invention, this level may comprise connections
which may be accomplished, for example, by a twisted pair wire, by coaxial
cable, by optical fiber, or by electromagnetic transmissions, including
but not limited to infra-red and radio, through the air. The functional
requirements for operation of the system relate to sufficient speed of
data transmission, which in turn depends on the number of student
terminals attached to the system, the complexity of the student tasks
(instructional activities), and the division and allocation of necessary
data processing between the central computer and student terminals.
Another functional requirement is the need for a robust and durable
installation which does not affect or alter the normal classroom
environment unduly. Also, if students own their terminals, then adequate
provision must be made for convenient locations for them to connect and
remove their terminals to or from the network (unless connection is
accomplished directly by infra-red transmission). Power delivery also may
be included in the system.
The Data Link layer defines the protocol that computers must follow to
access the network for transmitting and receiving messages. These messages
are sent onto the network as specially formatted discrete frames of
information rather than being continuously broadcast. For example, three
of the standard packet formats used for digital communications are the
non-LAN asynchronous byte, as used by terminals and modems (RS-232), the
SDLC frame (used by Appletalk (tm) networks, among others), and the
Ethernet Frame. The Network level defines how packets--communications
composed of a defined format of data--are routed and relayed between
computers on the network. Higher levels of the networking process
essentially define protocols for communication between the levels
themselves.
This invention does not require any particular implementation of the Data
Link and Network levels, or of higher level protocols, again because these
are not considered part of the inventive concept per se. Suitable
implementations will be known to ordinarily skilled artisans, and need not
be described here in detail.
Rather, networking requirements may be expressed in functional terms for a
particular embodiment of this invention. For example, for a class of
thirty to one hundred students, with student terminals possessing 64
kilobytes of random access memory (RAM), the network and communication
protocols might reasonably enable the following:
Reprogramming of Student Terminals
the central computer would be able to reprogram all student terminals (or a
specified group of terminals) with the same program of length up to 64
kilobytes in a time not exceeding 15 seconds,
a message from the central computer to all student terminals (or to a
specified group of terminals) to run an already resident program would
take no longer than one-half second,
the central computer would be able to reprogram a single specific student
terminal, and
two or more groups of student terminals would be separately accessible by
the central computer. Each of these groups would be able to be
reprogrammed and "run" with no noticeable interference on the processes of
other terminals.
Data Collection by Central Computer
all terminals must be able to return data to the central computer,
for timing purposes, assuming for example that these data take the form of
a terminal ID and 20 bytes of data, total transmission time for a class of
one hundred terminals would not exceed one second, and
although data transmission to the central computer from student terminals
normally would be event driven and initiated by individual terminals, the
protocol also should contain a facility for the central computer to be
able to issue a "stop and transmit" message. This | | |
