The original COCOMO 81 model was defined in terms of Delivered Source Instructions, which are very similar to SLOC.
ຕົ້ນສະບັບ COCOMO 81 ຮູບແບບໄດ້ຖືກກໍານົດໃນຂໍ້ກໍານົດຂອງສົ່ງຄໍາແນະນໍາແຫຼ່ງຂໍ້ມູນ, ທີ່ຄ້າຍຄືກັນກັບ SLOC.