The following message is a courtesy copy of an article that has been posted to comp.sys.ibm.sys3x.misc,alt.folklore.computers,bit.listserv.ibm-main as well.
[EMAIL PROTECTED] writes: > (For the AS/400 I never could figure the internal code architecture, > IBM used something called "LIC" that was rather vague. I once tried > to get an optional machine language listing of my application program > compilation but it was very confusing. I believe IBM used a multi- > layered approach for AS/400 internals, remnants of its "Future System" > effort. I was not a big AS/400 fan, except for a file-aid tool that > was better than mainframe tools.) one of the things that as/400 layered approach bought was that it could move from a CICS chip to a (power/pc) RISC chip w/o a lot of trouble. the future system project was going to replace 360/370 in the early-to-mid 70s ... when the project was eventually canceled there was big effort to make up for lost time resulting from the future system distraction http://www.garlic.com/~lynn/subtopic.html#futuresys attempting to get stuff back into the 370 (hardware & software) product pipelines ... crash program for 303x was part of that. part of the analysis "killing" the project was that if a "future system" machine was built from the fastest hardware then available (370/195) it would have the thruput of a 370/145. the folklore is that some of the future system participants regrouped in rochester, coming out with the s/38 (which didn't have nearly the thruput requirements). i've periodically commented that there is some characteristics of the 801 risc activities in the 70s .... to go to the exact opposite extreme of what went on in future system. a early, big push for 801/risc was effort to replace the multitude of corporate internal microprocessors with common risc architecture chips (every low-to-mid range 370 implemented with microcode on their own unique microprocessor, controllers, and other kinds of microprocessors). one of these was going to be the s/38 followon, as/400. the common 801/risc microprocessor effort ran into all sorts of problems and eventually died off ... at which time, as/400 had crash project to design a new CISC processor. misc. past 801, romp, rios, fort knox, power, power/pc, somerset, etc postings http://www.garlic.com/~lynn/subtopic.html#801 as well as some old email from the period http://www.garlic.com/~lynn/lhwemail.html#801 effectively the effort was revisited when rochester began move of as/400 from their CISC chip to its current use of 801/RISC chip. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
