Differentiating chips (Was: Newbie member saying

I didn't catch this one the first time round. What exactly did you mean by "the first computer where a user program couldn't grab the reset vector"? If you mean that the vector is not in alterable memory, the PET springs to mind - 6502 has the vector in locations $FFFC and $FFFD. On the PET this is ROM, and the routine it sends you to does not look in RAM... If you mean the reset vector was not in the computer's address space, and so incapable of alteration even if you put RAM there, does the Z80 not count? The reset vector is always zero, and the machine (afaik) always starts executing code at that address. Most Z80 machines allow this to be made RAM, but plenty don't - Sinclair springs to mind. In my day it was (among 8-bit home computer people) considered quite a luxury if you could redirect the reset vector... Or did you mean the first Intel 88/86 machine? I am puzzled. Philip. This E-mail message is private and confidential and should only be read by those to whom it is addressed. If you are not the intended recipient, you are hereby notified that any dissemination, distribution, copying, reproduction, modification or publication of this communication is strictly prohibited. Please delete the message from your computer and destroy any copies. This message is not intended to be relied upon by any person without subsequent written confirmation of its contents. This company therefore disclaims all responsibility and accepts no liability of any kind which may arise from any person acting, or refraining from acting, upon the contents of the message without having had subsequent written confirmation. If you have received this communication in error, or if any problems occur in transmission please notify us immediately by telephone on +44 (0)2476 425474