What was all that talk of memory managers and AUTOEXEC.BAT boot menus about? How would an 8MB 486 fail to run a game which worked fine on a 1MB 286? Why was EMM386.EXE definitely not on Ultima 7's Christmas card list? And why does your friend have digitised sound on that game when you do not, even though you both have the same soundcard?

It's #doscember , and so time to delve into one of those questions of DOS that I never quite understood: what were EMS and XMS, and how could I have the wrong sort of memory?

The DOS/Dos joke was done better (and earlier) here:    • A Bad Education Reviews...#DOSCember   . Maybe it'll become a tradition or something.

Memory map:

0:00 A premise of sorts
0:52 5150
2:16 Pinhead
3:46 That segment thing
5:18 Where 640K came from
8:35 The 80286 arrives
10:05 Popcorn
11:00 Where EMS came from
11:43 Bank switching
13:57 Where XMS came from
15:23 Emulation
16:13 Precious conventional memory
17:50 HMA and the A20 gate
18:55 DOS wars
21:22 Better DOS and making memory
22:54 Boot disks and menus
23:32 DOS/4GW and that

Media credits:

Installation floppy disks (3.5inch) for Microsoft MSDOS 6.22 image by Blake Patterson from Alexandria, VA, USA, CCBY 2.0
Raystown Lake, Huntington and Lititz trip image by Bob, CCBY 2.0
Some CC0 sounds used from Freesound
Some CC0 and public domain images used from Wikimedia Commons
Stock footage from Pexels
Some stock imagery from Pixabay

CCBY 2.0: https://creativecommons.org/licenses/...

Bonus fact: that 286 shown inexplicably on the floor of a very, very messy room was also later a 486/100, then eventually a K6/200 until lack of availability of AT motherboards supporting modern sockets forced me to finally buy a new case. I also did, eventually, tidy my room.

#doscember #⁠doscember2023