现有的文件材料,按其存储和检索文件信息的方式来划分,可以分为三大类.即通过直接目视就可以接受文件信息的直接可视型材料,通过电子信号间接输入输出文件信息的电声视听型材料,利用计算机具有智能功效的固体芯片自动记录并检索文件信息的固体智能型材料. Existing document materials, classified according to the way they store and retrieve document information, can be divided into three broad categories, namely, direct visual materials that can accept document information through direct visualization, indirect input and output of document information through electronic signals Of the audio-visual audio-visual materials, the use of computer intelligent function of the solid chip automatically record and retrieve the file information of solid intelligence material.