Re: Cycles per ASM instruction

"John W. Kennedy" <jwkenne@[EMAIL PROTECTED]
> writes:
> The 22s were the last 360 announced, and were simply recycled 30s,
> introduced after the S/370 135 came out and 30s were being returned in
> great numbers, but before the 115 and 125 were ready. The 115 and 125
> were microcoded up the wazoo, so it's easily imaginable that they were
> slower than the 30/22.

the 115/125 were nearly identical machines ... they had a nine
position bus for microprocessors. depending on what the customer
specified in the order, would govern how many of the nine slots had
microprocessors installed and what microcode got loaded into each
processor (all the microprocessors were the same, just had different
microcode loaded).

115 was rated at 80kips 370 ... that met that the microprocessor
executing the 370 microcode load ... emulated 370 instructions at
approx. 80,000 instructions per second. the 370 microcode load had an
avg. of ten microcode instructions per 370 instructions (of course
more complex 370 instructions would require significantly more
microcode instructions to execute).  all the other microprocessers in
the machine were identical but got microcode loads to perform other
types of functions, communication controller, disk controller, etc.
the microcode engine ... to make 80kips 370 ... executing an avg.  of
ten microcode instructions per 370 ... had an engine that ran just
under a mip "native".

the 125 was identical to 115 except the microprocessor engine that
executed 370 microcode load was about 50percent faster than the other
microprocessor engines (rather than about 800kips native ... it was
more like 1.2mips native).

in many respects ... 115/125 were SMP multiprocessors ... with up to
nine processors in a configuration ... executing different application
(micro)code.