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 secVoice-over is AI-generated; the script is written and checked by Kajal Ma'am. Confirm anything you plan around against your official board document. We never ask for a password or an OTP.