tyc@cbnewse.att.com (felix.a.lugo) (05/02/91)
Well, for those who said that it couldn't be done ... here it is ... The procedure for using two motherboards on a single NeXTcube! First of all, a disclaimer: ********************** DISCLAIMER DISCLAIMER ************************** The following procedure is not supported by NeXT, Inc. and will definitely void any warranty that remains on your NeXT computer. Follow it at your own risk. I disclaim all responsibilities for any damages caused by negligence in following the procedure. There is no guarantee that the procedure will work on all versions(?) of the NeXTcube. All I know is that it worked on the NeXT cube I was working on!!!! SO BEWARE! ********************** DISCLAIMER DISCLAIMER ************************** Here we go! I'll first give a description of the hardware I was using and an comment on what I accomplished and how I got the information on how to do it! The hardware I was using included a NeXTcube with 660 MB drive, OD etc., a 68040 upgrade, and a 68030 motherboard. I accomplished installing both the 68040 and 68030 boards on a SINGLE NeXTcube and linked them together through their ethernet ports. The 68040 was configured as a server and the 68030 was used as a client (booting off the network for lack of an additional hard drive). The procedure reconfigures slot #2 on the NeXTcube back-plane as slot #0. This provides two slots on the cube configured as #0 which is required for booting the two motherboards. Once I figured-out what the slot pin- outs were (thanks to my good friend John Chmielewski), it was a matter of time before the two boards happily co-existed. Now the procedure: 1. First, follow the procedure on the NeXT User's Reference manual for removing the system board (Appendix C: Opening the Cube on page 291 of the 2.0 manual). 2. Remove the two screws that attach the power-supply housing to the cube (using the NeXT supplied tool) and gently pull the housing out. Set it aside in a safe place (away from kids and nosey friends!) 3. Remove the two plastic grooved plates (used to slide the system boards in) at each side of the inside bottom of the cube. (For each plate, lift the side closest to the rear opening and gently pull them out). Set them aside. 4. Using the NeXT tool, remove three screws holding the back-plane to the cube and then take the back-plane out of the cube. Let the cube rest for a while. Inspect the back-plane. You should see five bus slots (four vertical and one horizontal). The horizontal slot connects the back-plane to the power supply housing. We're only interested in the four vertical slots. From the factory these slots are configured by NeXT as 6, 2, 0, and 4 (starting from the left and going right with the horizontal slot at the bottom of the back-plane). The main system board is connected to slot #0 (which you have probably noticed). Each slot contains three columns of 32 pins. Following is an ASCII representation of one of the slots: x y z C B A o-o o 32 . . . o-o o 31 . . . o-o o 30 . . . o-o o 29 . . . 28 . . . . . . 3 . . . 2 . . . 1 . . . where x, y, and z are labeled GND, SID, and VCC, respectively. The GND, SID, and VCC "holes" are used to configure the slot number using simple binary encoding, where GND is logical zero, VCC is logical one, and SID determines the current bit state (one or zero). From the diagram above, you'll notice that there are 4 rows of GND, SID, VCC triads; each row is equivalent to one bit position in the slot number, the bottom row being bit position 0 and the top row bit position 3. This gives a total of four bit positions, or 16 possible slot numbers. To encode a slot number, all that is required is to connect an SID row to its corresponding GND or VCC row. For example, the diagram below shows the configuration of the slots in my cube's back-plane: SLOT #6 SLOT #2 SLOT #0 SLOT #4 BIT 3: o-o o o-o o o-o o o-o o BIT 2: o o-o o-o o o-o o o o-o BIT 1: o o-o o o-o o-o o o-o o BIT 0: o-o o o-o o o-o o o-o o (you'll have to look very closely to see the connection between the "holes"). Now to continue with the procedure: 5. To reconfigure slot #2 as slot #0, you'll have to cut the trace between SID and VCC for bit position 1 above and connect SID to GND in the same row. To cut the trace, I used the NeXT supplied tool for removing SIMMs in the 040 upgrade (talk about multi-purpose!) Very gently, I scraped the solder between the two holes. I then took a paperclip, shaped it to fit between the holes in SID and GND, and trimmed it down to an even 1/4 inch (perfect fit!). That's all there is to it. If for some reason you ever want to revert to slot #2, just remove the paperclip from GND-SID and reconnect it to SID-VCC. 6. Now put the cube back together. First, re-install the back-plane and its three connecting screws, then the plastic plates, the power-supply housing and its two screws. At this point the cube is ready to take on the two system boards. How you decide on what or how to use them is up to you; I'll explain how I used mine ... 7. I installed the 68040 in the original slot #0 and the 68030 in the reconfigured slot #0 (previously slot #2). The 68040 was used as the main processor board. I connected the 660 MB drive, the OD, and the monitor cable to it. NOTE: Before I began the procedure, I went into the NeXT Monitor on the 68030 and disabled the SCSI tests and verbose test mode, enabled port A as a console terminal, and made "en" the default boot device. I also setup the 68040 as a boot server and taught it about the 68030 (which took some time to get it setup properly). 8. I connected the 68040 to the 68030 using a thin-ethernet cable and I booted. First thing I noticed was that the 68030 timed-out a couple of times waiting for the 040 to tell it to boot. But after the 040 was up, the 030 booted nicely. That's all folks. Hope all this made some sense and people find it useful. Some comments: - To power off the cube, I have to first shutdown the 030 (I run "halt -p" as root from a telnet connection and wait for the 030 to go down), and I then halt the 040. If you shut down the 040 before the 030, you'll have to pull the power plug to turn the machine off. The cube will not power off if either of the two boards is providing a load to the power-supply. - Remember, I've only performed this procedure on one system. I do not know what will happen on your system. So make sure you plan ahead what your going to do and that you understand the procedure. - I don't know what problems arise when you add a board that uses the NeXTBus, such as the NeXTdimension, or how it will behave. If someome is brave enough to perform the procedure and tries another board, please post your results to the net. - If you think this procedure has done any good to you, please feel free to send in donations. 8^) (think of it as "hardshare") =============================================================================== Felix A. Lugo E-Mail: (NeXTmail preferred) AT&T Bell Laboratories, Naperville, IL Felix_A_Lugo@ATT.COM coco@ihcoco.att.com AT&T NeXT User Group nug@ihcoco.att.com T.Y.C. Software, Lisle, IL coco@ihtyc.att.com ===============================================================================
ptok@void.caltech.edu (phillip tokumaru) (05/02/91)
In article <1991May2.070624.262@cbnewse.att.com> tyc@cbnewse.att.com (felix.a.lugo) writes: > > Well, for those who said that it couldn't be done ... here it is ... > The procedure for using two motherboards on a single NeXTcube! > > [a lot of Frankenstein-like stuff deleted] Couldn't you (for < $80) put the poor old 030 board in an enclosure with a power supply, and then ground the proper NUBUS ID on the connector? (I vaguely remember seeing an early 030 with an empty IC socket, I thought it was for the NUBUS logic...anyone else remember something like that?)
jiro@shaman.com (Jiro Nakamura) (05/03/91)
In article <1991May2.111001.26346@nntp-server.caltech.edu> ptok@void.caltech.edu writes: >Couldn't you (for < $80) put the poor old 030 board in an enclosure with a >power supply, and then ground the proper NUBUS ID on the connector? (I vaguely >remember seeing an early 030 with an empty IC socket, I thought it was for the >NUBUS logic...anyone else remember something like that?) I agree that this would be a much more elegant solution. My old 030 in my closet is getting restless. I was thinking of turning him into a coffee table ornament, but then again, if it acutally works.... Maybe I *could* turn it into a coffee table with a powercord and a ethernet cable to my real cube.......... :-) What blasphemy. - jiro nakamura jiro@shaman.com -- Jiro Nakamura jiro@shaman.com Shaman Consulting (607) 253-0687 VOICE "Bring your dead, dying shamans here!" (607) 253-7809 FAX/Modem
isbell@ucscf.UCSC.EDU (Art Isbell) (05/03/91)
In article <1991May2.205409.2623@shaman.com> jiro@shaman.com (Jiro Nakamura) writes: >In article <1991May2.111001.26346@nntp-server.caltech.edu> ptok@void.caltech.edu writes: >>Couldn't you (for < $80) put the poor old 030 board in an enclosure with a >>power supply, and then ground the proper NUBUS ID on the connector? (I vaguely >>remember seeing an early 030 with an empty IC socket, I thought it was for the >>NUBUS logic...anyone else remember something like that?) > > I agree that this would be a much more elegant solution. My old >030 in my closet is getting restless. I was thinking of turning him into >a coffee table ornament, but then again, if it acutally works.... > Maybe I *could* turn it into a coffee table with a powercord and >a ethernet cable to my real cube.......... :-) > What blasphemy. Just curious about those '030 boards that weren't returned to NeXT in the provided package and prepaid shipping. Wasn't part of the reasonable '040 upgrade deal contingent on the '030 boards being returned to NeXT? I appreciate the reasonable upgrade policy that NeXT has demonstrated so far and don't want future upgrades jeopardized by those who don't "play by the rules". I haven't heard of anyone paying NeXT a core charge (like in "rebuilt starter motor", not "core dump" :-) for the right to keep the '030 board. Is that what has happened, or are some people just refusing to return what belongs to NeXT? -- _____ ____ Art Isbell |\ | | | | \ 315 Moon Meadow Lane NeXT Registered Developer | \ | ___ |____| | | Felton, CA isbell@ucscf.UCSC.EDU | \ | |___| | \ | | 95018-9442 (408)438-4736(B) | \| |___ | \ |___/ (408)335-1154(H)