{"version":"1.0","provider_name":"Microsoft Open Source Blog","provider_url":"https:\/\/opensource.microsoft.com\/blog","author_name":"Stacey Haffner, Scott Hanselman","title":"Continuing the story of early DOS development | Microsoft Open Source Blog","type":"rich","width":600,"height":338,"html":"<blockquote class=\"wp-embedded-content\" data-secret=\"SOAqUCRNc2\"><a href=\"https:\/\/opensource.microsoft.com\/blog\/2026\/04\/28\/continuing-the-story-of-early-dos-development\/\">Continuing the story of early DOS development<\/a><\/blockquote><iframe sandbox=\"allow-scripts\" security=\"restricted\" src=\"https:\/\/opensource.microsoft.com\/blog\/2026\/04\/28\/continuing-the-story-of-early-dos-development\/embed\/#?secret=SOAqUCRNc2\" width=\"600\" height=\"338\" title=\"&#8220;Continuing the story of early DOS development&#8221; &#8212; Microsoft Open Source Blog\" data-secret=\"SOAqUCRNc2\" frameborder=\"0\" marginwidth=\"0\" marginheight=\"0\" scrolling=\"no\" class=\"wp-embedded-content\"><\/iframe><script type=\"text\/javascript\">\n\/* <![CDATA[ *\/\n\/*! This file is auto-generated *\/\n!function(d,l){\"use strict\";l.querySelector&&d.addEventListener&&\"undefined\"!=typeof URL&&(d.wp=d.wp||{},d.wp.receiveEmbedMessage||(d.wp.receiveEmbedMessage=function(e){var t=e.data;if((t||t.secret||t.message||t.value)&&!\/[^a-zA-Z0-9]\/.test(t.secret)){for(var s,r,n,a=l.querySelectorAll('iframe[data-secret=\"'+t.secret+'\"]'),o=l.querySelectorAll('blockquote[data-secret=\"'+t.secret+'\"]'),c=new RegExp(\"^https?:$\",\"i\"),i=0;i<o.length;i++)o[i].style.display=\"none\";for(i=0;i<a.length;i++)s=a[i],e.source===s.contentWindow&&(s.removeAttribute(\"style\"),\"height\"===t.message?(1e3<(r=parseInt(t.value,10))?r=1e3:~~r<200&&(r=200),s.height=r):\"link\"===t.message&&(r=new URL(s.getAttribute(\"src\")),n=new URL(t.value),c.test(n.protocol))&&n.host===r.host&&l.activeElement===s&&(d.top.location.href=t.value))}},d.addEventListener(\"message\",d.wp.receiveEmbedMessage,!1),l.addEventListener(\"DOMContentLoaded\",function(){for(var e,t,s=l.querySelectorAll(\"iframe.wp-embedded-content\"),r=0;r<s.length;r++)(t=(e=s[r]).getAttribute(\"data-secret\"))||(t=Math.random().toString(36).substring(2,12),e.src+=\"#?secret=\"+t,e.setAttribute(\"data-secret\",t)),e.contentWindow.postMessage({message:\"ready\",secret:t},\"*\")},!1)))}(window,document);\n\/* ]]> *\/\n<\/script>\n","thumbnail_url":"https:\/\/opensource.microsoft.com\/blog\/wp-content\/uploads\/2026\/04\/86-DOS-Changelist.webp","thumbnail_width":1260,"thumbnail_height":708,"description":"In 2018 we (re)-open-sourced MS\u2011DOS 1.25 and 2.11, and more recently in 2024 we were able to make the source for MS\u2011DOS 4.0 available to the public as well. Today, on 86-DOS 1.00\u2019s 45th anniversary, we\u2019re continuing that tradition with the earliest DOS source code discovered to date."}