In This Article
What is Conventional Memory?
Conventional memory refers to the first 640 KB of the IBM compatible memory. Ideally, this is the only section of the memory that can be accessed by the operating system without needing the help of the memory manager.
Technically, this is the contiguous memory that lies before the Upper Memory Area and can be used by applications directly.
- The conventional memory refers to the first 640 kilobytes of the memory space.
- This contiguous section of the memory lies before the Upper Memory Area which typically measures 384 KB.
- The conventional memory is not the same as the upper memory blocks because these are not connected to it.
- This read-write memory is directly addressable by the processor for the use of the application programs.
- This specific section of the memory can be used by the operating system without the help of the memory manager.
Understanding Conventional Memory
This specific section of the memory in a DOS system is available to all regular DOS programs.
The contiguous section of the conventional memory and UMA together make 1 MB of memory space, and anything beyond this amount is called either the extended memory or the expanded memory.
This memory area is different from the upper memory blocks because these are not connected to the conventional memory and therefore cannot be used directly by the applications.
Some of the most common Some very common Disk Operating System drivers and Terminate-And-Stay-Resident Programs or TSRs that use the conventional memory are:
Conventional Memory Vs Extended Memory
- Conventional memory refers to the contiguous memory which is used directly by applications running on any Intel 80×86 microprocessor in real mode or unimproved MS-DOS. However, extended memory is used in Windows and DOS and refers to memory beyond the first megabyte, or 220 bytes of address space.
- Conventional memory can handle from 0 KB to 640 KB in general hardware and device drivers and up to 736 KB with the special ones. On the other hand, extended memory is limited to 15 MB.
How is the Upper Memory Area Significant to Conventional Memory?
The use of the Upper Memory Area helps in freeing the conventional memory by moving the device drivers and the TSRs into the upper 384 KB of a 1 MB address space. However, it leaves the 640 KB of addressable memory intact.
What is the Size of Conventional Memory
Usually, the conventional memory in DOS memory management measures the initial 640 KB of the memory space.
The conventional memory is the initial section of read-write memory that can be accessed by the application programs and the operating systems.
This specific section of the memory is mostly used by the DOS drivers and TSRs in addition to the regular DOS software for the sake of their optimization.