Yeah, I was going to say, 40ms seems a bit out there. If you consider a touch typist typing 100WPM, that's about 8.3 characters/second, or about 120ms / character. You may think 40ms is fast enough to accommodate that, but not really. Typing is bursty by nature, and so many of those consecutive keystrokes will come close together. If you scan too slowly, you might see two keys "become active" on the same scan, and end up reordering them. At 40ms, that seems entirely likely for a touch typist at 100WPM.

10ms seems far more reasonable.

So, GGGP was less wrong than stated, but for the wrong reasons. Huzzah! That is a rather strange defense. "I thought I was supposed to go south, when actually I was supposed to go north. But, I misread the roadsign and got on a road that goes northeast, so I ended up not too far from my destination. See? I'm not a bad navigator!"

Anyway, in the interest of actual analysis:

Let's go at the low end: 10kHz. And let's pick a beefier keycode, say "R CTRL", that has a 2 byte scan code. No, we're not going to benchmark the hilarious pause key. Get real. The vast majority of the scan codes are 1 byte anyway.

The time to send a key down event should be 2 bytes * 11 clocks, or 22 clock periods at 10kHz. That's 2.2 milliseconds. The time to send a key-up event should be 3 bytes * 11 clocks => 3.3 milliseconds.

Both of those seem pretty fast. The OS itself, though, and whatever layers there are between the PS/2 connector and the OS, will add their own latency. But in a race between a PS/2 keyboard and a USB mouse? I think they're going to both be well under 50ms in any case. 50ms is 20Hz, which is "Intellivision games from the late 70s" speed.

I think it's probably fine to store non-empty cells as objects, as long as you use something like the Flyweight pattern to avoid carrying too much baggage in each cell. It makes for a fine user interface, I'm sure.

To really get good recalc performance, though, you really need to drag the cell dependence graph out of the grid and treat it like an actual program. Once you do that, you could actually JIT the computation represented by all those cells. If you're really walking the object forest for every recalc, you'll never speed up.

I'd like to see you implement an AND gate with just XORs and NOTs. Use as many as you like... ;-)

In all seriousness, you can build all other gates from NANDs. Or from NORs. In fact, that's how the Cray 1 was built, apparently. Tons and tons of ECL NAND gates.

Someone else (who I think I saw here on Slashdot the last time Voyager was mentioned) had a great analogy for what we're likely seeing. I can't take credit for this at all, but I think it makes a lot of sense.

Suppose we're a small probe, making our way off an island, down the beach, and into the ocean. All we have is a wind-speed detector, and a water detector. As we near the water, waves start lapping over us. When they do, our wind-speed detector says "no wind", and our water detector says "we're wet." Have we entered the ocean yet? The answer is "not quite, but we're really darn close."

It doesn't seem surprising to me at all that the boundary neither perfectly uniform, nor stationary in time. I think we'll be in this transition band for a while.

Even if this is discrimination, I'm also not clear that this is discrimination against fathers. It might well be discrimination against mothers. Fathers only have to spend eight weeks caring for the new baby. Mothers have to spend twelve.

After which you send it to the centralized child care facility, so the child is never a burden to either parent ever again?

I'm pretty sure both parents are on the hook for child care for as long as the child is a child. The issue is whether they're also on the hook for going to a job other than raising their child.

My high-tech employer only offers TWO weeks paid paternity leave. TWO. Not the generous eight that Yahoo! offers. That was probably considered progressive in the US in the 60s, but seems hopelessly behind the curve in high tech today. One of my coworkers took an extra two weeks out of his own vacation time to spend a total of four paid weeks with his newborn daughter.

I personally have 8 weeks of vacation time built up, because work keeps me busy enough that I never feel like I can take the time I'm entitled to off. I don't even feel like I can ask for the time off, and it's technically already mine. The culture works against it. We're a country of workaholics, and we're made to feel bad when we ask for a little space.

If we really wanted to do things "right" here in the US, I'd have to ensure I built up a big enough cushion that my wife and I could remain unemployed (and thus, unpaid) for a couple years. And then, hope I could find a job after 2 years out of high tech. Hmmm... yeah, seems unlikely. Or, at least, feels unlikely, even if perception doesn't match reality.

Ah, the American dream: To make enough money that you no longer have to work for a living. For the vast majority of us, it will always remain a dream.

Why it is that every time the moron politicians of the world reach for the cutting budget scissors they cut education, healthcare and social programs?

Hint: It's usually a rich politician whose family and friends wouldn't suffer the cuts directly. They sell it by painting the beneficiaries as slackers that are a drain on society, as opposed to the reality. These things solidify the very base of society.

Net result? An ever widening chasm between the haves and the have-nots. That chasm strains the very notion of society.

You either needed a PEB + Editor/Assembler (which I didn't have), or you could by the Mini Memory cartridge which comes with the Line-by-Line Assembler (which I did have) that left you 768 bytes free to program at location >7D00 (out of 4K total battery-backed memory)

You certainly could not, however, program assembly code on an unexpanded TI-99/4A. You needed at least the Mini Memory cartridge.

TI Extended BASIC didn't have PEEK and POKE in the same sense as other Microsoft BASICs. In other computers, you could literally read and write any location. TI Extended BASIC let you PEEK certain locations, but not really POKE anywhere.

The Mini-Memory did add a PEEKV and POKEV that let you manipulate VDP RAM, but again, that required the Mini Memory cartridge. (I don't know if E/A also provided anything like that; I didn't have E/A.) And if Mini Memory's plugged in, you don't get TI Extended BASIC.

There are a lot of good points in this thread. It's worth noting that there's no direct replacement for experience. You bring N years of experience to the job, and the only thing that can bring you N years of experience is N years of doing the job. While you can teach some the broad lessons (and, I would say, teach them specifically in the context of this app; you're not a professor and you're not teaching a class), there's no replacement for experience.

When I was fresh out of college, I could write programs that did very interesting and useful things. Now it's *mumblety* years later, and I know for a fact I would write my programs far differently now, with generally much better outcomes in maintainability, scalability and flexibility. Much of that was learned through trial and error—ie. experience. That only comes with time and practice.