19 Mar 2009
Introducing “Questions”
In the category “Questions” you can ask any question about Virtual Finite State Machines or about how to use StateWORKS development tools. Simply post a comment to this entry.
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Tags: Finite state machine, stateworks, VFSM
Posted in Questions
Posted by Ferdinand Wagner on 19 Mar 2009 at 13:16
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23 Feb 2009
What is a state machine, again?
For many years we have been trying to popularize the correct concept of a finite state machine. In fact, we do not invent anything, we just present a state machine as defined ca. 60 years ago. In the beginning it had been applied to a design of hardware systems as software did not exist at that time. But the concept of a finite state machine is not bound in any way to the hardware; it is just a notation to describe a behavior and as such it is not bound to the physical implementation.
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Tags: concurrency, event driven, Finite state machine
Posted in Finite state machine
Posted by Ferdinand Wagner on 23 Feb 2009 at 20:28
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22 Nov 2008
Ours is probably the only industry which gets paid, first to do a bad job and then to keep fixing it
Recently we’ve received an email which characterizes the software profession as cited in the title.
That characterisation is not flattering, but may be appropriate. There are professions such as banking that seem to attract criminals, or should we say incurable optimists? We do not mean to imply that all bankers are criminals, but that this group contains more of them than other professions because “that is where the money is”.
Obviously, programmers does not belong to this category. To be a (good) programmer requires appropriate talent, some knowledge or even education and experience in several years of hard work. It is not very attractive even if we are relatively well paid. Unfortunately, in the eyes of our customers, clients or employers “we do a bad job and then keep on fixing it”.
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Tags: programmer, software crisis, software problem
Posted in General
Posted by Ferdinand Wagner on 22 Nov 2008 at 17:36
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18 Jul 2008
Using tcp/ip as an I/O interface
StateWORKS RTDB is a tcp/ip server. All attributes of each object in RTDB can be accessed by tcp/ip clients. A client connects to the RTDB server using two sockets: Request and Event. The Request (R) socket is used for queueing of object attributes. The Event (E) socket delivers object attributes that are registered as “advise” in RTDB.
The primary goal of the server/client model of the RTDB has been communication with a User Interface. When the tcp/ip communication began to be used for input/output purposes we could extend the StateWORKS server/client model very easily by completing attributes of corresponding object by a concept of RawData. The completion of Raw data are required for objects: DI, DO, NI, NO, the objects CMD, XDA, PAR and DAT possessing per se the raw data values.
We have add another technical note to our web site describing the tcp/ip communication in RTDB. You may download the note http://www.stateworks.com/active/download/TN24-Using-tcpip-as-io.pdf to study the details.
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Tags: client, RTDB, server, server/client model, tcp/ip
Posted in stateworks
Posted by Ferdinand Wagner on 18 Jul 2008 at 12:09
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7 Jul 2008
Getting started
I received an email from John M. who is evaluating StateWORKS. He started with a fairly complex example that has confronted him with several issues that must be understood to use effectively our tools and the run-time system. Because of a general nature of his questions I put (with his acceptance) my answers into that blog.
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Tags: entry action, Finite state machine, input action, state transition, stateworks
Posted in stateworks
Posted by Ferdinand Wagner on 7 Jul 2008 at 12:38
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11 Mar 2008
Book critics
Our book “Modeling software with Finite State Machines” has received quite good reviews. Recently, I read in Amazon two controversial reviews on which I commented to my friends in an email as follows:
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Tags: Finite state machine, modeling software
Posted in General
Posted by Ferdinand Wagner on 11 Mar 2008 at 10:08
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3 Mar 2008
What is a state machine?
Our web site contains several technical notes and papers that discuss some aspects of software engineering associated with the concept of a finite state machine. On introducing our blog we have decided to present you a few topics covered by a group of our documents. We started with the Mealy and Moore models of a finite state machine, honoring the fact that it is a favorite topic according to visitors’ statistics. The topic that we would like to present you today is “What is a state machine”.
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Tags: automata, state, state machine, stateworks, thread
Posted in Finite state machine
Posted by Ferdinand Wagner on 3 Mar 2008 at 08:00
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22 Feb 2008
Moore or Mealy model
Moore and Mealy models are the basic two models of state machines as defined in the literature. To understand the differences between them the actions (outputs) must be defined and bound to state changes. The technical note “Moore or Mealy model?” discusses both models and shows that the optimal solution is achieved when features of both models are used in a mixed model. Although the concepts of these two models are useful when performing certain theoretical studies, they are also interesting for software developers, and StateWORKS makes the use of a mixed model easy and effective.
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Tags: Mealy, Moore, state machine, stateworks
Posted in Finite state machine
Posted by Ferdinand Wagner on 22 Feb 2008 at 17:58
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