Everything everyone has said so far is correct but IMHO all of the answers to question 1. (which is really two questions, kernel and architecture) have started at a level of detail beyond your question.
The z/OS hardware is its own architecture. It is not x86 or POWER or Sparc or any "popular" architecture such as those. I guess the correct name at this point for the processor hardware design is "zSeries architecture" but you will often hear it informally called "390 architecture" out of old habit - System 390, System 370, and System 360 were earlier names for the system. As others have pointed out, the processor is exhaustively, but not completely, documented in "Principles of Operation." The old name, System 360, was chosen to evoke an "all points of the compass" approach to the hardware. It implements byte-, word- (multiple sizes of word), decimal-, and floating point-oriented instructions, as well as many, many special-purpose instructions. As others have said, IBM has recently placed tremendous emphasis on multi-processor designs - the speed of the "box" is many times greater than the speed of any one CPU. The kernel and all programs run on these processors. Well, actually, the "channels" - the external buss - implement instructions of their own, but that's waaaaay beyond the scope of this e-mail. The apparent processor architecture is - like most modern machines - implemented largely in microcode running on a lower level processor. (Also something called millicode, but let's not go there for now.) IBM has been moving that lower level processor in the general direction of the POWER chips, but they aren't there yet, so far as I know. Someone will no doubt quibble with nearly everything I say above. Welcome to IBM-MAIN. Charles -----Original Message----- From: IBM Mainframe Discussion List [mailto:[EMAIL PROTECTED] On Behalf Of Kuredjian, Michael Sent: Tuesday, July 18, 2006 12:46 PM To: IBM-MAIN@BAMA.UA.EDU Subject: Newbie Questions! I'm currently in University on my Co-op term as a COBOL programmer for host systems (zOS). I have a few basic questions regarding the zArchitecture that I can't seem to elicit answers to from my co-workers. The questions are as follows: 1. zOS has a kernel called the BCP, or Base Control Program. In Linux or Windows, it's established that the kernel runs on a general purpose CPU( PowerPC, x86, MIPS, etc...); however, I would like to know if such a central CPU exists in the mainframe, and if that central CPU is of some common architecture like, POWER. If not, are there any documents that I can look into that will describe the CPU architecture for me? ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
