Operating system types, filesystems, and life cycles
Exam objective 1.1. An operating system (OS) manages the hardware, runs applications, stores files, and decides who may do what. A help desk technician supports several kinds at once, so the first skill is recognizing which OS a device runs and what that means for its tools, file formats, and support dates.
| OS | Made by | Where you meet it | Support notes |
|---|---|---|---|
| Windows 10 and 11 | Microsoft | Most business desktops and laptops | Windows 10 reached end of support on October 14, 2025; organizations can pay for Extended Security Updates for up to three more years. Windows 11 normally gets one feature update a year. |
| macOS | Apple | Mac desktops and laptops only | A new major version every fall; older Macs eventually stop receiving the newest version. |
| Linux | Open-source community and vendors (Ubuntu, Red Hat, Debian, Fedora) | Servers, cloud systems, developer workstations, network appliances | Free to use; each distribution sets its own support period. Ubuntu LTS releases, for example, get five years of standard updates. |
| ChromeOS (written Chrome OS in the objectives) | Chromebooks in schools, call centers, and frontline jobs | Built around the Chrome browser and web apps; each model has a published date when automatic updates end. | |
| iOS and iPadOS | Apple | iPhone and iPad | Apps come from the App Store (the EU also allows approved alternative app marketplaces). |
| Android | Google, with phone makers such as Samsung and Motorola | Most of the world's phones, rugged barcode scanners, tablets | How long a device gets updates depends on its maker and model. |
Workstation operating systems (Windows, macOS, Linux, ChromeOS) run on desktops and laptops. Mobile operating systems (iOS, iPadOS, Android) run on phones and tablets. They are built around touch, app stores, and app isolation: each app is kept in its own sandbox and cannot read another app's data unless the user grants permission.
A filesystem is the way an OS organizes data on a drive: names, folders, sizes, permissions, and where each file's pieces sit. The filesystem on a drive decides which operating systems can read it, how large one file can be, and whether file permissions are possible.
| Filesystem | Used by | Key facts |
|---|---|---|
| NTFS (New Technology File System) | Windows system and data drives | The Windows default. Supports permissions, encryption (EFS), compression, quotas, and journaling, which helps it recover after a crash. macOS can read NTFS but cannot write to it without extra software. |
| ReFS (Resilient File System) | Windows Server storage; Dev Drive volumes in Windows 11 | Built for very large volumes and data integrity: it checksums data and repairs corruption. Windows cannot boot from ReFS, and it is not supported on removable drives. |
| FAT32 (File Allocation Table 32) | Older USB drives, memory cards, the small UEFI system partition | Readable almost everywhere. No single file can be larger than 4 GB. No permissions. |
| exFAT (Extensible File Allocation Table) | Large USB flash drives and SD cards | Removes the 4 GB file limit and is readable and writable on both Windows and macOS. No permissions or journaling. |
| ext4 (fourth extended filesystem) | Many Linux distributions, such as Debian and Ubuntu | Journaling Linux filesystem with Linux permissions. Windows and macOS cannot read it without extra software. |
| XFS | Red Hat Enterprise Linux (RHEL) and similar distributions | High-performance journaling filesystem for large files and volumes; the RHEL default. |
| APFS (Apple File System) | macOS, iOS, iPadOS | Designed for SSDs, with snapshots and built-in encryption. Windows cannot read it natively. |
The 4 GB trap: a 6 GB video will not copy to a FAT32 flash drive even when the drive has 50 GB free. Back up the drive, then reformat it as exFAT (if Macs also use it) or NTFS (Windows only).
Vendor life-cycle limitations. Every OS version has an end-of-life (EOL) date, after which the vendor stops releasing security fixes. An EOL system still turns on and runs, but every new vulnerability stays open, so security policies and compliance rules usually forbid it. Update limitations work the other way round: older hardware may not be able to install the newest version. Windows 11, for example, requires TPM 2.0 and a supported processor, so many Windows 10 PCs could not upgrade and had to be replaced, retired, or kept on paid Extended Security Updates.
Compatibility concerns between operating systems come up daily in mixed offices:
- Filesystems: a drive formatted APFS or ext4 is unreadable on a Windows PC; exFAT is the safe choice for drives that move between systems.
- Applications: many business apps exist for Windows only, so Mac and Linux users may need a web version, a virtual machine, or an alternative app.
- Drivers and peripherals: a printer or scanner may ship drivers for Windows and macOS but not for Linux or ChromeOS.
- File sharing: Windows, macOS, and Linux can all use SMB file shares, but permissions and file names behave differently (Linux names are case-sensitive, and Windows forbids characters such as : and ? in names).
- Installers and shortcuts: a Windows .exe installer does not run on macOS and a Mac .dmg does not run on Windows; the Ctrl key on Windows is usually the Command key on a Mac.
Which filesystem travels: exFAT for exchange between Windows and Mac, NTFS for Windows-only drives, ext4 or XFS for Linux, APFS for Apple devices.
Word bank
All definitions →- Distribution (distro)
- A packaged version of Linux, such as Ubuntu, Fedora, or Red Hat Enterprise Linux.
- End-of-life (EOL)
- The date after which a vendor no longer provides updates or support for a product.
- Filesystem
- The structure an OS uses to store, name, and find files on a drive.
- Journaling
- The filesystem logs changes before making them, so it can recover cleanly after a crash or power loss.
- Operating system (OS)
- Software that manages hardware, runs applications, and controls access to the computer.
Knowledge check
A user needs one USB drive that a Windows laptop and a Mac can both read and write, and it must hold a single 7 GB file. Which filesystem fits?
What is the main risk of keeping a PC on an operating system after its end-of-life date?
Which filesystem is the default on Red Hat Enterprise Linux?