General Settings

When you select the section Preferences > General Settings in the sidebar of the control window, you can make general changes which are not directly related to the monitoring of system components.

Menu Bar

The menu bar part of System Monitor and the control window work independently of each other, as explained in the introduction. The preference setting Keep System Monitor in the menu bar controls when the display in the menu bar should be opened and closed:

If a check mark is set, the display in the menu bar will become active automatically when you log in to Mac OS X. It will quit when you log out from Mac OS X.
If the item is switched off, the display in the menu bar will become active only while the control window of System Monitor is opened, too.

Display of memory sizes

The buttons at Display of memory sizes allow you to choose how the app should round byte specifications used to represent sizes of storage space, main memory, or transfer rates:

Classic units use the old common practice of information technology to report memory sizes in multiples of powers of two. 1 kilo byte equals 1,024 bytes. Kilo is abbreviated by a capital K in this case, denoting that it refers to a binary interpretation and does not represent the usual decimal prefix with the meaning 1,000 here. Higher multiples (1 MB = 1,048,576 bytes, not 1,000,000 bytes) don't make this differentiation, however.
Kibi units resolve this ambiguity, by additionally marking the prefix with “bi”, indicating a binary prefix. 1 kibi byte (1 kiB) equals 1,024 bytes. 1 mebi byte (“megabinary”, 1 MiB) are 1,048,576 bytes.
Standard units enforce compliance with “correct” international conventions for quantities and units. 1 kilo byte equals 1,000 bytes, now abbreviated 1 kB. 1 mega byte (1 MB) represents 1 million bytes.

Mac OS X itself behaves inconsistently here. Most of Apple's applications are gradually being moved to use standard units.

Display of temperature values

The radio buttons in this section can be used to select the unit System Monitor should use for the display of temperature readings. You can choose between:

Degrees Celsius (℃),
Degrees Fahrenheit (℉),
Kelvin (K).

After clicking the respective item, the readings will automatically switch to the selected unit, the next time a temperature value is being refreshed.

Display of public Internet address

As mentioned in the chapter Monitoring Network Interfaces, System Monitor can show the public address of the network interface which is currently connected to the Internet if desired. Although the respective item will appear in the menu of the network section, it must be enabled or disabled in general preferences. Several settings are available:

Show WAN-side IPv4 address in the network menu: Check this option to show the Internet address within the menu for monitoring network interfaces.

Time interval to refresh WAN address: Depending on your Internet service provider, the public Internet address can change in regular or irregular time intervals. Retrieving the address information is costly, so you can configure in which time intervals System Monitor should verify whether the address has changed. With the default setting, the address will only be checked when the app is launching and each time it recognizes that network settings of the local computer have changed. The address can additionally be determined in regular intervals. Intervals between 1 minute and 24 hours can be set.

External service provider to use: The public Internet address is usually administered by a different computer or by an external router. For this reason, System Monitor has no direct possibility to determine the address on the local computer, but needs the help of an external service provider on the Internet which can perform such a check at no cost. The pop-up menu allows you to select between different service providers.

Please avoid to refresh the display of the WAN address more often than necessary in order not to annoy the free service provider. The external provider might record the IP address and the time of each update. Notice the privacy policy of the respective provider.

For this feature to work correctly, your network and possibly installed parental controls must be configured to allow your computer to access web services (port 80) of the selected provider.