kens

14 ms·

121.
by kens 8mo ago
Author here for all your 8087 questions...
122.
by kens 8mo ago
My unpopular opinion is that programming is stuck in the 1970s: a lot of programmers use a 1970s-style terminal window to enter 1970s OS commands, which run on a 1970s processor architecture (which is slowly getting replaced by a 1980s arch
123.
by kens 8mo ago
A historical note: even though the line/box-drawing characters go back to the IBM PC, they aren't ASCII. The PC used Code page 437, which added a bunch of characters to ASCII. To be genuinely ASCII, you need to draw your boxes wit
124.
by kens 8mo ago
The 80×24 display of the IBM 3270 is the reason that terminal windows nowadays are typically 80×24 (or 25 lines because the IBM PC added an extra line). IBM dominated the CRT terminal market in the mid-1970s, so other manufacturers were mos
125.
by kens 8mo ago
I thought hydragyrum was a made-up word, but it's the Latin word for mercury, which explains the Hg chemical symbol. (Just in case anyone finds this interesting.)
126.
by kens 8mo ago
As a historical note, the first President Bush proposed in 1989 to establish a base on the Moon and send astronauts to Mars by 2020. In 2004, the second President Bush set a goal of returning to the Moon by 2020 and going to Mars in the 203
127.
by kens 8mo ago
I'll mention that mainframes also had extensive libraries of shared software. The IBM user group SHARE (Society to Help Avoid Redundant Effort) started in 1955 to share software and had hundreds of programs in an IBM-maintained library
128.
by kens 8mo ago
Seriously, I consider this to be Microsoft's key innovation: the idea that people should pay for software and that people should be forced to pay for software.
129.
by kens 8mo ago
I was shocked to learn recently how China is crushing it in renewables and electric cars. BYD sold 600,000 more electric cars than Tesla in 2025, becoming the world's largest EV brand. Tesla's sales have been declining since 2023,
130.
by kens 8mo ago
Thanks for pointing that out. The real ad appeared in the computer magazine Interface Age, September 1976 page 13, as can be seen in the Internet Archive. I think it's important for Hacker News to avoid fake/replica historical inf
131.
by kens 8mo ago
A more practical option is using brain-dead humans for medical testing. This was discussed recently in the journal Science , using the term "physiologically maintained deceased". As they say, this "traverses complex ethical
132.
by kens 8mo ago
In the past decade, the five-year survival rate for pancreatic cancer has nearly doubled, from 7% to 13%. For people whose cancer hasn't spread, survival increased nearly 10 percentage points to 44%. So it's wrong to say that noth
133.
by kens 9mo ago
From what I've read, the 386 multiplication bug was a semi-analog problem, so the fix was probably making a transistor larger. As a result, it would probably be hard to find the fix on the die and wouldn't be as interesting as, sa
134.
by kens 9mo ago
It had the micro-instructions for most of the machine instructions, but a few simple instructions were implemented directly in hardware. https://www.reenigne.org/blog/8086-microcode-disassembled/
135.
by kens 9mo ago
The byte order doesn't make much difference. The more important difference compared to a typical RISC chip is that the 8086 supports unaligned memory access. So there's some complicated bus circuitry to perform two memory accesses
136.
by kens 9mo ago
I second the recommendation for Zotero, especially if you find yourself buried under PDFs. Two things make it very useful for me. First, it organizes my PDFs and lets me search them, instead of manually searching through directories. Second
137.
by kens 9mo ago
That's an interesting question. Keep in mind that the 8086 was built as a stopgap processor to sell until Intel's iAPX 432 "micro-mainframe" processor was completed. Moreover, the 8086 was designed to be assembly-languag
138.
by kens 9mo ago
Thanks! The reverse engineering is just for fun. I have a software background, so I'm entirely unqualified to be doing this :-) But I figure that if I'm a programmer, I should know how computers really work.
139.
by kens 9mo ago
Author here for all your 8086 questions...
140.
by kens 9mo ago
In the article, he lists his 14 major electronics purchases for 2025 along with "more mechanical watches than I can count". Serious question: is this a normal level of acquisition? I'm not a minimalist, but that's more e
141.
by kens 9mo ago
As John Steinback said in East of Eden : “I have spoken of the rich years when the rainfall was plentiful. But there were dry years too, and they put a terror on the valley. The water came in a thirty-year cycle. There would be five or six
142.
by kens 9mo ago
There's a difference between what Verilog will allow and what is "synthesizable". In other words, there is a lot of stuff that you can express in Verilog, but when you try to turn it into an FPGA bitstream, the software will
143.
by kens 9mo ago
If you feel cheated now, wait until you find out that the ALU in the 8-bit Z80 was just 4 bits. :-)
144.
by kens 9mo ago
Yes, the 8087 uses CORDIC. I extracted the constants from the 8087's internal constant ROM and they are arctangent and log values for the CORDIC algorithm. You can implement the same functions in software, which is what floating-point
145.
by kens 9mo ago
I use a basic metallurgical microscope (AmScope ME300TZB). An X-Y stage is very useful for taking photos of chips and stitching them together. A camera is also important; my scope has a 10MP camera. I'm not into optics, so I don't
146.
by kens 9mo ago
How to get started reverse engineering? That's a big topic for a HN comment, but in brief... Either get a metallurgical microscope and start opening up chips, or look at chip photos from a site like Zeptobars. Then start tracing out si
147.
by kens 9mo ago
As far as I know, you can't get the 8087 itself as an IP block. You can get generic IEEE-754 floating-point as an IP block, e.g. from AMD: https://www.amd.com/en/products/adaptive-socs-and-fpgas/inte...
148.
by kens 9mo ago
It would be difficult, but not impossible. The main problem is tracing out all the circuitry, which is very time-consuming and error-prone. Trust me on this :-) The second problem is that converting the circuitry to Verilog is straightforwa
149.
by kens 9mo ago
Author here if anyone has questions...
150.
by kens 9mo ago
> Henry VII What do you have against Henry VII? From Wikipedia he seems to have been a good king.

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