KwickClips Networks and the Internet · 37 sec · free
What is a checksum?
Short answer. A number worked out from a block of data and sent with it, so the receiver can recalculate and compare.
What is the drawback of an echo check?
It doubles the data sent, and cannot say which direction the error happened in.
Two checks
| Method | How |
|---|---|
| Checksum | Recalculate |
| Echo check | Send it back |
Remember
| Mismatch means resend |
Two ways to check a block of data. Which is which? Here they are. A checksum is recalculated and compared. An echo check sends the data back to compare. Remember. A mismatch means resend.
This clip is from the full lesson: Error Detection: Parity, Checksum, Echo Check and ARQ — 8 minutes, with the tables, the quick answers and the whole lesson in text.
Useful for: Cambridge IGCSE Grade 9 Computer Science (0478), Cambridge IGCSE Grade 10 Computer Science (0478), Cambridge IGCSE Grade 10 Computer Science (0478)
More KwickClips from this lesson
What is interference?40 sec
With even parity, is a byte with five 1s correct?42 sec
What is an acknowledgement?39 secDisclaimer. KwickAcademy is free study material for general learning and revision. Parts of it, including the voice-over, are produced with the help of AI tools and may contain errors; if you spot one, please tell us and we will correct it. Syllabus, marks and exam details follow the latest official board publications available to us, and boards can change them at any time, so always confirm against your board's official website and your school. Using this material does not guarantee any marks or result. Board names and trademarks belong to their owners; Kwickprep is not affiliated with or endorsed by any examination board. We never ask for passwords, OTPs or ID numbers. Your progress is saved only in this browser. Full disclaimer · Privacy