PCEM V13.1 Configure Memory for MS-DOS 5.0
8PCEM Tutorial Webpage
https://he-1000-1975.com/pcem-emulator-tutorial/
I was quite surprised to find that I could use 16 mbs of ram for a 386 sx based processor on the PCEM V13.1 emulator. The 386 SX based chipset allowed you to put a maximum of 16 mbs on the motherboard; however, there was no software/application that used that much ram at the time. Most programs in 1989 to 1993 used anywhere from 640 kbs to 4 megabytes. In addition, ram was very expensive back in 1989, one of the reasons why computers were expensive back then was due to the cost of ram.
A typical computer whether it be a 80286 to 80486 came with 1 mb of ram to 4 mbs of ram. A 386 DX or a 486 DX based computer would come with about 4 mbs of ram, and they would cost anywhere from $2900 to $5000. Most of those computers were used by businesses that needed that kind of computing power. You may laugh today and say, 4 mbs, or 16 mbs of ram isn't anything. Back then, that was a lot of ram. Today, we have computers that have 4 gbs 4,194,304 kilobytes or 4096 mbs of ram to 8 gbs (8,388,608 kilobytes) or 8192 mbs of ram. I wish I had 16 mbs of ram at the time, I could certain have boasting rights if I did!
When we used MS-DOS as a primary operating system, we had to change or edit autoexec.bat or config.sys files to enable certain features on our computers. Usually these files were located on the operating system's root directory. You could just go to the C:\dos directory and type in the commands to enable them; however, that is inefficient. You want to find a way to these features enabled every time you turn on and boot the computer. The Config.sys or Autoexec.bat files enabled to save these settings, so we could automate the process.
My config.sys file
DEVICE=C:\DOS\SETVER.EXE
DEVICE=C:\DOS\HIMEM.SYS
DEVICE=C:\DOS\DOS\EMM386.EXE
DEVICE=C:\MOUSE\MOUSE.SYS
DOS=HIGH
DOB=UMB
deviceHigh=c:\dos\ansi.sys
FILES=30
BUFFERS=40
(The mouse thing is associated with my mouse.sys file, if your mouse.sys file isn't in the directory c:\mouse then this command will not do anything)
You have 3 kinds of memory, the first is conventional memory, UMA, and extended memory.
Conventional Memory less than or equal 640 kbs
UMA Memory greater than 640 kbs less than or equal to 1024 kbs
Extended Memory greater than 1024 kbs
A lot of Dos games that utilized 1 mb or more usually required a certain amount of UMA or expanded memory. It didn't matter how much extended memory you had. For example, if you had 4 mbs of ram, and you had only 100 kbs of UMA or expanded memory. If the program required 200 kbs of UMA then you couldn't run the program. The total UMA memory is 384 kbs. In this video, my emulated system has 262,144 bytes or 256 kbs of free EMS. Computers back in those days were difficult to use, the way we kept up was by reading computer magazines, like PC Magazine. Magazines like these had articles which showed you how to use certain features in your operating system, or how to manage the resources on your computer.
PC Magazine survives to this very day, but back in the 1980s and 1990s we had many computer magazines. A lot of people in my generation learned a lot of things reading these magazines from working on computers to programming them as well. Earlier computer magazines put entire programming codes, so you could run games. This was when we didn't have floppy drives, so everything was loaded on the computer's memory. Often times, we would type in all this computer code, and it wouldn't work, because we didn't do one thing correctly! After you turned off the computer, the game was gone, because RAM can't store memory. RAM can only store things as long as the power is on. I guess, the adults were trying to get us kids to learn programming in a round about way.