Undocumented DOS
by Andrew Schulman, Ralf Brown, David Maxey, Raymond J. Michels, Jim Kyle · first published 1993
16mentions
7recommended by
14HN commenters
2017–2026first – last mentioned
50% recommend50% neutral
Why HN recommends it
Exposes the hidden complexity of DOS internals and interrupts. Teaches low-level techniques for assembly and INT 21h programming in the 1990s.
Summarised by Claude from recommending comments
Affiliate links. As an Amazon Associate I earn from qualifying purchases.
Mentions per year
What Hacker News says
Related books
2013–2026Undocumented Windows
Andrew Schulman, David Maxey, Matt Pietrek
Recommended by 3 · mentioned by 143 recommend · 14 mention3 recommend · 143 recommend
2007–2026The C Programming Language
Brian W. Kernighan, Dennis MacAlistair Ritchie
Recommended by 246 · mentioned by 501246 recommend · 501 mention246 recommend · 501246 recommend
…Cards (3rd Edition) - PC-Intern (where I learned how Central Point, Norton, and later FreeBSD made "GUI" with sub-character graphical pointers in text mode through custom fonts) - Undocumented PC - Undocumented DOS - PC Interrupts (and) Uninterrupted Interrupts (Ralf Brown) - Microsoft MS-DOS Programmer's Reference - The Programmer's PC Sourcebook: Reference Tables for IBM PCs and Compatibles, PS/2 Systems, EISA-based…
on “MS-DOS development resources” ↗…decent technical references... and I promptly dropped a few hundred bucks on dead tree carcasses when I was making minimum wage. Haha. X) - Programmer's PC Sourcebook - PC Intern - Undocumented PC - Undocumented DOS - Programmer's Guide to EGA, VGA ... - Michael Abrash books on assembly including self-modifying code and graphics programming - Turbo Assembler Quick Reference Guide - Code Complete Later, the MindShare…
on “Ask HN: What's the best resource for learning modern x64 assembly?” ↗…efficiency. It was originally a layer on top DOS which was written in assembly language. Being a "layer" or not was the subject of a very complex federal antitrust case back in the 90s. You can read "Undocumented DOS" and "Undocumented Windows" for some weird kind of technical investigation thriller which I found weirdly fascinating back in the day.
on “Unix: A History and a Memoir, by Brian Kernighan” ↗There was a pair of books that were instrumental to me: Undocumented PC and Undocumented DOS. Those books taught me so many tricks! I still remember the DWIM (Do what I mean) interrupt they used as the demonstration of how each interrupt was documented.
on “An Inside Look at MS-DOS – The design decisions behind the popular OS (1983)” ↗As documented in the excellent book "Undocumented DOS", whose red cover I can still picture. (Noted in the article, but it was a good book that I still recall fondly.)
on “How Microsoft faked errors in Windows 3 on top of DR DOS” ↗The last time I remember hearing about this was in the excellent book "Undocumented DOS": https://www.goodreads.com/book/show/603860.Undocumented_DOS I'd already done a little reverse engineering, writing a simple "undelete" utility for MS-DOS 3.3, etc, but that book opened my eyes to…
on “AARD Code, or how Bill Gates finished off the competition” ↗taking me back to creating fliphide, a utility I wrote in the early '90s. It utilized assembly and INT21, guided by "Undocumented DOS"—a book uncovering the OS's undocumented features. This resource was pivotal for crafting an executable (whether .exe or .com didn't matter) that manipulated file attributes, showcasing the power of accessing…
on “A 23-byte "hello, world" program assembled with DEBUG.EXE in MS-DOS” ↗…(including a Hayes compatible modem plugged into COM1) as well. I basically dug out a stack of my old PC books from the late ’80s and early ’90s, and they’ve been my bibles for the past several months (Undocumented DOS, The Programmer’s PC Sourcebook, etc.). It’s about 99% done at this point. I’m hoping to do a Show HN in the next couple of weeks.
on “Donkey.bas is 45 Years Old – 131 line of Glory” ↗…simulator (and corresponding virtual hardware layer) that runs entirely in the browser. I've got a stack of books on my desk from when I was a kid in the 90s that have literally been my religious texts (Undocumented DOS, The Programmer's PC Sourcebook, etc), so I know how hard it is to get this right. I've actually posted about it a couple times here in HN. Anyway small bit of feedback: Technically if you don't clear…
on “Show HN: QBasic 1.1 in the Browser” ↗…things, complete with instructions of the form "change byte at X to Y"; AFAIK they didn't violate any copyrights because they didn't distribute copyrighted material. Then there's the whole series of "undocumented DOS/Windows" books written by people like Matt Pietrek, Andrew Schulman, and Mark Russinovich; all of which required substantial amounts of reverse-engineering and analysis, but instead of them being persecuted,…
on “YouTube's ban on “hacking techniques” threatens to shut down infosec YouTube” ↗…could have become reactivated later by the change of a single byte in an installed system.” [1] [1] Schulman, Andrew; Brown, Ralf D.; Maxey, David; Michels, Raymond J.; Kyle, Jim (1994) [November 1993]. Undocumented DOS: A programmer's guide to reserved MS-DOS functions and data structures - expanded to include MS-DOS 6, Novell DOS and Windows 3.1 (2 ed.). Addison Wesley. ISBN 0-201-63287-X.
on “How Microsoft faked errors in Windows 3 on top of DR DOS” ↗…On the question of which to get rid of, the candidates fall into two groups. 1. Technologies that are pretty much dead now. It's very hard to imagine that I'm ever again going to need to crack open "Undocumented DOS" or "Inside AppleTalk", for example. 2. Technologies that are still in use, but my books cover older editions. For example, I have the second and third editions of Stroustrup's "The C++ Programming Language",…
on “Ask HN: What do you do with old technical books?” ↗…messages Reboot randomly Create unusual files And yet the antivirus can't find anything. :) BBS lists, Turbo Debugger and that giant purple & white Microsoft Press book with most of the Int 21h calls. Undocumented DOS, Undoc PC and Abrash's books were also helpful. Later, there were good free resources. Yeah, DOS viruses were bad: booting off an infected floppy, infected HD or running untrusted code was all it took.…
on “A dive into the world of MS-DOS viruses” ↗…hackerspace/makerspace in your area, and offer to donate some or all of you superfluous books to them, or their members. I think that's the kind of crowd where you might find somebody who actually wants a copy of Undocumented DOS or Inside AppleTalk. Another option might be to try selling them on Amazon.com.
on “Ask HN: What do you do with old technical books?” ↗To be fair my background is similar but the system isn’t really more opaque. I remember having the same books for the PC as (in this case my slightly older mentors) had for the C64. Undocumented PC and Undocumented DOS stand out. However you mentioned games , I too was distracted with such things (like the ABCs, alcohol, babes and cars). And had a nerd break until the web era. With maybe a little play around with VGA…
on “How DOS was able to use most of the 1 MB address space of the 8086” ↗