Fond memories. I was working for a financial services company when we went from an IBM mainframe complex to an Amdahl one. Besides being responsible for data center automation I was facilities manager, so I was in charge of the project. It only took 3 weeks to complete the entire migration. Thank you Gene.
Gene Amdahl has died
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Re: Gene Amdahl has died
#112Earlier quoted context omitted.
You have to wonder about the management at IBM that made him unhappy enough to leave in the first place. That kind of guy is going to do what he's going to do now matter what. Whether he does it for you or in competition against you is the only question. There are very few lengths management shouldn't have gone to keep a guy like that happy at IBM.
He disagreed with their technical staff about how to design a mainframe. The technical staff said that the operating system should run on microcode to abstract away the hardware. That way it would be easier for customers to migrate to new hardware as it became available. And they could easily add a new instruction if they needed to. Gene said that it would be an order of magnitude faster if it ran directly on the har…
I think you imply this, but to make it explicit: IBM mainframes run some instructions in microcode, others are native. The ones that are native are not slowed down by the existence of the microcode engine.
IBM analyzed programs-in-use to figure out which instructions bottlenecked real programs. These were the ones prioritized into native hardware. Others, where the bottleneck wasn't the central processor--like moving a block of memory from one location to another--were executed in microcode (at least back in the day: I was one of the engineers on the S/390 microcode engine.)
Re: Gene Amdahl has died
#113Honest question for those who got received CS/Engineering degrees in the last 10 years, did Amdahl's Law come up? I've seen programming courses go away from assembler/c/c++ over the years to Java and then scripting languages at a couple local schools. I wonder if the history/theory side changed as well.
Yes, I'm about to finish up my undergrad CS degree, and Amdahl's Law came up in at least three separate classes, most notably my computer architecture course and my operating systems course. Side note, we were assigned to read Soul of a New Machine and the Pentium Chronicles in the computer architecture course, and most everyone enjoyed the books.
Re: Gene Amdahl has died
#114Earlier quoted context omitted.
It meant that Amdahl's (and other manufacturer's) customers could buy IBM software and run it on non-IBM hardware.
I still don't know the answer: https://en.wikipedia.org/wiki/History_of_IBM#1969:_Antitrust... "After the unbundling, IBM software was divided into two main categories: System Control Programming (SCP), which remained free to customers, and Program Products (PP), which were charged for." So what were Amdahl's customers able to get? Didn't they get System Control Software from IBM (1)? Was it free for them? 1) I've fo…
SCP remained bundled with the hardware, so you only got it if you bought the hardware, but if you bought the software it belonged to you so you could run it on whatever hardware you liked. I suppose if you bought both an IBM and a non-IBM mainframe you could take the SCP from IBM and run it on a non-IBM box, but I'm not sure if that was addressed in the ruling. The point was to decouple software sales from hardware sales when it came to commercial (sold) software.