Path: utzoo!attcan!uunet!lll-winken!lll-lcc!pyramid!octopus!pete From: pete@octopus.UUCP (Pete Holzmann) Newsgroups: comp.sys.ibm.pc Subject: Re: GATHER and say NO to MCA! Summary: AT bus is sufficient for the *near term*, from a *user's* pt of view Message-ID: <267@octopus.UUCP> Date: 30 Jun 88 17:44:18 GMT References: <42900016@uicsrd.csrd.uiuc.edu> <257@octopus.UUCP> <978@gethen.UUCP> Reply-To: pete@octopus.UUCP (Pete Holzmann) Organization: Octopus Enterprises, Cupertino CA Lines: 61 In article <978@gethen.UUCP> farren@gethen.UUCP (Michael J. Farren) writes: >[Before I start, one question: Mr. Holzmann, have you ever designed a > high-speed digital bus? I have. Now, on with the show...] Not personally designed. Worked at the gut level on, yes. Been around for FCC hassles, yes. Is a 295 Mbit digital telecommunications architecture fast enough for you? >>My conclusion: the clone-makers need to pick a 32-bit AT bus exBension >> standard. There is little engineering reason (right now) to go to the ^^^^^^^^^^^ a VERY bad choice of word there on my part. Sorry! >> MCA. > >Unless you count greater reliability, better support for advanced architecture, >better support for I/O, greater noise resistance, less emissions problems >(therefore easier to get FCC type approval, therefore cheaper), etc.... > >Not that I think that MCA is the BEST bus around, mind, but anyone who >claims that the AT bus is sufficient is talking through his engineering >hat. Actually, I was talking from under my user's hat. I guess I shouldn't let myself go like that! :-) I shouldn't have said 'little engineering reason to go to MCA' without saying: Users want a compatible bus so they can keep their investment in boards. I guess my attitude is that the AT bus is going to survive a long time, simply because there is so much stuff out there that uses it. I agree, the AT bus is an engineering disaster. But users don't see that, and it looks like there's enough engineering miracles left to keep users happy as long as they don't need 32 bit data paths. On the other hand, I *do* agree that a new bus standard is needed. I really like what the clone-makers are doing. It looks like there is an active push going for the NuBus. Wouldn't it be amazing if Mac and PC boards eventually became compatible with each other!?! That'll be the day. >>1) MCA is cleaner, newer, nicer, etc etc: >> All true, all irrelevant. On a bus, what works is what counts! > >This is true. However, what is NOT true is the claim that the AT bus >"works". No 32-bit data/address path, insufficient DMA and interrupt >support, insufficient attention to loading and timing details essential >to truly high-speed operation, and a god-awful electrical emissions >characteristic. I es?n't blame IBM one bit for getting rid of the damned >thing. From an engineering point of view, you are absolutely right. But from a user's point of view, the AT bus is *great*. Just about everything is compatible. And there are new boards that get around the DMA problems. As an engineer, I appreciate with some amazement the amount of sweat that must have gone into making this stuff work on the AT bus. I'm also amazed at how well the users are insulated from gory details of timing, low level formats, and other stuff. Imagine an end user even adding their own printer port to a computer 10 years ago! It wasn't fun. Pete -- OOO __| ___ Peter Holzmann, Octopus Enterprises OOOOOOO___/ _______ USPS: 19611 La Mar Court, Cupertino, CA 95014 OOOOO \___/ UUCP: {hpda,pyramid}!octopus!pete ___| \_____ Phone: 408/996-7746