count-key-data(CKD) device

A disk storage device that stores data in the format:count field,usually followed by a key field,followed by the actual data of a record. The count field contains, among others,the address of the record in the format CCHHR (CC=cylinder number, HH=head number,R=record number) and the length of the data;the key field contains the record's key (search argument).; 一種磁盤存儲設備，它所存儲的數據按如下的格 式：計數字段，通常后跟一個鍵字段，再后面就是記錄中的實際數據。其中的計數字段包含 記錄的地址和數據的長度等,地址的格式為CCHHR (CC=柱面號, HH=磁頭 號, R=記錄號);鍵字段含有記錄的關鍵字(檢索參量)。