{"id":17953,"date":"2009-06-10T10:00:00","date_gmt":"2009-06-10T10:00:00","guid":{"rendered":"https:\/\/blogs.msdn.microsoft.com\/oldnewthing\/2009\/06\/10\/why-does-ms-dos-use-8-3-filenames-instead-of-say-11-2-or-16-16\/"},"modified":"2009-06-10T10:00:00","modified_gmt":"2009-06-10T10:00:00","slug":"why-does-ms-dos-use-8-3-filenames-instead-of-say-11-2-or-16-16","status":"publish","type":"post","link":"https:\/\/devblogs.microsoft.com\/oldnewthing\/20090610-00\/?p=17953","title":{"rendered":"Why does MS-DOS use 8.3 filenames instead of, say, 11.2 or 16.16?"},"content":{"rendered":"<p>When I discussed years ago  <a href=\"http:\/\/blogs.msdn.com\/oldnewthing\/archive\/2007\/04\/02\/2008357.aspx\"> why operating system files tend to follow the old 8.3 file name convention<\/a>, I neglected to mention why the old MS-DOS filename convention was 8.3 and not, say, 11.2 or 16.16.<\/p>\n<p> It&#8217;s a holdover from CP\/M. <\/p>\n<p> As I noted when I <a href=\"http:\/\/blogs.msdn.com\/oldnewthing\/archive\/2007\/12\/17\/6785519.aspx\"> discussed the old MS-DOS wildcard matching rules<\/a>, MS-DOS <a href=\"http:\/\/blogs.msdn.com\/oldnewthing\/archive\/2004\/03\/16\/90448.aspx\"> worked hard at being compatible with CP\/M<\/a>. And CP\/M used 8.3 filenames. <\/p>\n<p> Why did CP\/M use 8.3 filenames? I don&#8217;t know. There&#8217;s nothing obvious in the <a href=\"http:\/\/www.seasip.demon.co.uk\/Cpm\/format14.html\"> CP\/M directory format<\/a> that explains why those two reserved bytes couldn&#8217;t have been used to extend the file name to 10.3. But maybe they figured that eight was a convenient number. <\/p>\n","protected":false},"excerpt":{"rendered":"<p>When I discussed years ago why operating system files tend to follow the old 8.3 file name convention, I neglected to mention why the old MS-DOS filename convention was 8.3 and not, say, 11.2 or 16.16. It&#8217;s a holdover from CP\/M. As I noted when I discussed the old MS-DOS wildcard matching rules, MS-DOS worked [&hellip;]<\/p>\n","protected":false},"author":1069,"featured_media":111744,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[1],"tags":[2],"class_list":["post-17953","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-oldnewthing","tag-history"],"acf":[],"blog_post_summary":"<p>When I discussed years ago why operating system files tend to follow the old 8.3 file name convention, I neglected to mention why the old MS-DOS filename convention was 8.3 and not, say, 11.2 or 16.16. It&#8217;s a holdover from CP\/M. As I noted when I discussed the old MS-DOS wildcard matching rules, MS-DOS worked [&hellip;]<\/p>\n","_links":{"self":[{"href":"https:\/\/devblogs.microsoft.com\/oldnewthing\/wp-json\/wp\/v2\/posts\/17953","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/devblogs.microsoft.com\/oldnewthing\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/devblogs.microsoft.com\/oldnewthing\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/oldnewthing\/wp-json\/wp\/v2\/users\/1069"}],"replies":[{"embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/oldnewthing\/wp-json\/wp\/v2\/comments?post=17953"}],"version-history":[{"count":0,"href":"https:\/\/devblogs.microsoft.com\/oldnewthing\/wp-json\/wp\/v2\/posts\/17953\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/oldnewthing\/wp-json\/wp\/v2\/media\/111744"}],"wp:attachment":[{"href":"https:\/\/devblogs.microsoft.com\/oldnewthing\/wp-json\/wp\/v2\/media?parent=17953"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/oldnewthing\/wp-json\/wp\/v2\/categories?post=17953"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/oldnewthing\/wp-json\/wp\/v2\/tags?post=17953"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}