g3l@mentor.cc.purdue.edu (Robert S. Unoki) (05/05/90)
I have compiled a several articles and correspondence concerning info on the Marathon '030. For those who are interested, email me by May 5. if there is enough interest, I will post. -robert g3l@mentor.cc.purdue.edu (valid until 5/9/90)
g3l@mentor.cc.purdue.edu (Robert S. Unoki) (05/06/90)
Received a flood of requests for the Marathon '030 accelerator info summary. So here it is. Have at it... SUMMARY OF Marathon 030 ARTICLES: Article 91 of comp.sys.mac.wanted: From: g3l@mentor.cc.purdue.edu (Robert S. Unoki) Newsgroups: comp.sys.mac.wanted,comp.sys.mac.hardware Subject: Info on Marathon 030 for the Plus Date: 30 Apr 90 19:44:38 GMT Organization: Purdue University Does anyone have any experience with the Marathon 030 accelerator for the Mac+? Does it speed up operations significantly, or is the 16-bit data bus on the plus too much of a bottle neck? Remember, system 7.0 is coming soon and the 68030 processor will allow utilization of virtual memory. Robert g3l@mentor.cc.purdue.edu pava@purccvm >From: rbauer@oregon.uoregon.edu Newsgroups: comp.sys.mac.wanted Subject: Re: Info on Marathon 030 for the Plus Date: 30 Apr 90 23:34:34 GMT Followup-To: comp.sys.mac.wantedcomp.sys.mac.hardware Organization: University of Oregon > Does anyone have any experience with the Marathon 030 accelerator > for the Mac+? Does it speed up operations significantly, or is > the 16-bit data bus on the plus too much of a bottle neck? > > Remember, system 7.0 is coming soon and the 68030 processor will allow > utilization of virtual memory. First of all, System 7 is one big unknown right now with regard to virtual memory and how accessible it will be to 68000-based Macs. At Mac Expo earlier this month, the techies/engineers from most of the companies selling accelerators (a better source of info than salespeople) admitted that they had been advised by Apple that, as things now stand, the virtual memory module of System 7 would only work with the SE30 and Mac II family because the software would look for the ROM before running. Wrong ROM (i.e., Plus or SE) and it won't run, even if there is a 68020/68881 or 68030 attached as a daughterboard. They also reported that there were representatives from Apple telling them that "Apple was looking into the compatibility issue..." Since Apple is supposed to be going onto something like the 9th ALPHA version of system 7, I'm not surprised that they still haven't made a firm decision on this. So what does this all mean? Basically, nothing. Until Apple finally releases Sys. 7 or some committments to the specifications, everything's up in the air, just like the low-cost Mac, the new-improved portable, etc. Regarding your question of the Dove 030 for the Plus--it's just an '030 wafer potted onto a socket with a couple of support chips--the clock speed is still 8MHz off of the motherboard and there's no external cache to help speed things up more than the 10 to 15% improvement that the 68030 has over the 68000 based on more efficient internals, since you're still working with a 16-bit data path too. STANDARD DISCLAIMER, ET AL Bob Bauer Article 102 of comp.sys.mac.wanted: >From: jbritt@shumv1.ncsu.edu (Joe Britt) Newsgroups: comp.sys.mac.wanted Subject: Re: Info on Marathon 030 for the Plus Date: 1 May 90 04:27:49 GMT Reply-To: jbritt@shumv1.ncsu.edu (Joe Britt) Organization: NCSU Computing Center In article <19494.263c691a@oregon.uoregon.edu> rbauer@oregon.uoregon.edu writes: > >Regarding your question of the Dove 030 for the Plus--it's just an '030 >wafer potted onto a socket with a couple of support chips--the clock >speed is still 8MHz off of the motherboard and there's no external cache >to help speed things up more than the 10 to 15% improvement that the 68030 >has over the 68000 based on more efficient internals, since you're still >working with a 16-bit data path too. > >STANDARD DISCLAIMER, ET AL > >Bob Bauer On the contrary, the 68030 on the Dove board does run at 16MHz. True, there is no 16MHz oscillator on the board, but there is some logic to double the clock coming up from the motherboard. Eliminates a lot of nasty synchronization problems. All the Dove accelerators double the existing clock rather than having an oscillator & having to worry about syncing things up... How do I know? I co-designed the Plus/SE '030...(try clicking on the version number in the CDEV...:-) -joe :-) jbritt@shumv1.ncsu.edu +----------------------------++---------------------------------------+ | jbritt@shumv1.ncsu.edu || Give me a free Mac II. Please? | +----------------------------++---------------------------------------+ Article 3086 of comp.sys.mac.hardware: >From: jbritt@shumv1.ncsu.edu (Joe Britt) Newsgroups: comp.sys.mac.hardware Subject: Dave's accelerator request... Date: 2 May 90 05:23:16 GMT Reply-To: jbritt@shumv1.ncsu.edu (Joe Britt) Organization: NCSU Computing Center dce@icky.Sony.COM (David Elliott) sez: >Joe, would it be possible for you to do a short explanation of how >accelerators work without saying anything proprietary? For example, >what areas have to be handled specially because of the difference >between the motherboard speed and the accelerator speed? How much >does cacheing help, and how can one write code that will take best >advantage of the accelerator cache? So be it! As most folks know, accelerators replace the existing processor in a machine with a better/faster one. Some accelerators are fancier than others, having features other than simple increased clock frequency. And then some accelerators don't increase the clock speed, but just add a cache (like the Dove Racer and Orchid MacSprint). So what's the scoop? Well, the main problem is that the motherboard of whatever the accelerator is connected to has been designed to run at the old speed (big surprise, huh? :-). If the accelerator is of the faster processor variety, then the speedier CPU spends a lot of time waiting on the slower motherboard peripherals and memory. The only place where you get improved performance is from CPU intensive operations. The processor is executing instructions faster, but it still takes just as long to get them in and out. Internal caches (like on the 68020 and '030) help a lot here. Some designers add faster RAM to the accelerator, and leave it as an option to ignore the motherboard RAM. With the faster RAM, instructions and data now flow in and out of the processor faster (as well as execute faster) and a significant speed improvement follows. The Dove SE MaraThon '020 accelerators do this. In addition to faster RAM, you might want to add "wider" RAM. When you try to slap a processor with a 32-bit data bus onto a motherboard with only a 16-bit data bus (like plugging a 680x0 onto a 68000), you lose some (a lot) of possible horsepower. All Mac programs spend a great deal of time in ROM, which is slow and only 16 bits wide. The Dove SE MaraThon '020 boards alleviate this problem by pulling ROM into faster, wider RAM on startup. (as an option) Problems..:-( Naturally, since you are sticking something foreign into your Mac, the possibility of problems comes about. The guy building the accelerator also runs into more than a couple of problems...problems the user should never have to worry about. Just about all of them are timing problems, mainly due to assumptions the code in the ROMs make about how long it takes to do certain things. In some cases, the ROMs try to get around this problem (thoughtful of them :-) by measuring the speed at startup and setting some nice timing constants that other programs can use. Problems arise when you go to Warp 7 a little later, though. The ROM has set up the constants for one speed, then your Acme XP-7 Super-Stealth 600MHz accelerator comes along and makes them totally invalid. All this means it's Muckin' Time, as the engineer tries to figure out wha'happen... Cache cards take a different approach- don't increase the clock rate, just keep the most recently used chunks of code/data in some very fast RAM. Most programs tend to be in loops a lot, and if you can fit the loops into some really fast RAM, you'll see a definite speed improvement. The 68030 has 256-byte instruction and data caches built in, and they _do_ make a difference. Any very CPU intensive code that fits in the caches wil cook right along. It's important to note that Dove isn't marketing the Plus/SE '030 as an accelerator. I think that the ads aren't explaining this well enough...The main idea behind it was to give the user a PMMU and (soon!) a 68881/2. We sent the guy at Connectix one of the boards, and he got Virtual running on it. It's pretty neato to see a Plus that thinks it has over 10 megs of RAM! Multifinder Mecca... Well, I don't know if this was too simplistic or not. Let me know, and let know if you want to know any more. I do have to be careful what I say though, or the legal eagles will come down and swoop me away... -- +----------------------------++---------------------------------------+ | jbritt@shumv1.ncsu.edu || Give me a free Mac II. Please? | +----------------------------++---------------------------------------+ THE FOLLOWING IS A SUMMARY OF CORRESPONDENCE THAT I HAD WITH Joe Britt, CO-DESIGNER OF THE MARATHON '030; Does the Marathon '030 have a PMMU? Will this allow for use of Virtual Memory? > Date: Tue, 1 May 90 13:12:46 EDT > From: jbritt@shumv1.ncsu.edu (Joe Britt) > To: g3l@mentor.cc.purdue.edu > Subject: Marathon 030 > > > Yes, the 68030 has a built-in PMMU, _unlike_ the 68020. > > I've left Dove to go work for Apple (leaving soon!), and I've been out > of touch with the guys there for a week or so. Last time I talked to > the other co-designer (Mike Marks), the guy at Connectix who wrote Virtual > (for Mac II-class machines) had it running on a Plus with the Marathon '030. > (there apparently were some modifications to the Virtual software required), > but it was still neat to have a Mac Plus that thought it had about 10 megs! > > joe :-) > jbritt@shumv1.ncsu.edu Will the Marathon '030 be able to use the Virtual Memory features of System 7.0? > Date: Thu, 3 May 90 01:26:50 EDT > From: jbritt@shumv1.ncsu.edu (Joe Britt) > To: g3l@mentor.cc.purdue.edu > Subject: Sys 7.0 & MaraThon > > > Well, since we really haven't actually _seen_ 7.0 yet, its still up in the > air. Mike (the other guy who worked on the Plus/SE '030) talked to some > guy from apple at MacWorld San Francisco last month, and he hinted at the > likelyhood that 7.0 will require some stuff only found in the ROM's of > Mac II class machines. Dumb, if you asked me, 'cause Connectix has it working > already! (even on the plus! jeez!) > > I imagine that if there are any problems they can be resolved by appropriate > patches. This'll just mean a lot of time scratching the ol' noggin trying > to figure out what's goin on... > > -joe :-) As for me, I decided to save up for a IIcx... -robert ---------------------------------------------------------- | Robert S. Unoki | | g3l@mentor.cc.purdue.edu (account valid until 5/9/90) | ----------------------------------------------------------