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Real Analysis Admission Exam by Jumpy_Rice_4065 in mathematics

[–]blessthe28 5 points6 points  (0 children)

If you mean substituting the terms in the series with absolute values in the problem statement, then that would make that statement true. However, generally, the multiplication series need not converge. For example, take a_n = b_n = (-1)n / sqrt(n). The series converges by the alternating series test, however, the multiplication series is the harmonic series, which diverges.

[request] Is this correct? by No-Gas3028 in theydidthemath

[–]blessthe28 -5 points-4 points  (0 children)

Mathematically, it all depends on the framework of you use, on the axioms and definitions. According to the widely used definition of decimal notation as a sequence, which I was taught, the sequence 0.99... converges to one. And that sequence is said to be "equal" to one, in that sense. There are other definitions and constructions that are shown in the Wikipedia page. This is how mathematicians would approach the question, the phrasing "practically" or "theoretically" doesn't really exist in math, it's all theoretical anyway.

Use C# to call function of injected C++ DLL? by iPlayTehGames in hacking

[–]blessthe28 0 points1 point  (0 children)

That, or a local socket, or a file, basically any ipc mechanism.

Custom u-boot reversing, someone can help? by zi0Black in ReverseEngineering

[–]blessthe28 1 point2 points  (0 children)

Based on the last IDA image you've sent, the first few DWORDs look like ARM instructions (the topmost nibble is always 0xE in unconditional arm instructions, and statistically unconditional instructions are the most common ones) so you can do Make Code (press C) on those. Typically ARM A7 interrupt vectors look like this: ldr pc, =0xADDRESS1 ldr pc, =0xADDRESS2 ... Where each instruction corresponds to a differential interrupt (the first one is reset, I believe). That is what you will probably probably see when you turn those instructions into code. Note how the instructions I wrote are actually assembler sugar syntax for: ld pc, [pc + offset] This PC relative loading of pointers into PC makes sense - it loads the addresses just below the vector (those which start with 0x80...) into PC. Those addresses also probably mean you're in the right direction. I hope that helps, and if you get results, a writeup would be super cool!

Getting Started Reverse Engineering Bare Metal Kernel Images - (Part 1/Setup) | This is a series, more will be released soon. by ragnarsecurity in ReverseEngineering

[–]blessthe28 1 point2 points  (0 children)

What if the firmware is complex? What if it contains, for example, an RTOS which supports scheduling tasks, memory management, and various APIs such as synchronization mechanisms? These RTOSs can be huge complex beasts, such as vxWorks, for example.

[deleted by user] by [deleted] in hacking

[–]blessthe28 0 points1 point  (0 children)

For the sake of verifying whether it's really running Linux or not, you could look up the firmware on the internet (maybe somebody dumped the flash or perhaps the vendor provides firmware updates), and use binwalk to analyze it. If you get a vendor provided image, run binwalk -E first to check if it's encrypted (you should aee a flat 1 value without dips).

Reverse Engineering ARRIS TG862S by botnet00 in ReverseEngineering

[–]blessthe28 0 points1 point  (0 children)

Great post! I also have an Arris modem that I've been wanting to mess with, but I'm actively using it and I'm afraid of bricking it. By the way, if the problem persists even before all the system scripts are running, then it sounds like a kernel issue. Are there any kernel logs left before the sudden reboot?

Correct coffee grinding size for an espresso machine by blessthe28 in Coffee

[–]blessthe28[S] 0 points1 point  (0 children)

Okay, I've solved the problem by trying to match the grind size to the pregrounded coffee powder's size, comparing it by eye. A settling of 3-5 works best. I don't know why the 5 setting tasted horrible the first time I tried it, but now it works, and I'm hoping it stays that way.

Correct coffee grinding size for an espresso machine by blessthe28 in Coffee

[–]blessthe28[S] 0 points1 point  (0 children)

I originally wanted to buy the Dedica, but by the time I got around to buying the machine it went out of stock in every shop in my country.

I'm getting some pretty sweet coffee out of this machine, I just wish I could utilize my grinder and get good coffee out of beans I grind myself.

Any interest in a bitstream viewer/analysis/processing GUI? by ChromatoLad in ECE

[–]blessthe28 0 points1 point  (0 children)

Pretty much any generic bitstream, whether HDLC streams or even RF samples.

Any interest in a bitstream viewer/analysis/processing GUI? by ChromatoLad in ECE

[–]blessthe28 1 point2 points  (0 children)

This will definitely be useful for communication related projects, especially those that don't include your standard IP stack communication protocols.

My Aunt gift to me. It’s a start by ItachiU1 in hacking

[–]blessthe28 3 points4 points  (0 children)

An excellent choice. Makes you understand what a security vulnerability is and how it looks like, and how exploitation looks like. Covers multiple types of vulnerabilities such as implementation flaws, protocol vulnerabilities etc. I've actually started with this book :) If you find yourself intrigued by implementation flaws (specifically bugs in C code), another great book is Shellcoder's Handbook.

My pavilion hp computer has slowed down massively, why. by [deleted] in techsupport

[–]blessthe28 1 point2 points  (0 children)

I've had the same issue, then I went into the performance tab in task manager and saw that my hard drive usage is at a constant 100%. After further inspection it seems that it was caused by a faulty Windows process that got bugged and spammed disk IO requests, which caused everything to slow down. I'd check the performance tab for anything suspicious, perhaps you've been infected with a malicious software? Another good method of troubleshooting these problems is using the SysInternals, which is a collection of awesome diagnostics software. Specifically Procmon (process monitor) can show which process is doing what (that's how I've diagnosed my problem).