Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!masscomp!peora!tarpit!bilver!bill From: bill@bilver.uucp (Bill Vermillion) Newsgroups: comp.sys.tandy Subject: Re: Advanced Systems Message-ID: <1991Apr14.164352.28893@bilver.uucp> Date: 14 Apr 91 16:43:52 GMT References: <1991Mar29.162359.2428@pdn.paradyne.com> <1991Apr2.171206.12184@bilver.uucp> <3763@batman.moravian.EDU> Organization: W. J. Vermillion - Winter Park, FL Lines: 61 In article <3763@batman.moravian.EDU> halkoD@batman.moravian.EDU (David Halko) writes: >In article <1991Apr2.171206.12184@bilver.uucp>, bill@bilver.uucp (Bill Vermillion) writes: >> In article haroldt@paralandra.yorku.ca (Harold Tomlinson) writes: >> >In article <1991Mar29.162359.2428@pdn.paradyne.com> roth@pdntg1.paradyne.com (Mike Rothman) writes: >> > On the other hand there is the Tandy 5000MC, (The MC "does not stand for >> >Micro-Channel" according to Radio Shack.) the only non-IBM Micro-Channel >> >computer currently on the market. >> The 5000MC is >>**NOT**<< the ONLY non-IBM Micro-Channel machine on the >> market. I seem to remember at least 10 or so. ... >Careful.... there are several Microchannel bus'es out there... Tandy had >licensed the real thing, from what I remember... the clone manufacturers >made something SIMILAR and almost compatable, but not the exact same >thing... to my knowledge, the microchannel that Tandy and IBM use is >DIFFERENT from the clone microchannel... I met a computer consultant >who explained to me the difference, but that was awhile back, now. He may >have been wrong, but I am pretty positive that what he tells me is correct... Well, I believe that either he may have been wrong, or you misunderstood what he was saying. And I won't accept the proof of "a computer consultant who explained to me the difference". My city and county occupational licenses classify me that way to. But we all know what a "consultant" is. We're people who can't seem to find a real job. :-) A Microchannel is a hardware bus specification. It is a licensed spec from IBM. There are no MCA clone mfrs. If it's MCA it's licensed and meets the specs. It is designed so that even with newer additions to the specs the older boards designed for older machines will still run the way they were designed in the newer machines. It's probably one of the more mis-understood busses in the industry. I don't know how many times I have heard something like "IBM designed because the got tired of being ripped of by ISA clone mfrs" If you want to find out what the MCA bus is all about in a fairly easy to understand way, pick up the book "The Microchannel Architecture Handbook" published by Brady. About 300 pages and $30.00. The other thing to remember about MCA vs ISA machines, is that MCA is a hardware bus standard and CPU independant, while the ISA is a bus designed around a bus that is expecting an iNTEL type of chip. The IBM 6000's are a RISC type machine, but they are still MCA bus based, and boy are they FAASSTTT! There have been additions to the MCA specs since the initial release of the IBM 80 and the Tandy 5000, most noticeably the burst mode and the streaming mode. Since these are basically block move type modes you don't have to give an address with each byte. Makes them faster. And in the streaming mode, since you don't have to pass the addresses all the time, you can use the 32 bit address lines in addition to the data lines (in a multiplexed mode) to give you an effective 64 bit wide data path. bill -- Bill Vermillion - UUCP: uunet!tarpit!bilver!bill : bill@bilver.UUCP