kens

24 ms·

361.
by kens 2y ago
I discuss this a bit in footnote 1. Thousands of things were built on frames before computers, of course. However, IBM both built computers from semi-portable cabinets built around metal frames and also referred to the computer's units
362.
by kens 2y ago
There's also the Intel iAPX 432 "micro-mainframe" processor (1981) on two chips. (This was supposed to be Intel's flagship processor, but it was a disaster and the 8086 took over instead. The NYT called it "one of t
363.
by kens 2y ago
Author here. Anyone have interesting mainframe stories?
364.
by kens 2y ago
Unfortunately, not any time soon.
365.
by kens 2y ago
Intel said that BiCMOS decreased signal delays by up to 35%, although the total performance improvement would be less.
366.
by kens 2y ago
That's an interesting chip. You don't see many bipolar processors. (The Pentium has a few bipolar transistors sprinkled around, but it's mostly CMOS.)
367.
by kens 2y ago
No. I'm making fun of the comments on my previous article that called me "radical woke."
368.
by kens 2y ago
Is BiCMOS radical woke? :-) Author here for your Premium questions...
369.
by kens 2y ago
No, the adder was all CMOS. But there are some BiCMOS drivers visible at the bottom of one of the photos. The NPN transistors are big squares, unlike the CMOS transistors.
370.
by kens 2y ago
I especially like slide 36, the "time cube" diagram of adder architectures.
371.
by kens 2y ago
The short answer is that a large carry-save adder feeds into this 8-bit carry-lookahead adder to generate the table index for division. In more detail, the division algorithm uses a ≈64-bit carry-save adder to hold the partial remainder dur
372.
by kens 2y ago
Author here if anyone has questions about the obscure details of Kogge-Stone adders :-)
373.
by kens 2y ago
Pretty much anything that dissolves in lipids will work as an anesthetic, with effectiveness depending on how well it dissolves. This is why nitrogen under high pressure can cause nitrogen narcosis while diving. This is also why spot remove
374.
by kens 2y ago
Good idea. I'll change the title.
375.
by kens 2y ago
I can't tell if you're seriously accusing me of "full-on virtue-signaling" or being sarcastic. In any case, if I wanted to virtue signal there are much more effective topics that would take 1/100 of the work.
376.
by kens 2y ago
The popular cargo cult story is a mixture of stuff that happened, stuff that was made up, and focusing on the wrong stuff. It's basically an urban legend at this point of people copying from other people. It's a bit like saying th
377.
by kens 2y ago
No, I'm not claiming that anthropologists are the "natural and proper authorities charged with gatekeeping"; that's nonsense. What I'm claiming is that the description of cargo cults that everyone knows is fiction.
378.
by kens 2y ago
Author here. This is a change from my usual reverse engineering articles, but hopefully you'll find it interesting...
379.
by kens 2y ago
> I should’ve ate more apricots! Did you mention apricots deliberately? Apricot pits were a huge, huge alternative medicine in the 1970s under the name Laetrile. Proponents said that Laetrile would cure cancer and was being covered up. T
380.
by kens 2y ago
The comment is flagged and dead. You can see the comment tree if you go to your profile and turn on showed.
381.
by kens 2y ago
Shop is the same as Shopify? Thank you (seriously) for pointing this out. I've been getting Shop emails and I had no idea.
382.
by kens 2y ago
The FPU supports decimal numbers in BCD (binary-coded decimal). Presumably these large powers of 10 are useful for BCD conversion, especially since they are near other BCD-related masks. But they aren't normal floating-point numbers, s
383.
by kens 2y ago
The ries program is very cool for turning a number into an equation. However, I tried it on some of the Pentium constants and it didn't do very well. In particular, it seems to be allergic to numeric constants, preferring complicated s
384.
by kens 2y ago
A running system won't really help me since I'm sure it will give the right answer. I need to know what's happening internally, which remains hidden in a running processor.
385.
by kens 2y ago
It's sort of random. My intent is to focus on the 8086, but someone asked about the 386 so I looked at that a bit. Then I saw the Navajo Pentium rug in a museum so I figured I should look at a real Pentium to compare. And then I wonder
386.
by kens 2y ago
I've updated my article along with a credit to you. Unfortunately, I couldn't figure out the other constants despite a whole lot of brute-force checking.
387.
by kens 2y ago
Thanks! I think you've figured out those mystery constants. How did you recognize them?
388.
by kens 2y ago
Even modern chips have a single layer of transistors, although there is research into 3D transistor stacking. (Flash memory stacks dies for more density.) Modern CPUs have much, much smaller transistors as well as constructing them more ver
389.
by kens 2y ago
My guess is that it made things both easier and harder. Harder in the sense that you couldn't just throw together floating point circuits; you had to deal with lots of special cases. But easier in the sense that the tricky design decis
390.
by kens 2y ago
Author here for your Pentium questions...

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