-----Original Message----- From: IBM Mainframe Discussion List [mailto:[EMAIL PROTECTED] On Behalf Of Ted MacNEIL Sent: Friday, July 20, 2007 5:59 PM To: IBM-MAIN@BAMA.UA.EDU Subject: Re: PSI MIPS (was: Links to decent 'why the mainframe thrives' article)
>A dual core CPUs actually cause themselves a bottleneck if they only >have ONE bus to communicate to/with the outside world. This becomes >another design issue that while producing apparent processor speed has >to balance out against the ability of the bus (or buses) to handle data >flow (which gives effective processor speed) According to somebody I know from IBM Canada's Lab, all mainframe chips are dual core, but better. They don't only duplicate the core, but all connections to the world outside the chip. Including buses. I guess they learned after AP's in the late 1970's. <SNIP> Oh yeah. Between AP [AP Short], AP Long (kinda Dyadic Processor vs. Dual Processor, as I recall) that got us to MP, a few lessons were learned. And if I remember correctly, Amdahl (before my time there) had started what became XA I/O with MDF (Multiple Domain Feature) which answered even more problems in this area. Oh, and before I forget it, PR/SM was IBM's answer to MDF, not vice versa. I think IBM was actually the second paying customer for MDF. Later, Steve Thompson ---------------------------------------------------------------------- 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
