DOS memory query: In classic DOS, which command do you type to display how much memory is available and how it is allocated (conventional, UMB, XMS/EMS)?

Introduction / Context:
Before modern GUIs, memory layout and optimization were performed at the command line. DOS provided built-in tools to report memory usage and help troubleshoot drivers and TSRs that consumed conventional memory.

Given Data / Assumptions:

• The user needs a quick readout of free/used memory categories.
• System may have XMS/EMS providers like HIMEM.SYS and EMM386.EXE.
• We want the standard DOS command, not third-party utilities.

Concept / Approach:

The MEM command displays memory status, including conventional memory, upper memory blocks (UMBs), and the presence of XMS/EMS. CHKDSK focuses on disk and file system checking. MEMMAKER is a separate utility that attempts to optimize memory use, not simply display it. “EMM” is not a standard DOS command by itself.

Step-by-Step Solution:

Verification / Alternative check:

Compare MEM output before and after loading drivers or TSRs to see changes. Use MEM /C to list modules occupying conventional memory.

Why Other Options Are Wrong:

• EMM: Not a standard reporting command.
• CHKDSK: Disk integrity tool, not a memory usage reporter.
• MEMMAKER: Optimizes memory layout; does not just display it.
• None of the above: Incorrect because MEM is correct.

Common Pitfalls:

Misinterpreting EMS vs. XMS; forgetting that MEM’s detail switches provide deeper insights; assuming MEM exists in all non-DOS environments.

Final Answer:

MEM