Breaking the DOS 640k barrier on 8086 and 80286 systems

Most people who grew up with MS-DOS on 16-bit 8086 and 80286 CPUs learned about the 640K limit and accepted it -- but you may be surprised to know that 640K isn't the actual limit. In this video, I explain why the 640K limit is a myth, and how you can break past it using a variety of methods that don't require EMM386 or an 80386 CPU.

Chapters:

00:00 Intro
00:51 Benefits
01:43 The IBM PC Memory Map
02:48 The orthodox procedure
04:09 What are Upper Memory Blocks?
04:53 Orthodox procedure continued
06:46 An Unorthodox procedure
09:34 Q&A
11:31 DOScember

Hardware and software mentioned in this video:

Lo-tech 1MB RAM card: https://texelec.com/product/lo-tech-1...

PCjr jrIDE sidecar: https://texelec.com/product/jr-ide-fo...

All the software mentioned in this video is available via anonymous FTP: http://ftp.oldskool.org/pub/youtube/d...

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This video was a part of #DOScember ! Here's the #doscember official playlist:

https://bit.ly/DOScember2020

Also check out these other #doscember participating Channels:

Adrian's Digital Basement:    / adriansdigitalbasement  
ctrl-alt-rees:    / ctrlaltrees  
DaveJustDave:    / mrdavejustdave  
Jan Beta:    / janbeta  
Josh Malone:    / joshmalone_48kram  
LGR:    / lazygamereviews  
MindFlareRetro:    / mindflareretro  
Mr Lurch's Things:    / mrlurchsthings  
Noel's Retro Lab:    / noelsretrolab  
RetroSpector78:    / retrospector78  
RMC:    / rmcretro  
RoseTintedSpectrum:    / rosetintedspectrum  
Tech Tangents:    / akbkuku  
The 8-Bit Guy:    / adric22  
TheRetroChannel:    / theretrochannel  

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Thanks to winworldpc for supplying some software, and to Mike Brutman for boot sector patch ideas.

Want to support me, and help me make more videos like this? Consider becoming a patron:   / theoldskoolpc  

Some incidental music by coda, used with permission: https://coda.s3m.us/

Contact info:
Twitter: @MobyGamer
Email: http://www.oldskool.org/personal