On Wed, 8 Aug 2001, Heinz Wolter wrote: It didn't make a PC *pretend* it was an S/370, it used the PC's motherboard and I/O system as a backplane and accessory panel to an ACTUAL REAL S/390 processor board. Correction. P/370. The 68K just ran as a general purpose bus-I/O interface to the PC. The P/390 uses a proprietary chip that serves the same purpose. The P/370 ran at 0.8-1.3 (roughly) mainframe MIPS. This has nothing to do with the MIPS to which most people refer, because the mainframe MIPS is measured using VLIW instructions. The MCA and PCI P/390 run at 3.5-4 mainframe MIPS. The brand new P/390E, which incidentally is still being manufactured and lists for $15,000+ and is the basis for the Multiprise/3000, runs at 7-7.5 mainframe MIPS. Incidentally, the P/390 MCA, P/390 PCI, and P/390E can all be run alternately (and quicker) in an RS/6000 with that particular kind of slot. To rehash, the P/370 is an 8-bit XT-bus card that runs at 0.8 MIPS and has 32 MB main storage with no extended storage (mainframes divide main memory between main storage and extended storage, kind of like an Amiga, and call disk either minidisk -> temporary disk, or DASD -> main disk), the P/390 MCA is a 32-bit Microchannel card that runs at 3.5 MIPS with 32 MB main storage with a daughtercard connection for either a 32 MB or 96 MB daughtercard, which added that much additional main storage and no extended storage. The P/390 PCI is a 32-bit busmastering PCI card that runs at 3.5 MIPS, and has 128 MB main storage, can use PC (or RS/6000) memory as extended storage. The P/390E operates at 7 MIPS, has either 256 MB or 1 GB of main storage, and can also use PC or RS/6K memory as extended storage. Not exactly. On the P/370, and the P/390 MCA, the DASD would be an external mainframe DASD box (containing large-platter HDDs on a 3380/3390 interface). The internal HDDs of the PC or RS/6000 would be used for minidisk (in addition to virtual minidisk on DASD). The P/390 PCI and P/390E can use PC and RS/6K disk as DASD, and can emulate a 3390 9-track tape drive using a SCSI DAT. No offense, but bullshit. IBM still makes UNIX workstations based on the POWER architecture even today. Before the POWER machines, it was the RT/PC based on the ROMP. The IBM IISC was largely an experimental CISC workstation exercise. Have you ever seen a POWER2SC or POWER3II or even an old POWER RS/6000 running (PowerPC RS/6Ks don't count, they're el-cheapo)? They're surprisingly fast. Everything is coprocessed. They were designed to do CAD, and they excel at it. CATIA was dreamt up and implemented on RT/PCs and RS/6000s. P/370s are FAR from rare. It's just they are largely still being used in production environments. They are pure mainframe hardware. They never *ever* crash. If you don't need to replace one, you just don't. I have four P/390s running myself, along with an S/390 9672 G5. Peace... Sridhar P.S. I am an IBM employee, working on low-level mainframe server technology manufacturing. Here's my sigfile from work. -- Sridhar Ayengar sayenga(a)us.ibm.com Tool Control Software Development Sridhar Ayengar/Fishkill/IBM@IBMUS Interconnect Products (845)892-3496 IBM Corp. East Fishkill Facility, Hopewell Junction, NY