OSLab: Module 2 - Memory Management

Overview

Module 2 contains the memory management software and the monitor output software. The monitor output software is included in this module because the PC is designed so that its output is memory-mapped.

The memory management software implements a simple segmentation algorithm, dividing some 320kb into five segment sizes. When a process requests memory, the address of the first available segment with sufficient memory to satisfy the request is returned. Memory is allocated as follows:

There are two target executables: M2M.EXE, for exercising the memory management software, and M2D.EXE, for testing the display. M2D.EXE, when run, invites the user to type as many characters as possible within 15 seconds (module 1's devices are used in this executable).

Support Files

The .H (header) files contain data structures required for this module. The .C files contain the source code for:

• the memory management software (MEMMGR.C),

• the display access software (DISPLAY.C),

• module initialization (MOD2INIT.C),

• the memory management mainline (M2M.C),

• the display mainline (M2D.C), and

• determining the actions to be taken when external input is received (HWDATA.C).

Note that neither of the executables are used outside this module.