{"id":14600,"date":"2022-05-10T22:25:56","date_gmt":"2022-05-11T02:25:56","guid":{"rendered":"https:\/\/carleton.ca\/scs\/?page_id=14600"},"modified":"2026-06-02T14:59:22","modified_gmt":"2026-06-02T18:59:22","slug":"tr-20-not-quite-linear-random-access-memories","status":"publish","type":"page","link":"https:\/\/carleton.ca\/scs\/research\/scs-technical-reports\/technical-reports-1983\/tr-20-not-quite-linear-random-access-memories\/","title":{"rendered":"TR-20: Not-Quite-Linear Random Access Memories"},"content":{"rendered":"\n<section class=\"w-screen px-6 cu-section cu-section--white ml-offset-center md:px-8 lg:px-14\">\n    <div class=\"space-y-6 cu-max-w-child-5xl  md:space-y-10 cu-prose-first-last\">\n\n            <div class=\"cu-textmedia flex flex-col lg:flex-row mx-auto gap-6 md:gap-10 my-6 md:my-12 first:mt-0 max-w-5xl\">\n        <div class=\"justify-start cu-textmedia-content cu-prose-first-last\" style=\"flex: 0 0 100%;\">\n            <header class=\"font-light prose-xl cu-pageheader md:prose-2xl cu-component-updated cu-prose-first-last\">\n                                    <h1 class=\"cu-prose-first-last font-semibold !mt-2 mb-4 md:mb-6 relative after:absolute after:h-px after:bottom-0 after:bg-cu-red after:left-px text-3xl md:text-4xl lg:text-5xl lg:leading-[3.5rem] pb-5 after:w-10 text-cu-black-700 not-prose\">\n                        TR-20: Not-Quite-Linear Random Access Memories\n                    <\/h1>\n                \n                                \n                            <\/header>\n\n                    <\/div>\n\n            <\/div>\n\n    <\/div>\n<\/section>\n\n<p>Carleton University<br>\n<a href=\"https:\/\/carleton.ca\/scs\/research\/scs-technical-reports\/technical-reports-1983\/\">Technical Report<\/a> <strong>TR-20<\/strong><br>\nMarch 1983<\/p>\n\n\n\n<h2 id=\"not-quite-linear-random-access-memories\" class=\"wp-block-heading tr_t1\">Not-Quite-Linear Random Access Memories<\/h2>\n\n\n\n<p>Jim des Rivieres &amp; Wilf R. LaLonde<\/p>\n\n\n\n<h3 id=\"abstract\" class=\"wp-block-heading\">Abstract<\/h3>\n\n\n\n<p>Not-quite-linear random access memories (NQL-RAMs) are an alternative to conventional linear RAMs, that are better suited to list processing applications, such as LISP systems. Some of their advantageous characteristics are:<\/p>\n\n\n\n<p>General-Purpose.<br>\nLike conventional memories, NQL-RAMs are quite simple and flexible. They do not impose severe constraints on the shapes of objects that may be represented. All words within a multi-word object have addresses.<\/p>\n\n\n\n<p>Compact Representations.<br>\nNQL-RAMs are well-suited to applications involving a large number of small objects. Tagged pointers, tagged words, &#8220;immediate&#8221; pointers, &#8220;invisible&#8221; words, and compact list representations (&#8220;CDR-coding&#8221;) are all supported with memory system overhead as little as three bits per word.<\/p>\n\n\n\n<p>Memory level garbage collection.<br>\nSufficient information is encoded in an NQL-RAM to support application independent garbage collection and compaction, with linearization of sequence-like multi-word structures.<\/p>\n\n\n\n<p>Implementable.<br>\nAll primitive operations of NQL-RAMs can be efficiently implemented either in microcode or with special-purpose hardware. Conventional memory technologies can be used at the implementation level.<\/p>\n\n\n\n<p>The general structure of NQL-RAMs, their use in list processing, and their implementation are all discussed in this paper.<\/p>\n\n\n\n<h3 id=\"download\" class=\"wp-block-heading\">Download<\/h3>\n\n\n\n<p><a href=\"https:\/\/carleton.ca\/scs\/wp-content\/uploads\/sites\/260\/TR-20.pdf\">TR-20.pdf<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Carleton University Technical Report TR-20 March 1983 Not-Quite-Linear Random Access Memories Jim des Rivieres &amp; Wilf R. LaLonde Abstract Not-quite-linear random access memories (NQL-RAMs) are an alternative to conventional linear RAMs, that are better suited to list processing applications, such as LISP systems. Some of their advantageous characteristics are: General-Purpose. Like conventional memories, NQL-RAMs are [&hellip;]<\/p>\n","protected":false},"author":2,"featured_media":0,"parent":11785,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"_acf_changed":false,"_cu_dining_location_slug":"","footnotes":"","_links_to":"","_links_to_target":""},"cu_page_type":[88],"class_list":["post-14600","page","type-page","status-publish","hentry","cu_page_type-technical-report"],"acf":{"cu_post_thumbnail":false},"_links":{"self":[{"href":"https:\/\/carleton.ca\/scs\/wp-json\/wp\/v2\/pages\/14600","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/carleton.ca\/scs\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/carleton.ca\/scs\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/carleton.ca\/scs\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/carleton.ca\/scs\/wp-json\/wp\/v2\/comments?post=14600"}],"version-history":[{"count":1,"href":"https:\/\/carleton.ca\/scs\/wp-json\/wp\/v2\/pages\/14600\/revisions"}],"predecessor-version":[{"id":14601,"href":"https:\/\/carleton.ca\/scs\/wp-json\/wp\/v2\/pages\/14600\/revisions\/14601"}],"up":[{"embeddable":true,"href":"https:\/\/carleton.ca\/scs\/wp-json\/wp\/v2\/pages\/11785"}],"wp:attachment":[{"href":"https:\/\/carleton.ca\/scs\/wp-json\/wp\/v2\/media?parent=14600"}],"wp:term":[{"taxonomy":"cu_page_type","embeddable":true,"href":"https:\/\/carleton.ca\/scs\/wp-json\/wp\/v2\/cu_page_type?post=14600"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}