kens

39 ms·

451.
by kens 2y ago
There are multiple factors that limit the number of writes that FRAMs can handle: changes in crystal structure as Ti ions replace O, mobile ions collecting at grain boundaries, and something to do with 90º domains.
452.
by kens 2y ago
This was an IBM board so all the chips were in large, square, metal packages. These packages are descendants of the SLT modules used in the System/360.
453.
by kens 2y ago
Yes, since reads destroy the data, each read causes a write. The chip will handle 100 trillion read/writes. So yes, the chip will wear out rapidly if you do a lot of reads.
454.
by kens 2y ago
The FM1808B and FM1608B might work for you. These are 32Kx8 and 8K×8 FRAM chips with standard SRAM pinouts, in DIP packages. If you don't need a DIP, you have a lot more choices.
455.
by kens 2y ago
The metal ions from the ferroelectric material can contaminate the silicon production line. I read that they would manufacture the silicon die at one facility (i.e. make the transistors) and then do the rest of the fabrication (the ferroele
456.
by kens 2y ago
From looking at various patents, I believe they put down a layer of PZT and then etch it into cubes with photolithography. Look at the process diagram at the bottom of my article, step 1128.
457.
by kens 2y ago
It wouldn't make sense to use FRAM for ROM, since the big feature of FRAM is fast write speed. I found one DEC document that says the Flash ROM on one product is the Intel 28F008SA, an 8Mb flash chip. So I expect the VAXstation uses bo
458.
by kens 2y ago
Someone gave me a board with bubble memory chips to examine, but when I opened up the chip it turned out to be regular DRAM; they were mistaken about the type of memory.
459.
by kens 2y ago
Thanks, I've fixed those!
460.
by kens 2y ago
Author here if anyone has questions about ferroelectric RAM...
461.
by kens 2y ago
No, logic operations aren't "recognized as necessary". For instance, the IBM 1401—the most popular computer of the early 1960s—did not have logic operations. (This was very annoying when I implemented Bitcoin mining on it.) T
462.
by kens 2y ago
I'm glad to see the Datapoint 2200 is getting attention, but by reasonable definitions of "microprocessor", the Intel 4004 was first, the Texas Instruments TMX 1795 was second, and the Intel 8008 was third. It seems like you&
463.
by kens 2y ago
Intel left the military business in 1997 because making chips for the military is kind of awful. The volume is small and if a military plane gets canceled, the volume can suddenly become zero. (See the F-22 and Comanche.) Moreover, the mili
464.
by kens 2y ago
Strangely enough, the Saturn V Flight Control Computer is analog and has no software. You're probably thinking of the LVDC.
465.
by kens 2y ago
The IBM 305 RAMAC is demonstrated at the Computer History Museum on Wednesdays at 1:00 p.m. It's an impressive machine to see in action. It has one arm for all the platters; the seek time is very slow as the arm is retracted, moves up
466.
by kens 2y ago
Interestingly, Peter MacDonald, the Navajo tribal leader at the time, had been a code talker during World War II.
467.
by kens 2y ago
I think it's more likely that someone at Intel thought, "You know what would be cool? A rug that looked like the Pentium die." Note that unlike Fairchild, Intel's plant is not on Navajo land so there are no tribal agreem
468.
by kens 2y ago
Unfortunately it's not that easy. I was working with John McMaster to get backside die shots of the 386 using infrared but it didn't work out.
469.
by kens 2y ago
That doesn't make sense, since computers were using punch cards before von Neumann got involved.
470.
by kens 2y ago
Trying to sort out aerospace companies is always a mess. I got the dates mostly right but reversed the timeline. GM acquired Hughes Aircraft in 1985, forming the Hughes Electronics unit which consisted of Hughes Aircraft and Delco Electroni
471.
by kens 2y ago
A few years ago I bought an 8086 chip on eBay and it turned out to be fake, a random logic array chip relabeled as an 8086. It made for interesting die photos at least. It hardly seems worthwhile for someone to fake a chip that gets sold fo
472.
by kens 2y ago
The other side is plain gray silicon; I've looked at the back side of dies by mistake many times. (Intel is starting to do power through the back side, which would make the back more interesting.)
473.
by kens 2y ago
Thanks! Curiously, the article doesn't show up on HN. Maybe my domain got banned or something?
474.
by kens 2y ago
Author here for your obscure Pentium questions...
475.
by kens 2y ago
Strangely enough, a few months ago I came across the bug fix for that Space Shuttle problem. "CR 93160: Year End Roll Over (YERO) Reset. Allows in-flight reset to January 1 without an IPL and complicated procedures while maintaining a
476.
by kens 2y ago
Debunking of the bug story as etymological folklore has been going on since at least 1984. Every few years there's another article about it (which is good for the daily 10,000.) The first appears to have been in Byte magazine and then
477.
by kens 2y ago
My "unpopular opinion" is that in 100 years, people will consider it very strange that most of the population was permanently infected with a bunch of viruses like EBV/HSV/CMV/HPV and nobody cared or did anything ab
478.
by kens 2y ago
This actually happened on Apollo 13. Backup pilot Jack Swigert was assigned to Apollo 13 two days before launch because the expected pilot, Mattingly, had been potentially exposed to rubella. The flight launched on April 11, just a few days
479.
by kens 2y ago
I'll point out an interesting New York Times article "Ask it no questions: the camera can lie". This article discusses how photography had been seen as a medium of truth, but now "the veracity of photographic reality is
480.
by kens 2y ago
Since I work with punch cards at the Computer History Museum, I can answer this. A standard IBM punch card has 80 columns and 12 rows, with each character represented by 1-3 punches in a column. A lace card has all the holes punched, so it&

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