Demos

The programs demonstrated during the lecture, one directory per part of it.

Each demo is small on purpose: it makes one point, and it is meant to be run rather than read. The write-up in each directory says what to expect, what actually happens, and why.

Demo	Part of the lecture	What it shows
00-pitch/	00. Pitch	A browser with 1.5 TB, a program that takes 10 TB, and two processes that disagree about the same address.
01-recap/	01. What we already know	Allocation as a change to the list of areas, under pmap and strace.
03-virtual-vs-physical/	03. Virtual memory and physical memory	VSZ against RSS, and a reservation that costs no physical memory at all.
04-reserve-allocate-map/	04. Reserve, allocate, map	Physical memory arriving at the first touch, one page fault per page.
05-page-table/	05. Pages and the page table	The process's own page table, read from /proc/self/pagemap: present bits flipping, frame numbers, a frame shared by two processes.

Part 02 has no demo of its own; the pmap listings of part 01 are the address space it describes.

Running them

Every demo that needs building has a Makefile, so make inside its directory is enough. The tools the demos need, beyond a C compiler and make, are:

• pmap and ps (procps), to look at a running process from outside
• strace, to see the system calls behind malloc()
• sudo, once, for the frame numbers in 05-page-table/pagemap; everything else runs as a normal user

Most demos wait at prompts so that pmap or ps can be run on them from a second terminal; they are marked as such in their READMEs. utils/utils.h holds the DIE() macro the sources share.

The numbers quoted in the write-ups were measured on one machine (Ubuntu 25.04, Linux 6.14, glibc 2.41, x86-64, 4 KB pages). Addresses and exact kilobyte counts differ from run to run and from machine to machine; the shapes do not.