> I believe the 370/155 and 370/165 had core memory, and later in > their lives DAT was available as an RPQ or a field upgrade on > those processors. I think the 370/168 and certainly the 370/158 > came with DAT and solid state memory on the base model.
OK, here is a little correct history of the models. S/370 155 and S/370 165 did not have DAT capability and therefore were not virtual storage (VS) capable systems. The S/370 135 and S/370 145 did have DAT but this was NOT in the original announcement. When VS was announced on August 2, 1972 the 135 and 145 got VS support via a microcode EC. There was a very expensive option to upgrade the 155 to a 155-II and the 165 to a 165-II which basically added DAT. Very few customers took up this option as the more attractive ($) option were the S/370 158 and S/370 168 which had DAT and VS built-in. And as a side note, the expansion memory frames on some of the S/370 machines did have their own machine number, but I can't remember those numbers (except 3360 for the 155). http://ibm.com/ibm/history/exhibits/mainframe/mainframe_intro.html Mod MT Announce Memory 155 3155 1970-06-30 core 165 3165 1970-06-30 core 145 3145 1970-09-23 silicon 135 3135 1971-03-08 silicon 155-II 3155 1972-08-02 core 158 3158 1972-08-02 silicon 165-II 3165 1972-08-02 core 168 3168 1972-08-02 silicon 138 3138 1976-06-30 silicon 148 3148 1976-06-30 silicon http://ibm.com/ibm/history/exhibits/mainframe/mainframe_FS370B.html Jim
