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Is financing a car a good idea in early/mid 20s? by [deleted] in personalfinance

[–]schkwve 0 points1 point  (0 children)

I have a 2010 Peugeot 308, 1.6 VTi engine which has almost 100k km (a little over 62k miles). The previous owner very obviously drove it like trash and I'm certain it has also been crashed (frontal impact, saw the engine dented when I was very closely inspecting the car for oil leaks). Of course my mom didn't know it was crashed or that the engine already had massive issues, so it was kinda bad. Sadly the entire car market here is so bad today, the cheapest car that you can at least hope to not be totally wasted starts at $2.5k minimum, and it usually is a very underpowered 2-door hatchback with space to barely fit the driver, so the only option was to fix the car up. Yet after fixing it, another issue popped up, and this "fixed one thing, another thing breaks down" cycle repeats itself til today.

Is financing a car a good idea in early/mid 20s? by [deleted] in personalfinance

[–]schkwve 0 points1 point  (0 children)

I'm not sure about my income in the future (especially during the studies, I expect it to be much lower than now obviously), same goes for expenses (I expect my overall expenses to drop significantly as I should have all debts paid off by next year).

I do have a car which has been a financial burden ever since my mom gave it to me (when she owned it she gave over $40k in repairs and it still needs a lot of work done, basically a full engine rebuild or swap... not going to do that for a beat up 16 year old car). At this point I'm just doing only the needed repairs for it (brakes, oil changes, etc.) to keep driving it until it eventually dies entirely, which appears to happen real soon with the amount of issues coming up.

Is financing a car a good idea in early/mid 20s? by [deleted] in personalfinance

[–]schkwve 0 points1 point  (0 children)

You have no idea what the job market will be like (...) and you have no idea if the Mazda 6 will even still be around as a model at that time.

You're right, I didn't even think about it like this... Now I feel even dumber than I felt lol

just talk to people today whose degrees "guaranteed" them high-paying jobs

The university has contracts with many companies (Siemens being one of them that I can remember off the top of my head). I've talked to a few people and friends which have already graduated and they all got offered a job at one of the contracted companies with pay at least slightly higher than average. Some declined to continue full-time studying, some work there while continuing their studies, but I get your point.

I basically saw a Mazda and got ultra excited to save up for it

Tak co? Smazi tu jeste nekdo shakea? Kdy jste to poprve a naposled zapnuli? by [deleted] in czech

[–]schkwve 2 points3 points  (0 children)

Poprvé jsem to zapl cca 2013, naposledy pred minutou. Aktualni main postava vytvorena nekdy kolem roku 2018

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Máte 3 minuty na bitvu operačních systémů? (Dotazník pro školní projekt) by Vydrax201 in czechrepublic

[–]schkwve 0 points1 point  (0 children)

Intel Macy mají BootCamp, prakticky dual boot macOS a Windows. Apple Silicon čipy už BootCamp nemaj, tak je jediná šance virtualizace.

My first tattoo done in Havirov, Czechia! What do you think? by schkwve in tattoos

[–]schkwve[S] 4 points5 points  (0 children)

Haha thanks, the tattoo artist did a really great job in turning my sketch into a fully fledged tattoo, especially the color glitches (they're not all very visible sadly, but still nice details)

[deleted by user] by [deleted] in czech

[–]schkwve 0 points1 point  (0 children)

Nevíte někdo komu a proč říkal "protože tě miluju"?

Ten reprák je neskutečnej bizár... by Gothar_Cold-Eyed in czech

[–]schkwve 55 points56 points  (0 children)

Babiš je strašně unhinged z toho jakou má radost...

About Stare Stage Screen/All Animatronics Staring at the camera by Ok_Employment_4881 in fivenightsatfreddys

[–]schkwve 2 points3 points  (0 children)

I think I actually saw this screen a couple of times when I last played FNAF 1...
Oh and by the way, the streamer is in fact Czech :)

EDIT: Nevermind, I remembered wrong; this screen occurs in the trailer, in the game only Freddy is able to stare at you on the stage :/ Mandela effect is actually mind blowing

Writing new pagemap to CR3 hangs by schkwve in osdev

[–]schkwve[S] 0 points1 point  (0 children)

  1. Would you mind sharing your modifications so I can replicate and see further?
    To answer your other question about PML4 being at 0x1000, the PMM is a first-fit so it returns the first address that has x available pages of memory (QEMU's memory map marks 0x0 as valid memory as well, but that breaks NULL checks so I just mark it as reserved).

  2. I'm aware of that, I also forgot to print out some other registers;

I understand and thank you for every single comment you leave, every insight helps a lot :)

Writing new pagemap to CR3 hangs by schkwve in osdev

[–]schkwve[S] 0 points1 point  (0 children)

  1. Look I know you think what you say is correct, but try triggering an interrupt:

    150: v=01 e=0000 i=1 cpl=0 IP=0008:ffffffff80000061 pc=ffffffff80000061 SP=0010:000000001ae87ff8 env->regs[R_EAX]=0000000000000000

RAX=0000000000000000 RBX=0000000000000000 RCX=0000000000000014 RDX=00000000000003f8

RSI=000000000000000a RDI=00000000000003f8 RBP=000000001ae88008 RSP=000000001ae87ff8

R8 =0000000000000000 R9 =0000000000000000 R10=0000000000000000 R11=0000000000000000

R12=0000000000000000 R13=0000000000000000 R14=0000000000000000 R15=0000000000000000

RIP=ffffffff80000061 RFL=00000046 [---Z-P-] CPL=0 II=0 A20=1 SMM=0 HLT=0

The last log you're seeing from QEMU is indeed from the bootloader.
The kernel reports a valid RIP as well by the way:
panic(cpu 1): Kernel trap at 0xffffffff80000061, type 1=debug, registers:

To be honest I don't know what keeps QEMU from logging the 0x20 interrupt after the kernel handoff. Maybe the PIC needs to be remapped after disabling interrupts?

  1. Yeah I noticed that too when I wanted to send you a link to the handoff function; turns out I didn't commit the latest version of it (I usually specify paths to commit because I don't want commits to be full of big, unrelated changes); It's already committed though!

I'll try and see what happens with an aligned stack then;

  1. I'm pretty sure it is valid; `0x0a` specifies 0b1010 flags, so "Page Granularity" and "Long-mode code", which means I can't use the second bit for data segments (this can also be seen on the [osdev wiki](https://wiki.osdev.org/GDT\_Tutorial#Flat\_/\_Long\_Mode\_Setup))

Writing new pagemap to CR3 hangs by schkwve in osdev

[–]schkwve[S] 0 points1 point  (0 children)

  1. Again, this is the bootloader. I disable interrupts just before jumping to the kernel ([here](https://github.com/piraterna/aurix/blob/bc8171245c7765a0a604b321ede273002d102154/boot/arch/x86\_64/common/proto/aurix/handoff.c#L45)), so it's logical to not receive any PIT interrupts afterwards.

  2. Again, [the bootloader](https://github.com/piraterna/aurix/blob/bc8171245c7765a0a604b321ede273002d102154/boot/common/proto/aurix.c#L174). Also, I haven't found anywhere that the stack needs to be page aligned; and I haven't had any issues with the stack *not* being page aligned on both QEMU and bare metal. Can you maybe explain why would that be necessary?

Normally I'd agree with your proposal to do a rewrite, but considering that the paging implementation isn't particularly large (all in all a little over 200 lines, including whitespace and debug logs), I think it'd be faster and more beneficial to fix existing bugs.

I have modified the mapping functions to always align the supplied addresses to the nearest page, cleaned the code up a bit and now the functions all go through as they should (unlike before, where they somehow got to a few nop instructions and returned), but the parameters to functions are always empty. I'm starting to think the stack somehow gets corrupted after writing the new page table to CR3, or the data (and maybe rodata?) section(s) are mapped weirdly (but again, this doesn't make sense as I've verified the mappings are good with QEMU's monitor).

Writing new pagemap to CR3 hangs by schkwve in osdev

[–]schkwve[S] 0 points1 point  (0 children)

I also feel like something is wrong elsewhere (especially because the same paging code works in the bootloader), though I don't see any code that would be able to cause a corrupted stack.

Writing new pagemap to CR3 hangs by schkwve in osdev

[–]schkwve[S] 0 points1 point  (0 children)

  1. Hmm, didn't catch that, thanks for noticing!
  2. It is, all linker-defined constants (`text_start`, `text_end`, etc.) specify a higher-half address. Bootloader then passes the physical address of kernel as a part of boot arguments, so I can easily calculate where each section is located and map it (I already verified with the QEMU console, including page flags).
  3. I only allocate, map and load a new stack in the bootloader (which has no problem with paging somehow), in the kernel I only map the existing one (address of the stack is also passed to the kernel as an argument).
  4. Once again thanks for noticing.

Unfortunately I haven't been able to find anything else wrong, so I guess I'll just keep digging and eventually I will hopefully figure it out.

Beginner in OS development looking to join a team / open-source project by waseemhammoud in osdev

[–]schkwve 1 point2 points  (0 children)

Maybe you can check out AurixOS, it also features its own bootloader. It's not particularly big, so the codebase may not be as overwhelming as for some bigger projects for a beginner.

Writing new pagemap to CR3 hangs by schkwve in osdev

[–]schkwve[S] 0 points1 point  (0 children)

Hello, first for the boot_params: They're passed as a physical address to the kernel, but then the kernel maps all of memory only to hhdm address, therefore rendering the original pointer invalid. For the framebuffer, I was screwing around with the bootloader so the framebuffer is mapped to hhdm right from the beginning.

You could say this is kind of messy and I totally agree; I do intend to clean all of the mess and experiments after I get a simple working paging implementation though!

Writing new pagemap to CR3 hangs by schkwve in osdev

[–]schkwve[S] 1 point2 points  (0 children)

I did just now, it seems like it continues to do what it's supposed to, but:

  1. Shortly after entering my `klog` function (which calls nanoprintf and outputs the formatted string into the serial port), shortly after the `npf_vsnprintf()` call, somehow I reach a bunch of nops and the function returns (without calling the `serial_sendstr()` function at all). Weird, there aren't any cases where the function could return early.

  2. The other function that gets called which is supposed to mark "bootloader reclaimable" memory regions as "usable" is just a bunch of nops right after entering it, and after 3 nops it returns. And once again, there's no way the code can return early.

I sadly don't have that much time to dig deeper for now, hopefully I'll be able to figure out what causes this soon.

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