Quadra 605/LC475: "EViL RAS LINE HACK" revisited . . .

[Trash80toHP_Mini]

.  .  .  after finding pics from the 2012 30-pin SIMM recreation thread.

Does anyone know if a schematic was ever developed for the 605/475? I've got 72-pin SIMMsaver/multiplier examples on hand to experiment for cribbing or maybe even hacking.

 

[Trash80toHP_Mini]

Object of the hack is to hijack the RAS lines from the pads of the desoldered Ram of Bank A on the mobo, jumpering them to an adapter PCB with sockets for a pair of 128MB SIMMs. IIRC this was done in just about the ugliest kluge imaginable back around 2005.

A MicroQuadra with the RAM ceiling of a maxed out Quadra 950 would be very cool indeed.

 

[360alaska]

Not trying to be critical but it seems like you make a lot of these “idea threads” without any sort of follow through.  This clutters up the forum and nothing is accomplished, perhaps maybe we should focus on a few and actually accomplish something eh?

Just a thought…

 

[Cory5412]

I agree. I'm genuinely curious as to what's worth running on a 475 that needs more than 36 megs of RAM anyway? AppleShare surely can't possibly use that much, can it? Hell, I don't even have 36 in my 840av and I'm multitasking 1998-era apps and running a web site with it.

 

[Cory5412]

Not that 36 itself is bad per se. I could actually use just a few mroe megs myself, as 8.1+PWS+IE4+GC+CHP is just a tiny bit more than will run in the 24 I've got, so I have to swap between things all the time.

The 610 can run 68 as an option for a small machine that can use more RAM and fit two disks and a nubus card and sometimes has ethernet onboard anyway.

 

[360alaska]

Cory,

Would you believe me if I told you my Q605 has 132 mb of ram already?  I got this logic board with the ram simm in a P475 on trade, I tried to swap the simm in my Q605's original logic board but it would not boot so I took the 475 board and swapped it into my 605. (And installed the jumper to make it a 605.) This thing takes a good while to boot due to the ram test.

 

[Trash80toHP_Mini]

You didn't get that board from uniserver did you? Very interesting if you found one out in the wilds with 8MB on the floor. uniserver experimented, found out a lot of interesting things and developed that memory hack of the IIsi, inspired by my ongoing 128MB in a IIsi project.

Case in point, in discussions here, uniserver developed the Portable HDD conversion cables he and Hap were selling on eBay.  You went on to develop a PCB adapter solution to better that kluge. We'd discussed a far more elegant PCB solution at the time to be hidden beneath the original HDD assembly, disguised as OEM cabling diverted a bit and tucked away in its camouflaged niche, so   .  .  . 

This thread isn't an "idea thread" of mine clogging this forum. The awful (IMHO) "all activity" page clogs the site with Lounge threads that were easily ignored in years past, that's why it was hidden away in the first place.

Many times serial responses to only a couple of threads are clogging up the entire page. I HATE that, the old software limited the page to only the single, most recent response to any given thread! The lounge was something you had to click to open, being able to ignore it was an intentional feature for off topic discussions. Now the Lounge is out in the open, right in registered members faces and clogged with ON TOPIC threads that are supposed to be posted out in the proper fora for lurkers to see and so be enticed to register. Some members only ever post any topic at all in the lounge! Now THAT is objectionable.

This hack was done elsewhere by others, it is NOT mine. It was discovered and documented here and on 'fritter by danamania way back in the early Snitz days. The info was hot-linked and appears to have fallen prey to the ephemeral nature of the web. This is an archaeological expedition trying to figure out something that was done in a nasty as hell way already. The infamous Evil RAS Line Hack came up in a discussion by others very recently, so I think it's time to figure out how it was done.

@Cory: as to why it was done back then I don't know. It might even have been done to get 128MB in the 605/475 waaaay back before 128MB SIMMs hit the market or when a pair of 64s were a much less expensive alternative. I don't remember, do you? Something being "practical" when this stuff was new has little if not nothing to do with hacking done here on PaleoMacs today.

Like much of what I do or try to accomplish here it may have been "because I can." The back and forth discussion about "why you shouldn't be able to" or "you might try this" leads to a deeper understanding of the Mac architecture in general for myself and more than a few of my fellow hackers like the much missed bbraun and hopefully some of the non-hackers as well. Long ago the two of us determined what was probably going on in the PAL on the Artmix adapter and that morphed into the ProtoCache1 project. By teamwork some pretty cool stuff has been accomplished here over the years. That's what the Hacks forum back in the day and Hacks and Development forum in the present day is all about.

I've had many supportive comments from non-hacker members interested in my projects over the years. Yours is the first complaint about them not coming to fruition and so not being worth posting. Chalk it up to ADD and my insanely curious nature.

Sorry about the overly long response, no offense intended.

 

[Cory5412]

Would you believe me if I told you my Q605 has 132 mb of ram already?

Yes! I remember reading about this long ago and it slipped my mind that the 475/57x et al could do this.

Very interesting if you found one out in the wilds with 8MB on the floor

128+4=132.

Some members only ever post any topic at all in the lounge! Now THAT is objectionable.

Why? Some people only have time and effort to participate by being present in mroe casual discussions.

Not all of us fancy being hardware or electrical engineers. It's bad gatekeeping to suggest that we should be or want to be in order to be on the forum or to participate in vintage 68k Mac enthusiasm.

 

[360alaska]

You didn't get that board from uniserver did you? Very interesting if you found one out in the wilds with 8MB on the floor. uniserver experimented, found out a lot of interesting things and developed that memory hack of the IIsi, inspired by my ongoing 128MB in a IIsi project.

Case in point, in discussions here, uniserver developed the Portable HDD conversion cables he and Hap were selling on eBay.  You went on to develop a PCB adapter solution to better that kluge. We'd discussed a far more elegant PCB solution at the time to be hidden beneath the original HDD assembly, disguised as OEM cabling diverted a bit and tucked away in its camouflaged niche, so   .  .  . 

This thread isn't an "idea thread" of mine clogging this forum. The awful (IMHO) "all activity" page clogs the site with Lounge threads that were easily ignored in years past, that's why it was hidden away in the first place.

Many times serial responses to only a couple of threads are clogging up the entire page. I HATE that, the old software limited the page to only the single, most recent response to any given thread! The lounge was something you had to click to open, being able to ignore it was an intentional feature for off topic discussions. Now the Lounge is out in the open, right in registered members faces and clogged with ON TOPIC threads that are supposed to be posted out in the proper fora for lurkers to see and so be enticed to register. Some members only ever post any topic at all in the lounge! Now THAT is objectionable.

This hack was done elsewhere by others, it is NOT mine. It was discovered and documented here and on 'fritter by danamania way back in the early Snitz days. The info was hot-linked and appears to have fallen prey to the ephemeral nature of the web. This is an archaeological expedition trying to figure out something that was done in a nasty as hell way already. The infamous Evil RAS Line Hack came up in a discussion by others very recently, so I think it's time to figure out how it was done.

@Cory: as to why it was done back then I don't know. It might even have been done to get 128MB in the 605/475 waaaay back before 128MB SIMMs hit the market or when a pair of 64s were a much less expensive alternative. I don't remember, do you? Something being "practical" when this stuff was new has little if not nothing to do with hacking done here on PaleoMacs today.

Like much of what I do or try to accomplish here it may have been "because I can." The back and forth discussion about "why you shouldn't be able to" or "you might try this" leads to a deeper understanding of the Mac architecture in general for myself and more than a few of my fellow hackers like the much missed bbraun and hopefully some of the non-hackers as well. Long ago the two of us determined what was probably going on in the PAL on the Artmix adapter and that morphed into the ProtoCache1 project. By teamwork some pretty cool stuff has been accomplished here over the years. That's what the Hacks forum back in the day and Hacks and Development forum in the present day is all about.

I've had many supportive comments from non-hacker members interested in my projects over the years. Yours is the first complaint about them not coming to fruition and so not being worth posting. Chalk it up to ADD and my insanely curious nature.

Sorry about the overly long response, no offense intended.

A lot to unpack here...

1. I didn't get my 475 from Uniserver and also the board is stock beside having a CPU upgrade. This leads me to believe that newer 475/605 board will be able to handle a 128mb simm. Maybe it has something to do with the speed of the onboard ram? The 605 actually came out a year before the 475 did.

2. Uniserver didn't create that adapter, Micheal McMaster (SCSI2SD) did, Uniserver manufactured it. I've actually never held one of his "adapters" but I took a look at it and it looked bulky and difficult to mount so I came up with another solution. I spent many hours getting my adapter to be the size it is and also a two layer board. I actually offered to Uniserver to sell my invention and give me a small royalty but he already had 100s of his boards. When I put mine on Ebay I purposely priced mine 10$ above his so we both could sell some but it seems he has actually stopped selling his. Oh and by the way Haplain has bought some from me too.

3. Not trying to complain or stir up problems, I just would like to see you complete some of your ideas. For instance on page one of this forum I count 6 of your “Idea threads.” I call them idea threads because they don’t actually lead to any hacks or development.

 

[Trash80toHP_Mini]

128+4=132.

Oopsie, that was late at night and didn't check the arithmetic this morning. 8MB on the floor ought to be a snap to do.

Why? Some people only have time and effort to participate by being present in mroe casual discussions.

Troubleshooting specific machines and conquests have their own ON TPOIC places for discussion, get real, check it out. Lounge has always been for OFF TOPIC discussion.

Not all of us fancy being hardware or electrical engineers. It's bad gatekeeping to suggest that we should be or want to be in order to be on the forum or to participate in vintage 68k Mac enthusiasm.

Read what I say and stop jumping twisting it around to suit your insulting ASSUmptions.

 

[Gorgonops]

I've had many supportive comments from non-hacker members interested in my projects over the years. Yours is the first complaint about them not coming to fruition and so not being worth posting. Chalk it up to ADD and my insanely curious nature.

...

While I'll admit there's moments when it can be a little difficult to follow some of these threads because of their... sometimes scattershot nature, overall I appreciate bait being thrown out there for technical discussions. Even the ones that end up as little more than a trip down a rabbit hole and never produce anything particularly actionable can at least trigger some... non-linear thinking that pays off later. About the only negative thing I'd say here is the opening could have been a little clearer about whether this is a thing that was actually pulled off at some point and was lost to history, or if this was a (potential) cul-de-sac that was vaguely discussed at some point but never went anywhere. (And greater specifics about *where* it was discussed would obviously be useful. And, also, for instance, you open with a reference to "that 2012 SIMM recreation thread"... by all means feel free to include links to the supporting material you think are relevant so anyone who might be interested in joining can more easily figure out the backstory?) If we could work on the clarity and grounding just a *little* it might make the ideas in the threads more accessible, and therefore actionable? (And thus possibly goosing the completion rate a bit?) Just tossing that out there as a maybe a nice-to-have.

Anyway... back on topic, I guess?

Object of the hack is to hijack the RAS lines from the pads of the desoldered Ram of Bank A on the mobo, jumpering them to an adapter PCB with sockets for a pair of 128MB SIMMs. IIRC this was done in just about the ugliest kluge imaginable back around 2005.

Just tossing this out there: do you know for sure it's the RAS lines that are unique between the SIMM socket and the onboard memory? I only ask because I went to my go-to  "DRAM memory for Dummies" schematic (IE, the Dynamic Board Commodore PET schematics) and in that case it's the CAS lines that are separate between the two memory banks, RAS are paralleled. I'm scratching my head a little as I read this to try to figure out if it would matter on a 72 pin SIMM which you had in parallel and which were separate, and... okay, this sentence: "Driving RAS without CAS is probably ok too, but the chip will consume its active current (approx 1000 times the idle)" makes me think you're probably right, it's RAS they separate. Maybe that didn't matter with 4116s.

I mean, in principle this seems like a potentially easy hack as long as the ROM in the system can actually grok the idea that there's more than X much memory in the bank allocated to the onboard RAM and the rest of the data/address lines are all wired in parallel between the motherboard socket and the RAM bank. The other thing that maybe be worth mentioning: a 128MB SIMM is a dual-banked; according to the document I linked above when you're using a 72 pin SIMM in a 32 bit configuration each bank uses 2 of the four RAS lines. Since the 605 only has 4MB soldered on the board, which is presumably all one bank, I kind of wonder if ultimately you'd be limited to 192MB, not 256, because the memory controller might not have a fourth set of RAS lines. (IE, the RAM controller only supports 3 total banks, not four.) I have no answer to that in a vacuum.

 

[Gorgonops]

Read what I say and stop jumping twisting it around to suit your insulting ASSUmptions.

Sigh.

Maybe it's time to go get some lunch or something and take a deep breath. Cory's response to this:
 

Some members only ever post any topic at all in the lounge! Now THAT is objectionable.

Seems fair enough, given that this reads like a personal slam against anyone/everyone who's current headspace in relation to this hobby is "I like chatting with other people who have similar interests despite the fact that I'm not actively pursuing said interests at the moment".

Escalating "insulting ASSUmptions" are why we can't have nice things. Can we settle down a bit?

 

[Gorgonops]

IIRC this was done in just about the ugliest kluge imaginable back around 2005.

I mentioned Trag. (edit: no, I didn't, I was going to be rephrased that paragraph before posting.) On the old forum there was this:

https://web.archive.org/web/20101009042811/http://68kmla.org/forums/viewtopic.php?f=8&t=4559

Re: ECC EDO SIMMs in Macs?


by trag » 03 Aug 2009, 23:06




equill wrote:The cards are 1-7/16in high, and labelled hp D4893A, as cited by trag. There are 8 x SEC KM44C16100BK-6 (5V, 4k?, 16M x 1?, FPM, 60ns) chips, and 4 x Hitachi HM5116100S6 (5V, 4k, 16M x 1, FPM, 60ns) on each side.

The KM44C16100BK-6 are 16M X 4, i.e., four bits wide with 16M addresses. Because there are 16M addresses, this requires 24 bits, which means the row/column organization must be 12 X 12. A 12 bit row address gives the 4K designation, as the 1K, 2K, 4K designator is just the number of row addresses, corresponding to 10 bits, 11 bits or 12 bits of row addresses.

Eight of these chips (one side of the D4893A SIMM) gives 64 MB of capacity. 16M X 4 X 8 (chips) = 16M X 32 bits and 1 byte = 8 bits => 4 bytes = 32 bits. So 16M X 32 bits = 16M X 4 bytes = 64MBytes.

Two sides to the SIMM gives 64MB X 2 = 128 MB.

I used two of the KM44C16100BK-6 to build each of my 16MB IIfx SIMMs.

Oh, and a thing I meant to mention a year ago... I've used two of the 128MB SIMMs in a SIMM doubler to take the Q605 up to 260 MB of RAM. I'm not quite sure how that works, as I wouldn't have expected there to me enough RAS lines in the Q605. One of these days I'll dig out the SIMM doubler again and trace it's circuitry.




More information about that might be useful. I don't know if that's the "2005 ugly kludge" that you're thinking of or not.

 

[Trash80toHP_Mini]

2. Uniserver didn't create that adapter, Micheal McMaster (SCSI2SD) did, Uniserver manufactured it. I've actually never held one of his "adapters" but I took a look at it and it looked bulky and difficult to mount so I came up with another solution. I spent many hours getting my adapter to be the size it is and also a two layer board. I actually offered to Uniserver to sell my invention and give me a small royalty but he already had 100s of his boards.

Date reference for his "invention" needed, no offense intended. The discussion here is dated along with the PCB I whipped up (mistakes and all) for it.

 

[360alaska]

His adapter dates back to January 2014, Mine was invented around late 2015.

 

[Trash80toHP_Mini]

Not all of us fancy being hardware or electrical engineers. It's bad gatekeeping to suggest that we should be or want to be in order to be on the forum or to participate in vintage 68k Mac enthusiasm.

G, that was one of Cory's many somewhat veiled personal attacks on/insults to me and requires an apology. I thought we'd buried the hatchet quite a while back, but that very clear, sarcastic inference that I fancy myself something I've made clear I'm not is as clear as day is unacceptable in any polite society..

What I said was that ON Topic discussion belongs outside the lounge, Cory was one of the main complainants back when uniserver posted EVERYTHING in the lounge.

 

[Trash80toHP_Mini]

His adapter dates back to January 2014, Mine was invented around late 2015.

 They may very well have been independent inventions, but  .  .  .  []



My whipped up adapter PCB study (mistakes acknowledged in the thread) was uploaded May, 27, 2013.

mcdermd did his adapter much earlier, he didn't claim to be the inventor, BTW.



I complimented you on your achievement quite a while back as you may recall, nice work comrade.

 

[Gorgonops]

What I said was that ON Topic discussion belongs outside the lounge

I just poked five pages deep through the history of Lounge topics and it doesn't look to me like there's much a problem with people posting on-topic (technical discussion related to 68k Macs) material in there today. What do you consider on-topic?

If you have an issue with seeing a glut of Lounge posts in the default "recent activity" link you can create a custom stream that excludes whatever forums you don't want to see. Go to "Activity", hit the "My Activity Streams" dropdown, and hit the "Create new Streams"  button. Under "Content Types" select "topics". Hit the gear next to "Topics", "Narrow by Forums" and select only the forums you *do* want to see. Set everything else how you want it (unread only vs everything, etc) and save it. Problem solved, you don't have to see the lounge traffic anymore.
 

G, that was one of Cory's many somewhat veiled personal attacks on/insults to me and requires an apology.

See, the thing is, I'm not really privy to you being called an "engineer" being a personal attack, so whether that's true or not, I read what you said as a slam on people who come here to enjoy the lounge. (Which, again, is a thing that probably happened because I just don't really see this tidal wave of on-topic discussion in the lounge. There are *technical* discussions that go on there of things that are not related to 68k Macs; if the forum had specific categories for Windows, Intel Macs, or whatever then I suppose those things would belong in those respective categories, but it doesn't. So they're by definition off-topic.)

 

[Trash80toHP_Mini]

No offense was intended, the lounge is great and I see clearly why folks might enjoy that most of all. I apologize profusely for any wording which might have implied such.

I absolutely did not mean to slam anyone for anything until I felt very insulted by Cory's comments.