The HAC (Handy ACcess) parameters denote the offset of attributes within each officially maintained ALEPH BOS bank. For banks accessible by mnemonic symbols in ALPHA (see Ch. 6), this offset is taken into account automatically, and the corresponding HAC parameters are available in QCDE (note that names of HAC parameters and mnemonic symbols are closely related).
A separate include file QHAC is provided for the HAC parameters of all banks appearing on POT/DST/MINI event files which are NOT available in QCDE. QHAC contains only HAC parameters of banks needed by ALPHA and which are official ALEPH banks maintained in the standard documentation system. It can be included in the same way as QCDE and may be used in conjunction with it.