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为了以较低的成本得到很高的速度,ILLIAC Ⅳ的中央处理装置分成了四个可以执行单独指令组的控制器,每个控制器管理64个处理单元,总共有256个处理单元。每个处理单元可以作为一个运算和逻辑装置,具有它自己的2048字(每字64位)存贮器,并能和所有其它的处理单元发生联系。 由于运算和逻辑功能分配在256个处理单元上,因此ILLIAC Ⅳ可以同时完成很多类型数据结构的操作。根据这种平行机理,就要求处理单元本身是一台快速计算机:存贮器周期小于300ns;64位的浮点加法为250ns;二个64位数的浮点乘法为450ns。 然而,ILLIAC Ⅳ在目前尚未被程序编制者所“了解”。也就是说,还不能用某些高级语言写成程序,对机器的“内幕”也尚不清楚。为了充分利用ILLIAC Ⅳ这种平行机理,程序编制者必须对计算机的语言有一定的知识。当然,对ILLIAC Ⅳ的高级语言正在研制中,因此新的程序编制者将很容易地使用它。
To achieve high speed at a lower cost, ILLIAC IV’s central processing unit is divided into four controllers that can execute separate instruction sets, each managing 64 processing units for a total of 256 processing units. Each processing unit can operate as an arithmetic and logic unit with its own 2048 words (64 bits per word) of memory and can interface with all other processing units. Since the arithmetic and logic functions are allocated on 256 processing units, ILLIAC IV can perform many types of data structures simultaneously. According to this parallel mechanism, the processing unit itself is required to be a fast computer: the memory cycle is less than 300 ns; the 64-bit floating-point addition is 250 ns; and the two 64-bit floating-point multiplications are 450 ns. However, ILLIAC IV is not currently known to programmers. In other words, it is not yet possible to write programs in some high-level languages and it is unclear what the “insider” of machines is. To take full advantage of this parallel mechanism of ILLIAC IV, programmers must have some knowledge of computer languages. Of course, a high-level language for ILLIAC IV is under development so new programmers will be able to use it easily.