- #Vogons dosbox windows 3.1 how to#
- #Vogons dosbox windows 3.1 drivers#
- #Vogons dosbox windows 3.1 driver#
- #Vogons dosbox windows 3.1 code#
- #Vogons dosbox windows 3.1 free#
The Extended Memory Specification ( XMS) describes an application interface that allows to copy memory between conventional and extended memory. This frees 64 kB in the Upper Memory Area for loading TSR-programs. In the case no EMS is required this feature can be deactivated by using the parameter NOEMS.
#Vogons dosbox windows 3.1 free#
The amount of free main memory beyond 1 MB can be shared between EMS and XMS by adding the parameter AUTO to EMM386.EXE. To achieve this it has to switch the CPU to Protected Mode. EMM386 emulates expanded memory by using main memory beyond the High Memory Area.
#Vogons dosbox windows 3.1 driver#
The most commonly used memory management driver implementing EMS is EMM386.EXE that has to be loaded in config.sys as second driver after HIMEM.SYS. The latest EMS 4.0 allowed to use up to 32 Mb as expanded memory. The 64 kB region within the Upper Memory Area is referred to as EMS Page Frame. The specification describes that this memory can be used by mapping a 64 kB large part to the Upper Memory Area between 640 kB and 1 Mb. Expanded Memory can be either memory on an memory expansion card or a part of the main memory. The Expanded Memory Specification ( EMS) is a standard developed by Lotus, Intel and Microsoft. The external program MEM reports if DOS is using the HMA. If DOS=HIGH was specified but loading to HMA fails HMA not available/loading DOS low is reported.
#Vogons dosbox windows 3.1 code#
Directly after an XMS driver is loaded in config.sys with DEVICE= and the HMA is still unoccupied DOS will move parts of code there. By specifying the line DOS=HIGH in config.sys DOS is asked to load parts to HMA. To use HMA it is required to load HIMEM.SYS in config.sys. The High Memory Area ( HMA) are the 64 kb directly above 1 Mb and are part of XMS. The external program MEM with parameter /C reports additionally the UMA RAM status. Since UMA memory is managed in blocks the amount of free Upper Memory is usually larger than the largest contiguous free block. If no contiguous free Upper Memory Block is available the driver will be loaded to Conventional Memory. this allows TSR-programs to be loaded to UMBs (in High Memory) in config.sys by using DEVICEHIGH=driver.sys or in autoexec.bat with the loadhigh statement, like LH. The driver tries to detect common unused blocks and maps XMS memory there creating Upper Memory Blocks.īy specifying DOS=UMB in config.sys MS-DOS allocates all UMBs through XMS and takes over memory management of them. It has to be loaded in config.sys as second driver after HIMEM.SYS. The default memory management driver that enables this mapping through XMS memory is EMM386.EXE. These blocks are called Upper Memory Blocks (UMB) and are treated from DOS as High Memory. The Extended Memory Specification (XMS) allows to map blocks of mainboard RAM in the remaining UMA memory range. can use parts of the UMA for own BIOS ROMs or buffer RAM. Additional hardware like mass storage controllers, network adapters. Usually present in this region is a part of the graphics cards RAM and the BIOS ROMs of the graphics card and mainboard. By default there is no RAM in this range as it is reserved for use with hardware that is able to map own memory to this range. The upper memory area ( UMA) is memory in the range between 640 kb and 1 Mb. The amount of free conventional memory is reported by CHKDSK or MEM.
#Vogons dosbox windows 3.1 drivers#
By default such drivers are placed in conventional memory. This is called Terminate and Stay Resident (TSR). The available free memory can be lower as some drivers have to leave a part of their code in memory to handle e.g. Programs are loaded to this memory range. If you really want to understand how this all works, see the Wikipedia article on DOS memory management, or use your web search engine of choice.Ĭonventional memory or base memory is the memory range between 0 kb and 640 kb. This page will try to explain, in simple language, all the technical terms you will encounter in DOS memory management, and provide you with practical information to get your favorite games and programs running. Optimizing your system to attain enough free memory for your programs is called memory management. It is also helpful to know the most common memory management drivers. To use the available RAM effectively in DOS you have to know how the x86 architecture splits up RAM, what these different regions are for. In DOS memory is split into different regions and there are several standards as EMS and XMS for accessing memory. In DOS hardware and memory access is closely related to the standards defined by the x86 architecture.
#Vogons dosbox windows 3.1 how to#
The OS determines how to use it, and you usually don't need to worry about it at all. With modern operating systems, all memory management you need to do is installing enough RAM.
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