EMS RAM Requirements
Some IBM PC MS-DOS games require a certain amount of EMS RAM in order to execute. EMS stands for Expanded Memory Specification. EMS is a form of high memory that is contrasted with 640K conventional RAM, which is low memory.
The amount of EMS RAM available can be checked via Microsoft Diagnostics (msd) or the chkdsk and mem commands.
Via expansion boards packed with bank-switched DRAM chips, LIM EMS (Lotus, Intel and Microsoft) 3.0 of 1985 supports 4 megs of RAM, LIM EMS 3.2 of 1986 supports 8 megs of RAM and LIM 4.0 of 1987 supports 32 megs of RAM. [1]
Thus, DOS games that adhere to EMS can take advantage of RAM far beyond the 640K limitation imposed by DOS. In some DOS games EMS RAM facilitated the likes of digitized sound and square-pixel SVGA display resolutions.
Expanded memory managers (EMMs) include QEMM, 386 MAX and EMM386. Via some EMMs XMS RAM can be converted to EMS RAM.
The EMM386 driver of MS-DOS 5.0 provides only 256 kbytes of EMS RAM by default. Thus, for more demanding RAM-hungry games EMM386 will need to be manually configured in config.sys via:
DEVICE=C:\DOS\EMM386.EXE [RAM in kbytes].
EMS RAM requirements for each game are given below. The requirement is not the absolute minimum requirement but rather the minimum requirement that executes all game features (such as digitized speech).
Format is: Computer Game / Developer / Year / EMS RAM requirement.
- Alien Breed IBM PC MS-DOS Team 17 1993: 192 kbytes
- Alone in the Dark IBM PC MS-DOS Infogrames 1992: 128 kbytes
- Beneath a Steel Sky IBM PC MS-DOS Revolution 1990: 2 megs
- Betrayal at Krondor IBM PC MS-DOS Dynamix 1993: 1,048,576 bytes
- BloodNet IBM PC MS-DOS Microprose 1993: 800 kbytes
- Command and Conquer IBM PC MS-DOS Westwood 1995: 6 megs
- Dark Sun Shattered Lands IBM PC MS-DOS SSI 1993: 1 meg
- Dark Sun Wake of the Ravager IBM PC MS-DOS SSI 1994: 2 megs
- Darklands IBM PC MS-DOS MicroProse 1992: 176 kbytes
- Dungeon Hack IBM PC MS-DOS Dreamforge 1993: 960,000 bytes
- Earthworm Jim IBM PC MS-DOS Shiny Entertainment Inc 1995: 8 megs
- Elder Scrolls: Arena IBM PC MS-DOS Bethesda 1994: 2 megs
- Eye of the Beholder 3 IBM PC MS-DOS SSI 1993: 983,040 bytes
- F-15 Strike Eagle 3 IBM PC MS-DOS 1992 MPS Labs: 752 kbytes
- Falcon 3.0 IBM PC MS-DOS Sphere Inc. 1991: 4 megs
- Frontier Elite 2 IBM PC MS-DOS David Braben 1993: 768 kbytes
- Joe and Mac Caveman IBM PC MS-DOS Ninja Elite Systems 1992: 288 kbytes
- Last Eichhof, The IBM PC MS-DOS Alpha-Helix 1993: 4 megs
- Master of Magic IBM PC MS-DOS Simtex 1994: 2.7 megs
- Moonstone IBM PC MS-DOS Images Software 1992: 400 kbytes
- Space Hulk IBM PC MS-DOS Electronic Arts 1993: 260 kbytes
- Star Wars X-Wing IBM PC MS-DOS Totally Games 1993: 896 kbytes
- Star Wars TIE Fighter IBM PC MS-DOS Totally Games 1994: 2,084 kbytes
- Strike Commander IBM PC MS-DOS Origin Systems 1993: 2,765,000 bytes
- System Shock IBM PC MS-DOS Looking Glass 1994: 7,168 kbytes
- Ultima Underworld IBM PC MS-DOS Blue Sky Productions 1992: 480 kbytes
- Ultima 7 Black Gate IBM PC MS-DOS Origin Systems 1992: 491,520 bytes
- Wing Commander IBM PC MS-DOS Origin Systems 1990: 2 megs
- Wing Commander 2 IBM PC MS-DOS Origin Systems 1991: 2 megs
- Wing Commander: Academy IBM PC MS-DOS Origin Systems 1993: 2 megs
[1]
RAM expansion boards were often stacked. For example, install 4x 2 meg boards jam-packed with 64K-256K DRAM chips in order to get 8 megs of RAM.
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