The box in the cupboard
A small firm keeps its customer records on a real server. It is a heavy metal box in a cool cupboard. It hums day and night.
The owner says, "It is ours. We touch it, we control it." The accountant says, "It costs a fortune."
Who is right? Both are.
Key words
| Word | What it means |
|---|---|
| Physical server | a real computer, built to serve other computers, that you can touch |
| Business-critical | so important that the business stops if it fails |
| Resource | a part of a computer that does work, such as the CPU, memory and storage |
| CPU | the main processor of a computer |
| Configure | to set up a system the way you need it |
| Scale | to add more power or space when more is needed |
| Running cost | the money spent each year to keep something working, such as power and cooling |
| Virtual machine | a computer made of software that runs inside a real one |
| Firmware | the basic program stored in a device's hardware |
The cells students fill in are left blank in this preview.
By the end of this lesson
Note
I can give two gains and four limits of a physical server and choose when one is right for a job.
Starter
Have a go
Starter
3 questionsYour answers are marked here and are not kept. A college account keeps every student’s marks.
Two gains of a physical server
Full access to the resources. The whole CPU, all the memory and all the disks are yours. Nothing is shared with another customer. That suits a business-critical job, such as a payments system that must be fast every time.
Fully customisable. You pick every part. You can configure it to the exact needs of the firm, from the disks to the system software.
Four limits of a physical server
High costs. You pay a lot to buy it, and every year for power, cooling and support.
More time to maintain. Someone must fit parts, update firmware and fix faults on site.
Storage is hard to scale. To add space you often fit more disks, and there is a limit to what fits.
It needs physical space. A rack or a cool room, with power and safe floors.
Worked example: the real cost over three years
| Item | Cost | Notes |
|---|---|---|
| Buy the server | 4000 pounds | Paid once, at the start |
| Power, cooling and support, year 1 | 900 pounds | Paid every year |
| Power, cooling and support, year 2 | 900 pounds | Paid every year |
| Power, cooling and support, year 3 | 900 pounds | Paid every year |
| Total over three years | 6700 pounds | 4000 plus 900 three times |
The cells students fill in are left blank in this preview.
Try it: cost over time
price = 4000
yearly = 900
for year in range(1, 6):
total = price + yearly * year
print("After", year, "years:", total, "pounds")
# Change the yearly cost to 1200 and run it again.Check
Have a go
Check
4 questionsYour answers are marked here and are not kept. A college account keeps every student’s marks.