SATA & NuBus Architecture . . .

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Oddball's picture
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. . . can the controller ICs be useful on PaleoMacs?

HEH! Had you goin’fer a bit, didn’t I? Laughing out loud

No, I’m not talkin’bout trying to adapt the drives to the poor lil’ole things, but the interfacing ICs . . . :?

Does anybody know offhand how many signal & control lines are implemented where the serial connection meets the road, so to speak, or if the controller ICs care what kinds of data a/o control protocols they send across that smokin’serial connections?

I was wondering if just maybe the controller ICs for SATA might finally allow for the PBX ‘030 Bridge IC of the NuBus PowerMacs to be lifted from the mobo and relocated to a prototyping card?

This would enable fiddling around with the Fast I/O bus of such dinosaurs as the PowerBook Duos (which naturally come to mind for some inexplicable reason :?) and various other non-upgradable PowerBooks . . . maybe even the MicroQuadras.

I’ve always wondered how much good might come from expanding on the memory limit of such systems by adapting larger, faster, more modern memory types. Utilizing a Virtual Memory scheme as was commonly done back in the heyday of SE acceleration could very well get around the Apple imposed limitations on several obsolescent Macs.

. . . And then again, there’s always the G3 accelerator tomfoolery much maligned by the eminent Dr. Bob.

Where has he disappeared to, and does he ever make an appearance here, BTW? :?

jt: still tilting at digital windmills after all these years! =8-O

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Eudimorphodon's picture
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Uhm...

There are stand-alone SATA PHY chips. Here's an example. They're mostly used for those parallel ATA to SATA disk adapters that don't work very well, but I suppose in principle you could use them for "other things".

I do suspect it would be a non-trivial task to use them to bridge a CPU bus. SATA/IDE transactions involve sending data packets over a single channel, and since there's already support in the protocol for "soft" arbitration timing isn't super-critical. Serializing an entire general-purpose *bus* means more circuitry to packetize (and on the other end, un-packetize) things like the addresses, interrupts, DMA, etc, etc. In other words, you'll need a transaction layer like PCI Express has. High speed serial busses (SATA, USB, PCI Express, Hypertransport...) also include CRC checking and retransmit mechanisms to deal with electrical noise/interference (high speed serial busses being to some degree fundamentally unreliable), which means you need "replay buffers" on either end to handle the error, and that the bus as a whole will have somewhat unpredictable latency due to missed transfers. Which means if you just try shoehorning a "bus adapter" like this in place of an existing asynchronous parallel bus (like a 680x0 or PowerPC frontside) it's going to have a *really tough time* behaving exactly like the existing wiring. (Either it's going to introduce latency where there was none, which might cause fatal errors with interrupt handling or memory tranfers, or it's going to have to operate *much* faster then the original bus in order to allow for the occasional retransmit.) Which means of course in the end analysis the bus adapter is likely to be substantially more complicated then whatever chip you're intending to move is.

I really hate to say something cruel and heartless, but... have you or anyone on the 68kMLA ever crafted anything even *remotely* in the ballpark of a device that requires lifting ICs off the motherboard of a Power Mac to interface it? There's lots of big talk about "magic mods", but there doesn't seem to be a whole lot of actual logic-probe-and-oscilloscope action that I've seen.

(By saying this I'm not implying I'd be remotely capable of it myself, mind you. Just saying that, I dunno, the Amiga nuts out there seem to be able to turn out the occasional CPU-piggybacking IDE/RAM/CPU accelerator board, whilst Mac "hacking" seems to be pretty much limited to restoration/minor repairs/recasing/daydreaming.)

--Peace

Dr. Webster's picture
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I'm curious as to what the en

I'm curious as to what the end purpose of all of this would be anyway. Sounds a lot like putting lipstick on a pig to me.

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dankephoto's picture
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pretty pig, of course!

Maybe I'm missing something, but if by "SATA" you mean serial ATA storage, and by "nubus" you mean use SATA devices on a nubus Mac, for ~$100 you can buy an SATA-SCSI bridge.

Yeah, I'm sure I've misunderstood the need and thusly offer a useless observation.

re: Eudi's observation that PATA-SATA bridges are problematic - I have only the one data point, but I picked up some nifty very compact PATA-SATA bridges on eBay for $4 apiece and so far they've proven trouble-free. They fit snugly at the back of an SATA drive and you plug yer ATA cable and molex power in and it just works. Only problem is that you may not be able to (AFAIK) use more than the one drive on that ATA bus. Still, that worked for me in the FW800 array I built, my FW bridges can each see only one drive anyhow . . .

dan k

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Eudimorphodon's picture
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Re: pretty pig, of course!

dankephoto wrote:

Yeah, I'm sure I've misunderstood the need and thusly offer a useless observation.

I'm not sure I've not misunderstood it either, but it didn't sound like it involved disk drives. ;^)

Quote:

re: Eudi's observation that PATA-SATA bridges are problematic - I have only the one data point, but I picked up some nifty very compact PATA-SATA bridges on eBay for $4 apiece and so far they've proven trouble-free. They fit snugly at the back of an SATA drive and you plug yer ATA cable and molex power in and it just works. Only problem is that you may not be able to (AFAIK) use more than the one drive on that ATA bus. Still, that worked for me in the FW800 array I built, my FW bridges can each see only one drive anyhow . . .

I only have a couple data points myself, but the amusing one is how the "Driver Guy" working in my company's platform engineering lab used those SATA-PATA bridges. In order to simulate a failing-but-not-dead disk in a software RAID pair he used to sub a PATA drive with a bridge in place of one of the SATA drives. Inevitably the adapted drive will produce many more detectable errors (CRCs/timeouts) then the "real" one. ;^b (This isn't with any one particular brand of SATA bridge. The guy says it applies to every one he's tried.)

Admittedly these for the most part aren't the sort of thing you'll see unless you're regularly querying your device driver for low-level errors. I'm sure they work well enough for most people.

--Peace

Oddball's picture
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Re: I'm curious as to what the en

Dr. Webster wrote:

I'm curious as to what the end purpose of all of this would be anyway. Sounds a lot like putting lipstick on a pig to me.

HEH! You got that one right! I know hacking old Duos is a complete waste of time in any practical sense, but I'm not one to dwell on the practical aspects of hobby level pursuits, who is anyway?

Nope, no HDD directly involved, just wondering if I can move the PBX '030 bus bridge IC off the mobo by using some relatively inexpensive/available chipset.

IMHO, LOTS of playtime projects become possible if you can move the fast I/O bus off Apple's PCB and onto a prototyping board.

Yes, I've been involved in PCB layout/prototyping.
Yes, I've fooled around with my logic probe.
No, I was never the guy on the SillyScope, nor do I have one.

I was the instigator of the project & tried to get the Programmer/SillyScope/Logic Analyzer guy to do things that were productive in terms of the success of the overall project . . . but you know how it goes with softheads. I should have at least have learned c! :Smile

Nothing practical will ever come of this, just some cool add-ons that Apple never wanted to see happen. The most promising project doesn't involve anything as outrageous as shifting whole buses.

Apple intended for there to be a PCMCIA MiniDock for the Duos and even announced that there would be one . . .

. . . never happened, but from the configuration of some of the more esoteric (and funny shaped) MiniDocks, I think it's fairly obvious that the card cage assembly from the 1400 and its T-REX PCMCIA controller were slated/designed for the Duo's docking connector as well as the 1400's interboard connection.

then again, I AM just a little bit crazy!
jt =8-0

eeun's picture
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Re: I'm curious as to what the en

Oh, how I've missed these mad scientist threads!

You know, jt, while you were gone I actually had to do my own hacking to fill the empty void. ;D

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Eudimorphodon's picture
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Re: I'm curious as to what the en

eeun wrote:

Oh, how I've missed these mad scientist threads!

I'm all for "Mad Science" myself. I guess my problem is, well... after hearing enough *talk* of mad schemes you start wishing someone would actually yank out a soldering iron and deliver. (Or die trying.)

--Peace

Oddball's picture
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Re: I'm curious as to what the en

Eudimorphodon wrote:
eeun wrote:

Oh, how I've missed these mad scientist threads!

I'm all for "Mad Science" myself. I guess my problem is, well... after hearing enough *talk* of mad schemes you start wishing someone would actually yank out a soldering iron and deliver. (Or die trying.)

I almost died by NOT trying!

My whole life has been about making/doing things that nobody else could, literally. I owned a Sign Shop in NYC and I got referrals from other companies that I'd never heard of, or certainly, had never met the owners or had any dealings with them previously.

In the last three years I've done nothing at all, except install some cabinets in the grlf's laundry room . . . and it almost put me in the ground.

But now I'm baaaaack and I'm building a third lifetime consisting of doing the things I've always loved and re-connecting with the people in the same category from my two previous lifetimes.

The professionals say I'm doing great, I had my first day back at work yesterday, I'm broke (yet again) and I'm happier than I've been in years!

Many toys, along with all my large tools, were kept in a storage room and were lost the first time I was hospitalized. The ones I still have are now out of their boxes. Most of them haven't seen the light of day in over 5 years!

Take it from this old guy, take good care of yourselves, folks. I've finally got a proper diagnosis and a treatment regime that's effective against my BiPolar II mental illness.

It's great to be back here on the web and the world is a wonderful place again!

jt Laughing out loud