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2 posts

FreeDOSDeep Dive August 27, 2026 6 min read

FreeDOS SHARE: File Sharing Modes and Byte-Range Locks in Real Mode

How FreeDOS SHARE implements DOS open-sharing rules, tracks byte-range locks by process, reports conflicts, and fits into a practical compatibility test.

#freedos#share#file-locking

FreeDOSDeep Dive July 9, 2026 7 min read

Understanding Interrupts on FreeDOS: INT 21h and the DOS API

A register-level guide to the interrupt vector table, FreeDOS INT 21h dispatch, file and process calls, Carry Flag errors, BIOS services, TSR hooks, and reentrancy.

#interrupts#dos-api#freedos