[cctalk] Re: Did Bill Gates Really Say That?

I don't think Gates ever actually said this - but that's just based on my own examination into this from a few years back. But, over the years I've done some thread programming, and I was once solving a problem by loading a lot of data into main memory (like 8-16GB of data to process as one huge chunk, on a system that only had 32GB total). A while later, I had a thought that actually maybe this quote has some merit. Maybe not the specific amount (of 640KB) - but the general notion that there is rarely a reason for a single application to consume the entirety of main memory. It may be better, especially with threads or multi-core, to work a problem in smaller chunks -- specifically, to work a problem in chunks smaller than the CPU cache. And in fact, I found a huge jump in my programs performance when I kept the buffers exactly 1 byte less than the CPU cache (at the time that was 1MB) - as soon as I went 1 byte over, I noticed a huge (~3X) hit in performance. Now that's just a single data point, and the old advise of "never optimize your program for performance too early" is probably still good. And especially most shops won't spend the time/resources to cache optimize their builds - I suspect some games do at startup, they maybe profile what your L3 cache size. Anyhow, years ago I recall coming across a quote or an article where Gates stated the IBM PC (or maybe the 8088 cpu itself) was designed or intended to only "last" about 10 years. Not that the system components itself would only last that long, but as it being a "useful" system. In that context, maybe he was right (if he had said it) - 640K was maybe "enough for anyone" for the remainder of the 1980s. I recall starting with 384KB (thinking anything past 128KB was "huge") and doing upgrades in the late 1980s to get to 640KB, and not getting into extended/expanded memory until the early 90s. This would be for "typical" household applications (taxes, small business, word processing) - obviously image processing (CAD, movie rendering, etc.) or multi-user servers do need more memory. I also recall that it was Intel that requested to keep it to 10 segments of 64KB (640KB), not really a Microsoft or MS-DOS doing. i.e. aspects beyond Microsoft wanted to reserve the "upper memory" for other stuff (video memory). You have 16 segments, how many to hold in reserve? Someone chose 6. Quick and Dirty OS indeed. On Tue, Jun 13, 2023 at 11:47 PM Ali via cctalk <cctalk(a)classiccmp.org> wrote: