It was interesting, going looking at some of the youtube videos from some of the inventors. It seems that the only reason it didn't have a machine writable program memory was cost. It had the ability to do conditional flow and used an instruction decoder. Previous computers were patched pieces like counters, adders, inverters and constants. Flow control was done with counters and data was passed to the next patch. RAM was just becoming available with things like the William's tube. Otherwise RAM was a number of flipflops made with vacuum tubes. At two triodes per latch the cost per bit was quite high. A diode ROM array made sense. The concept was there, only the implementation was different. I was like that two with the thought of how the program was loaded but when one considers the leap from a number of patched elements to a cpu, the ability to have RAM loadable wasn't as relevant until until they got away from the Manchester architecture. Dwight Dwight ________________________________ From: cctalk <cctalk-bounces at classiccmp.org> on behalf of Paul Birkel via cctalk <cctalk at classiccmp.org> Sent: Monday, November 13, 2017 11:52:15 PM To: 'Noel Chiappa'; 'General Discussion: On-Topic and Off-Topic Posts' Subject: RE: Computing Pioneer Dies -----Original Message----- From: cctalk [mailto:cctalk-bounces at classiccmp.org] On Behalf Of Noel Chiappa via cctalk Sent: Monday, November 13, 2017 5:00 PM To: cctalk at classiccmp.org Cc: jnc at mercury.lcs.mit.edu Subject: Re: Computing Pioneer Dies Just to clarify my understanding of your position, is a system with a CPU chip (say one of the 68K models) with only ROM not a 'stored program machine'? Noel PS: You really should look at the book ("ENIAC In Action"), and not rely on the articles; it's later, more coherent (not being split across a handful of papers), and much more detailed (e.g. it includes the instruction set for the 'programmed' version of the ENIAC). ----- Note that most of the BRL references in the three articles in the IEEE Annals of the History of Computing are available online through DTIC. Search using Google Scholar. Unfortunately the referenced manuscripts located in private archives appear to remain inaccessible to the general public. Tables I thru III in the second paper, offering a set of side-by-side comparisons for "ENIAC, EDVAC, and three other computers of the late 1940s" are well worth contemplation. The third paper puts a practical perspective on the somewhat more theoretical perspectives of the first two papers. "1948 ENIAC" was a quite interesting reorganization/application of the computing resources available in the "1945 ENIAC". It looks like the somewhat less expensive paperback for "ENIAC in Action" is due for publication in January. Noel: Does the book make any attempt to trace any technological/social effects *from* the "1948 ENIAC" to other computer developments? Or are we to conclude that the "1948 ENIAC" was aa significant "existence proof" for aspects of the First Report (and evidently quite productive as a computational tool) but sterile with respect to direct progenitors and impact on other computer developments of the late-1940's? For example, do they cite any evidence that either BINAC or early UNIVAC were other than "from whole cloth" in nature? Any of the "IACs"? Perhaps more at the level of "coding style/procedures" than hardware architecture/design/implementation? As an engineer, I like systems that "get stuff done" and the "1948 ENIAC" certainly qualifies. As a (computer) scientist I like what SSEM demonstrated and the fact that it had direct (physical & intellectual) offspring. As a practical person I like that the SSEM directly led to the "first general-purpose commercially produced computer" (Ferranti Mark 1). There's a lot to like in the span of 1945-1955! ----- paul