  Min, Veeravalli, and Barlas proposed strategies to minimize the overall
execution time of one or several divisible loads on a heterogeneous linear
network, using one or more installments. We show on a very simple example that
the proposed approach does not always produce a solution and that, when it
does, the solution is often suboptimal. We also show how to find an optimal
scheduling for any instance, once the number of installments per load is given.
Finally, we formally prove that under a linear cost model, as in the original
paper, an optimal schedule has an infinite number of installments. Such a cost
model can therefore not be sed to design practical multi-installment
strategies.
