Many of you out there work for large companies that ship well-known software. I was wondering, how much of original code (basically, code that was v1.0 release) is left in modern massive applications, such as, say, Firefox, Photoshop, Windows, Linux, etc? I'd really prefer first-hand experience and real-world war stories.Thanks for satisfying my curiosity.EDITTurns out there's a degree of misunderstanding. What I'm after is basically as follows: when you blame/annotate source code, are there any parts or even whole files untouched since the initial 1.0 release.
How much of original code is left in modern software products?
source code;history
More than you'd expect and much older than you'd expect. Even with total rewrites and big refactors there are many modules that stay untouched. Pter suggest that for example you won't find old Netscape code in Firefox. Which is wrong, if you search through source code you'll find quite a few files with disclaimer like:* The Initial Developer of the Original Code is* Netscape Communications Corporation.* Portions created by the Initial Developer are Copyright (C) 1994-2000 For example in Linux kernel headers you can find things like:include/linux/if_ppp.h: * Copyright (c) 1989 Carnegie Mellon University.include/linux/quota.h: * Copyright (c) 1982, 1986 Regents of the University of California. include/linux/coda.h:          Copyright (c) 1987-1999 Carnegie Mellon Universityinclude/linux/mc146818rtc.h: * derived from Data Sheet, Copyright Motorola 1984 (!).include/net/slhc_vj.h: * Copyright (c) 1989 Regents of the University of California.