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Undocumented DOS

Undocumented DOS by Andrew Schulman

by Andrew Schulman

Shares rank 71 of 115 programming books by recommenders

People recommend it as a deep reference on undocumented DOS internals, valued enough that readers call it a bible for months of work.

People recommend it as a deep reference on undocumented DOS internals, valued enough that readers call it a bible for months of work.

3 people gave an opinion

recommend it
3
criticize it
0
approval share
100%
Each figure is one person. RecommendsCriticizes

Recommended in 3 of 13 months

  1. November 2025: recommended
  2. December 2025: not recommended
  3. January 2026: not recommended
  4. February 2026: not recommended
  5. March 2026: not recommended
  6. April 2026: not recommended
  7. May 2026: not recommended
  8. June 2026: not recommended
  9. July 2026: not recommended
  10. August 2026: recommended
  11. September 2026: recommended
  12. October 2026: not recommended
  13. November 2026: not recommended (month in progress)

Why it doesn’t carry the badge

  • 3 people recommend itNeeds 10 or more, not met.
  • Nobody criticizes itNeeds 2 to 1 or better, met.
  • Recommended in 3 of 13 monthsNeeds 4 or more, not met.

The same three rules apply to every product, and the badge can’t be bought. How the badge works

What people say about it

The reasons people give, with the number of comments that give each one. Open a reason to read what they said.

Why people recommend it

Each mark is one comment

  • Deep reference for DOS internals

    “I remember the books on undocumented functionality like”

    Comment from 16 Nov 2025 in “Writing a DOS Clone in 2019”
  • Read as a core reference

    “they've been my bibles for the past several months”

    Comment from 14 Aug 2026 in “Donkey.bas is 45 Years Old – 131 line of Glory”
  • Treated as essential sacred text

    “have literally been my religious texts”

    Comment from 23 Sep 2026 in “Show HN: QBasic 1.1 in the Browser”

Other programming books people recommend

The four most recommended other programming books, with the same counts for each, so you can compare like for like. The tick on each bar marks the 2 to 1 line the badge needs.

Undocumented DOS by Andrew Schulman compared with 4 alternatives
ProductRecommendCriticizeApprovalMonthsOwnedBadge
Crafting Interpretersby Robert Nystrom60494%10—Approved
Clean Codeby Robert C. Martin318726%9——
The Pragmatic Programmerby Hunt and Thomas28197%7—Approved
How to Design Programsby Felleisen, Findler, Flatt and Krishnamurthi18290%7—Approved
Undocumented DOSby Andrew SchulmanThis page30100%3——
See all 115 programming books, ranked

What people said

3 of the 4 comments that mention it, newest first. Each links to the original comment.

“have literally been my religious texts”

RecommendsComment from 23 Sep 2026 in “Show HN: QBasic 1.1 in the Browser”

“they've been my bibles for the past several months”

RecommendsComment from 14 Aug 2026 in “Donkey.bas is 45 Years Old – 131 line of Glory”

“I remember the books on undocumented functionality like”

RecommendsComment from 16 Nov 2025 in “Writing a DOS Clone in 2019”

Counts come from 1,795,640 Hacker News comments, November 2025 to November 2026. How we count. Report a mistake.