feed 该翻译成什么？

The notation is 'first:last(nbytes)' which means 'sequence numbers first up to but not including last which is nbytes bytes of user data'.

关键是词组【up to】，这句该如何翻译啊？

The notation is 'first:last(nbytes)' which means 'sequence numbers first up to (last) but not including last which is nbytes bytes of user data'.

原句省略了一个last。