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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal style='margin-bottom:12.0pt'><span style='color:#1F497D'>[Len is also having posting problems with the list. While I’m here, to address his final point, self modification of code goes much earlier than Wilkes, Wheeler & Gill. The instruction set described original 1945 EDVAC Report would have relied on code modification during execution for looping, conditional branching, or indexing through a matrix. However this capability was confined to address modification rather than unrestricted instruction modification. This restriction was relaxed in subsequent work by von Neumann’s group and, as mentioned earlier, in Turing’s 1946 description of the ACE design. Designers of early stored program computers added conditional branch instructions and indirect addressing capabilities such as Manchester’s famous index register to sharply reduce the need for self modifying code. There’s a clear description of this in Priestley’s Science of Operations, particularly pages 164- 172.] </span><br><br>Tom,<br><br>I'm not sure why the first appearance of the precise bigram "stored program" is so significant. There were certainly very early near-misses, such as this from the 1947 Burks, Goldstine, and von Neumann "Preliminary Discussion" paper:<br><br>"It is evident that the machine must be capable of storing in some manner not only the digital information needed... but also the instructions which govern the actual routine to be performed. ... Hence there must be some organ capable of <b>storing </b>these <b>program </b>orders."<br><br>Even earlier is this from the 1945 "Description of the ENIAC and Comments on Electronic Digital Computing Machines". It is farther from the precise linguistic target, but exactly on point conceptually:<br><br>"This requirement as to instruction speed can be met in a direct and simple fashion by <b>storing instructions</b> (in numerical code, so to speak) <b>in memory</b> elements or registers of the same type as those used to store the numerical data."<br><br>If your focus is on the ability of programs to modify themselves, I don't know whether there is a reference earlier than the one in Wilkes, Wheeler, and Gill that Allan Olley pointed out. The significance of that ability is interesting to ponder. Doron Swade has done some research in this area, and in his article in the December 2009 "EDSAC at 60" issue of The Computer Journal he says of the expert opinions he received, "whether the primary benefit was one of principle or practice was frustratingly blurred."<br><br>-- Len Shustek<span style='color:#1F497D'><o:p></o:p></span></p></div></body></html>