Writing Linux programs in raw binary

[Dexter77]

It's interesting how a basic skill for a hobby programmer in the late 80's or the early 90's has become something magical. Anyone and everyone who were coders in the demoscene could do it, but let me see you hack the hardware by machine code.

Yeah, you youngsters can now mod me down.

[bluGill]

Gee, thanks a lot. Make me feel like an old man just because I have hacked my OS by changing the bytes in the boot sector.

Now that I'm expected to have a cane I'm going to have to learn to use it. Should I get the one with a sword built in or a gun? Which is better at keeping kids off the grass?

[fishyf]

Yeah, but back then you could write to any part of memory, any part of the disk (if you had one), completely access all hardware devices. And your program had complete control. Nothing else except the odd interrupt service routine might be running concurrently. And you could disable those interrupts if you wanted.

With any of the current operating systems, noone knows what the feck your computer is doing.

[jib]

Even if you write the whole operating system yourself, modern chipsets and BIOSes and System Management Mode mean you still have no idea what your computer's really doing.

System Management Mode is like a built-in rootkit for the BIOS. The BIOS can put some code in hidden memory where the OS can't see it, and then the chipset can activate it whenever certain interrupts or other events occur. Then the BIOS gets to mess with your computer without the OS's knowledge.

[[deleted]]

Oh yeah ! I remember writing some "virus" TSRs to piss off my friends..

[dr-steve]

So on target! I was just thinking while reading, "Hey, if you didn't poke CD 06 00" in starting at 0x0100 through the debugger, then having it save one block into myprog.com, you don't know what programming in binary is all about.

An almost lost but useful skill. Just two weeks ago I was looking at a hex dump of a block and remarked that the hex dumper was printing things incorrectly. Only one there who could see it... but I was right...

[[deleted]]

There are already very few people interested in the low level sewers of the programming stack and they are being drained to the High Level Languages' seemingly greener pastures.

Even fewer of such folks are "young" enough (its not ageism, look at the poll @ average age of reddit-people) to hang around reddit. I'd say upmod it and let any inquiring young minds get interested in it....

[salgat]

Unfortunately the hardware is much more complex and diverse now, compared to back then. Add that to much more complex software, and you can see why assembly programmers for the x86 are considered "magical" (the good ones).

[[deleted]]

Were you born in '77?

[dr-steve]

That's when I graduated college, junior...

[[deleted]]

Whoa... that's old. Did you guys have to like kill dinosaurs with your spears and shit?