What version of Julia are you using? Looks like things have changed from 0.6 to 1.0. According to the 0.6 docs for the norm function, norm(A,Inf) should give the matrix norm induced by the vector infinity norm, so the maximum row sum of A rather than just the entry with largest absolute value. However, in 1.0 the norm function just treats a matrix as if it were a vector of all the entries. You now need to use the new function opnorm for matrix norms induced by vector norms. E.g. on 1.0 I get
julia> A = [1 2;3 4]
2×2 Array{Int64,2}:
1 2
3 4
julia> norm(A,Inf)
4.0
julia> opnorm(A,Inf)
7.0