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Author Topic: Corvus HDDs and the Lisa  (Read 95 times)

compu_85

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Corvus HDDs and the Lisa
« on: February 22, 2021, 08:07:01 am »

I've seen some tidbits saying that a Corvus hard disk could be connected to the Lisa:

  • The Lisa OS Guide: https://lisaem.sunder.net/cgi-bin/bookview2.cgi?zoom=-1?page=4?book=22?Go=Go
  • This post from someone using Unisoft back in the day: https://macgui.com/usenet/?group=9&id=914
    "...if anyone hears of a RAM disk for the Uniplus System V, I'd love to hear it. 
    (PS: one of our staff has a Lisa with a Corvus disk.  Aside from the fact that the Corvus disk has failed a few times, he loves it.
    The problem is strictly with the slowness of the Profile.)"
  • These notes from the Lisa Handbook, page 27 https://www.apple.asimov.net/documentation/applelisa/The_AppleLISA_Handbook.pdf
    "Any additional drive must always be connect via a parallel card, whether its augmenting a profile drive or a 10-megabyte drive.
    Lisa now supports a 70-megabyte drive manufactured by Priam and distributed by Tecmar.
    UNIX and XENIX users have the option of attaching drives from Corvus and Sunol in sizes from 20 to 100 megabytes. "
  • References in the Uniplus (and I think Xenix?) manuals for the procedure to create the device file for a Corvus and format the disk

So here's the question... how was the Corvus disk attached? It also used an 8 bit parallel interface, but looking the the pinouts it seems quite different from the ProFile.

CHM has a prototype Lisa with a Pippin (Profile) / Corvus card: https://www.computerhistory.org/collections/catalog/102719928
Al has some pictures of the card here (which looks quite similar to the 1 port Parallel card I got last year..):
http://www.bitsavers.org/pdf/apple/lisa/pcb_pictures/Pippin_Corvus_F.jpg
http://www.bitsavers.org/pdf/apple/lisa/pcb_pictures/Pippin_Corvus_B.jpg

Does anyone have more info on this? A friend has some Corvus drives and I'd love to give this a try.

Thanks,

-Jason
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rayarachelian

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Re: Corvus HDDs and the Lisa
« Reply #1 on: February 22, 2021, 10:04:44 am »

Every LOS 3.x has a Priam specific driver on it, just like it has one for the profile. Actually there's two files, one is for the running OS, and another is for booting. (There is a third driver for the parallel port itself when used with ProFiles/Widgets.) I don't yet know enough about why a different driver is needed during booting, perhaps it's invoked by the loader blocks (BB,BB).

UniPlus has drivers in the kernel for these as well, and there is source for the kernel (and these drivers). The schematics and drive manuals are up on bitsavers for this drive. These are a totally different protocol than the ProFiles.

I know there were several drives compatible with the ProFile protocol, SunRem made a controller also that accepted an MFM/RLL drive. It's possible Corvus had an interface to this or a model that supported this protocol. Perhaps it needed a driver (or not.)

OSCONFIG is a clue for me, thanks for finding that. I did see differences in BLU widget dumps from profile dumps in SYSTEM.CONFIG - the clue there is the boot device failure and moving from say motherboard parallel port to expansion slot parallel port, or profile to widget, etc. I'll have to figure out more info about OSCONFIG and perhaps how to replace it when moving data from a Widget to a ProFile.
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compu_85

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Re: Corvus HDDs and the Lisa
« Reply #2 on: February 22, 2021, 05:41:44 pm »

The Priam drive had its own dedicated controller card.

I've not seen mention of a specific Sunol / Corvus card, which makes me think they were hooked up to a standard system somehow.

I'd love to have a DataTower... but I think they are very very rare at this point.

-J
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stepleton

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Re: Corvus HDDs and the Lisa
« Reply #3 on: February 22, 2021, 07:29:36 pm »

Here are pictures of a "Corvus/Pippin" card on Bitsavers:

http://bitsavers.org/pdf/apple/lisa/pcb_pictures/Pippin_Corvus_F.jpg
http://bitsavers.org/pdf/apple/lisa/pcb_pictures/Pippin_Corvus_B.jpg

I'm pretty sure that Pippin was the codename for ProFile, based on some of the docs surrounding the Monitor. Now, this card is obviously a prototype, but it's interesting that both the Corvus and the Pippin ports have 34 lines. If Pippin was ProFile at some point, this card must have talked to an earlier version of it!

The board is simple enough that you might be able to guess a schematic --- you can't see where the lines go when they go under the chips and resistor packs, but you might be able to figure it out. One bit of good news is that the chips are just a VIA and some glue logic; there aren't any ROMs or anything.

How many pins do the cables for your friend's Corvus drives use?
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compu_85

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Re: Corvus HDDs and the Lisa
« Reply #4 on: February 23, 2021, 12:04:06 am »

To Bitsavers again :) http://www.bitsavers.org/pdf/corvus/7100-03289_DiskSysTechRef.pdf

See PDF page 7 (1 in the document). The signal that I didn't spot on the ProFile interface was bus direction.

The Corvus disk has a pin header on the back, the same type as the proto board you linked to. If it is usable with a standard parallel card it wouldn't be a hard job to wire up to a DB25.

I've also seen that the dev name for the ProFile was Pippin.
« Last Edit: February 23, 2021, 12:07:02 am by compu_85 »
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stepleton

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Re: Corvus HDDs and the Lisa
« Reply #5 on: February 23, 2021, 01:30:32 pm »

Great find! There seem to be lots of close analogues between these pins and what the ProFile uses, and so using a Corvus drive from a Lisa parallel port seems tractable to me.

* DIRC: seems like ProFile PR/~W, but the drive sets it
* READY: seems a lot like ~PBSY
* STROBE: seems like a combination of ~PSTRB and ~PCMD

I don't see a parity line like the ProFile uses, and one thing I might be curious to find out later is why the drive is the one that controls ~RESET, not the computer (cf. ~PRESET on the ProFile).

Either way, at a glance it looks like you could probably bash together some software to repurpose my device into "Cameo/Cepheid" I guess (Corvus Parallel Hard Drive, compare Apple Parallel Hard Drive) without very much trouble.
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rayarachelian

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Re: Corvus HDDs and the Lisa
« Reply #6 on: February 24, 2021, 10:04:42 pm »

Here's the corvus driver for uniplus, it does look like it attaches to the parallel port, there's references to CA2, port a, port b, and it even includes profile structures.

https://github.com/arcanebyte/uniplus/blob/master/v1.5/sys/cv.c
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