kens

35 ms·

601.
by kens 3y ago
The terminology is a bit of a mess, but usually a PLA is highly structured with an AND plane and an OR plane, so it implements sum-of-products logic. A gate array is more general, with arbitrary connections.
602.
by kens 3y ago
Knuth's famous paper "The Complexity of Songs" (1977) deserves a mention. He describes how most songs of length n require a text of length proportional to n. But he goes on to prove the complexity of Old MacDonald had a farm
603.
by kens 3y ago
I'm not sure what you're asking. IDT used the same gate array for numerous 7400-series products. As a result, simple chips would waste most of the die, while complex chips would use most of it. The tradeoff is that using a gate ar
604.
by kens 3y ago
Yes, a ULA is another name for a gate array. A while ago I bought an 8086 chip on eBay that turned out to be a random ULA chip that was re-labeled: https://www.righto.com/2020/08/inside-counterfeit-8086-proce...
605.
by kens 3y ago
Author here if there are any questions...
606.
by kens 3y ago
Thanks!
607.
by kens 3y ago
> I think it's grossly disingenuous to say "computing market" and then ignore the entire smartphone/tablet market. Note the presence of the sentence: "Of course, mobile phones are almost entirely ARM."
608.
by kens 3y ago
According to Dave Bradley, one of the creators of the IBM PC, "We chose the 8088 [over the 8086] because of its 8-bit data bus. The smaller bus saved money in the areas of RAM, ROM, and logic for the simple system." Another thing
609.
by kens 3y ago
Neat! Eventually, Intel added the CPUID instruction so you could determine the processor type without trickery.
610.
by kens 3y ago
Author here for your 8086/8088 questions...
611.
by kens 3y ago
I reverse-engineered the HN ranking algorithm a few years ago [1]. To answer your question, posts have a sudden drop due to several types of penalties. Many posts are penalized from the start due to their title or domain. A "controvers
612.
by kens 3y ago
The explanation for why they chose this printer is in a conference paper published in the National Telesystem Conference, 1982. Unfortunately, I can't find these conference proceedings anywhere (even in physical form). If anyone happen
613.
by kens 3y ago
I answered that question elsewhere in this thread: https://news.ycombinator.com/item?id=39768125
614.
by kens 3y ago
As far as cryptography, the military AN-UGC/74 teleprinter worked with cryptographic equipment such as TSEC/KG-30, KG-84, KW-7, and KY-57 [1]. You'd send the data stream into the crypto equipment and then to the teleprinter.
615.
by kens 3y ago
You don't need to speculate. As I explained in the thread, the Shuttle teleprinter was based on the military AN/UGC-74 teleprinter but had many modifications including new three circuit boards for the FSK decoding.
616.
by kens 3y ago
Serious answer: I post things on Twitter because it is easy, lets a huge number of people read my thread, and provides easy interaction. I post the same threads to Mastodon and get orders of magnitude less interest. I also write blog posts,
617.
by kens 3y ago
Three ways you can read the thread: a) Log into Twitter. b) Read the same thread on Mastodon [1]. c) Wait until I turn it into a blog post. [1] https://oldbytes.space/@kenshirriff/112124283096167861
618.
by kens 3y ago
To clarify, that is an emulator specific for the IBM 360/50 that runs the microcode. It is a demo, not a useful system. It has nothing to do with Hercules.
619.
by kens 3y ago
Curiously, early Intel 386 processors had a bug where 32-bit multiplies were genuinely nondeterministic: some answers would depend on the voltage, frequency, temperature, and manufacturing conditions. The problem was essentially analog, a l
620.
by kens 3y ago
I'm confused by one statement in the article: "Lockheed turned the Hiller Helicopter plant in East Palo Alto into the control facility for all spy satellites". Presumably the control facility was the Blue Cube (later Onizuka
621.
by kens 3y ago
Author here for your vintage computer questions :-)
622.
by kens 3y ago
An APL keyboard typically wasn't exactly a custom keyboard, but a standard keyboard with APL characters accessible through modifier keys. Often there were adhesive labels on the front of each key showing the special characters or you c
623.
by kens 3y ago
I'm not familiar with that. But if you can't build them with modern technology, 1950s technology wouldn't work either.
624.
by kens 3y ago
Author here for all your electromechanical computer questions :-)
625.
by kens 3y ago
Author here for any analog computer questions...
626.
by kens 3y ago
That history is a bit muddled so let me clarify. I'm a big fan of Federico Faggin, but Stan Mazor, Ted Hoff, and Masatoshi Shima are also co-inventors of the 4004. Next, the 4004 had approximately nothing to do with later processors in
627.
by kens 3y ago
> Does 99.995% [1] of hackernews sound reasonable enough to you? How did you come up with that number? I looked at the link and just one of the outages listed on January 10 was 59 minutes. That alone makes the uptime worse than 99.99% fo
628.
by kens 3y ago
No, eight nines is 316 milliseconds of downtime per year. 30 seconds of downtime a year is six nines. (I spent a long time working on high availability at Sun, so the numbers immediately looked wrong.) https://en.wikipedia.org&#x
629.
by kens 3y ago
I investigated 132 columns in detail and wrote a blog post about it. It's complicated but essentially, 14 7/8" paper was a standard size going back to the IBM 402 tabulator in 1948, where it was used for 88-column output usin
630.
by kens 3y ago
The original definitions of "hard error" and "soft error" were for disks and go back to the early 1970s at least. A soft error was a recoverable error that could be handled by re-reading the disk sector. A hard error was

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