Amin Girasol<p>I'm finding D. F. Parkhill's 1966 book "The Challenge of the Computer Utility"[0] to be endlessly fascinating. It provides quite a detailed snapshot of the state of computer development. It was written at the tail end of the "Patent wars of 1962–1966"[1], yet there's no mention of integrated circuits, nor "Micrologic" (an early name for ICs).</p><p>In the discussion on memory technology, the book contains several tables as two-page spreads, which are awkward to assimilate when reading the book as a PDF on a small screen. I've included the relevant pages here as two-up images for my own benefit as much as yours! </p><p>The information summarised in the tables is fascinating. In the table "Classification of Memories by Function", much of the language is familiar to a modern reader (compared to, say 1940s discussions of 'organs'); CPU registers, RAM and persistent storage are recognisable:</p><blockquote><p>Storage register: Usually a one- or two-word memory used for the temporary storage of some quantity before it is transferred to another memory or circuit; i.e., accumulator register, multiplicand register, index register, etc.</p><p>Internal working memory: The main working memory of the computer, in which intermediate results and instructions are stored. </p><p>Mass data memory: A high-capacity storage system, external to but under the control of the computer, used for the storage of bulk data such as tables, files, and sub-routines.</p></blockquote><p>...yet the "Classification of Memories by Operating Characteristics" reflect mid-1960s (or older) technologies:</p><blockquote><p>Regenerative: A memory whose contents gradually vanish unless they are periodically regenerated, e.g., a Williams tube.</p></blockquote><p>Modern RAM is of this type!</p><blockquote><p>Read only: A memory whose contents can be changed, if at all, only by off-line human intervention, usually involving rewiring, the removal or insertion of plugs or the punching of holes, e.g., a card capacitor store, diode matrix, etc. </p></blockquote><p>"Memory Devices" is fascinating. Here's just one row:</p><blockquote><p>Type: Magnetic core<br>Physical Principle: remanent magnetization on small cores of square hysteresis-loop <br>ferrite material <br>Application: high-speed internal memory, registers, and buffers <br>Status: standard memory for majority of all computers in all price classes <br>Remarks: in addition to the normal coincident-current destructive readout single-core/bit systems embodiments there are also multiaperture core systems such as Biax and the transfluxor systems, and multiple-core/bit systems also wired-core read-only systems </p></blockquote><p>Biax? Transfluxor systems?</p><p>...and what on earth was "Magnetic rod memory"?</p><blockquote><p>Type: Magnetic rod<br>Physical Principle: magnetic coupling via removable ferrite rods between loops in a <br>woven mesh <br>Application: read-only very high-speed auxiliary internal store <br>Status: in use on Univ. of Manchester MUSE, Ferranti ATLAS computers, and several Italian machines <br>Remarks: retains advantages of wired-core memories but permits easy modification. Highest speed operating memory of comparable size to date, (0.15 microsecond access time, 8192 words, 48 bits)</p></blockquote><p>...sounds promising! Why haven't I heard of this technology? Check Wikipedia[2]:</p><blockquote><p>Rod memory is one of the many variations on magnetic core memory that attempts to lower costs by automating its manufacturing. [...] Like many similar concepts [...] rod memory was competing for the role of taking over from core when the first semiconductor memory systems wiped out the entire market in 1970.</p></blockquote><p>Oof.</p><p>I'm finding it very much worthwhile to read not only older histories of computing, but also old books that provide a survey of the state of the art at a given time.</p><p>[0] <a href="https://archive.org/details/challengeofcompu0000park" rel="nofollow noopener" translate="no" target="_blank"><span class="invisible">https://</span><span class="ellipsis">archive.org/details/challengeo</span><span class="invisible">fcompu0000park</span></a><br>[1] <a href="https://en.wikipedia.org/wiki/Invention_of_the_integrated_circuit#Patent_wars_of_1962–1966" rel="nofollow noopener" translate="no" target="_blank"><span class="invisible">https://</span><span class="ellipsis">en.wikipedia.org/wiki/Inventio</span><span class="invisible">n_of_the_integrated_circuit#Patent_wars_of_1962–1966</span></a><br>[2] <a href="https://en.m.wikipedia.org/wiki/Rod_memory" rel="nofollow noopener" translate="no" target="_blank"><span class="invisible">https://</span><span class="ellipsis">en.m.wikipedia.org/wiki/Rod_me</span><span class="invisible">mory</span></a></p><p><a href="https://oldbytes.space/tags/retrocomputing" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>retrocomputing</span></a> <a href="https://oldbytes.space/tags/vintagecomputing" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>vintagecomputing</span></a> <a href="https://oldbytes.space/tags/computerhistory" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>computerhistory</span></a> <a href="https://oldbytes.space/tags/historyoftechnology" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>historyoftechnology</span></a></p>