OS X notes Part 2 — system tweaks

Additional system tweaks or tips for using OS X (Mac)

§ 1. Eliminating the Dock’s delay

OS X 10.8 Lion dock

If the dock is set to automatically hide and show, when one moves the mouse over the edge of the dock, there is a half second delay before the dock pops out. It would feel much snappier and nicer if the dock display delay is removed. Here is how to eliminate the delay (source).

To eliminate the delay, open Terminal, type or copy and paste the following line and hit return:

defaults write com.apple.Dock autohide-delay -float 0 && killall Dock

To undo the changes and restore the default behavior, enter:

defaults delete com.apple.Dock autohide-delay && killall Dock

In OS X 10.9 Mavericks, a system restart seems to be required for the above commands to take effect.

§ 2. Enabling TRIM support for non-Apple SSDs

Replacing the original old mechanical hard drive (HDD) with a light-weighted, less energy-consuming, silent, and most importantly, lightening fast solid-state drive (SSD) is a common and worthy upgrade. One would immediately notice the tremendously improved speed when booting up/shutting down OS X and launching applications. For all SSDs, TRIM is definitely needed to avoid excessive wear and slowing down. However, OS X does not automatically support TRIM for the non-Apple SSDs (e.g., Intel, Samsung, and Crucial). Therefore, we have to turn TRIM on manually in OS X for these SSDs.

Trim Enabler icon

I used to recommend a command line method using the Terminal, but the commands need to be adjusted and re-applied after each major OS X updates. Fortunately, there is a free app called Trim Enabler by groths.org (icon on the right) that allows turning on/off TRIM support for non-Apple SSD with a single click. The TRIM enabler supports the latest OS X, even the developer versions (e.g., the current Mavericks 10.9 Developer Preview 5).

To check if TRIM is on, open up About This Mac, click on “More Info…” then “System Report…”. In the list on the left, choose “Serial-ATA” or “SATA/SATA Express”. Click on the name of your SSD Drive and in the lower half of the window find “TRIM Support: Yes” instead of “No”, which means TRIM is on.

Remember to check the TRIM status after a major OS X update and re-apply the TRIM Enabler patch if TRIM is off.

§ 3. Changing the output file type of the native screenshot

In OS X, screenshot of the whole screen and of a selection can be easily obtained by using keyboard shortcuts (shift + command + 3 and shift + command + 4, respectively). The default output image format of the screenshot utility is .png; it can be changed to many other formats, including .pdf, .jpg, .tiff, .bmp, .gif, and .psd, by entering the lines below in Terminal:

defaults write com.apple.screencapture type jpg
killall SystemUIServer

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