DOS APPEND Command: Bridging the Gap Between Old and New
2024-12-20
While reconstructing the DOS 2.11 source code, the author encountered a challenge: the ancient MASM 1.25 assembler lacked directory support, clashing with modern file organization using a tree structure. To avoid a monolithic directory, the author cleverly employed the DOS APPEND command. APPEND is a TSR (Terminate and Stay Resident) program that intercepts system calls like file opening and searches a predefined path list if the file isn't found in the current directory. This allowed MASM 1.25 to locate files within the hierarchical structure, resolving the incompatibility and highlighting APPEND's surprising utility in specific scenarios.
Read more
Development