A 40-seat online examination lab built from donated hardware
A government college is converting a hall into a 40-seat computer lab for online proctored examinations. Donations have produced 26 desktops (a mix of Core 2 Duo and i3 machines, 2 to 8 GB RAM, several with no OS licence sticker), 9 CRT monitors and 5 LCD monitors. The room has one 32 A single-phase point, a 5 kVA stabiliser and no UPS. A six-hour power cut is announced for exam day on the neighbouring feeder. The exam software requires Windows 10 or later, a working webcam and 4 Mbps per candidate. The college plans to buy Windows 10 from a local vendor at 1,000 rupees per machine and to hand the old CRTs to the municipal scrap dealer. The exam is in ten weeks.
1. Evaluate the hardware plan and recommend a configuration for all 40 seats, including what to do with the non-compliant machines and the CRTs.
Read the worked answer
The current plan fails on count, capability and peripherals. 26 desktops for 40 seats; Core 2 Duo machines cannot realistically run Windows 10 with proctoring clients; several have no licence sticker; nine CRT monitors are hot, heavy and 4:3; no webcams or headsets are mentioned, and proctoring needs one of each per seat; 40 × 4 Mbps = 160 Mbps sustained, which the college link almost certainly cannot provide.
Recommendation:
- Keep only i3 machines with at least 4 GB RAM, and only if they pass a boot-and-login test of the actual exam client. Fit an SSD (the single change that makes an old i3 usable) and upgrade to 8 GB where the board allows, roughly 4,000–5,000 rupees each. These become the 14–20 lower-priority seats.
- Do not spend money on the Core 2 Duo units. Use two as spare parts and dispose of the rest as e-waste.
- Buy 20–26 refurbished business-grade i5 desktops with a genuine Windows 10/11 Pro licence tied to the machine, so the whole 40-seat batch is identical. Heterogeneity is the biggest single cause of exam-day failure - one driver difference can cost a candidate their paper.
- Consider 40 thin clients plus one server with RDP/VDI if the LAN can be made reliable: about 15 W per seat, central patching and licensing. But it introduces a single point of failure, so keep two spare fat clients as a fallback.
- Replace CRTs with 19–22 inch LCDs; CRTs are an e-waste disposal problem, not a scrap-dealer opportunity.
Why: on exam day reliability dominates capital cost. Identical images, tested webcams and a spare machine matter more than CPU generation.
2. Size the UPS and check the electrical supply against the requirement. Show your workings.
Read the worked answer
Load:
- 40 desktops at about 120 W average (i3/i5, SSD, no discrete GPU) = 4.8 kW
- 40 LCDs at about 25 W = 1.0 kW
- switch, router, exam server console ≈ 0.4 kW
- Total ≈ 6.2 kW, which at power factor 0.9 is about 6.9 kVA.
UPS: specify a 10 kVA online double-conversion unit, not line-interactive, because the exam client must not see a transfer glitch when mains drops.
Battery for 30 minutes: 6.2 kW × 0.5 h = 3.1 kWh. With 0.9 inverter efficiency and 80% depth of discharge, 3.1 / (0.9 × 0.8) ≈ 4.3 kWh. On a 48 V DC bus that is about 90 Ah, so 4 × 12 V 100 Ah blocks in series - or follow the manufacturer's battery table if the UPS uses a 240 V string.
Supply check: one 32 A single-phase point gives 32 × 230 = 7.36 kVA. That is barely above the 6.9 kVA load and leaves nothing for UPS recharge, which typically needs another 10–20%, and nothing for air-conditioning. The 5 kVA stabiliser is undersized. Ask for a dedicated 63 A three-phase supply, or at minimum a separate 45 A circuit for the lab, with surge protection and earthing below 5 ohms. Put air-conditioning on its own circuit so it does not drain the UPS.
Mandatory test: run a full 40-seat mock exam on battery before exam day.
3. Identify the licensing and e-waste compliance failures in the plan and state what should be done instead.
Read the worked answer
Licensing failures:
- Installing Windows 10 at 1,000 rupees per machine almost certainly means non-genuine or recycled volume keys, and the college - not the vendor - carries the liability. Use OEM licences that ship with refurbished business PCs (COA label matching the BIOS marker), or an education volume licence through an authorised partner. Keep invoices and a register mapping each licence to a machine serial number; a software audit should take an hour, not a month.
- The exam client, the proctoring plug-in, antivirus and any office suite are also licensed per seat and are missing from the budget.
E-waste failures:
- Handing CRTs and dead PCs to an informal scrap dealer is not compliant. Educational institutions are covered as bulk consumers under the E-Waste (Management) Rules: e-waste may go only to registered dismantlers or recyclers, or back to the producer under take-back. Keep the recycler's registration number, the transfer records and the annual return.
- Wipe or physically destroy every disk before disposal - donated machines often carry student or staff data - and obtain a certificate of destruction with a weighment record.
Also missing: an asset register with warranty dates, a UPS maintenance contract, a documented exam-day standard operating procedure, and a named technician on call. Compliance here is not paperwork: a licence audit or an unsafe e-waste transfer can close the lab faster than a hardware failure.