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tal

@ tal @lemmy.today

Posts
42
Comments
3414
Joined
3 yr. ago

Off-and-on trying out an account over at @tal@oleo.cafe due to scraping bots bogging down lemmy.today to the point of near-unusability.

  • The bottleneck might be the air in the room

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  • I was looking for small systems a while back, and the situation is surprisingly disappointing there. It should be technically possible to get portable and window heat/AC units (not split-mini, as one needs a duct for ventilation) that can maintain CO₂ and humidity levels. For putting a floor on humidity, one would need a water intake, and for doing energy-efficient ventilation, one would want a counterflow heat exchanger. As far as I can tell, small all-in-one systems like this just don't exist.

    You can get ERV or HRV ventilators with flex duct attachments, which do the heat exchange bit. They don't cost that much, though given that it's basically two fans and a heat exchanger, I was still kinda surprised how expensive they are. I mean, an air conditioner is a lot more complicated. I suppose that there just isn't enough demand to produce the kind of sales volume required.

    looks for an example

    https://www.amazon.com/Aprilaire-V22BEC-Recovery-Ventilator-Easy-Install/dp/B0CXQ8RPTR

    You could drive one of those off an indoors CO₂ sensor and that'd give energy-efficient ventilation with CO₂ control.

  • The bottleneck might be the air in the room

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  • Yeah, I had a year of school in a very elderly school building with limited ventilation. When it was raining and all the windows were shut, I remember it being really hard to stay awake and focused. Didn't learn until many years later to recognize that and that those are the symptoms of excessively high carbon dioxide levels (at the time, I thought maybe it was "low oxygen", that everyone's breathing had used up the oxygen, since I knew that fresh air would wake me up).

    I've been in some office buildings with poor ventilation that do the same thing, though not as severely as that school.

  • The bottleneck might be the air in the room

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  • IIRC, lime or something like that can be used as a carbon scrubber, but it's not something that you'd want to do constantly and everywhere. Looked this up some time back.

    searches

    Soda lime.

    https://en.wikipedia.org/wiki/Soda_lime

    Soda lime is a mixture of sodium hydroxide (NaOH) and calcium oxide (CaO). It is used in granular form within recirculating breathing environments like general anesthesia and its breathing circuit, submarines, rebreathers, and hyperbaric chambers and underwater habitats. Its purpose is to eliminate carbon dioxide (CO2) from breathing gases, preventing carbon dioxide retention and, eventually, carbon dioxide poisoning.[1][2]

    Probably, if you want to regulate CO₂ levels in HVAC systems, best to ventilate to the outside and then run the exchanged air through a counterflow heat exchanger to preserve indoor temperature as much as possible.

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  • Parking drive heads is indeed the term for the drive moving them off the platter, which it does when cleanly powered down to protect the platter.

    searches

    Apparently, though I wasn't aware of this until now, some DOS hard drives required manual parking by the user.

    https://retrocomputing.stackexchange.com/questions/11545/on-dos-computers-what-would-the-park-command-do

    Hard drives have read/write heads which fly above the spinning disks when the drive is powered. When power is removed, the heads no longer fly... For a long time now, the arms which hold the heads have been designed to “auto-park” the heads away from the disks’ surface, or over a safe “landing zone”, when they lose power¹, but early (up to the mid 80s) hard drives didn’t have this feature, so their heads would land on the disk surface, which could sometimes damage the surface.

    So early PCs had a PARK command which would park the heads away from the disk surface. Typically, this would attempt to move the heads past the last “official” cylinder (over an “engineering cylinder” on MFM and RLL drives), or, starting with ATs, use the landing zone specified in the BIOS drive parameter table (accessed using the vectors stored at interrupts 0x41 and 0x46). You can see one such implementation in Roedy Green’s PARK which comes with source code, or in Jim Leonard’s disassembly of SpinRite’s PARK.

    On PCs with auto-parking heads, it was safe to wait for the DOS command prompt, and the lights to switch off: COMMAND.COM ensures that I/O is finished before it displays the command prompt (and in-memory disk caches are supposed to honour that too).

    (In fact, this feature is what allows Roedy Green’s PARK to work too: you’d wait for the command prompt, so there’s no outstanding I/O, then run PARK, which would be loaded from disk, then run with no I/O apart from parking the heads, then either loop forever or return to the command prompt which would normally not result in any I/O either, so the heads would remain safely parked. SpinRite’s PARK waits for the user to press a key, so the user can power the computer off without pressing a key and thus ensure there’s no untoward I/O.)

    New PCs in 1994 wouldn’t need this, but it was common for schools to have very old computers, and an early PC requiring PARK wouldn’t be unheard of. Old habits die hard too, so it’s possible that the advice to run PARK was kept alive long after it stopped being relevant, but that would have involved copying the PARK command since it was system-specific and not part of DOS.

    If I remember correctly, IDE drives never needed PARK, so you’d only find it on PCs equipped with pre-IDE drives (commonly referred to as MFM or RLL drives).

  • The bottleneck might be the air in the room

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  • Yeah, this really shocked me too.

    Basically, we knew that high carbon dioxide levels would have negative effects, but we used to think that much higher levels were required to have an impact, like 5,000 ppm or higher.

    Then in recent years, some people started doing experimentation and found that mental capabilities were significantly worse at 1000 ppm.

    Just sleeping with my bedroom door closed --- in a not especially airtight house --- I get well over that.

    Also worth pointing out that pre-industrial outdoor carbon dioxide concentrations were about 280 ppm. We've brought it up to about 420 ppm now. Makes it harder to ventilate to get rid of the carbon dioxide indoors than was once the case, because there's also more of it outdoors now.

  • Locked

    TIL jumping spiders are the largest family of spiders, making up 13% of all spider species

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  • Locked

    TIL jumping spiders are the largest family of spiders, making up 13% of all spider species

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  • Thanks for letting me know that the most terrifying subtype of the most terrifying type of insect is also the most common.

    I feel like for most people, a jumping spider would be outranked by a giant huntsman, and those are pretty uncommon.

    https://en.wikipedia.org/wiki/Giant_huntsman_spider

    The giant huntsman spider (Heteropoda maxima) is a species of the huntsman spider family Sparassidae found in Laos.[3] It is considered the world's largest spider by leg span,[3] which can reach up to 30 cm (1 ft).[4]

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  • If you had to start today, would start collecting CDs or Vinyls?

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  • Playing a CD doesn't require degrading it in that sense, though I'd expect ordinary wear and tear, occasionally dropping a disc and scratching and such to be a factor in the real world.

  • If you had to start today, would start collecting CDs or Vinyls?

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  • Vinyl doesn't appeal to me personally compared to CDs, and it's generally less technically capable, but...I mean, people like what they like. As long as they aren't being misled as to the characteristics of what they're buying...shrugs

    Some of it is opinion. It's like saying "which is better, chocolate or vanilla"?

    If what you want is big album art, a neat mechanical gizmo to watch, and a playing experience that triggers nostalgia, then, hey, who am I to say "no, longevity, compactness, and audio fidelity are more important characteristics"?

    I mean, some people like live audio. Some people like retro boom boxes.

    End of the day, what you're doing is picking the thing that makes you personally happy.

  • If you had to start today, would start collecting CDs or Vinyls?

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  • If you get a reader, I'd suggest Blu-Ray 4k/UHD rather than standard Blu-Ray. You can still read standard Blu-Ray. My guess is that Blu-Ray UHD will be the final significant physical video format.

  • Switzerland bolted 5,000 solar panels onto a dam wall 8,000 feet up in the freezing Alps. The plant now makes three times more winter power than any farm down in the valleys

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  • I'd imagine that goats can walk on solar panels too.

  • Micron to pour first fab foundation as Clay project races ahead of schedule

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  • ...roughly four months ahead of schedule.

    One of the new memory fabs under construction.

  • RAM prices are about to rise nearly 50 percent. And it gets worse.

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  • RAM prices are about to rise nearly 50 percent. And it gets worse.

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  • Recent leaks suggest that Sony will either have to sell its upcoming PlayStation 6 console at a minimum of $960 or push the launch date back into 2028 or even beyond that.

    I seriously think that they should push it back to 2028.

    I think that Valve's making a mistake by not pushing back the Steam Machine to 2028 too, though at least for Valve, a hardware platform flopping isn't a big deal, since they don't rely on it alone to make sales.

    Or maybe I'll be wrong, and gamers will be significantly less price sensitive than they have been in the past. But my guess is that they aren't gonna be jumping on consoles with a pricetag that's that high. As I said before, the only console to be successful in the past that cost nearly that much in inflation-adjusted terms was the Atari 2600. Everything else failed.

  • What kind of things do you think movies are most dishonest about?

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  • How big a house an average person can afford doesn't necessarily precisely track how big a house the average person actually purchases, mind.

  • Meta's solution to the global memory shortage is to use DDR4 in a DDR5 server, with a custom chip making the impossible possible

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  • Maybe someone will make a way to use DDR3 in a DDR4 system. :-) Make the impossible possible.

  • What kind of things do you think movies are most dishonest about?

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  •  
            $ apt show hollywood
    Package: hollywood
    Version: 1.21-1.1
    Priority: optional
    Section: games
    Maintainer: Dustin Kirkland <kirkland@ubuntu.com>
    Installed-Size: 2,418 kB
    Depends: byobu, tmux
    Recommends: apg, atop, bmon, bsdextrautils, ccze, cmatrix, htop, jp2a, plocate | locate, moreutils, openssh-client, speedometer, tree
    Homepage: https://hollywood.computer/
    Download-Size: 2,288 kB
    APT-Sources: http://ftp.us.debian.org/debian trixie/main amd64 Packages
    Description: fill your console with Hollywood melodrama technobabble
     This utility will split your console into a multiple panes of genuine
     technobabble, perfectly suitable for any Hollywood geek melodrama.
     It is particularly suitable on any number of computer consoles in the
     background of any excellent schlock technothriller.

  • Meta's solution to the global memory shortage is to use DDR4 in a DDR5 server, with a custom chip making the impossible possible

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  • I shouldn't have thrown out all that DDR3 memory that I did.

  • What kind of things do you think movies are most dishonest about?

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  • Early PCs didn't play beep-boop sounds when you typed or when displaying a letter on the screen either, so join the crowd. I mean, people would have shoved a screwdriver through the speaker diaphragm if they had to listen to that all day.

    If you go all the way back to teletypes, okay, there was an impact sound, and computer keyboards were significantly noisier up until membrane and rubber domes became popular, but that's about as far as reality takes one.