At 02:14 PM 6/24/01 -0400, you wrote: Hi Chad, In the 4000/300 DEC decided to make a "new kind" of Q-bus box, one where the CPU was upgradable again. In the early MicroVAXen the CPU was a single card, memory was a single card(s), disk interfaces, and then ethernet. Since the Q-bus is limited to about 3Mbytes/sec that set a limit on the I/O performance of the machine. With the KA640 DEC put ethernet, disk I/O (DSSI), and memory on the same card. This gave them a direct disk channel (4Mbytes/second), ethernet not on the bus (saves interrupts and bus latency) and some local memory. I did not work as well as they would have hoped apparently. But the ultimate expression of this idea was the KA660 which used Q-bus "fingers" had only DSSI and Ethernet on the CPU card and pushed the memory bus that ran over a 50 pin ribbon cable to its limit. For the 4000/300 they knew 64bit wide memory was going to help them get performance gains and they knew that leaving the processor on the Qbus meant they had to connect things with ribbon cables that could have easily (and less expensively) been connected on the backplane. So a new bus was invented (I don't know if it is named or not) and the "CPU Box" was born. This borrowed from the mainframe VAXen of the time that had the CPU/memory/bus interconnects in one box, and then either BI, XMI, or even UNIBUS boxes hanging off of that. In the 4000/300, 400, 500, 600, 700, 700a, 705, and 705a. The backplane consists of about 5 "slots" on the right edge that hold the CPU / memory / DSSI interconnects and to the left of the CPU is the Q-bus. The KA670,-675,-680,-690,-691,-692,-693,and -694 CPUs use this bus. (note they could not go to KA7xx because that would interfere with the module numbers of the 700 series processors :-) Everything from the KA675 were variations on the NVAX implementation of the VAX architecture (as is the 4000/90, 4000/105, etc) So you're correct in that the back plane connector on the KA694 looks almost like a eurocard connector but it actually plugs into a backplane that has Q-bus slots to the left of the CPU. So the KA660 is the fastest "true Q-bus" processor and the KA694 is the fastest "integrated Q-bus" processor. The 4000/105 has a desktop enclosure and actually brings the Qbus out to a pair of connectors on the back of the box, These connect with cables to a B215F or B213F expansion box where the first card in that box is the Q-bus extender. I don't consider the 105 to be an integrated Q-bus processor like I do the 4000/705a. --Chuck

Yeah, me too. I need 4. Peace... Sridhar On Sun, 24 Jun 2001, Eric Dittman wrote:

On Sun, 24 Jun 2001, Marvin wrote: Cordata (Corona Data Systems) also made a laser printer controller that they marketed with a CX engine laser printer (nothing special about the printer). The printer controller's drivers would refuse to initialize on 286 or above computers. They had their own font format (supported by the POEMS font editor, which would also convert HP soft fonts), and their own formatting codes (used extensively in the XenoCopy-PC manuals), and they had an HP emulation (which I never used). If anybody really wants them, I have a few. I also have an Eiconscript board (with AT compatible drivers) that emulates Postscript. ANd, I have a bunch of JLASER cards. All of which I used to use with the Cordata (CanonCX) laser printer. -- Fred Cisin cisin(a)xenosoft.com XenoSoft http://www.xenosoft.com PO Box 1236 (510) 558-9366 Berkeley, CA 94701-1236

It might be of interest to some, that Corona was one of the early PC mfg's that used the Western Digital FDC's. I don't know about this particular one, but that holds out some promise of doing some interesting things with "classic" diskette formats that are more difficult with standard PC FDC's. Dick ----- Original Message ----- From: "Mike Ford" <mikeford(a)socal.rr.com> To: <classiccmp(a)classiccmp.org> Sent: Sunday, June 24, 2001 10:33 PM Subject: Corona PC, last chance.