Thread View: alt.folklore.computers
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Started by smul... Stephen K Mulrine
Thu, 18 Jan 1990 17:12
Another hidden message
Author: smul... Stephen K Mulrine
Date: Thu, 18 Jan 1990 17:12
Date: Thu, 18 Jan 1990 17:12
30 lines
1956 bytes
1956 bytes
During the early 1980s there was a home micro known as the Dragon 32 which had an m6809 CPU and limited compatibility with the TRS-80. One of the lecturers here was involved in its development and managed to hide a secret message in the ROM. This was to do with the EOL sequence for the printer. During the boot sequence this was copied from ROM to RAM to allow the user to get (eg) double spaced output if he wished. Address Initial Value Function &H14A 1 The number of characters in the end-of-line sequence. The EOL characters followed in succeeding locations from &H14B to &H150. Thus there could be a maximum of 6 characters in an EOL sequence &H14B 13 CR code (normal EOL sequence) &H14C 10 LF code. If the printer needed a CRLF EOL sequence &H14A could be POKEd with 2. In fact &H14D to &H150 contained DNS<CR> so to get his initials printed at the end of every line a user could POKE &H14A,6. This micro also had a novel "feature" - a certain POKE would speed up the CPU so your BASIC Space Invaders would run faster... -- +-------------------+ +------------------------------+ +---------------+ | Stephen K Mulrine |--| "DO DUP I SWAP PLOT" - Forth |--+ | Robotron 2084 |-+ +-------------------+--------------------------------------+---------+----++ | | Ministry |---| Favourite film: "Merry Christmas Mr Ceausescu" |--| :) |--+ +----------+ +------------------------------------------------+ +----+
Re: Another hidden message
Author: holl... The Polymath
Date: Tue, 23 Jan 1990 20:14
Date: Tue, 23 Jan 1990 20:14
22 lines
1643 bytes
1643 bytes
In article <15...@baird.cs.strath.ac.uk> smul...@cs.strath.ac.uk (Stephen K Mulrine) writes:
}&H14A 1 The number of characters in the end-of-line
} sequence. The EOL characters followed in succeeding
} locations from &H14B to &H150. Thus there could be
} a maximum of 6 characters in an EOL sequence
}&H14B 13 CR code (normal EOL sequence)
}&H14C 10 LF code. If the printer needed a CRLF EOL sequence
} &H14A could be POKEd with 2.
}
}In fact &H14D to &H150 contained DNS<CR> so to get his initials printed at
}the end of every line a user could POKE &H14A,6.
A minor quibble: That would print his initials at the _beginning_ of
every line (_after_ the CRLF) and overprinted with the first three
characters of the line (after the final CR), assuming the printer wasn't
in auto-linefeed mode. I wonder if he ever tested it. (-:{
--
The Polymath (aka: Jerry Hollombe, holl...@ttidca.tti.com) Illegitimis non
Citicorp(+)TTI Carborundum
3100 Ocean Park Blvd. (213) 450-9111, x2483
Santa Monica, CA 90405 {csun | philabs | psivax}!ttidca!hollombe
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