mark@sleepy.cs.unm.edu (Mark McLaughlin) (03/02/89)
I have a Macintosh II and in anticipation of running A/UX need to obtain the 68851 Paged Memory Management Unit (PMMU). I have a few questions, however, which I was hoping somebody out there might be able to answer. First, what comes with Apple's product #M0221 68851 PMMU, i.e., if I bought the chip through Apple what do I get--just the chip itself? Second, what is the exact chip number? There are several versions of the MC68851 running at different speeds. I think it might be MC68851RC-16A. If someone out there has a Mac II with this chip perhaps they could look at it and get the precise number. And finally how do I install the chip, i.e., where exactly does it go? Any help would be greatly appreciated. --------------------------------------------------------------------------- Mark A. McLaughlin Applied Computing Systems, Inc. (505) 662-3309 mark@sleepy.cs.unm.edu
malczews@castor.usc.edu (Frank Malczewski) (03/03/89)
In article <2295@unmvax.unm.edu> mark@sleepy.cs.unm.edu () writes: >I have a Macintosh II and in anticipation of running A/UX need to obtain >the 68851 Paged Memory Management Unit (PMMU). I have a few questions, >however, which I was hoping somebody out there might be able to answer. >First, what comes with Apple's product #M0221 68851 PMMU, i.e., if I >bought the chip through Apple what do I get--just the chip itself? >Second, what is the exact chip number? There are several versions of >the MC68851 running at different speeds. I think it might be MC68851RC-16A. >If someone out there has a Mac II with this chip perhaps they could look >at it and get the precise number. And finally how do I install the chip, >i.e., where exactly does it go? Actually, I was about to post a similar query concerning the PMMU, and would like to see the replies to the above; additionally I would like to know (since I won't be using AUX) if using the PMMU now (in anticipation of 7.0) with the current 6.0 system will result in ANY compatibility problems (of, say, the nature of those seen with some of the 68030 models) with currently released software, especially software development software. -- Frank Malczewski (malczews@castor.usc.edu)
steveg@tove.umd.edu (Steve Green) (03/04/89)
The pmmu from apple is just the 68851rc16. The 16 is the speed (mhz). The pmmu replaces the BIG BLACK CHIP. That is, the only big black chip in a socket. There is no compatability problems as the mac os ignors it completely. (for now) Warning: The pmmu's pin 1 is not in the same orientation as the pin 1 of the cpu, look carefully when installing this at the markings on the board and the notch on the socket for the pin 1 position.
malczews@castor.usc.edu (Frank Malczewski) (03/05/89)
As a followup to my own followup, I further would like to know if the PMMU will be the only hardware that will need to be replaced when the 32-bit Mac O.S. (version 7??) becomes available. I am asking this as I have the original set of ROMs for Nubus access, and know that these may have to be replaced at some point in time; will there be a need to replace the 256K Roms, or something similar. (I just have a plain old Mac II, if you hadn't guessed). -- Frank Malczewski (malczews@castor.usc.edu)
goldfarb@hcx9.UCF.EDU (03/07/89)
Let's get back (sorta) to the original issue. What is a fair price
for a 68851 and from whence does one obtain one?
Apple charges over $400, even with an academic discount. The chip
supply houses (retail discount ones) I have talked with don't stock
them. Seems like Motorola is selling them all to OEM's. Am I really
stuck with the inflated Apple price?
Ben Goldfarb
Department of Computer Science
University of Central Florida
uucp: {peora,decvax,uflorida}!ucf-cs!goldfarb
Internet: goldfarb@hcx9.ucf.educarter@PORTIA.STANFORD.EDU (Thomas J. Carter) (03/08/89)
I recently got Virtual (which I love) and put in the 68851, but now I'm wondering what to do with the old chip. Can it be sold and used elsewhere? Thanks in advance. Tom Carter Stanford University carter@portia.stanford.edu (bitnet) "I tawt I taw a puddy tat!"
stevel@eleazar.dartmouth.edu (Steve Ligett) (03/10/89)
In article <2600010@hcx9> goldfarb@hcx9.UCF.EDU writes: > >Let's get back (sorta) to the original issue. What is a fair price >for a 68851 and from whence does one obtain one? Yow. I thought this would be an easy question. I called Time Electronics and asked for the part (mc68851rc16). After a few minutes, the salesman came back with "We have no stock; and no pricing either. I'd have to call Motorola to find out what a minimum buy would be." (No sweat, I'd had Time let me down before.) So, I called Hamilton/Avnet. They once *had* a kit - MC68020KIT, with an '020, '881, and '851 in it, plus some rams, A/Ds, and lots of documentation - including user manuals for all three chips. Well, they too didn't have the part, and would have to call Motorola. So, I asked about the kit. I mean they had the kit a year ago - I bought one then for $330. The salesman said they had no stock on the kit either, and didn't know if it would be available again. I don't buy from anyone else who carries Moto, so my guess is that you'll have to have a distributor call the factory, and get a price on one piece, if Moto will sell one. Steve Ligett steve.ligett@dartmouth.edu or (decvax harvard linus true)!dartvax!steve.ligett
beres@cadnetix.COM (Tim Beres) (03/10/89)
In article <2600010@hcx9> goldfarb@hcx9.UCF.EDU writes: > >[Wants low cost PMMU] > >Ben Goldfarb Hi Ben. You might try calling an Electronic Disti. H/A or Arrow. They'll usually sell you a single chip, esp. if you promise to let them quote on some other (disk drive, etc.) business. BTW, how's Tony B. and Jennifer? Tim (former admin for tslvax) ------>MY SOAPBOX (I speak for myself) "Any accord based on Ortega's promises is like trying to leash a dog with sausages" - Adolfo Calero Tim Beres beres@cadnetix.com {uunet,boulder,nbires}!cadnetix!beres
sidlives@mit-vax.LCS.MIT.EDU (David Rho) (03/11/89)
In article <8903080956.AA22840@Portia.stanford.edu> carter@PORTIA.STANFORD.EDU (Thomas J. Carter) writes: >I recently got Virtual (which I love) and put in the 68851, but now >I'm wondering what to do with the old chip. Can it be sold and used >elsewhere? Thanks in advance. The chip that you pulled out of your Mac II is essentially and for all purposes useless. It is just a brain dead version of the 68851 which (from what I heard) always sends back page faults at every memory reference. sidlives@mit-vax.lcs.mit.edu David Rho Disclaimer: I cannot and will not take any responsibility for anything in this article. If anything is not correct, sorry.
urlichs@smurf.ira.uka.de (Matthias Urlichs) (03/16/89)
In article <2600010@hcx9> goldfarb@hcx9.UCF.EDU writes: > >Let's get back (sorta) to the original issue. What is a fair price >for a 68851 and from whence does one obtain one? Hmmmm.. A year ago or so, when PMMUs didn't really exist (they were in whatever a chip designer's equivalent of beta testing is) a friend of mine went to the US and wanted to get a PMMU. I said, get one for me too. So he wrote Motorola and said he'd like to have two 68851s. Sure enough, he got them. For free. They work. They aren't quite release chips but that does not seem to be a problem. What else would one want of life? Disclaimer: This worked a year ago. It certainly won't work today. Although you might try... -- Matthias Urlichs -- Humboldtstrasse 7 -- 7500 Karlsruhe 1 -- FRG urlichs@smurf.ira.uka.de -- ++49+721-621127@PTT