Data Flow 4.{1,2}, 3.2

Transcription

1 < = = Computer Science Program, The University of Texas, Dallas Data Flow 4.{1,2}, 3.2 Batch Sequential Pipeline Systems Tektronix Case Study: Oscilloscope Formalization of Oscilloscope "systems where data flows linearly thru a sequence of discrete processing steps" Early database applications transactions were collected into large batches Batch Sequential Pipeline Systems *! " # # " # # $ % & ' ( ( )! " # # $ % & ' ( ( ) +, -. / " # # $ % & ' ( ( ) +, -. / 0 ' 1. 2 " # # $ % & ' ( ( ) 4 5 " # # " # # $ ' 6 ( ( ) a small number of large stand-alone programs performed sequential updates on flat (unstructured) files. / # #! 7 /.! 7!. /! / #! #, # 9 8 / 5 - : ; 3 < 3 =! / > / 5, / / 2 7! >?????. 8 / 5 -. /! / #!. # / #,. /! / #! /! 2 /. 1 5 ; 3 < 3 = 4 A B C. #. - #.. " 4 4

2 «< 3 = Batch Sequential Pipeline Systems input K N O M N I / # #! 7 /.! 7!. /! / #! I F M H transactions #, # 9 8 / 5 - : ; 3 < 3 =! / > / 5, / / 2 7! rejected J K L H validated transactions. 8 / 5 -. /! / #! P Q R S T U V W X Y Z W [ S T U V W X Y P Q R S T U V W X \ Z W [ S T U V W X \ rejected rejected D E F G H I D E F G H I E L M N H sorted transactions sorted transactions sorted transactions reports. # / #,. /! / #! /. - 7 #. - #..! 2 /. 1 5 Constraints: processes run in a fixed sequence; but they do not know each other each runs to completion, producing an output, before the next process begins Internal Structure of Batch Update Process ] ^ _ ` a _ b ^ c d ^ ` _ e f c g b e h i b o p q p r s t procedure call ^ ` ` i d d j c i k _ l _ b ^ c d ^ ` _ e f c m b f g n ` i j c i k _ l _ b ^ c d ^ ` _ e f c ] ^ d e ` h ^ ~ e g ^ _ e f c ` a i ` ^ ` ` i d d ^ ` ` _ e _ i u v v w s t x y s z q { v p t s } s t m f d _ ^ ` ` _ e _ i ƒ ˆ Š Œ Š Ž Œ Š Š Ž Œ Œ Š ƒ Š Ž Œ Š Ž š œ ž Ÿ œ Ÿ ª š œ Ÿ ± ª Ž Š ƒ ƒ Š Œ Œ š ª š ² ³ µ ª

3 < 3 Background Tektronix Case Study industrial development of oscilloscope SA 3-year collaborative effort between several Tektronix product divisions and Computer Research Laboratory Oscilloscope patient monitoring (ECG, EEG, EMG) automotive diagnostics radar control, auto pilot, etc. 5 #. # / 5 <! / 5 # 7.! 1 Oscilloscope Sw. Sys. old: simple analog device modern: rely primarily on digital technology, complex sw 5 #. # / 5! / 5 real-time continuous signal (in voltage) * # 5 5 # sample signals at discrete pts, measure them, display traces huge internal data storage, interface to a network of workstations sophisticated GUI, >>300 user-level commands Tektronix Case Study Needs accommodate frequent changes in hw capability new reqs on UI tailor general-purpose oscilloscope to specialized markets better reconfigurability (how/when/where signal is acquired & displayed) Problem "little reuse" -> not "better, cheaper, faster,..." L K F D ¹ H º M» M J M K N ¼ development convention A PL A tool set A L K F D ¹ H º M» M J M K N ½ L K F D ¹ H º M» M J M K N ¾ Goal: develope an architectural framework development convention B PL B tool set B development convention C PL C tool set C Result: a domain-specific SA as the basis of the next generation oscilloscopes

4 An OO Model object signal waveform trace measurement trigger mode max-min wvfm x-y wvfm accumulate wvfm waveform trace measurement trigger mode a (seq. of) oscillations, in voltages, in a given time interval a (seq. of) oscillations, on screen, in a given time interval frequency in general #peaks in a given segment max/min/avg peak max/min/avg rise or fall in slope rise/decline time slopes greater than a given threshold value + led to a concept recognition & clarification of the data types - no overall model for explaining how the types fit together A Layered Model User Interface Visualization Digitization Hardware interacts with the user and decides which data to show on the screen manipulates saveform (incl. waveform addition) Fourier transformation (converting input signal from time domain to frequency domain) maps digitized waveforms (& measurements) to visula rep. digitize signals and store them internally for later processing waveform acquisition (extracting a bounded time slice of a signal) manipulates fns that filter signals as they enter the oscilloscope À Á Â Ã Ä Å Æ Á Ã communication between neighboring layers only + intuitively appealing, due to partitioning of fns into well-defined groupings - boundaries of abstraction conflicted with the needs for fn interactions users need to affect setting channels in Hardware layer choosing acquisition mode & parameters (e.g., threshold values) in Digitization layer creating derived waveforms (e.g., scaling factor) in Visualization layer

5 OSI Reference Model Application Presentation Session Transport Network Data Link (SMTP, MIME), ftp, telnet, gopher, usenet (NNTP), rlogin, mosaic, netscape,... Ç È É Ê Ë Ì Í É Ì Î È Í Data Rep. (ASCII, EBCDIC), Compression, Encryption graceful data exchange, dialog mgmt, (re)synchronization Split messages Quality Of Service (QOS) multiplexing error-free transmission fast transmission routing accounting Physical Version Management Version Management Object Management Database System Operating System + incremental development + modifiability + portability - structuring can be difficult - performance

6 ä clipped signal waveform trace trace Couple Acquire To-XY Clip times Trigger subsystem A Pipe&Filter Model Measure measurement Couple conditions external signals DC: nothing gets changed AC: the value should be subtracted from the appropriate DC offset Ground: the voltage value = 0 Acquire derive digitized waveforms from the signals, when a trigger event is detected by the Trigger subsystem To-XY Clip converts waveforms into visual data by scaling it and positioning/translating it fits the visual data into a display of certain size + intuitively appealing; well-partitioned functions, etc. - interactive control difficult A Modified Pipe&Filter Model Ï Ó Û Ò Ô ã Û Ó Ö Ð Þ Ô Ý á Ð Ü Ü Ô Ó Ï Ú Þ Ü Ð Ó Ö Ø Ò Ô clipped signal waveform trace trace Couple Acquire To-XY Clip times Trigger subsystem Ô Ó Ð Ø Ï Ð Ñ Ò Ó Ô Õ Ð Ö Ô Ï Ð Ñ Ò Ó Ô Ù Õ Ð Ö Ú Û Ü Ï Ý Ð Ó Ú Ü Þ ß Ð Ý Ö Û Õ Ö Õ Ð Ü Ï à Ï Ý á Ô Ñ Ô Ï Ú â Ô Measure measurement Users dynamically control the oscilloscope by setting parameters + intuitively appealing; well-partitioned functions, etc. + interactive control possible \ å Q T æ W X T X ç è é V W ç V ê X W

7 Oscilloscope in Action -> Formalization Volts Waveform AbsTime Vert scaleh, scalev Trace Horiz 0, maxy Clipped Trace maxx, maxy 0, -maxy maxx, -maxy