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Thread: Are there Chips on your PowerCache Adapter? HELP REQUEST


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Permlink Replies: 5 - Pages: 1 - Last Post: Dec 12, 2016 10:09 AM Last Post By: Trash80toHP_Mini Threads: [ Previous | Next ]
Trash80toHP_Mini

Posts: 45
Registered: 10/19/12
Are there Chips on your PowerCache Adapter? HELP REQUEST
Posted: Nov 28, 2016 1:37 PM
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I'm developing a “truth table” based upon the presence of ICs on PowerCache adapters for various Macs or the lack thereof for comparison to other available data.

Presence of chips (assumedly PAL or CPLD ICs) indicates an adapter is ACTIVE
Lack of chips on an adapter indicates that it is PASSIVE.

Here is the info on the adapters I have in hand or info from pics I've found online:
SE/30-adapter is ACTIVE
IIsi---adapter is ACTIVE
LCIII--adapter is PASSIVE: no chips on board

Posting high resolution pics here of both sides of your adapter would be awesome! Such would be also make a great contribution to the NuBus Mafia project over on applefritter.

Pics found online indicating presence of chips on specific adapters would also work! Posting such here would be greatly appreciated.

If you've previously owned a PowerCache/Adapter combo or seen one, identification of a specific Mac's combo as represented in this family tree might also suffice!

PowerCache/Adapter Family Tree

I've also posted a WTB for a IIsi or SE/30 PowerCache adapter. I've got a spare LCIII adapter and OODLES of other trade goods as further enticements for a deal.

In advance, thanks much for any help you can give me in this endeavor.
Trash80toHP_Mini

Posts: 45
Registered: 10/19/12
Re: Are there Chips on your PowerCache Adapter? HELP REQUEST
Posted: Dec 7, 2016 8:12 AM   in response to: Trash80toHP_Mini in response to: Trash80toHP_Mini
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Bunsen confirmed that the IIcx PowerCache adapter is passive. I had one and can't find it, but that's what I recalled.

Results so far:

AFAIK, every Mac that has an implementation of Slot ID $E in any form except the LCIII and IIci require active adapters.

IIci doesn't count because its implementation of cache memory space (possibly NuBus SuperSlot memory space is involved?) and $E implemented in NuBus are compatible by (definition) design.

LCIII is a special case because its PDS is an oddball hardware implementation of a full '030 PDS connector at Slot ID $E. Installation of the PowerCache adapter in its PDS precludes any other use of $E, hence no possible conflict and its passive adapter.

Members of the Mac II series have NuBus implemented in Slots $9-$E. The IIci is an oddball, with slots $C-$E implemented in NuBus.

IIcx follows the pattern of its big brother the IIx, implementing the first of its three NuBus slots at $9-$B. No implementation of Slot ID $E is made as a physical slot or a pseudoslot in its design. No possible conflict there means only a passive adapter is required for the PowerCache.
__________________________________________________________________

From this, I think it's pretty safe to say that unraveling the mess of the SE/30 and IIsi video implementation at $E as compared to the IIci's implementation of NuBus at $E would be the way to begin understanding the workings of their slot adaptation mechanism. First guess is that it has to do with where cache is addressed in slot space memory?

Message was edited by: Trash80toHP_Mini
Arbee

Posts: 61
Registered: 11/29/12
Re: Are there Chips on your PowerCache Adapter? HELP REQUEST
Posted: Dec 7, 2016 5:57 PM   in response to: Trash80toHP_Mini in response to: Trash80toHP_Mini
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Because of the way QuickDraw and the Slot Manager work, PDS video cards typically want to be seen by software as NuBus. And video cards want to be in the highest numbered slot, because the interrupt latency is lower at the top end of the range.

Due to the way NuBus slots map to memory addresses, slot $F isn't possible (the slot $F super space is where the other slots' non-super space goes), and so slot $E is your most efficient place to park a video card. That's why the SE/30's on-board video pretends to be slot $E. The IIci and LC series on-board video mostly doesn't pretend to be NuBus at all, and isn't subject to those restrictions (they report interrupts in an entirely different way, for one thing).
Trash80toHP_Mini

Posts: 45
Registered: 10/19/12
Re: Are there Chips on your PowerCache Adapter? HELP REQUEST
Posted: Dec 7, 2016 7:19 PM   in response to: Arbee in response to: Arbee
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Yep, know how Slot Manager treats Slots and Pseudoslots.

Synopsis of information on pp. 410 & 412 of GttMFH2e*

IIci Video is addressed as PseudoSlot $0 (the same as the rest of the Mac) while video memory is accessed in NuBus memory space $B.

I've not seen a DevNote on the LC or info on this in the Bound PaperDocs. It's probably similar to the IIci as you said. It's curious that the LCIII PDS is located at $E.

I've heard much about the importance of slot positions for video cards, but never actually seen it documented in print or in PDF about hardware, DevNotes included. Is that information from Inside Macintosh documentation?

Message was edited by: Trash80toHP_Mini

Message was edited by: Trash80toHP_Mini
Bunsen

Posts: 39
Registered: 10/15/12
Re: Are there Chips on your PowerCache Adapter? HELP REQUEST
Posted: Dec 10, 2016 8:08 PM   in response to: Trash80toHP_Mini in response to: Trash80toHP_Mini
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Trash80toHP_Mini wrote:
Bunsen confirmed that the IIcs PowerCache adapter is passive.
IIc*x* - and it goes in the 030 CPU socket, not the PDS.
Trash80toHP_Mini

Posts: 45
Registered: 10/19/12
Re: Are there Chips on your PowerCache Adapter? HELP REQUEST
Posted: Dec 12, 2016 9:54 AM   in response to: Bunsen in response to: Bunsen
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Thanks for the typo alert: fixed

The additional info about the IIcx PowerCache adapter plugging directly into the CPU socket is much appreciated, the assumption (ass me) that this would be known to all readers was my bad. I might further clarify that no PDS exists in the IIcx, hence the adapter plugging directly into the 68030 socket.

This would be analogous to the "socketed" PowerCache for the SE/30. Now I wonder if there is any adaptation on the Logic Board of that version of the PowerCache Accelerator?

Another possible point of differentiation in the case of that particular implementation and much food for thought there.

Thanks much, B

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