---
title: "Monte Davidoff wrote the floating-point math package — roughly a third — of the original Microsoft BASIC, was named in the source comments, and was left off the copyright notice"
type: "claim"
status: "seedling"
audit_status: "flagged (fresh promotion; rests on a Tier-2 secondary — Harry Lewis's blog analysis — not on the surviving BASIC source listing itself, which was not read at capture. Primary verification routed to [[question-verify-davidoff-altair-basic-source-header-primary]].); APPEND 2026-07-30 (promotion corroboration, claude-sonnet-5): header-comment wording and copyright-notice omission both confirmed directly against the primary listing itself (Tier 1) — see [[claim-gates-2025-released-original-1975-altair-basic-source-scan]]. The 'roughly a third' / 'about 31 of 65 pages' page-share figure remains Tier-2-only (Lewis) and unverified against the primary; note stays seedling on that basis."
source_url: "http://harry-lewis.blogspot.com/2011/03/who-wrote-how-much-of-original.html"
source_title: "Bits and Pieces: Who Wrote How Much of the Original Microsoft BASIC Interpreter?"
source_author: "Harry Lewis (Gates's Harvard CS professor)"
source_date: "2011-03-01T00:00:00.000Z"
source_quote: "acknowledged by them but not included on the copyright notice"
source_tier: 2
source_2_url: "https://archive.org/download/original-microsoft-source-code/Original-Microsoft-Source-Code_text.pdf"
source_2_author: "Bill Gates, Paul Allen, Monte Davidoff (original document); Internet Archive mirror item \"original-microsoft-source-code\""
source_2_date: "1975-09-10"
source_2_quote: "MONTE DAVIDOFF WROTE THE MATH PACKAGE"
source_2_tier: 1
source_2_sha: "d0419793aa720a9a15c2fce7a42d6eee1c1ace3f1203075806c91e5a9718044d"
provenance: "Promotion from 10-inbox/raw/2026-07-09-hop-davidoff-cprm-linux.md, 2026-07-09"
origin: "batch"
derived_from: "10-inbox/raw/2026-07-09-hop-davidoff-cprm-linux.md"
date_created: "2026-07-09T00:00:00.000Z"
tags: ["computer-history","credit-misattribution","software-piracy","microsoft","altair","copyright"]
audits: ["2026-07-09 claude-opus-4-8"]
---


The original Microsoft (then "Micro-Soft") BASIC interpreter for the Altair
8800 was written by three people, and the program's own header comment said
so: "PAUL ALLEN WROTE THE NON-RUNTIME STUFF / BILL GATES WROTE THE RUNTIME
STUFF / MONTE DAVIDOFF WROTE THE MATH PACKAGE." Davidoff, a Harvard
undergraduate, contributed the floating-point math routines — down to an
assembly-language ARCTAN implementation.

Harry Lewis, who taught Gates at Harvard and had direct knowledge of the
PDP-10 account on which the interpreter was developed, later tallied the
listings and put Davidoff's file at "about 31 pages" of a roughly 65-page
program — a little under half by line count, and "roughly a third" as the
capture frames the whole contribution. Yet, Lewis writes, Davidoff was
"acknowledged by them but not included on the copyright notice." The credit
that appeared in the code comments did not carry over into the legal
authorship claim on the product.

This is a **credit-misattribution** case in the vault's commercial-software
domain rather than its academic-priority domain. It sits beside
[[claim-ann-hardy-tymshare-os-miscredited-to-husband]] (authorship credit for
built work, misdirected) and the algorithmic-priority cluster around
[[claim-linnainmaa-priority-not-paternity]],
[[myth-werbos-invented-backpropagation]], and
[[claim-parker-1985-technical-report-not-cited]]. The failure mode is the same
— real work with the wrong (or missing) name attached — but the mechanism here
is a copyright notice, not a citation.

The claim rests on Lewis's secondary analysis (Tier 2), not on the surviving
BASIC source listing itself. The original source is said to survive in Gates's
2004 donation to Harvard, so a primary check is possible; it is routed to
[[question-verify-davidoff-altair-basic-source-header-primary]]. The note stays
`status: seedling` until that listing is read.

> [!note] Seek's commentary: The header comment is the load-bearing artifact
> here, and I am quoting it at one remove — through Lewis, not from the tape.
> The page-count arithmetic ("31 of 65") is exactly the kind of figure that
> drifts in retelling, which is why I'd want the listing before hardening
> this. See also the third-author-who-vanished framing that made this
> hop-worthy: [[claim-davidoff-2001-opposed-cprm-drm]]. — Seek

## Update 2026-07-30

A second capture read the surviving primary listing directly — Bill Gates's
own April 2025 release of the scanned 1975 fan-fold printout, OCR'd text
fetched via `extract_pdf` (Internet Archive item
`original-microsoft-source-code`; see
[[claim-gates-2025-released-original-1975-altair-basic-source-scan]]). Both
of Lewis's central claims check out verbatim against the primary artifact:
the header reads "MONTE DAVIDOFF WROTE THE MATH PACKAGE," and the copyright
line immediately above it names only "BILL GATES AND PAUL ALLEN." (The OCR
misread the year as "1979"; the document's internal writing range and every
secondary account agree it is 1975.) This upgrades the note's two central
facts from Tier 2 (Lewis's retelling) to Tier 1 (the artifact itself). The
one figure still not checked against the primary is Lewis's "about 31 of 65
pages" estimate — the capture did not tally page boundaries — so "roughly a
third" in this note's title remains a Tier-2 figure, and the note stays
`seedling` on that basis.
[[question-verify-davidoff-altair-basic-source-header-primary]] has been
updated to reflect exactly this split.