mash@mips.COM (John Mashey) (02/01/90)
In article <3427@odin.SGI.COM> pkr@maddog.sgi.com (Phil Ronzone) writes: >In article <3204@aimt.UU.NET> phil@aimt.UU.NET (Phil Gustafson) writes: >>Dealing with TRANSLATE AND TEST and the even more barouque EDIT AND MARK >>left me very receptive to the idea of RISC. > >Yeah - EDIT AND MARK took almost 14% of the entire microcode memory for >that one instruction (360/65). And the 360/91, a hardwired non-microcoded >machine (mostly) didn't support it or any of the other packed decimal >instructions. A relevant analysis can be found inGordon Bell & Allen Newell's "Computer Structures: Readings and Examples", McGraw-Hill, 1971. In particular, pages 561-587 look at the S/360 family, and examine tradeoffs and cost/performance comparisons. In particular, the hardwired 360/91 had good cost/performance characteristics, but the best of all was the (hardwired) 360/44, which also lacked the variable-length instructions. ALso, the 360/91 (which had REAL scoreboarding, and was extermely complex, was shortly withdrawn from the market in favor of the 360/85, which if not the first, was certainly one of the earliest systems to use a cache memory. This is a very useful chapter in many ways, as it also shows the methods used at the time to scale the same ISA across technologies. -- -john mashey DISCLAIMER: <generic disclaimer, I speak for me only, etc> UUCP: {ames,decwrl,prls,pyramid}!mips!mash OR mash@mips.com DDD: 408-991-0253 or 408-720-1700, x253 USPS: MIPS Computer Systems, 930 E. Arques, Sunnyvale, CA 94086
pkr@maddog.sgi.com (Phil Ronzone) (02/03/90)
In article <35321@mips.mips.COM> mash@mips.COM (John Mashey) writes: >A relevant analysis can be found inGordon Bell & Allen Newell's "Computer >Structures: Readings and Examples", McGraw-Hill, 1971. In particular, >pages 561-587 look at the S/360 family, and examine tradeoffs and >cost/performance comparisons. In particular, the hardwired 360/91 >had good cost/performance characteristics, but the best of all was the >(hardwired) 360/44, which also lacked the variable-length instructions. >ALso, the 360/91 (which had REAL scoreboarding, and was extermely complex, >was shortly withdrawn from the market in favor of the 360/85, which if >not the first, was certainly one of the earliest systems to use >a cache memory. This is a very useful chapter in many ways, as it also >shows the methods used at the time to scale the same ISA across >technologies. They also really liked the 360/25, which was a double-microcode machine. It had a "nano-code" engine which drove the microcode which implemented the 360 instruction set. As I recall, they proposed a 360 family line of 360/25's (MPs) and 360/44's as the best in terms of P/P. ------Me and my dyslexic keyboard---------------------------------------------- Phil Ronzone Manager Secure UNIX pkr@sgi.COM {decwrl,sun}!sgi!pkr Silicon Graphics, Inc. "I never vote, it only encourages 'em ..." -----In honor of Minas, no spell checker was run on this posting---------------