General Category > LisaList2
Sun Remarketing SCSI Card Reverse-Engineering
AlexTheCat123:
--- Quote ---PCB artwork, drawings and software code is protected by copyright law. Circuits and algorithms might be patented.
So it is legal to draw a schematic from something you own and publish it, but you must not distribute the original documents without permission from the owner.. Assuming there is no patent on the circuit you could create your own pcb artwork, but you must not copy the original one.
--- End quote ---
So it looks like it's okay to proceed, right? I'm only going to publish my reverse-engineered schematics, not the originals, and the circuit doesn't seem to be patented so it seems like I'm free to make my own PCB.
Lisa2:
--- Quote from: AlexTheCat123 on February 04, 2022, 01:46:00 pm ---So it looks like it's okay to proceed, right?
--- End quote ---
I am not cool with this. Legal or not, copying a design chip-for-chip, net-for-net, is plagiarism. Just because the intention is that the result may be good for all, does not alone justify it. The owner of the Sun SCSI design has asked that this forum not to distribute this information at this time. As a forum administrator and the owner of the LisaList2.com domain I wish to proceed with caution, respecting the rights of all the members.
Rick
compu_85:
Who is the owner of the Sun Remarketing IP at this point? Did they buy everything, or just bits / pieces?
Lisa2:
--- Quote from: compu_85 on February 05, 2022, 07:45:24 pm ---Who is the owner of the Sun Remarketing IP at this point? Did they buy everything, or just bits / pieces?
--- End quote ---
John of VintageMicros bought the remaining inventory from SunRem many years ago and he also acquired from Bob Cook the rights to the SunRem products at that time.
Later John transferred the rights to the SunSCSI product to another person. That person is the one who contacted me.
I want it to be clear that I am not John or the current owner of the SunSCSI design. Nor do I have any interest in VintageMicros, business or otherwise.
stepleton:
I hope I won't cause offence with the following --- it's not intended!
Is it known whether the current IP owner intends to sell more of these devices? I know you can get the bare boards from VintageMicros, but the ROM is useful for booting the Lisa, and if that's not for sale, then you'll have to boot MacWorks Plus II some other way. I'm also not sure how easy it is to source the L5380 SCSI controller IC. Incidentally, I found this technical post (by James MacPhail I assume) interesting. It looks like you only need two bytes in the ROM to allow MacWorks to use the card, provided you have some other way of booting MacWorks, like a floppy disk.
(ETA: The ROM situation described in the post is an interesting one. I wonder how easy it is for the IP owner to make working ROM/PAL hybrid assemblies these days.)
I can understand misgivings about copying the PCB net (regardless of legality, which I think permits it for the reasons Patrick said, although I'm no lawyer!). I don't think this is plagiarism: Alex is not trying to say that the card is their own invention.
But if reverse-engineering and copying the net isn't fair play for other reasons, then we can abide by that, especially on this forum. Suppose instead you identified the "theory of operation" of the card and built some kind of replacement that MacWorks could use in the same way --- would this be all right?
It seems pretty likely that the card is the L5380 IC and some glue logic, and that basically MacWorks talks to the L5380 pretty directly. One of the chips on the card is a flip-flop, so there's a little additional state, but the rest is buffers and logic gates from what I can tell. Some of the glue logic may be for switching between the way the Lisa expects to talk to the ROM (using 16-bit 68000 peripheral interfacing) and how the MacWorks software might talk to the L5380 (which would be different if it uses 8-bit 6800 peripheral interfacing). The AppleNet card does the same thing.
The L5380 datasheet can be found on pages 424-447 of this PDF. I would bet MacWorks might only use a subset of the L5380's features, and you might be able to guess what they are by looking at the card's wiring or by examining MacWorks itself. From that knowledge you could make a new, compatible card, maybe one that makes use of modern ICs and a microcontroller that wouldn't be too hard to source. There's a lot of open-source activity these days in creating disk-emulating devices like BlueSCSI, so it may be possible to reuse some of that work here to recreate an L5380-based computer SCSI interface.
Alternatively, suppose you did have access to some L5380s, plus knowledge of what the support chips are doing (some logic function plus some state). You got this knowledge by understanding what the SCSI card logic does and/or by reverse-engineering MacWorks. You think you can probably replicate that same logic with a couple of GALs and some buffers, which you also have to hand, or maybe with your own 74-series design, or maybe with some other kind of programmable device.
Would either of these options be possible to discuss here? I promise I'm not trying to play games by asking. These alternative routes to a MacWorks-compatible SCSI card are ones that Alex or someone else might enjoy, and that bystanders like me would probably find enjoyable and educational to read about and discuss. If it's allowable on the premier Apple Lisa forum on the internet, then it's good to know it's an option. If not, there's always other projects.
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