lesson
Working memory and saved files differ
1 · Learn
A processor executes instructions. Main memory holds instructions and data currently in use, while secondary storage retains files for longer-term use. In a typical system, volatile RAM loses its contents when power is removed.
Saving a document writes a stored version; seeing it on screen does not prove the latest edits are saved. A backup is a separate recoverable copy, not merely a second shortcut to the same file.
2 · Worked example
I edit a document, save it and reopen the saved file to verify the change. A screenshot of the unsaved editor would not prove the file contains it.
3 · Your turn
Does increasing RAM automatically mean a document is backed up?
Check your answer
No. Working memory capacity and a separate recoverable saved copy are different things.
4 · Apply your learning
Use a sample file to compare an unsaved edit, a saved version and an approved separate copy without touching important files.
Adult guidance and safety
Use an approved private programming or authoring environment and fictional data. Do not install unknown software or enter personal credentials for these exercises. Trace first, then run and test where a suitable tool is available; these text examples do not themselves provide an executable assessment environment.
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Write, draw or show your working. Use a mouse, pen or finger. This pad is not a submitted answer.
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Open a picture saved on this device to draw on it again. Opening replaces the drawing, but Undo can restore it. PNG only, up to 4 MB and 4096 × 4096 pixels. The picture stays in this browser; it is not uploaded. Paper lines in a saved picture become part of that picture.
Clear the drawing? Your typed notes will stay. You can undo this action.
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Open a UTF-8 TXT file from this device, up to 40 KB and 10,000 characters. It stays in this browser. Opening can be undone until you type again. Downloads keep a new copy; they do not change the file you opened.
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Typed notes are not submitted answers.
Check a calculation · Year 5 onward
Use this only when your teacher or adult allows a calculator for the task. Show your thinking first. It does not replace mental or written arithmetic and does not mark your lesson answer.
Powers, roots and trigonometry · Year 7 onward
Use only when the task allows a calculator. Choose one operation at a time and record your working. Trigonometry here always uses degrees (DEG), not radians. Inverse sine, cosine and tangent return an angle, not a reciprocal. Keep exact fractions and π in answers when requested.
Approximate numerical results use up to 12 significant digits. Inverse sine returns −90° to 90°, inverse cosine 0° to 180°, and inverse tangent −90° to 90°; these are principal values, not every possible solution of a trigonometric equation.
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