======================================================= -----Original Message----- From: "McKown, John" <[EMAIL PROTECTED]> Sent: 7/20/2006 9:13 AM To: "[email protected]" <[email protected]> Subject: Re: Why is zSeries so CPU poor?
> -----Original Message----- > From: IBM Mainframe Discussion List > [mailto:[EMAIL PROTECTED] On Behalf Of Kuredjian, Michael > Sent: Thursday, July 20, 2006 9:59 AM > To: [email protected] > Subject: Re: Why is zSeries so CPU poor? > > > How do we know the number of hardware design errors? With > IA32, it's easier to discover these problems because the CPU > is used by many people under many operating systems. IBM > designs the OS and CPU, making it much easier to cover up any > problems that do exist. It depends on where the error is. If it is in some of the more exotic instructions or facilities not normally used by a standard application program, then you are likely correct. If the problem is that UNPK is "broken", then everybody will notice. This was proven in the original CMOS processor where the mantra was "don't use packed decimal, it performs very slowly!" due to the fact that most of the packed decimal instructions went from hardware to millicode. -- John McKown ======================================================= When TRAP2/TRAP4 was first released on the P390 (sometime around circa 1998-1999 IIRC), it was broken (storing into the TRAPSA in the primary space instead of the home space). We complained and IBM sent out a "fix". The P390 apparently had some form of millicode that was easier to change compared to changing silicon (or whatever passes for "silicon" in a P390). Jeffrey D. Smith Farsight Systems Corporation 24 BURLINGTON DR LONGMONT, CO 80501 303-774-9381 direct 303-709-8153 cell 303-484-6170 fax ---------------------------------------------------------------------- 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
