IBM Vision 2020 - Cybernetics in a Paradigm of Threes
Cybernetics is a perpetual fascination of science fiction. We are transported to a time in the future were the rules have changed. Almost always frightening, future shock is not for the timid. The same could be said of cybernetics. However, cybernetics does not exist today. While fascinating and relevant to a small group of professionals, the best we have is Watson. Watson shows great promise, but today is nowhere near the concept of cybernetics. Given that research indicates the human brain is ternary, binary computers are inadequate to process trivalent logic. Therein lays the caveat. But IBM is both a computer company of today and of tomorrow. Confusion starts attempting to understand today’s technology as a road map to tomorrow. Just as there are no ternary computers operating today, there are no androids and no vision of future technology based on sound research. Despite all these limitations science fiction is impatient to make tomorrow happen today. That proves to be both impractical and unrealistic without understanding current technology, its advantages, as well as its limitations. So it is important to appropriately set the stage to enable tomorrow’s technology. This is the beginning of the IBM Vision.
Be aware that IBM’s leadership in inventiveness stands unparalleled with its competitors. Throughout all the ups and downs IBM’s patent portfolio has remained larger than its most significant competitors combined. With the application of the paradigm of threes theory it is possible to unlock the inventiveness of IBM. By looking at IBM through paradigm of threes theory the company is theoretically over 100 years ahead of the marketplace. Beyond, today’s mainframes, quantum and super computers, research indicates that 100 years from now IBM will be producing trinary, optical supercomputers. They will be based on a triaxle Chrystal Chip. The caching algorithm will use Algorithm Language Three. This is to be a human language based caching algorithm. This should pave the way for sentient computers. Soon these computers will process information faster than humans think, at least in theory. But what is a valid theory, and how can you tell?
A theory represents systematically organized knowledge applicable in a relatively wide variety of circumstances, especially a system of assumptions, accepted principles, and rules of procedure devised to analyze, predict, or otherwise explain the nature or behavior of a specified set of phenomena. It requires abstract reasoning; speculation. It is a belief that guides action or assists comprehension or judgment. It is also an assumption based on limited information or knowledge; a conjecture. Then why pursue theories?
A theory offers a model of proving and verifying the correctness of a futuristic concept. This requires a consciously directed concentration of the powers of reasoning to assemble all related thoughts of a given subject. Abstraction and then theory application allows one to analyze, penetrate and hopefully understand the reality of a concept. Theory application is very important as it disciplines thought processes and helps the human mind to understand and grasp exceptionally complicated structures, ideas and concepts.
A paradigm of threes theory appears as a unifying set of methodologies, with the results as variations on a theme. The theme manifests itself in a consistent and repeatable way. Then non-technicians observe evidence to support the premises of the theory. Surprisingly, this occurs for a valid theory regardless of all that is going on in an industry. This is why IBM’s Vision is so important and why you will be able to see the evidence to support this cybernetic theory.
Beyond IBM, threes theory universally makes a visionary statement about the entire computer industry. This statement impacts current knowledge with a confirming effect in business and industry. So what’s new and different? All modern day computers have been designed by the application of a two position electric switch. Binary computers have software that is layered with graphical user interfaces. These interfaces hide the binary codes that computers understand, the 1's and 0's. But paradigm of threes theory proposes that computer technology would work better if using base 3, instead of base 2. This is also known as trivalent logic.
As applied to the computer industry parallels emerge presenting empirical evidence to support the theory. First, is the application of the theory to computer hardware and architectures. This area demonstrates three-tier becoming pre-emergent over all large computer architectures, as well as clusters of three computers appearing. Second, are software and the software development life cycle. This relates to application development of software, exploration of formal metrics and presenting the idea of sentient and autonomic computing. Third, is the identification of patterns of three to marketing in business and industry. All told, this assessment only highlights this theory application. Bear in mind that most existing methods and metrics are theoretically unsound and intuitively unpersuasive. It is this point of vision in the computer industry that has created value in looking at the computer industry with a theory. It asks the question, “is there empirical evidence to support a paradigm of threes concept applied to the computer industry?”
If valid, this theory would have to be highly applicable to the computer industry. Specifically, the limitations of the binary architecture would hint at three tier and ternary concepts. Not since the Setun of 1958 has anyone seriously tried to confirm the validity of ternary concepts. However, if looking for this type of confirmation, it starts with IBM’s System Application Architecture (SAA). Before SAA, there was almost nothing to support this theory. IBM announced this architectural initiative in the spring of 1987. Before SAA there were no multi-tier computer architectures. Either everything was on a PC, a server or a mainframe. Unique to SAA was the presentation of a three-tier architecture, including interoperability between PC's, servers and mainframes. This was five years before the computer industry started to explore the concept of client-server, generally a binary or two-tier architecture. Soon after, SAA became a misunderstood idea. Nevertheless, SAA was based on a futuristic scientific phenomenon, specifically, a paradigm of threes.
Confirmation of IBM’s Paradigm of Threes is well documented and can be found in IBM Systems Journals. For example, the Enterprise Information System documents contain an architectural blueprint for workstations, mid-range and large computer systems. It has three components,
Common User Access
Common Programming Interface
Common Communication Support
System Application Architecture was the first three-tier architecture presented to the computer industry. Conjecture indicates trinary concepts predict the obsolescence of binary computers. Then all software would need to enable trinary instead of binary architectures. Conclusion, SAA was ahead of its time. Therefore, at some future time all computers that currently exist will be replaced with those having three-position switch technology. This is the basis of the IBM Vision, and most of the products of its application are years into the future.
Since this concept obsoletes all software currently in existence. How could something this advanced find relevance in today's world of commercial software development? This answer can be found in software, or methods of software development. Again a confirmation of threes theory can be found in an IBM strategy, specifically AD/Cycle. AD or Application Development has three models...
Enterprise Model
Design Model
Technology Model
The process of enterprise modeling controls and directs many aspects of creative license, specifically computer knowledge and enthusiasm. For enterprise modeling there is IBM’s RUP or CASE Technologies, Business Architect. These are the only two mainframe enterprise modeling tools to grow out of AD/Cycle. The "how" to improve things would appear to find fulfillment with enterprise modeling. But why use a paradigm of threes modeling metric?
IBM’s threes theory speculates that human minds process information with a trinary, rather than a binary method. Then computers and software work better if based on a threes concept. This is the primary hypothesis. Specifically, if computers and software were modeled after the human brain artificial intelligence could evolve from a few selected industries into the mainstream.
To support this premise a “variations on a theme” would need to present themselves to the computer industry; otherwise a premise of theoretical universality fails. Now let us look more deeply into some of IBM's strategies; again, the AD/Cycle. Its repository has…
A Conceptual View
A Storage View
A Logical View
Again, the threes pattern occurs with a
Specification Level
Implementation Level
Operational Level
As IBM’s threes theory is valid, the logical and enterprise models proposed years ago still represent futuristic ideas to business and industry. However, it does cause confusion. If these ideas were ahead of the marketplace in 1987, then where is the three-tier concept now? More recently note IBM's MVC, J2EE Architectural Strategy. It appears to be based on threes theory and looks similar to previous three tier architectural blueprints. Therefore, to answer the premise of the theory, large computer architectural strategies are perpetually based on patterns of three. This is the basis of the IBM Vision. See MVC samples as follows.
The performance architecture has these levels of modeling (Model, View, Controller). The Model View Controller (MVC) application architecture helps in design and analysis. Its architecture is a way to divide functionality among objects involved in maintaining and presenting data so as to minimize the degree of coupling between the objects. The MVC architecture was originally developed to map the traditional input, processing, and output tasks to the graphical user interaction model. However, it is easy to map these concepts into the domain of multi-tier Web-based enterprise applications. Three parts define the separation of these areas.
1) Controller - Manages and controls all interactions between the user and the application. Usually the controller is a servlet that receives the user request and passes the input parameters to the model that does the work. Also, when the business process ends, it controls the creation of the View. The Application Development Life Cycle phases are composed of a...
Logic model
IT Component model
Enterprisewide model
2) Model - Encapsulates the business logic, rules, and data, and does the business processing, usually implemented by Enterprise Java Beans or EJBs. Initiation, design, development, test, transition and production with EJBs contain these three logical tiers…
Presentation logic
Controller logic
Business logic
3) View - Uses the results of the business processes and constructs the response presented to the user, usually implemented through Java Server Pages (JSP's).
This pattern of threes can also be found in the IBM's mainframe Parallel Sysplex coupling technology. Specifically, the heart of the Parallel Sysplex coupling facility provides three behavioral models to enable efficient clustering protocols: Lock model, Cache model, Queue Model. The Cache structure architecture supports three caching protocols, Directory-only cache, Store-through cache, Store-in cache. Please refer to the information below for more information on IBM’s Triplex. Therefore the most advanced computer in the world is based on paradigm of threes. It is not a cloud of computers, but a definitive three cluster mainframe architecture, as the top tier in SAA. In perhaps the greatest of paradoxes IBM is both the most inventive company in the computer industry, however, the most advanced ideas are all based on threes theory. If you are uncertain about how to react to this information, simply, how difficult could patterns of threes become? Click this link to review IBM’s Triplex Mainframe cluster .
Outside the computer industry further evidence of pattern of threes phenomenon is found. For example, cognitive analysis. Cognitive analysis is the basis for knowledge engineering. Expert systems need to capture expert knowledge in software. This requires working with a human expert and figuring out what they know. It also includes an analysis of how they tie together varying facts to reason about the problems that they solve.
As all minds inadvertently use a threes concept to think, to reason and to organize thoughts there is empirical evidence. Also, there are indications that minds describe and classify knowledge by the application of threes theory. For this example there are three ways to classify knowledge.
Heuristic knowledge
Domain knowledge
Theoretical knowledge
Using a hierarchy or classification that explains response data approaches the process of cognitive analysis. Chunking is a term to describe a process where people group objects together into some more abstract high level object. Human memory is composed of different hierarchies, each containing different domains. This hierarchy illustrates three levels of chunks or objects. A domain theory is derived from more than one deep theory. Drawing a parallel to computer software development and expert systems, a procedural model for software includes…
Inquiry rules
Recognition rules
Transfer rules
When applying a threes metric a knowledge, software or expert systems engineer has three types of tools for analyzing cognitive tasks.
Intellectual tools
Notation tools
Empirical tools
Summarizing, IBM’s threes theory focuses the computer industry's vision based on old premises that were ahead of their time. Specifically, then as now three-tier concepts and methods could be applied to better understand aspects of directing computer architectural initiatives. This is especially true for Internet systems linked to mainframe systems for security, interfaces and recoverability. Therefore, the three-tier initiatives of the late 1980's and early 1990's stand as a timeless vision in a period of rapid expansion and then increasing complexity in technology. Yet they all have the same theoretical foundation. That foundation is universally in patterns of three.
Today autonomic computer initiatives are hoping to eventually create sentient computers. As the evidence supports the theory, sentient computers might be achieved by applying the threes metric; "self-configuring, self-healing, self-tuning". eLiza is IBM’s vision of a sentient computer. Computers will then be able to mimic and emulate human thought processes. Computers based on threes theory will be taught as they listen and learn. Theoretically, computers should learn how to think. This theory presents a hypothesis of how this might occur. In short, if you construct a brain like a human’s, then it becoming intelligent may be a foregone conclusion. This is the foundation of the IBM Vision, but also a caveat. Computers today have the intelligence of a lizard. Within a few years IBM could be demonstrating significant breakthroughs in Artificial Intelligence based on threes theory. IBM predicts that computers will become as smart as a mammal within the next 25 years. Then what of Watson? Watson is best understood as a prototype. The things that have been learned from Watson are invaluable, but also confirm many of the limitations of binary computers and binary logic.
As predicted, the application of threes theory to marketing presents consistent and repeatable patterns and sets of three. The paradigm of threes marketing concept would therefore be of futuristic significance. Here are numerous examples of paradigms of three in marketing. Look for them on your own and you will be able to find them quite easily.
Eye it. Try it. Buy it.
Best Haulers. Best Savers. Best Sellers.
So light, So crisp, So refreshing.
New elegance, New excellence, New excitement!
First in style. First in vision. First by far with a post war car.
Over the phone. Over the web. Over the desk.
Open Hearts. Open Minds. Open Doors.
Want it. Get it. Own it.
Unbundle, Untangle, Unwire.
Easy to Buy. Easy to Own. Easy as Dell.
That fast. That easy. That advanced.
Think first. Think fast. Think different.
Do it. Try it. Fix it.
People who think. People who do. People who get it.
Conclusion: Paradigm of Threes is evidence to support the IBM Vision
Cybernetics is a perpetual fascination of science fiction. We are transported to a time in the future were the rules have changed. Almost always frightening, future shock is not for the timid. The same could be said of cybernetics. However, cybernetics does not exist today. While fascinating and relevant to a small group of professionals, the best we have is Watson. Watson shows great promise, but today is nowhere near the concept of cybernetics. Given that research indicates the human brain is ternary, binary computers are inadequate to process trivalent logic. Therein lays the caveat. But IBM is both a computer company of today and of tomorrow. Confusion starts attempting to understand today’s technology as a road map to tomorrow. Just as there are no ternary computers operating today, there are no androids and no vision of future technology based on sound research. Despite all these limitations science fiction is impatient to make tomorrow happen today. That proves to be both impractical and unrealistic without understanding current technology, its advantages, as well as its limitations. So it is important to appropriately set the stage to enable tomorrow’s technology. This is the beginning of the IBM Vision.
Be aware that IBM’s leadership in inventiveness stands unparalleled with its competitors. Throughout all the ups and downs IBM’s patent portfolio has remained larger than its most significant competitors combined. With the application of the paradigm of threes theory it is possible to unlock the inventiveness of IBM. By looking at IBM through paradigm of threes theory the company is theoretically over 100 years ahead of the marketplace. Beyond, today’s mainframes, quantum and super computers, research indicates that 100 years from now IBM will be producing trinary, optical supercomputers. They will be based on a triaxle Chrystal Chip. The caching algorithm will use Algorithm Language Three. This is to be a human language based caching algorithm. This should pave the way for sentient computers. Soon these computers will process information faster than humans think, at least in theory. But what is a valid theory, and how can you tell?
A theory represents systematically organized knowledge applicable in a relatively wide variety of circumstances, especially a system of assumptions, accepted principles, and rules of procedure devised to analyze, predict, or otherwise explain the nature or behavior of a specified set of phenomena. It requires abstract reasoning; speculation. It is a belief that guides action or assists comprehension or judgment. It is also an assumption based on limited information or knowledge; a conjecture. Then why pursue theories?
A theory offers a model of proving and verifying the correctness of a futuristic concept. This requires a consciously directed concentration of the powers of reasoning to assemble all related thoughts of a given subject. Abstraction and then theory application allows one to analyze, penetrate and hopefully understand the reality of a concept. Theory application is very important as it disciplines thought processes and helps the human mind to understand and grasp exceptionally complicated structures, ideas and concepts.
A paradigm of threes theory appears as a unifying set of methodologies, with the results as variations on a theme. The theme manifests itself in a consistent and repeatable way. Then non-technicians observe evidence to support the premises of the theory. Surprisingly, this occurs for a valid theory regardless of all that is going on in an industry. This is why IBM’s Vision is so important and why you will be able to see the evidence to support this cybernetic theory.
Beyond IBM, threes theory universally makes a visionary statement about the entire computer industry. This statement impacts current knowledge with a confirming effect in business and industry. So what’s new and different? All modern day computers have been designed by the application of a two position electric switch. Binary computers have software that is layered with graphical user interfaces. These interfaces hide the binary codes that computers understand, the 1's and 0's. But paradigm of threes theory proposes that computer technology would work better if using base 3, instead of base 2. This is also known as trivalent logic.
As applied to the computer industry parallels emerge presenting empirical evidence to support the theory. First, is the application of the theory to computer hardware and architectures. This area demonstrates three-tier becoming pre-emergent over all large computer architectures, as well as clusters of three computers appearing. Second, are software and the software development life cycle. This relates to application development of software, exploration of formal metrics and presenting the idea of sentient and autonomic computing. Third, is the identification of patterns of three to marketing in business and industry. All told, this assessment only highlights this theory application. Bear in mind that most existing methods and metrics are theoretically unsound and intuitively unpersuasive. It is this point of vision in the computer industry that has created value in looking at the computer industry with a theory. It asks the question, “is there empirical evidence to support a paradigm of threes concept applied to the computer industry?”
If valid, this theory would have to be highly applicable to the computer industry. Specifically, the limitations of the binary architecture would hint at three tier and ternary concepts. Not since the Setun of 1958 has anyone seriously tried to confirm the validity of ternary concepts. However, if looking for this type of confirmation, it starts with IBM’s System Application Architecture (SAA). Before SAA, there was almost nothing to support this theory. IBM announced this architectural initiative in the spring of 1987. Before SAA there were no multi-tier computer architectures. Either everything was on a PC, a server or a mainframe. Unique to SAA was the presentation of a three-tier architecture, including interoperability between PC's, servers and mainframes. This was five years before the computer industry started to explore the concept of client-server, generally a binary or two-tier architecture. Soon after, SAA became a misunderstood idea. Nevertheless, SAA was based on a futuristic scientific phenomenon, specifically, a paradigm of threes.
Confirmation of IBM’s Paradigm of Threes is well documented and can be found in IBM Systems Journals. For example, the Enterprise Information System documents contain an architectural blueprint for workstations, mid-range and large computer systems. It has three components,
Common User Access
Common Programming Interface
Common Communication Support
System Application Architecture was the first three-tier architecture presented to the computer industry. Conjecture indicates trinary concepts predict the obsolescence of binary computers. Then all software would need to enable trinary instead of binary architectures. Conclusion, SAA was ahead of its time. Therefore, at some future time all computers that currently exist will be replaced with those having three-position switch technology. This is the basis of the IBM Vision, and most of the products of its application are years into the future.
Since this concept obsoletes all software currently in existence. How could something this advanced find relevance in today's world of commercial software development? This answer can be found in software, or methods of software development. Again a confirmation of threes theory can be found in an IBM strategy, specifically AD/Cycle. AD or Application Development has three models...
Enterprise Model
Design Model
Technology Model
The process of enterprise modeling controls and directs many aspects of creative license, specifically computer knowledge and enthusiasm. For enterprise modeling there is IBM’s RUP or CASE Technologies, Business Architect. These are the only two mainframe enterprise modeling tools to grow out of AD/Cycle. The "how" to improve things would appear to find fulfillment with enterprise modeling. But why use a paradigm of threes modeling metric?
IBM’s threes theory speculates that human minds process information with a trinary, rather than a binary method. Then computers and software work better if based on a threes concept. This is the primary hypothesis. Specifically, if computers and software were modeled after the human brain artificial intelligence could evolve from a few selected industries into the mainstream.
To support this premise a “variations on a theme” would need to present themselves to the computer industry; otherwise a premise of theoretical universality fails. Now let us look more deeply into some of IBM's strategies; again, the AD/Cycle. Its repository has…
A Conceptual View
A Storage View
A Logical View
Again, the threes pattern occurs with a
Specification Level
Implementation Level
Operational Level
As IBM’s threes theory is valid, the logical and enterprise models proposed years ago still represent futuristic ideas to business and industry. However, it does cause confusion. If these ideas were ahead of the marketplace in 1987, then where is the three-tier concept now? More recently note IBM's MVC, J2EE Architectural Strategy. It appears to be based on threes theory and looks similar to previous three tier architectural blueprints. Therefore, to answer the premise of the theory, large computer architectural strategies are perpetually based on patterns of three. This is the basis of the IBM Vision. See MVC samples as follows.
The performance architecture has these levels of modeling (Model, View, Controller). The Model View Controller (MVC) application architecture helps in design and analysis. Its architecture is a way to divide functionality among objects involved in maintaining and presenting data so as to minimize the degree of coupling between the objects. The MVC architecture was originally developed to map the traditional input, processing, and output tasks to the graphical user interaction model. However, it is easy to map these concepts into the domain of multi-tier Web-based enterprise applications. Three parts define the separation of these areas.
1) Controller - Manages and controls all interactions between the user and the application. Usually the controller is a servlet that receives the user request and passes the input parameters to the model that does the work. Also, when the business process ends, it controls the creation of the View. The Application Development Life Cycle phases are composed of a...
Logic model
IT Component model
Enterprisewide model
2) Model - Encapsulates the business logic, rules, and data, and does the business processing, usually implemented by Enterprise Java Beans or EJBs. Initiation, design, development, test, transition and production with EJBs contain these three logical tiers…
Presentation logic
Controller logic
Business logic
3) View - Uses the results of the business processes and constructs the response presented to the user, usually implemented through Java Server Pages (JSP's).
This pattern of threes can also be found in the IBM's mainframe Parallel Sysplex coupling technology. Specifically, the heart of the Parallel Sysplex coupling facility provides three behavioral models to enable efficient clustering protocols: Lock model, Cache model, Queue Model. The Cache structure architecture supports three caching protocols, Directory-only cache, Store-through cache, Store-in cache. Please refer to the information below for more information on IBM’s Triplex. Therefore the most advanced computer in the world is based on paradigm of threes. It is not a cloud of computers, but a definitive three cluster mainframe architecture, as the top tier in SAA. In perhaps the greatest of paradoxes IBM is both the most inventive company in the computer industry, however, the most advanced ideas are all based on threes theory. If you are uncertain about how to react to this information, simply, how difficult could patterns of threes become? Click this link to review IBM’s Triplex Mainframe cluster .
Outside the computer industry further evidence of pattern of threes phenomenon is found. For example, cognitive analysis. Cognitive analysis is the basis for knowledge engineering. Expert systems need to capture expert knowledge in software. This requires working with a human expert and figuring out what they know. It also includes an analysis of how they tie together varying facts to reason about the problems that they solve.
As all minds inadvertently use a threes concept to think, to reason and to organize thoughts there is empirical evidence. Also, there are indications that minds describe and classify knowledge by the application of threes theory. For this example there are three ways to classify knowledge.
Heuristic knowledge
Domain knowledge
Theoretical knowledge
Using a hierarchy or classification that explains response data approaches the process of cognitive analysis. Chunking is a term to describe a process where people group objects together into some more abstract high level object. Human memory is composed of different hierarchies, each containing different domains. This hierarchy illustrates three levels of chunks or objects. A domain theory is derived from more than one deep theory. Drawing a parallel to computer software development and expert systems, a procedural model for software includes…
Inquiry rules
Recognition rules
Transfer rules
When applying a threes metric a knowledge, software or expert systems engineer has three types of tools for analyzing cognitive tasks.
Intellectual tools
Notation tools
Empirical tools
Summarizing, IBM’s threes theory focuses the computer industry's vision based on old premises that were ahead of their time. Specifically, then as now three-tier concepts and methods could be applied to better understand aspects of directing computer architectural initiatives. This is especially true for Internet systems linked to mainframe systems for security, interfaces and recoverability. Therefore, the three-tier initiatives of the late 1980's and early 1990's stand as a timeless vision in a period of rapid expansion and then increasing complexity in technology. Yet they all have the same theoretical foundation. That foundation is universally in patterns of three.
Today autonomic computer initiatives are hoping to eventually create sentient computers. As the evidence supports the theory, sentient computers might be achieved by applying the threes metric; "self-configuring, self-healing, self-tuning". eLiza is IBM’s vision of a sentient computer. Computers will then be able to mimic and emulate human thought processes. Computers based on threes theory will be taught as they listen and learn. Theoretically, computers should learn how to think. This theory presents a hypothesis of how this might occur. In short, if you construct a brain like a human’s, then it becoming intelligent may be a foregone conclusion. This is the foundation of the IBM Vision, but also a caveat. Computers today have the intelligence of a lizard. Within a few years IBM could be demonstrating significant breakthroughs in Artificial Intelligence based on threes theory. IBM predicts that computers will become as smart as a mammal within the next 25 years. Then what of Watson? Watson is best understood as a prototype. The things that have been learned from Watson are invaluable, but also confirm many of the limitations of binary computers and binary logic.
As predicted, the application of threes theory to marketing presents consistent and repeatable patterns and sets of three. The paradigm of threes marketing concept would therefore be of futuristic significance. Here are numerous examples of paradigms of three in marketing. Look for them on your own and you will be able to find them quite easily.
Eye it. Try it. Buy it.
Best Haulers. Best Savers. Best Sellers.
So light, So crisp, So refreshing.
New elegance, New excellence, New excitement!
First in style. First in vision. First by far with a post war car.
Over the phone. Over the web. Over the desk.
Open Hearts. Open Minds. Open Doors.
Want it. Get it. Own it.
Unbundle, Untangle, Unwire.
Easy to Buy. Easy to Own. Easy as Dell.
That fast. That easy. That advanced.
Think first. Think fast. Think different.
Do it. Try it. Fix it.
People who think. People who do. People who get it.
Conclusion: Paradigm of Threes is evidence to support the IBM Vision
.
IBM Blueprint 2000 - circa 1993