hckrnws

Long ago, before access to the Internet was cheap and plentiful, and way before search engines made finding this kind of information easy, this was a priceless find for an aspiring low-level programmer. All the (semi-)common PC hardware and software documented in one place.

Endless hours spent exploring VGA hardware registers and trying to apply them for cool visual effects. Learning how the then-new 32-bit Windows interacted with DOS extenders, and trying to make a homemade - very basic - operating system that could do it, too. The thrill of writing a Terminate and Stay Resident alarm clock, and having it finally not explode...

I have very fond memories of the Ralf Brown's Interrupt List.

Absolutely. Title says 2018 but it really comes from the dawn of pc. DOS was at 21h, and now linux system calls in x86 are INT 80h.

Linux system calls WERE 80h. If your code is still using an interrupt to access kernel functions then you've got problems. Syscall exists for the simple reason that interrupts are expensive.

What do you mean by that? Most syscalls are still interrupt based.

x86-64 introduced a `syscall` instruction to allow syscalls with a lower overhead than going through interrupts. I don't know any reason to prefer `int 80h` over `syscall` when the latter is available. For documentation, see for example https://www.felixcloutier.com/x86/syscall

Int 80h still works as well as ever on i386.

I recently found out about swi 0x123456 on ARM...

many of the int 21h interrupts were virus install checks, telling for the future direction of microsoft?

When I came upon this list, and I don't remember how, I went from the The 97 Pound Weakling to a perfectly developed hacker. Seriously, it was a game changer and launched me into a game of catchup on the PC (I was a Apple II and C64 guy). I had so much fun at work with hacks but also making cool utilities.

Are there any interviews with Ralph Brown around?

It doesn't help that he's not the only RB.

There was unloved informatics in school and loved informatics at home. Unloved informatics consisted of graph flow optimizations. Loved informatics consisted of EGA programming and IRQ interrupt handling for multiple keypress detection and other stuff. Both informatics were in Turbo Pascal, but in sport olympiads going to interrupts or assembler was prohibited. Not that it was going to help, but… when olympiads end, I was going those doors again, and others did not. For others my loved informatics was door remaining shut.

20 years later it is an excercize to find a device where loved EGA programming tricks work. Only unloved informatics remained

86Box is what you want for this kind of nostalgic programming, comrade.

Our teachers didn't know much about this stuff in school. The origin of my username here (and elsewhere) is from those classes at school; I once submitted an assignment that, under certain conditions, used inline asm in Turbo Pascal to do "INT 19h". Had to explain it later, but thankfully that particular teacher was more amused than offended.

For those way to young to even know what this is, it's basically like MDN web documentation but for the DOS era. It was a community-maintained API reference for IBM PC hardware, DOS operating system, and other software.

I too have spent hours of assembly code on PC hardware. My freshly downloaded copy of the interrupt list has always been at my (virtual) side when designing tests or libraries.

I think that has been one of the very first and largest information collection shared for free on the internet.

Kudos to Ralf Brown and whoever participated in keeping the list compete, accurate and timely.

This was, and for some purposes still is, one of the most useful documentation sets for the PC architecture. It's worth noting that Ralf himself isn't a specialist low-level programmer, as this came from an era when there was a far smaller divide between users, power users, and developers.

Oh the memories :) I still have somewhere a dot-matrix printed copy of the list I used religiously in the 90's

I remember looking at a print out of some of it in the late 80's and learning about the "list of lists", the critical section flag, and the alternate stack.

HTML version if you're just curious about what it looks like (all the links on the linked site seem to be zip files).

https://www.ctyme.com/rbrown.htm

This was invaluable when I was tasked with writing a stay-resident boot loader just after the turn of the century. Even then, such information was considered arcane and Ralf Browns Interrupt List was much better than any official documentation I could find.

Many hours spent reading this even if I was quite late to the party.

how much of this info has been subsumed by standardized uefi?

presumably nothing because its about old devices which dont have UEFI. that being said, i suppose you mean BIOS interrupts are silly and you dont really want to know about them these days. that's true. (theres more than bios stuff in this list tho).

for ppl looking to discover BIOS interrupts and their meanings in this list, follow the breadcrumb given and go and checkout EDK2.

Was my bible at some point. Thanks for memories