VMTester

This is a utility designed for testing the behaviour of OS X's virtual memory system as memory is allocated and de-allocated by applications. The system and program info is updated every 5 seconds and several hours worth of the data is stored so that you can go back and look at the state of the system at an earlier time.

Holding down the Option key when you click on the arrows at the top makes it jump by 10 intervals for each click. Note that you can click and hold on the arrow buttons to scan through an interval of time. Holding down the Option key makes this go faster.

You can export the data by using the "Export..." menu item in the "File" menu. The data is exported in a comma-separated format that is easy to import into Excel for example. The first line in the file supplies a legend indicating the meaning of each of the comma-separated fields.

This application was partially inspired by Shawn Erickson's "Memory Muncher" app.

download the VMTester executable (PowerPC only)

download the VMTester project files (licensed under the GPL)
(Requires the Apple Developer Tools - I used XCode version 2.4)

This project illustrates several aspects of programming for Mac OS X using the Cocoa API:

use of NSTableView data sources & notifications
use of an NSMutableArray to create a "ring buffer"
use of applicationShouldTerminateAfterLastWindowClosed
using a "sheet" for error notification and for simple dialogs
use of NSTimer (to get regular updates)
use of NSTask (to run a shell command)
detecting modifier keys (Option key) on button clicks