In the early 1990s PC memory management became a huge issue.
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\nEventually, PC hardware surpassed the abilities of PC software. Specifically, DOS was limited to only 640K of main memory. Yet the PC’s processor, the 386, could access up to 4MB of RAM.<\/p>\n
Yes, that’s 4MB.<\/p>\n
You could pack your PC with 4MB of RAM, but DOS would use only 640K. So to make the rest of the memory useful, various memory management schemes were used.<\/p>\n
One scheme used something called high memory<\/em>. That was 64K of bonus memory that could be used to load DOS itself, making more of the basic 640K of RAM available for running programs.<\/p>\n Another scheme was expanded memory<\/em>, which was used by some DOS programs.<\/p>\n Then there was extended memory<\/em>, which was too closely named like expanded memory to just about confuse everyone.<\/p>\n Extended memory was used by the 386 when it ran in protected mode<\/em>. DOS ran in real mode<\/em>. Protected mode was where the processor actually protected areas of memory from having one program stomp all over another one. For DOS, which ran only one program at a time, protected mode meant nothing. But DOS wasn’t the only PC operating system at the time.<\/p>\n Oh, yeah, there was Windows. The Windows 386 system did multitask and use protected mode. So did the OS\/2 operating system. But there wasn’t much software for those two operating systems.<\/p>\n Technically, Windows was not an operating system until Windows 95. Before then, Windows was merely a DOS shell, or a program that ran on top of DOS. Weird, yes, but that was the late 1980s\/early 1990s.<\/p><\/blockquote>\n During this time, I toyed with Windows\/386, and later Windows for Workgroups, as well as OS\/2. But I really got work done using a multitasking utility called DESQview.<\/p>\n DESQview came with a memory management program I was writing about, called QEMM. (I did a bestseller for Microsoft Press called PC Memory Management<\/em> back in 1990. It was the #1 computer book until DOS For Dummies<\/em> knocked it off its perch in 1991.)<\/p>\n Using DESQview I could run multiple DOS sessions on a single 80386 computer. Unlike the primitive versions of Windows back then \u2014 or even the Mac OS \u2014 DESQview provided true multitasking. I mean, you could format a floppy disk in one window, download a file in another, and play a game in a third. Even the Mac wouldn’t let you do that, holding you hostage while a disk formatted.<\/p>\n DESQview used full screen text windows, not graphics. Well, actually, you could run graphics in one DESQview window and text in another. I remember running Windows\/386 in one DESQview window, a DOS prompt in another, communications program in a third, and WordPerfect in a fourth. In fact, I didn’t see that level of multitasking or computer sophistication until Mac OS X came out 8 years ago.<\/p>\n Memory management madness continued until Windows 95 freed the PC from its memory hell. It’s a time I’m happy has passed.<\/p>\n","protected":false},"excerpt":{"rendered":" In the early 1990s PC memory management became a huge issue.<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"class_list":["post-794","post","type-post","status-publish","format-standard","hentry","category-main"],"_links":{"self":[{"href":"https:\/\/www.wambooli.com\/blog\/index.php?rest_route=\/wp\/v2\/posts\/794","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.wambooli.com\/blog\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.wambooli.com\/blog\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.wambooli.com\/blog\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.wambooli.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=794"}],"version-history":[{"count":4,"href":"https:\/\/www.wambooli.com\/blog\/index.php?rest_route=\/wp\/v2\/posts\/794\/revisions"}],"predecessor-version":[{"id":801,"href":"https:\/\/www.wambooli.com\/blog\/index.php?rest_route=\/wp\/v2\/posts\/794\/revisions\/801"}],"wp:attachment":[{"href":"https:\/\/www.wambooli.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=794"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.wambooli.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=794"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.wambooli.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=794"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}