This has been discussed on HN some times before. User xornot looked at the zfs source code and debunked "faulty ram corrupts more and more on scrub", for more details see https://news.ycombinator.com/item?id=14207520

I don't think this is entirely due to Wozniak. Early "home" computer systems were based on connecting cards to a bus (eg the S-100 bus), eg. with one card supporting the CPU, another RAM, a third for disk drive, video card etc, etc. The cards where then memory mapped, presumably you controlled the memory mapping by setting jumpers. (I guess you're saying that Apple II managed this automatically?) Of course the full story might be a bit more complicated: 6502 and 6800 used memory mapped I/O, whereas 8080 (and Z80?) had certain I/O pins coming out of the CPU.

Memory mapping happened automatically. Each card was mapped based on the slot it was in. $C000 - $C700 I believe with each slot assigned 256 bytes.

You're correct; slot 6 for instance is $C600. If you crashed to the system monitor you could boot a disk by entering C600G (with the 'G' standing for 'go to').

IIRC the disk controller had firmware that loaded the first 256 byte sector from disk into memory.

If you crashed to the monitor, you could hit Ctrl+B and get back to BASIC, then type IN#6 to boot the disk.

Yeah. It was neat. But it rebooted in under a second so a complete crash was no biggie.

RAM wasn't even cleared so usually no (or limited) data loss.

I thought it was PR#6 (redirect output) to boot from the disk controller in slot 6. I wonder what redirecting input would do.

That was it at the AppleSoft BASIC prompt (or IN#6). But the parent poster commented on how to do it from assembly.

There is an even quicker way from the monitor:

6 CTRL+P

Will instantly divert output to slot 6. (and boot the disk if there is hardware there)

Both worked to start a boot from the disk controller in that slot.

Fun historical fact: knot theory got a big boost when lord Kelvin (yeah, that one) proposed understanding atoms by thinking of them as "knotted vortices in the ether".

If you have a child who likes math I highly recommend "Really Big Numbers" by Richard Schwarz. Tons of nice illustrations on how to "take bigger and bigger steps".

"Infinity is farther away than you thought."

I recently got into making some sort of budget hifi setup, and found audiosciencereview.com quite helpful - a good amount of reviewed gadgets with focus on measurements. Ended up with kali lp-6v2 speakers and a SMSL SU-1 dac. Please don't tell me I screwed up. :-)

I have used merlin for quite a while, mostly happy (except for some security holes...) However, once asus drops support for older devices (e.g. rt-ac68u and rt-ac86u), merlin might also drop it. For now rt-ac68u is dropped by merlin, but ac86u is fine for now (at least until the end of the year.)

Upshot: if you care about very long term support, openwrt is nice.

Based on reddit [1] and other some other recommendations I got an asus ax4200 and put openwrt on it. I'm fairly happy, but some people have run into connection dropping (possibly due to ISP power saving resulting in link dropping down to 10 mbs, and something then goes wrong.) With forum help [2] I found a workaround: either turn off auto negotiation (works) or using a lan port as a wan port (have not tried).

1:

https://www.reddit.com/r/openwrt/comments/1cr1lvp/is_the_asu...

2:

https://github.com/openwrt/openwrt/issues/14192#issuecomment...

There is a nice picture of the "best" for different ranges of sizes of numbers to be multiplied at

http://gmplib.org/devel/log.i7.1024.png

More context and explanation can be found at: http://gmplib.org/devel/

BTW, I like Bernstein's survey of different multiplication algorithms at

https://cr.yp.to/papers/m3.pdf

(there is a unifying theme about using ring isomorphisms to explain many of the "standard" routines.)

PS: if you're interested in multiplying "ludicrously large numbers", Harvey and van der Hoeven had a nice breakthrough and got multiplication down to "FFT speed" (n*log(n)), see

https://hal.science/hal-02070778v2/document

A pop-sci description can be found at

https://theconversation.com/weve-found-a-quicker-way-to-mult...

Check out "Diamond Age" by Neal Stephenson.

GP, if you like HN, but haven't yet read Neal Stephenson, you're in for a treat!

Thanks, but it happens that I've tried NS but didn't love it. But I appreciate the question answer.

Speaking of books - I really like your CS textbook. Thank you!

Oh, bless you, that's very kind. I am proud of it and I think it is very good for its intended audience. But almost no one has read it, that I can tell.

Well, add one grateful reader to your tally

It's very inefficient, both on terms of runtime and in terms wasted entropy.

Indeed, haha.