Operating Systems · Topic 2 of 15
OS Installations and Upgrades
Choose a boot method, installation type, partition style and upgrade path for a Windows install, and know what to check before upgrading an OS.
- 5 min
- Common boot sources are USB, optical, PXE network boot, internal drive and recovery partition.
- A clean install erases the target partition. An in place upgrade keeps apps and data.
- Image deployment and unattended installs scale to many computers.
What it is
Installing an operating system (OS) means placing it on a drive and configuring it for first use. Upgrading means moving an existing system to a newer version. A technician picks the method that fits the scenario: a new drive, a damaged system, a large rollout or a user who wants to keep apps and files.
How it works
Boot methods
The firmware, either the Basic Input/Output System (BIOS) or the Unified Extensible Firmware Interface (UEFI), decides which device starts first. The boot order can be changed in the firmware setup or by pressing a boot menu key during startup.
| Boot method | Typical use |
|---|---|
| Universal Serial Bus (USB) drive or other flash media | Most common for modern installs |
| Optical disc | Older systems with a drive |
| Network boot with PXE (Preboot Execution Environment) | Installing many machines from a server |
| Internal drive or recovery partition | Factory restore and recovery tools |
| External or hot swappable drive | Running or installing from a portable drive |
| Internet based | Downloading the installer, as in macOS Recovery or cloud reset options |
| Multiboot | Several operating systems installed side by side, choosing one at startup |
Types of installation
| Type | What happens | When to choose it |
|---|---|---|
| Clean install | Erases the target partition and installs fresh | New drive, or a system with deep problems |
| In place upgrade | Installs the new version over the old one and keeps apps, settings and files | User wants to keep data on the same hardware |
| Repair installation | Reinstalls system files and tries to keep data | Damaged OS that still partly starts |
| Reload | Reinstall of the OS, usually from scratch | System beyond repair |
| Image deployment | Copies a prepared disk image to many machines | Standard company desktops |
| Unattended install | Uses an answer file so no one has to click through setup | Large rollouts |
| Remote network install | Setup files come from a server over the network, often with PXE | Many computers, no media |
| Recovery partition or reset | Restores the factory image or resets the OS | Return a device to a known state |
Partitioning: MBR and GPT
A partition style defines how the drive layout is stored.
| Feature | MBR (Master Boot Record) | GPT (GUID Partition Table) |
|---|---|---|
| Disk size | Up to 2 TB | Far larger disks |
| Partitions | Four primary, or three primary plus one extended | Many more (128 in Windows) |
| Firmware | Legacy BIOS | UEFI |
| Resilience | One copy of the table | Backup copy of the table |
A primary partition can hold a bootable OS. An extended partition can contain logical drives, which was the old way to get past the four partition limit.
Formatting
After partitioning, the volume is formatted with a file system. For Windows the choice is normally NTFS (New Technology File System). A quick format only rewrites the file system structures, while a full format also checks the disk for bad sectors and takes longer.
Upgrade considerations
Before an upgrade or feature update, check these points.
- Hardware compatibility. The device must meet the minimum requirements for processor, memory, storage and firmware features.
- Application and driver compatibility. Older programs and drivers may not support the new version.
- OS compatibility. Confirm that the current version has a supported upgrade path to the new one.
- Backup. Save user data and settings before any change.
- Free space and power. Use enough free drive space and keep a laptop plugged in.
A feature update is a major release that adds new capabilities. It differs from a quality update, which is a smaller monthly patch that fixes problems and security flaws.
After the install
Once the OS runs, install drivers, apply updates, install the security software and applications, and restore user data. A driver for the storage controller may need to be loaded during setup if the installer cannot see the drive.
If a scenario says the user must keep programs and files, choose an in place upgrade. If it says the system is badly infected or unstable, choose a clean install after backing up data.
What to remember for the exam
- Common boot sources are USB, optical, PXE network boot, internal drive and recovery partition.
- A clean install erases the target partition. An in place upgrade keeps apps and data.
- Image deployment and unattended installs scale to many computers.
- MBR supports disks up to 2 TB and four primary partitions. GPT supports larger disks and many partitions.
- GPT goes with UEFI. MBR goes with legacy BIOS.
- Back up data before any upgrade.
- Check hardware, driver and application compatibility first.
- A feature update is a major release. A quality update is a smaller patch.
Common mistakes
Choosing an upgrade for a damaged system. An in place upgrade keeps the problems along with the data. A clean install or repair is better when the OS is corrupted.
Forgetting the backup. Even an upgrade that normally keeps data can fail, so the backup comes first.
Mixing up MBR and GPT limits. The 2 TB limit and the four primary partitions belong to MBR, not GPT.
Confusing quick and full format. A quick format does not scan the surface, so a drive with bad sectors can seem healthy.
Check yourself
Which installation type keeps the user's apps and files?
An in place upgrade installs the new version over the old one and keeps them.
Which partition style is needed for a disk larger than 2 TB?
GPT, because MBR cannot address that much space.
Which boot method suits installing the OS on many computers from a server?
Network boot with PXE, often combined with an unattended install.
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