If you have kept reading you would have seen this,
"As is clearly stated in the novel (Chapter 16), HAL stands for Heuristically programmed ALgorithmic computer. However, about once a week some character spots the fact that HAL is one letter ahead of IBM, and promptly assumes that Stanley and I were taking a crack at the estimable institution ... As it happened, IBM had given us a good deal of help, so we were quite embarrassed by this, and would have changed the name had we spotted the coincidence.
Also, IBM is explicitly mentioned in the film 2001, as are many other real companies. IBM is given fictional credit as being the manufacturer of the Pan Am Clipper's computer, and the IBM logo can be seen in the centre of the cockpit's instrument panel." -
Wikipedia