High Quality Content by WIKIPEDIA articles! Basic Assembly Language (BAL) is a low-level language used on IBM mainframes from the earliest 360 series, through systems 370, 390, and System z, as well as the Univac 90/60, 90/70 and 90/80 mainframes made by Sperry Corporation. The earliest version was provided with the System/360 in 1964; the latest version is known as the IBM High-Level Assembler (HLASM). Programmers utilizing this family of assemblers also refer to them as ALC, (for Assembly Language Coding), or simply "assembler".