<operating system>

A real time operating system for the DEC PDP-11 computers, used in the early 1980s and still in 2005 found occasionally in old embedded systems.

Last updated: 2005-01-26


(Unix) Read The Bloody Manual.

Commonwealth Hackish variant of RTFM. RTBM is often the entire text of the first reply to a question from a newbie; the *second* would escalate to "RTFM".

[Jargon File]

Last updated: 1994-12-08


A real-time extension of C++.

["Object-Oriented Real-Time Language Design: Constructs for Timing Constraints", Y. Ishikawa et al, SIGPLAN Notices 25(10):289-298 (OOPSLA/ECOOP '90) (Oct 1990)].

Last updated: 1994-12-08


Real-Time Common Design Language


Real Time Engineering Environment: a set of CASE tools produced by Westmount Technology B.V.


Rich Text Format


(Usenet, primarily written, by analogy with RTFM) Read the FAQ!

An exhortation that the person addressed ought to read the newsgroup's FAQ list before posting questions.

[Jargon File]

Last updated: 1994-12-08



(By analogy with RTFM) Read The Fucking Binary.

Used when neither documentation nor source for the problem at hand exists, and the only thing to do is use some debugger or monitor and directly analyse the assembler or even the machine code.

"RTFB" is the least pejorative of the RTF? forms, the anger is directed at the absence of both source *and* adequate documentation rather than at the person asking a question.

[Jargon File]

Last updated: 1995-08-20



/R T F M/ Read The Fucking Manual (always abbreviated, sometimes bowdlerised to "Fine" or "Friendly") An (unhelpful) guru's traditional response when someone asks a question in a newsgroup or mailing list which he could have easily answered for himself had he bothered to RTFM.

The term may also be used to indicate that you couldn't find the answer in the manual. E.g. "How do I interface Unix to my toaster? And yes, I did RTFM but the FM didn't help and I can't RTFS."

Other derived forms include RTFAQ, RTFB, RTM, RYFM and, more recently, STFW. Compare: UTSL. A web site in the same vein is lmgtfy.com.

[Earliest use?]

[Jargon File]

Last updated: 2003-06-07



Bogus inbound link to RTFM.

Last updated: 2020-03-08



1. Read The Fucking Source. Variant form of RTFM, used when the problem at hand is not necessarily obvious and not answerable from the manuals - or the manuals are not yet written and maybe never will be. For even trickier situations, see RTFB. Unlike RTFM, the anger inherent in RTFS is not usually directed at the person asking the question, but rather at the people who failed to provide adequate documentation.

2. Read The Fucking Standard; this oath can only be used when the problem area (e.g. a language or operating system interface) has actually been codified in a ratified standards document. The existence of these standards documents (and the technically inappropriate but politically mandated compromises that they inevitably contain, and the impenetrable legalese in which they are invariably written, and the unbelievably tedious bureaucratic process by which they are produced) can be unnerving to hackers, who are used to a certain amount of ambiguity in the specifications of the systems they use. (Hackers feel that such ambiguities are acceptable as long as the Right Thing to do is obvious to any thinking observer; sadly, this casual attitude toward specifications becomes unworkable when a system becomes popular in the Real World.) Since a hacker is likely to feel that a standards document is both unnecessary and technically deficient, the deprecation inherent in this term may be directed as much against the standard as against the person who ought to read it.

[Jargon File]


Return from interrupt



1. Resistor-Transistor Logic.


2. Register Transfer Language.



Real Time Language.

A real-time language written by J.G.P. Barnes of ICI in 1971. It was the predecessor of RTL/2.

["Real Time Languages for Process Control", J.G.P. Barnes, Computer J 15(1):15-17, Feb 1972].

Last updated: 1994-11-09


Real Time Language.

A small real-time language based on ALGOL 68, with separate compilation designed by J.G.P. Barnes of ICI in 1972 as a successor to RTL/1.

A program is composed of separately compilable modules called "bricks" which may be datablocks, procedures or stack. A stack is a storage area for use as a workspace by a task. The language is block-structured and weakly typed. Simple types are byte, int, frac and real. There are no Booleans. Compound types may be formed from arrays, records and refs (pointers). There are no user-defined types. Control statements are if-then-elseif-else-end, for-to-by-do-rep, block-endblock, switch, goto, and label variables.

["RTL/2: Design and Philosophy", J.G.P. Barnes, Hayden & Son, 1976].


1. [Usenet] Read The Manual. Politer variant of RTFM.

2. Robert T. Morris Jr.

The perpetrator of the great Internet worm of 1988 (see Great Worm); villain to many, naive hacker gone wrong to a few. Morris claimed that the worm that brought the Internet to its knees was a benign experiment that got out of control as the result of a coding error. After the storm of negative publicity that followed this blunder, Morris's user name on ITS was hacked from RTM to RTFM.

[Jargon File]

Last updated: 1995-03-31


Routing Table Maintenance Protocol


Real-Time Operating System


Real-Time Transport Protocol



RISC Technology Personal Computer.

(Commonly, but incorrectly, known as the "PC-RT", later changed to just "RT") IBM's first RISC-based Unix computer. The RT-PC was the predecessor to IBM's RS/6000. It ran AIX 1.x and 2.x and had a PC-AT bus and IBM's ROMP microprocessor. It was withdrawn from the marketing around 1989 or 1990.

Last updated: 1995-04-06


<operating system>

1. run-time system.


2. return from subroutine.

Last updated: 1999-07-26


real-time structured analysis


Real Time Streaming Protocol


Round-Trip Time


Run Time Type Information


radio teletypewriter

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