The report that builds itself at 2 am
Asha works at a small shop chain. Every night at 2 am a big sales report builds itself. Nobody is in the building. By 8 am the managers open it.
Next day Asha runs a chart, reads her mail and plays music, all on one processor. How does one machine do all this? Today you find out, and why some machines need a different trick.
Key words
| Word | What it means | Example |
|---|---|---|
| Operating system | the main program that runs the computer and shares its parts | |
| Batch | a group of jobs run one after another with no user | the nightly sales report |
| Multitasking | running many tasks so they seem to run together | |
| Time-slicing | giving each task a short turn on the CPU | |
| Interrupt | a signal that makes the CPU stop and deal with something urgent | a key press |
| Real-time | must answer within a fixed, very short time | |
| CPU | the processor that runs program instructions | |
| Scheduling | choosing which job runs and when |
The cells students fill in are left blank in this preview.
By the end of this lesson
Note
I can describe batch, multitasking and real-time operating systems and say when each is used.
Starter
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Starter
3 questionsYour answers are marked here and are not kept. A college account keeps every student’s marks.
Batch systems run jobs with no user
A batch system collects jobs and runs them later, one after another, with nobody watching. Nothing asks the user a question while a job runs. That is called non-interactive.
It suits a huge amount of the same work, such as scoring 200,000 survey answers overnight. Scheduling decides the order and the start time, so the machine is busy at quiet hours.
Batch processing at a glance
| Feature | What it means | Example |
|---|---|---|
| Non-interactive | No user input while it runs | The nightly sales report |
| High volume | A large amount of similar work | 200,000 survey answers |
| Scheduling | Jobs are queued and started at set times | Starts at 2 am |
The cells students fill in are left blank in this preview.
Check
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Check
3 questionsYour answers are marked here and are not kept. A college account keeps every student’s marks.