Setting up a home office system
- Plan: list the tasks (documents, video calls, printing) and choose parts that meet them: CPU, RAM (8β16 GB for office work), SSD storage, monitor, printer, router, UPS for power cuts.
- Connect: monitor to HDMI or DisplayPort, keyboard and mouse to USB, printer to USB or Wi-Fi, PC to router by Ethernet for a stable link.
- Configure: install the OS and drivers (small programs that let the OS talk to a device), set display resolution, add the printer, connect to the network, make user accounts, turn on updates and antivirus.
- Ergonomics and safety: screen at eye level, cables tidy, surge protector, good airflow.
Port standards
A standard is an agreed rule, so any brand's plug fits. It fixes the connector shape, pins, power and data speed.
| Port | Used for | Typical speed |
|---|---|---|
| USB 2.0 | Keyboard, mouse, printer | 480 Mb/s |
| USB 3.2 Gen 1 | External drives | 5 Gb/s |
| USB-C / Thunderbolt | Fast drives, displays, charging | 10β40 Gb/s |
| HDMI / DisplayPort | Monitors, TVs (video + sound) | up to tens of Gb/s |
| Ethernet (RJ-45) | Wired network | 1 Gb/s common |
Data can move serially (one bit after another, like USB) or in parallel (many bits at once, like old printer ports). Modern ports are serial because they can run much faster.
Firmware: what BIOS and UEFI do
Firmware is software stored on a chip on the motherboard. It runs before the operating system.
- BIOS (Basic Input/Output System) is the older type. UEFI is the modern type: it has a mouse-friendly menu, supports very large disks (GPT) and Secure Boot, which only lets trusted boot loaders start.
- POST (Power-On Self-Test) checks CPU, memory and key devices. Beep codes or messages show faults.
- Firmware holds settings: boot order, date and time, fan speeds, virtualisation on/off.
- Other devices have firmware too: printers, routers, SSDs. Updating firmware can fix bugs, but a failed update can make a device unusable, so follow the maker's steps and keep power on.
Multiple operating systems, drives and permissions
Multi-boot
- Back up all data first.
- Shrink the existing partition to make free space.
- Install the second OS into the free space.
- A boot manager shows a menu at start-up to choose the OS.
A separate data partition both systems can read keeps files in one place. Another option is a virtual machine: a second OS runs in a window inside the first one, with no repartitioning.
Permissions and attributes
Each file or folder has an owner and rules for read (open), write (change or delete) and execute (run). Rules can be set for one user, a group, or everyone. Follow least privilege: give each person only the access they need. Attributes such as read-only, hidden or encrypted add extra control. Whole drives can also be shared with set permissions on a network.
Optimising, maintaining and backing up
Making a computer faster
- Remove unneeded start-up programs and uninstall unused apps.
- Free disk space (disk clean-up); keep at least 15β20% free.
- Defragment a hard disk (HDD) occasionally; an SSD should not be defragmented (the OS uses TRIM instead).
- Update the OS, drivers and firmware; scan for malware.
- Upgrade hardware: more RAM, or replace an HDD with an SSD (the biggest single speed-up for old PCs).
- Check temperatures and clean dust from fans.
Backups
Types: full (everything), incremental (only what changed since the last backup), differential (what changed since the last full backup), and system image (the whole disk, to restore quickly). Follow the 3-2-1 rule: 3 copies of data, on 2 types of storage, with 1 copy off-site or in the cloud. Test that you can restore.
Backup time
Time (s) = size in bits Γ· speed in bits per second. 1 GB = 8 Gb = 8000 Mb.
Key formulas and definitions
- 1 byte (B) = 8 bits (b)
- 1 GB = 1000 MB; 1 Gb/s = 1000 Mb/s
- Transfer time = data size (bits) Γ· speed (bits per second)
- 3-2-1 backup rule: 3 copies, 2 media, 1 off-site
- Boot order: Power β Firmware β POST β Boot loader β OS
Worked examples
1. How long does a 10 GB backup take over USB 2.0 at 480 Mb/s (ideal)?
10 GB = 80 Gb = 80 000 Mb. Time = 80 000 Γ· 480 β 167 s β 2.8 minutes.
2. The same 10 GB over USB 3.2 Gen 1 at 5 Gb/s?
80 Gb Γ· 5 Gb/s = 16 s. About 10 times faster than USB 2.0.
3. Monday: full backup. Tuesday and Wednesday: incremental. The disk fails on Thursday. What do you restore?
Restore Monday's full backup, then Tuesday's incremental, then Wednesday's incremental, in that order.
4. A PC shows a black screen and three beeps at power-on. What stage failed and what do you check?
POST failed, so the OS never started. Beep codes often mean memory problems: reseat or test the RAM, then check the maker's beep-code list.
5. A teacher wants students to open the marks folder but not change it. Which permission?
Give the students group read (and list) only, no write. The teacher (owner) keeps read and write. This is least privilege.
6. An old laptop takes 4 minutes to start. Suggest three fixes in order of cost.
1) Disable start-up apps (free). 2) Clean the disk and scan for malware (free). 3) Replace the HDD with an SSD (low cost, biggest gain).
Common mistakes
- Mixing up bits and bytes. A 100 Mb/s link moves only about 12.5 MB each second.
- Defragmenting an SSD. It wears the SSD and gives no speed gain.
- Installing a second OS without a backup. Partitioning can wipe data.
- Giving everyone full control of shared folders. Use least privilege.