Separate Client Work from Server Work
Identify where the described operation runs and whether the server must verify it independently.
About 18 minutes, plus any extended practice
Open lesson 1Coordinate Client and Server State
A service holds private work, serves an old cached v2 while source v3 exists, and retrieves 20 items in batches of 4. Identify the security check, freshness issue and request count.
Before you begin
- Explain a request/response and divide whole numbers.
Choose by skill rather than age alone. Read with an adult when useful, revisit a lesson, or explore another grade.
Follow the lesson sequence
Distinguish Session Information from Document Contents
Use the stated session identifier for request context and the work record for saved contents.
About 18 minutes, plus any extended practice
Open lesson 2Read a Cache Record with Its Freshness Rule
Compare the copy’s stated version and freshness rule with the requested resource.
About 18 minutes, plus any extended practice
Open lesson 3Budget Repeated Requests
Divide total items by items per batch under the exact-fit model.
About 18 minutes, plus any extended practice
Open lesson 4Review and transfer
After the lessons, try 4 new review cases and a practical task. Each answer has an explanation and a link back to the related lesson.
Open the unit reviewGuest answers are temporary. Keep your own paper or document; this unit does not certify completion or record a school grade.
Topic references
- 2026 CSTA PK–12 Computer Science Standards: topic reference — Systems & Security
These references informed the topic selection. They do not certify complete standards alignment.