Display managers and accessibility settings

Accessibility: the assistive technologies a Linux desktop provides, and the keyboard and display settings that make a machine usable for people who cannot use the defaults.

Lesson 3 of 3 in objective 106. User interfaces and desktops, part of LPIC-1 Exam 102-500.

Each accessibility name, matched to the need it answers. Left column, The name in the question; right column, The need it answers. Sticky keys, Slow keys and Bounce keys all point at Typing on a keyboard (Settings in a desktop panel, not programs). Mouse keys points at Moving the pointer without a mouse (The numeric keypad moves it instead). GOK and A desktop's own on-screen keyboard both point at Typing with a pointer (GOK is the historic name for it). Orca and Emacspeak both point at The interface spoken aloud (Orca ships with GNOME; Emacspeak is built around Emacs). Magnifier, High contrast and Large print all point at Seeing the screen more easily (Magnification, or themes for when it is not needed). BRLTTY points at Braille output (A refreshable braille display, at the console too). The name in the question The need it answers Sticky keys Slow keys Bounce keys Typing on a keyboard Settings in a desktop panel, not programs Mouse keys Moving the pointer without a mouse The numeric keypad moves it instead GOK A desktop's own on-screen keyboard Typing with a pointer GOK is the historic name for it Orca Emacspeak The interface spoken aloud Orca ships with GNOME; Emacspeak is built around Emacs Magnifier High contrast Large print Seeing the screen more easily Magnification, or themes for when it is not needed BRLTTY Braille output A refreshable braille display, at the console too
Each accessibility name, matched to the need it answers.

Keyboard and pointer settings

Sticky keys let a modifier be pressed and released before the key it modifies, so a one-handed user can type Ctrl-C in two presses. Repeat keys controls whether a held key repeats and how fast. Slow keys require a key to be held for a moment before it registers, filtering accidental brushes, and bounce keys — debounce keys is the same setting under another name — discard a second press of the SAME key arriving within a short interval of the first. That is the setting a hand tremor calls for, because the symptom it fixes is one press producing two identical characters.

The three filters are told apart by the moment each one acts, and a question will describe a symptom rather than name the setting. Slow keys judges how long the FIRST press is held; bounce keys judges how soon the SECOND press of that key arrives; repeat keys governs auto-repeat while a key stays down and is neither of the other two. The names are also written two ways, and both are asked for: a desktop panel spells them as two words, while the X server's AccessX controls underneath run them together, so a tool such as xkbset takes stickykeys, slowkeys, bouncekeys and mousekeys, and the bounce-keys interval set in a panel is that same AccessX value.

Mouse keys move the pointer with the numeric keypad, which is the answer when a pointing device cannot be used at all. Every one of these is a setting, not a program, and each desktop exposes them in its own accessibility panel.

Four keyboard settings, told apart by the moment each one acts. In order: A modifier is pressed and released (Sticky keys holds it for the next key), then The next key goes down (Slow keys ignores it until it is held), then That key is still held (Repeat keys decides if it repeats and how fast), then The same key is pressed again (Bounce keys drops it if it came too soon). A modifier is pressed and released Sticky keys holds it for the next key The next key goes down Slow keys ignores it until it is held That key is still held Repeat keys decides if it repeats and how fast The same key is pressed again Bounce keys drops it if it came too soon
Four keyboard settings, told apart by the moment each one acts.

Screen and speech

A screen reader speaks the interface: Orca is the one shipped with GNOME, and emacspeak is a long-standing alternative built around Emacs. A screen magnifier enlarges part of the display, and high-contrast themes plus a large-print setting cover the middle ground where magnification is not needed. An on-screen keyboard — GOK historically, or a desktop's own — lets a pointer be used to type. Braille output is handled by BRLTTY, which drives a refreshable braille display and works at the console rather than only in a desktop.

Worth carrying in

Sticky keys
Press a modifier and the next key in sequence rather than together.
Slow keys / bounce keys
Require a hold before registering; ignore rapid repeats of the same key.
Mouse keys
Move the pointer with the numeric keypad.
Orca
The GNOME screen reader. Emacspeak is the Emacs-based alternative.
BRLTTY
Drives a refreshable braille display, including at the text console.
High contrast / large print
Theme settings for low vision short of magnification.

What the exam does with this

Objective
106. User interfaces and desktops
Share of the exam
6.67% (the whole objective)
Questions in this lesson
6
Signed for by a person
0

Partly checked. None of the 6 questions here has been read against the cited source by a person. 6 questions have been checked against their cited clause by an automated pass — which is not the same thing, and is not a signature.

Only questions a person has signed for are used in mock exams here. That is the whole difference between the two kinds of checking above.

How these questions are written — where each question comes from, what the verification ledger records, and what happens when one is found wrong.

Drill this lesson

A lesson is one sitting: the trainer draws a short run from these questions alone and spaces the ones you get wrong.

Practise Display managers and accessibility settings

Questions in this lesson

Practise Display managers and accessibility settings

The rest of objective 106