In PSS, IBMprovided functions that cannot be modified. These functions can be performed by programmable point of sale terminals operating only in fixed mode.; 在可編程商店系統(tǒng)(PSS)中,IBM提供的一些不能修改的操作程序,可編程銷售點(diǎn)終端可 按固定方式操作執(zhí)行這些操作程序。