Do all the things like ++ or -- rants, post your own rants, comment on others' rants and build your customized dev avatarSign Up
Get a devDuck
Rubber duck debugging has never been so cute! Get your favorite coding language devDuckBuy Now
Search - "control ram"
There is. My latest creation. A 8bit microcontroler made in minecraft.
(1.0 version without control room)
-8bit full adder + overflow flag
-16x8(4bit instruction, 4bit address)
-64 possible microinstructions (16 instructions with 4 step each)
-uncondintional and if oveflow jumps
(place determined using address written with instruction)
-1/3Hz clock speed 😨
New working version (2.0) has 1Hz clock and new faster instruction decoder.
In 3.0 in addition to that useless bus was replaced with 16x8bit "hardware" stack that can store adresses and data. The clock is going to be yeeted out because it is unnecesary #clocklessisbetter (WIP tho)
Might add more documentation and post it as learning model for CS wanabees 🤔. What do you think?
Picture: Old working version 1.0
(the only one with fancy diagram)
Newer version screenshots in comments.37
I'm getting ridiculously pissed off at Intel's Management Engine (etc.), yet again. I'm learning new terrifying things it does, and about more exploits. Anything this nefarious and overreaching and untouchable is evil by its very nature.
(tl;dr at the bottom.)
I also learned that -- as I suspected -- AMD has their own version of the bloody thing. Apparently theirs is a bit less scary than Intel's since you can ostensibly disable it, but i don't believe that because spy agencies exist and people are power-hungry and corrupt as hell when they get it.
For those who don't know what the IME is, it's hardware godmode. It's a black box running obfuscated code on a coprocessor that's built into Intel cpus (all Intell cpus from 2008 on). It runs code continuously, even when the system is in S3 mode or powered off. As long as the psu is supplying current, it's running. It has its own mac and IP address, transmits out-of-band (so the OS can't see its traffic), some chips can even communicate via 3g, and it can accept remote commands, too. It has complete and unfettered access to everything, completely invisible to the OS. It can turn your computer on or off, use all hardware, access and change all data in ram and storage, etc. And all of this is completely transparent: when the IME interrupts, the cpu stores its state, pauses, runs the SMM (system management mode) code, restores the state, and resumes normal operation. Its memory always returns 0xff when read by the os, and all writes fail. So everything about it is completely hidden from the OS, though the OS can trigger the IME/SMM to run various functions through interrupts, too. But this system is also required for the CPU to even function, so killing it bricks your CPU. Which, ofc, you can do via exploits. Or install ring-2 keyloggers. or do fucking anything else you want to.
tl;dr IME is a hardware godmode, and if someone compromises this (and there have been many exploits), their code runs at ring-2 permissions (above kernel (0), above hypervisor (-1)). They can do anything and everything on/to your system, completely invisibly, and can even install persistent malware that lives inside your bloody cpu. And guess who has keys for this? Go on, guess. you're probably right. Are they completely trustworthy? No? You're probably right again.
There is absolutely no reason for this sort of thing to exist, and its existence can only makes things worse. It enables spying of literally all kinds, it enables cpu-resident malware, bricking your physical cpu, reading/modifying anything anywhere, taking control of your hardware, etc. Literal godmode. and some of it cannot be patched, meaning more than a few exploits require replacing your cpu to protect against.
And why does this exist?
Ostensibly to allow sysadmins to remote-manage fleets of computers, which it does. But it allows fucking everything else, too. and keys to it exist. and people are absolutely not trustworthy. especially those in power -- who are most likely to have access to said keys.
The only reason this exists is because fucking power-hungry doucherockets exist.27
- If I buy x amount of ram | hard drive space | cpu power I will never need more.
- No need for version control | Tests. This is a small project
- git commit -m "changes" (its a small change. I will remember why I did it)
- It is too obvious that I put a lot of personal time in this so my boss will definitely notice!
- Why comment this simple method? Anyone should know what it does. Especially me!
- "this should never happen"
- This call can't be from work. Everyone knows I am on vacation.
- I will back up next week. It's not like it is going to crush today.
- It’s 11:30 already? I will work on this for only a half hour more and then I will definitely go to bed!
- This project will take x amount of time!2
I love Linux, but its community can be so full of incompetent assholes..
Just now I asked in Freenode ##linux how to get the process ID of my current running process in bash. I got my answer - it's a shell built-in called "$$".
Then people start to nitpick some more - why do you need it? How is that different from an exit? - to which my response was.. well I know the whole idea behind exit codes, and I'd use it whenever possible, in all defined behavior that allows my program to terminate itself whenever it can. This pidfile however would be used to exit itself and provide diagnostic information whenever the program enters undefined behavior - a segfault in C language. Scenarios in which I don't have full control over the script's behavior anymore, such as the system entering an unworkable state where the system stalled, still got some binaries in RAM but the rootfs got unwritable, such as now - very helpfully, thanks HP! - when my laptop likely overheated and shat itself. I issued sudo reboot into it, but even that wouldn't issue properly anymore due to the /sbin/poweroff binary becoming inaccessible too. I had to issue a hard power cycle.. one of the few times in which I'm thankful to HP for actually causing shit like this, lol.
Point is, that undefined behavior is what I'm trying to mitigate against. I certainly can't let any files other than diagnostics remain in nonvolatile storage like that, especially when their state should be predictable in order to ensure good operation (like files expressing whether the script is already running or not, i.e. lock files).
Back to that IRC chat. Aside from the answer, I got ridicule from people who probably don't even know how to properly compile a kernel. Ubuntu users, overconfident scum. Sometimes I feel like I should ask questions in channels like #archlinux only, where such incompetency is ridiculed on its own.13
I'm only two step far from having an intelligent house, just missing finish my own domotic system and then a bot to control, music, TV, and electricity.
Let's do the list:
1.- Kodi on TV ✔
2.- MPD on a hidden PC inside my old grandpa's stereo ✔
3.- a small data server to provide music, movies and series to Kodi and mpd ✔
(This is something that im trying to do with spare PC's running Linux on my free time)
MPD on a PIII (500mhz + 512mb RAM)
Kodi on a dual core (2.80ghz +3gb RAM)
Server on a opteron (1.80ghz + 1.5gb RAM)4
Went back to KDE over the weekend from i3wm. I was getting tired of having to configure my setup manually everytime I wanted to change a setting, and having things break, and having to bug fix said breaks, while also trying to handle Java MVC and node.js dev work.
Nope. Too much. I want the macOS experience but with the control of Linux. Much happier with KDE. It does use about 720MB more RAM on an average session but when you have 8GB does it really matter?
Now to figure out how to get Firefox to play nice with Plasma, or give Konqueror a spin.15
Wtf bs is this? Can't governments just stop trying to control the internet?
It's literally the closest thing we have to a free and fair society on the planet and that's with all the tracking and abuse of information going on. I think we need to start applying our minds to creating a decentralised network with p2p discovery routed through our phones if we want to keep any semblance of freedom of speech or privacy around for our kids. Routing traffic wouldnt use more than 50-100mb of ram and would probably use a lot less battery than Google does listening to our conversations or transmiting our location data so we wouldn't even notice. If only we could find a cable free decentalized way to get data across the ocean no one would be able to control it again, I doubt we would be able to shut it down either.10
How control the RAM when working by Androidstudio and chrome?!
Well, just tell the magic spell
Can anyone help me with this theory about microprocessor, cpu and computers in general?
( I used to love programming when during school days when it was just basic searching/sorting and oop. Even in college , when it advanced to language details , compilers and data structures, i was fine. But subjects like coa and microprocessors, which kind of explains the working of hardware behind the brain that is a computer is so difficult to understand for me 😭😭😭)
How a computer works? All i knew was that when a bulb gets connected to a battery via wires, some metal inside it starts glowing and we see light. No magics involved till now.
Then came the von Neumann architecture which says a computer consists of 4 things : i/o devices, system bus ,memory and cpu. I/0 and memory interact with system bus, which is controlled by cpu . Thus cpu controls everything and that's how computer works.
Let's take an easy example of calc. i pressed 1+2= on keyboard, it showed me '1+2=' and then '3'. How the hell that hapenned ?
Then some video told me this : every key in your keyboard is connected to a multiplexer which gives a special "code" to the processer regarding the key press.
The "control unit" of cpu commands the ram to store every character until '=' is pressed (which is a kind of interrupt telling the cpu to start processing) . RAM is simply a bunch of storage circuits (which can store some 1s) along with another bunch of circuits which can retrieve these data.
Up till now, the control unit knows that memory has (for eg):
Value 1 stored as 0001 at some address 34A
Value + stored as 11001101 at some address 34B
Value 2 stored as 0010 at some Address 23B
On recieving code for '=' press, the "control unit" commands the "alu" unit of cpu to fectch data from memory , understand it and calculate the result(i e the "fetch, decode and execute" cycle)
Alu fetches the "codes" from the memory, which translates to ADD 34A,23B i.e add the data stored at addresses 34a , 23b. The alu retrieves values present at given addresses, passes them through its adder circuit and puts the result at some new address 21H.
The control unit then fetches this result from new address and via, system busses, sends this new value to display's memory loaded at some memory port 4044.
The display picks it up and instantly shows it.
1. Is this all correct? Does this only happens?
2. Please expand this more.
How is this system bus, alu, cpu , working?
What are the registers, accumulators , flip flops in the memory?
What are the machine cycles?
What are instructions cycles , opcodes, instruction codes ?
Where does assembly language comes in?
How does cpu manipulates memory?
This data bus , control bus, what are they?
I have come across so many weird words i dont understand dma, interrupts , memory mapped i/o devices, etc. Somebody please explain.
Ps : am learning about the fucking 8085 microprocessor in class and i can't even relate to basic computer architecture. I had flunked the coa paper which i now realise why, coz its so confusing. :'''(14
Need some help choosing a laptop (budget is up to 2000 EUR)
Initially 6 months ago I bought Dell G5 (5587) for 1300 EUR and it had i7 8750H CPU, 6GB NVDIA GeForce GTX 1060 Max-Q GPU, 16GB RAM, 256GB SSD+1TB HDD.
However turned out to be a piece of shit because dell fucked up their thermal management badly and they don't give proper access for their users to control the fans. Even when you force fan control via Windows test build then you will face a dissapointment since most games won't run properly on Windows test mode. So anyways I got rid of that laptop. For more info you can have a look here https://dell.com/community/... and there are dozens of topics on reddit about that.
So yeah currently looking for a decent gaming/movies/coding laptop which gives full access to undervolting/fan control.
Currently I'm looking into Razer Blade 152
nano or IDLE, depending on need.
nano is the best terminal text editor by far, as i don't wanna have to learn a new command line and 2 control modes just to type in ffffffffffucking vim and it's just powerful enough to do what is needed without extra crap on top.
IDLE is super-light-weight, has a somewhat-handy debugger if i need to see what's up when my code interacts with modules or some such, takes up very little RAM and is open-source. Works exactly as needed and no more.
TL;DR: Embedded software guy needs to create a multi-instance sandbox environment in Jenkins for testing and not sure what good solutions are out there. Looking for suggestions.
So at work, we have these really cool integration tests that validate our system for flight safety. What's not so cool is that due to factors outside of my control, each test has to be run serially and the entire test suite can take many many hours. This is mostly due to a hardware limitation (not enough physical NICs), but there are other SW factors as well.
What I would like to do is somehow be able to wrap up all the resources into a neat little package and then deploy that package into some kind of virtual environment that can be instantiated on a Jenkins job. The NIC issue would be replaced with a virtual one and *theoretically* I should be able to spawn as many instances of this virtual environment as my CPU and RAM can handle. In short, I want to pseudo parallelize our test suite and drive down our testing time. Somehow I would need to be able to control this entire thing from a script of some sort.
Does anyone know of something out there that would satisfy these kinds of requirements? Double internet points if it's open source.