CompTIA Exam Prep - ITF+, A+, Network+, Security+, CySA+

Remote Disc lets a Mac without an optical drive use the CD or DVD drive in another computer over the local network. Apple introduced it when the MacBook Air shipped without a drive, and it remains in macOS. On the A+ exam it is a named macOS feature, and the more useful knowledge is what it cannot do — because that is where the support calls come from. How it works On the machine with the drive, sharing is enabled in Sharing preferences — DVD or CD Sharing on a Mac, or a small Apple-supplied utility on Windows. The client Mac then shows Remote Disc in the Finder sidebar under Locations, and an inserted disc appears there as though it were local. Both machines must be on the same local network. Discovery uses Bonjour, Apple's zero-configuration service discovery over multicast DNS, which means it works without any configuration on a flat network and stops working the moment the two machines are on different subnets. An option exists to prompt the sharing machine's user b...

Mission Control is the macOS feature that shows every open window, every full-screen application, and every desktop space on one screen. On the A+ exam it appears in the macOS features objective alongside Spotlight, Time Machine, Keychain, and FileVault, and the questions are usually about what a named feature does rather than how to configure it. What Mission Control shows Activating it zooms out to a bird's-eye view of the current desktop. Open windows spread out so none is hidden behind another, grouped by application. Along the top sits a bar containing every desktop space and every full-screen application, and clicking any of them switches to it. The activation methods matter because support calls often start with someone triggering it by accident. A four-finger swipe upward on a trackpad, a three-finger swipe upward if the gesture setting was changed, the Control and Up Arrow keys, the F3 key on Apple keyboards, and a hot corner if one is configured all do the same thing....

APFS is the default file system on macOS, iOS, iPadOS and watchOS. For the A+ exam it appears in two places: knowing which file system belongs to which operating system, and knowing what APFS does that its predecessor did not. Why it replaced HFS+ HFS+ dates from 1998, when storage meant spinning platters and a few gigabytes. It was extended repeatedly but its assumptions were wrong for flash storage: it had no native snapshots, weak crash protection, and second-granularity timestamps. APFS arrived in 2017 designed for SSDs from the start. Feature HFS+ APFS Designed for Hard drives Flash and SSD Snapshots No Yes Copy-on-write No Yes Space sharing Fixed partitions Containers share free space Encryption Bolt-on (FileVault) Native, multi-key Timestamps 1 second 1 nanosecond Containers and volumes The structural change most worth understanding. On HFS+ you partitioned a disk and each partition had a fixed size; running one out of space while another sat half empty meant repart...