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jhallenworld

4,964 karma · joined October 31, 2013

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jhallenworld··on A little more speed from the 6502
With pre-processing: sort the source data so that the same bytes (along with their offsets) are grouped together, then convert this to code. It could be useful for drawing things like fixed sprites quickly.
jhallenworld··on A little more speed from the 6502
It could be faster:

    lda #firstbyte
    sta dest+0
    lda #secondbyte
    sta dest+1
    etc.
6 cycles per byte, so 166KB/sec. But we can do better: there are only 256 different bytes, so group the stores by byte value so that you don't have to reload before each one:

    lda #0
    sta dest+10  ; All the places that get 0
    sta dest+29
    sta dest+42
    lda #1
    sta dest+3   ; All the places that get 1
    sta dest+82
    etc.
Up to 250 KB/sec and less space. If the prior data in dest is known, it could be even faster: skip stores where the destination already has the correct data. And even faster: for video, skip stores which have a low hamming distance from the prior bytes and put up with a bit of noise..
jhallenworld··on AT&T lawyer stopped Plan 9 release CD with songs by Lou Reed, Debbie Harry
Well I had kind of the reverse situation: I wanted to contribute to Cygwin, owned by RedHat. RedHat would not accept my contributions unless I got a signed release from my employer, IBM at the time. Well I tried to get this signed release, but all I got was the run-around. Nobody would bother taking the risk. It's one of the reasons I left.
jhallenworld··on Texas repeatedly raises pollution limits for Cheniere LNG plant
> if we can't bear trivial negative consequences?

Instead of we, how about you move right next to this plant..

But if the only consequence is price, I agree with you. I speculate that the Freeport LNG fire was sabotage. Of course I have no evidence, but many interests are served.. Russia, but also industrial natural gas users in the USA trying to limit the price..

The fire reduced our exposure to the global natural gas market, and the price in the USA immediately plunged:

https://tradingeconomics.com/commodity/natural-gas

jhallenworld··on Motorola 6800
Perfect system == 6809 + SIO from the Atari800 + C64 SID + IBM PC keyboard + C64 VIC or maybe V9938.
jhallenworld··on Motorola 6800
I wrote a multi-tasking OS for the 6809 and used the DP to hold the current task ID: task local variables would be in the direct page.
jhallenworld··on Motorola 6800
The 6809 was nice, but I think the CoCo otherwise was crap. Aside from the 32 column display and awful color scheme, the built-in serial port was bit-banged. This meant that floppy drive and serial access could not happen at the same time. This is very relevant when trying to use OS-9.

There was an external serial port as an option, but there was only one slot. So you also had to buy a slot expander (a Multi-Pak).

jhallenworld··on Motorola 6800
This was my first microprocessor: I developed assembly language for it and the 6809 using Motorola's Exorciser development system (which was already old in the mid 80s when I used it). Here is a simulator I wrote for it, in case you want to try it in Linux or Cygwin:

https://github.com/jhallen/exorsim

8 inch floppies! I remember we had an old GE chain-train printer for it which was awesome because it was so fast.

jhallenworld··on Cheap, green hydrogen would be a breakthrough in clean energy
I'm interested if you could have a hydrogen stove, or hydrogen space heater- just as diesel, kerosene, propane, methane, electricity, alcohol, wood, and coal are all viable. What practical problems would arise? For example, gasoline camping stoves exist, but are too dangerous for indoor use.

If hydrogen is widely available, surely someone will want to do this..

This is what the flame looks like:

https://www.youtube.com/watch?v=r-8H5u4YzuY

jhallenworld··on DOE announces breakthrough in residential cold climate heat pump technology
I just got a quote: $30K to upgrade a 1000 sq ft. apartment from oil fired steam (59% efficiency boiler from the 40s) and hot water to heat pumps near Boston. Includes removing oil tank, radiators and installing resistance electric hot water heater.

Or I could upgrade from oil to gas for $14K (to an 82% efficiency boiler). I have a strong incentive to do this since the cost of heating with gas will be 1/3.5 compared with heating with oil.

I think these are insane prices, but that's what contractors get around here. There is a $10K incentive for the heat pumps, but it requires a home inspection and probable upgrade of the insulation. IMHO, the incentive is not enough- it needs to make the heat pumps the cheapest option.

As far as fuel costs, the gas would definitely be cheaper. The electricity comes from gas (especially in the middle of the winter). The price is more because you are paying someone to convert the gas to electricity. The efficiency of getting the heat from gas via electricity is only a little more with heat pumps (when accounting for generation and transmission loss and much higher heat pump efficiency).

Maybe in the future the electric supply will be greener, but it isn't today. They are trying to build a HVDC line from Boston to Quebec for more hydropower, but Maine and NH are not allowing it due to NIMBY (a referendum in Maine, financed by gas companies, killed it).

jhallenworld··on Chemist pursues answers to why promising solar cell material quickly degrades
Maybe they need a UV blocking film? It seems to be a thing:

https://onlinelibrary.wiley.com/doi/10.1002/anie.202100218

jhallenworld··on Nuclear is back on the table for a green future
PV + storage is cheaper than nuclear:

https://www.lazard.com/perspective/levelized-cost-of-energy-...

(you have to compare cost of nuclear on first page with wholesale PV+storage energy on subsequent pages).

jhallenworld··on Nuclear is back on the table for a green future
>Where are we going to get enough cobalt?

Nobody would use this kind of lithium ion battery for grid storage. Instead use Lithium Iron Phosphate (LiFePo4) batteries- no cobalt needed. LiFePo4 batteries are absolutely good enough right now for grid storage.

jhallenworld··on Vintage Computing
I like the very early microcomputers where the storage is paper tape punch / reader. Your ASR-33 basically types in your program, or punches it on tape when you "list".

You can see some of these on "deramp"'s videos (he is selling Altair clones, but even so the videos are great demos).

https://www.youtube.com/watch?v=qv5b1Xowxdk

The next upgrade to this is something like the AC-30 for SWTPC. It does exactly the same thing, except uses cassette tape.

https://www.youtube.com/watch?v=gLvfUJd5PjQ

Then came disk drives, but no DOS. Instead they use disk the same way you used the cassette:

https://www.youtube.com/watch?v=rdCnj8iL1hI

It was up to you to remember which track your file was on..

Next step: file names, but no automatic space management:

https://www.youtube.com/watch?v=w4xmZwcM52w

You write files sequentially to the disk, and you can only write to the end. When you delete there are holes. You can run a defrag program to recover the space.

This stuff was all just before my time, but there were vestiges of it in later operating systems in the early 80s.

jhallenworld··on Shotcut is a free, open-source, cross-platform video editor
I've used it for youtube videos and some school projects for the kids. I'm happy that it's free. It did not have any crashes, but definitely I'm not a heavy user. I used it in Linux.

The user interface could be easier, for example deleting "ahs and ums" and silent time is a bit tedious. Also there are many output options, and it's confusing for a light user which to choose.

I've also used Lightworks, which is much nicer, but not free (except for 720p). Many of the non-free options want you on a subscription basis.

jhallenworld··on Ask HN: I miss Usenet. Are there any modern equivalents?
"GIANT FILE" == porn...

How many of us attempted to automate this process :-)

jhallenworld··on Ask HN: I miss Usenet. Are there any modern equivalents?
Reddit is in theory the same.. but it also is loaded with spam, in the form of ads paid to reddit. This is worse.

Compare: FPGA group on USENET, very little spam: https://groups.google.com/g/comp.arch.fpga

Reddit, full page animated old-spice ads: https://www.reddit.com/r/FPGA/

Also as much as you dislike google groups, just compare the UI of the above two.. ugh.. of course there is old reddit:

https://old.reddit.com/r/FPGA/

jhallenworld··on I’m nearly 60. Here’s what I’ve learned about growing old so far
This concept that old-people skills are obsolete is a completely modern phenomena, and I'm dubious that it's even true.

The pace of change is fast, but only because we are still dealing with the consequences of the scientific and industrial revolutions. I now think of all technologies past ~1800 as "modern". Basically you should learn all of it to some degree.

19th century machinist skills? Still useful and valid. The basic design of a lathe has not changed since the late 1700s.

COBOL from the 1970s? Nobody is going to throw away so much working code. The first generation of programmers is dying off only now, trust me this stuff is going to be around for a long time. Same deal with C / C++.

Oil burner heating from the 1940s? It's a convenient upgrade from the prior coal technology (much easier to pour oil than bunker coal). Most of the systems installed are still there and running. Diesel fuel / jet fuel / heating oil is still probably the most convenient to use energy source.

A slight change to how web technologies work? Really not a big deal..

AWS? Their servers are still basically IBM PCs.

jhallenworld··on The Atari Years (2014)
I remember at that time that the discounted Atari 800 was something like $400, then only a year and half later the discounted Atari 800 XL was $99. I was very happy to be able to afford these computers at the time, I didn't understand that this was the death knell.

I was annoyed at having to use a C64 for one of my first for pay projects, when the 800 XL was so much better as a development machine (yes the sound and graphics were better on the C64, but slow disk and lack of good OS ruined it for everything else). But they correctly deduced that the C64 would have more longevity so they chose it.

jhallenworld··on The Atari Years (2014)
>Apple’s big advantage in the early days was its color display, but this advantage was shattered with the appearance of the Atari computers, whose graphics far outshone that of the Apple.

I have a recent direct comparison between the two, Prince of Persia. The Atari port is recent:

Apple: https://www.youtube.com/watch?v=JZDAPp61aak

Atari: https://www.youtube.com/watch?v=aD2Z5FqZi7I

jhallenworld··on The last Howard Johnson's restaurant closes in Lake George, N.Y.
Here is a nice nostalgic video about them:

"Howard Johnson Restaurants - Life in America"

https://www.youtube.com/watch?v=EbNvT0vxrzM

jhallenworld··on I hate LaTeX, I love LaTeX
I found The Advanced TeXbook by David Salomon to be helpful. It shows how to make your own format on top of plain TeX, including table of contents, page numbering, cross-references and insertions.

I also found A Beginner's Book of TeX by Raymond Seroul and Silvio Levy helpful as a quick reference.

Also I have an anti-recommendation for Knuth's TeXBook. I did not find this book helpful at all- too much information buried in exercises (which I don't think is appropriate for a reference), and not enough directly said on how to do useful things. Figure out how to make a table of contents using only the TeXBook..

jhallenworld··on Modern programming languages require generics
I've written code just like this. Another option is to make the entire sort function a C macro. This would be feasible for something simple like quicksort.

But generics provide another benefit: in theory with them, the compiler should be able to determine that two high-level types are actually the same machine type, so in the above example, SORT_ELEMENT_TYPE int and long would not generate duplicate code on many machines.

jhallenworld··on A whole age of warfare sank with the Moskva
Also access to oil was a big deal. Hitler attacking the Soviet Union was at least partially to secure access to oil.
jhallenworld··on A whole age of warfare sank with the Moskva
They were impressive: a four tube electronic device that could survive being fired from a gun.
jhallenworld··on Restoring a $25k Convergent Technologies Miniframe CTIX Unix Computer [video]
Around 1990 we (students) inherited a bunch of these. I remember they were pretty slow for the time, and I think the compiler was K&R only...

The terminal was pretty nice, I mean the keyboard had a nice feel. I think it deviated from ANSI in some weird ways, it needed its own termcap entry... ah yes, pt1500 I think- 26 rows!

    pt|pt1500|gt|t0|Convergent Technologies PT:\
 :ae=\17:al=\E[1L:am:as=\16:bs:\
 :cd=\E[0J:ce=\E[0K:cl=\E[2J\E[1;1H:cm=\E[%i%2;%2H:co#80:\
 :dc=\E[1P:dl=\E[1M:do=\E[1B:ei=:ho=\E[1;1H:\
 :ic=\E[1@:im=:kb=\10:kd=\E[B:kl=\E[D:kr=\E[C:ku=\E[A:li#26:\
 :k0=\EOY:k1=\EOP:k2=\EOQ:k3=\EOR:k4=\EOS:\
 :k5=\EOT:k6=\EOU:k7=\EOV:k8=\EOW:k9=\EOX:\
 :nd=\E[C:se=\E[m:sf=\E[1S:sr=\E[1T:so=\E[7m:ue=\E[m:up=\E[A:us=\E[4m:
Here is one on eBay: https://www.ebay.com/itm/125308811771?hash=item1d2cfcb9fb:g:...
jhallenworld··on How to Multiply Roman Numerals
Use Claude Shannon's THROBAC-I

https://cacm.acm.org/blogs/blog-cacm/235492-calculating-with...

jhallenworld··on The Sound of Bells – The acoustics, sound, tuning and history of church bells
Here is my bell related science-fiction recommendation: Doomsday Book by Connie Willis.

"The drop had been scheduled for noon. If she had come through on time and Probability was right about the slippage, it would be six o'clock in the evening, which was too late for vespers. And if it were vespers, why did the bell go on tolling?

It could be tolling for mass, or for a funeral or a wedding. Bells had rung almost constantly in the Middle Ages—to warn of invasions or fires, to help a lost child find its way back to the village, even to ward off thunderstorms. It could be ringing for any reason at all."

jhallenworld··on Where are the low level system engineers?
I work at a product design firm here in the US, we're also organized like this. Engineers that can deliver end up getting more clients, so it does end up somewhat like a law firm (their hourly rates are still higher, which IMHO is crazy..).

We also make cameras, I've become the MIPI expert.

Our bread and butter includes mechanical design, PCB design and firmware / FPGA design. This maybe sounds like basic stuff, but includes things like RF and COMSOL / ANSYS physical and mechanical modeling and simulation.

A startup company in India hired us: they had plenty of software developers, but wanted experts to de-risk the hardware and low level firmware.

https://www.nklabs.com/

jhallenworld··on Mechanical Watch
Where are the comments in his code? :-)
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