{"id":22388,"date":"2025-10-14T11:34:07","date_gmt":"2025-10-14T15:34:07","guid":{"rendered":"https:\/\/carleton.ca\/scs\/?page_id=22388"},"modified":"2026-06-22T13:41:02","modified_gmt":"2026-06-22T17:41:02","slug":"vin134","status":"publish","type":"page","link":"https:\/\/carleton.ca\/scs\/vintage-computing\/item\/vin134\/","title":{"rendered":"Morrow Designs Micro Decision MD-3"},"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                        Morrow Designs Micro Decision MD-3\n                    <\/h1>\n                \n                                \n                            <\/header>\n\n                    <\/div>\n\n            <\/div>\n\n    <\/div>\n<\/section>\n\n\n\n<div class=\"wp-block-buttons is-layout-flex wp-block-buttons-is-layout-flex\">\n<div class=\"wp-block-button is-style-fill\"><a class=\"wp-block-button__link wp-element-button\" href=\"https:\/\/carleton.ca\/scs\/vintage-computing\/item\">Vintage Computing Collection<\/a><\/div>\n<\/div>\n\n\n\n<h2 id=\"morrow-designs-micro-decision-md-3\" class=\"wp-block-heading\">Morrow Designs Micro Decision MD-3<\/h2>\n\n\n\n<p>[Vin134]<\/p>\n\n\n\n<figure class=\"wp-block-image alignright\"><a href=\"https:\/\/carleton.ca\/scs\/wp-content\/uploads\/sites\/260\/PXL_20250716_185727888-scaled.jpg\"><img loading=\"lazy\" decoding=\"async\" width=\"400\" height=\"300\" src=\"https:\/\/carleton.ca\/scs\/wp-content\/uploads\/sites\/260\/PXL_20250716_185727888-400x300.jpg\" alt=\"Morrow Designs Micro Decision MD-3\" class=\"wp-image-22391\" srcset=\"https:\/\/carleton.ca\/scs\/wp-content\/uploads\/sites\/260\/PXL_20250716_185727888-400x300.jpg 400w, https:\/\/carleton.ca\/scs\/wp-content\/uploads\/sites\/260\/PXL_20250716_185727888-160x120.jpg 160w, https:\/\/carleton.ca\/scs\/wp-content\/uploads\/sites\/260\/PXL_20250716_185727888-240x180.jpg 240w, https:\/\/carleton.ca\/scs\/wp-content\/uploads\/sites\/260\/PXL_20250716_185727888-768x577.jpg 768w, https:\/\/carleton.ca\/scs\/wp-content\/uploads\/sites\/260\/PXL_20250716_185727888-1536x1153.jpg 1536w, https:\/\/carleton.ca\/scs\/wp-content\/uploads\/sites\/260\/PXL_20250716_185727888-2048x1538.jpg 2048w, https:\/\/carleton.ca\/scs\/wp-content\/uploads\/sites\/260\/PXL_20250716_185727888-800x600.jpg 800w, https:\/\/carleton.ca\/scs\/wp-content\/uploads\/sites\/260\/PXL_20250716_185727888-360x270.jpg 360w\" sizes=\"auto, (max-width: 400px) 100vw, 400px\" \/><\/a><\/figure>\n\n\n\n<p>The Morrow Designs Micro Decision MD-3, released in the early 1980s, was a Z80A-based CP\/M microcomputer designed to offer affordable, quiet, and user-friendly desktop computing. The MD-3 distinguished itself with two double-sided, half-height 5.25-inch floppy drives, providing a total storage capacity of 400 KB\u2014an upgrade over earlier MD models. It featured a single-board design with 64 KB RAM, two RS-232 serial ports, a parallel port, and convection cooling, resulting in near-silent operation. The MD-3 shipped with bundled software and a menu-driven interface to make CP\/M accessible to novices, and it was often paired with a dedicated terminal such as the Freedom-100. Its compact, RF-shielded metal case and lack of a noisy fan made it stand out among contemporaries, while its design reflected a transitional period just before the dominance of IBM PC compatibles.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Manufacturer<\/strong>: Morrow Designs, Inc.<\/li>\n\n\n\n<li><strong>Type<\/strong>: Desktop<\/li>\n\n\n\n<li><strong>Release Date<\/strong>: 1982<\/li>\n\n\n\n<li><strong>Cost at release<\/strong>: USD $1,790 (CAD ~$6,500 adjusted for inflation)<\/li>\n\n\n\n<li><strong>MIPS<\/strong>: 0.58 (580KIPS)<\/li>\n<\/ul>\n\n\n\n<h3 id=\"hardware-specifications\" class=\"wp-block-heading\">Hardware Specifications<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>CPU<\/strong>: Z80A running at 4 MHz<\/li>\n\n\n\n<li><strong>Memory<\/strong>: 64 KB dynamic RAM<\/li>\n\n\n\n<li><strong>Storage<\/strong>: Two 5.25-inch double-sided, double-density floppy drives (400 KB total storage)<\/li>\n\n\n\n<li>Single-board computer design (no S-100 bus)<\/li>\n\n\n\n<li>Two RS-232C serial ports (for terminal and printer\/modem)<\/li>\n\n\n\n<li>One parallel port (for printer)<\/li>\n\n\n\n<li>Convection-cooled, fanless operation (very quiet)<\/li>\n\n\n\n<li>RF-shielded metal case<\/li>\n\n\n\n<li><strong>Dimensions<\/strong>: ~16.7&#8243; wide x 11.3&#8243; deep x 5.3&#8243; high<\/li>\n\n\n\n<li><strong>Weight<\/strong>: ~6 kg<\/li>\n<\/ul>\n\n\n\n<h3 id=\"operating-system-programming-languages\" class=\"wp-block-heading\">Operating System &amp; Programming Languages<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>OS<\/strong>: CP\/M 2.2 operating system, enhanced with a user-friendly menu system called Micro Menu.<\/li>\n\n\n\n<li><strong>Programming Languages<\/strong>: Microsoft BASIC-80, Morrow\u2019s own BaZic, PILOT, and other CP\/M-compatible languages such as FORTRAN, COBOL, and assembly language.<\/li>\n<\/ul>\n\n\n\n<h3 id=\"notables\" class=\"wp-block-heading\">Notables<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li>George Morrow was a key innovator in early personal computing, best known for his work in standardizing the S-100 bus (IEEE-696), which enabled broad hardware compatibility and expansion in microcomputers. He founded Morrow Designs and introduced affordable, reliable memory boards, S-100 floppy disk controllers, and complete systems that bundled CP\/M, BASIC, and business software. Notably, Morrow Designs offered branded 8-inch floppy drives and hard disk systems, making high-capacity storage accessible to small businesses and hobbyists at a reasonable price.<\/li>\n\n\n\n<li>The Morrow Micro Decision MD-3 was one of the last popular CP\/M business computers before the IBM PC era, known for its quiet, fanless operation and compact, all-in-one design.<\/li>\n\n\n\n<li>The MD-3 was praised for its reliability and expandability, with users often modifying systems to add more drives or RAM.<\/li>\n\n\n\n<li>The MD-3 was featured in creative advertisements highlighting its quietness and value, and it was used in small businesses, schools, and even early BBS systems.<\/li>\n\n\n\n<li>Its place in history is as a transitional machine\u2014bridging the gap between hobbyist S-100 systems and the dominance of IBM PC compatibles, and representing the end of the CP\/M era in business computing.<\/li>\n<\/ul>\n\n\n\n<p><strong>Donated by<\/strong>: Dr. Arlen Michaels<\/p>\n\n\n\n<div class=\"wp-block-buttons is-layout-flex wp-block-buttons-is-layout-flex\">\n<div class=\"wp-block-button is-style-fill\"><a class=\"wp-block-button__link wp-element-button\" href=\"https:\/\/carleton.ca\/scs\/vintage-computing\/item\">Vintage Computing Collection<\/a><\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"<p>Morrow Designs Micro Decision MD-3 [Vin134] The Morrow Designs Micro Decision MD-3, released in the early 1980s, was a Z80A-based CP\/M microcomputer designed to offer affordable, quiet, and user-friendly desktop computing. The MD-3 distinguished itself with two double-sided, half-height 5.25-inch floppy drives, providing a total storage capacity of 400 KB\u2014an upgrade over earlier MD models. [&hellip;]<\/p>\n","protected":false},"author":2,"featured_media":0,"parent":19704,"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":[128,90,123],"class_list":["post-22388","page","type-page","status-publish","hentry","cu_page_type-desktop","cu_page_type-vintage-computing","cu_page_type-vintage-inventory"],"acf":{"cu_post_thumbnail":""},"_links":{"self":[{"href":"https:\/\/carleton.ca\/scs\/wp-json\/wp\/v2\/pages\/22388","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=22388"}],"version-history":[{"count":4,"href":"https:\/\/carleton.ca\/scs\/wp-json\/wp\/v2\/pages\/22388\/revisions"}],"predecessor-version":[{"id":25062,"href":"https:\/\/carleton.ca\/scs\/wp-json\/wp\/v2\/pages\/22388\/revisions\/25062"}],"up":[{"embeddable":true,"href":"https:\/\/carleton.ca\/scs\/wp-json\/wp\/v2\/pages\/19704"}],"wp:attachment":[{"href":"https:\/\/carleton.ca\/scs\/wp-json\/wp\/v2\/media?parent=22388"}],"wp:term":[{"taxonomy":"cu_page_type","embeddable":true,"href":"https:\/\/carleton.ca\/scs\/wp-json\/wp\/v2\/cu_page_type?post=22388"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}