I had a fun meeting yesterday, and I won't say who with (unless he wants me to), but it was initially a business meeting related to the organisation for which he works, but went on rather a lot, ending in a meal in cafe rouge. I have met him before, but this time we managed to take a lot about old times and "stuff".
I actually found myself out-geeked for a change. Heck, he had a rare "portable" BBC micro (i.e. big box with power, CRT, BBC micro, 5 1/4" floppy disks, and fold out keyboard) in the boot of his car. Next to that the half restored teletype and fibreglass orc in the office were no match.
I tell a story of old days doing "purely research" in to the way some games managed protection on tapes or disks, and how the Elite game does various scrambling (XOR) of data it loads from tape/disk in various stages so that you cannot simply access or change the underlying machine code of the game. TBH I am not 100% sure the game was "elite" or not now. But what was fun is that if you are manually simulating the various stages, then part way through there is a pattern in memory that you can see with text "Does you mother know you do this?". I remember it well as it was after I had left uni and was temporarily staying at my parents, and she was behind me at the time! That text is not on the tape/disk and not in the final memory image but an intermediate stage that only a "hacker" would ever see. Before I got to tell that story, this person told of a similar story with another game and intermediate text "You are in a maze of twisty passages all alike" (a classic line from text based adventure games). I was out geeked on one of the most geeky anecdotes I have in my arsenal!
I'd say I "won" on the forcing the teletext chip in a BBC micro in to "reveal mode" by rapid random screen mode switching, that is, until I saw his "portable BBC micro" in his boot. And yes, I had BBC with 6502 and Z80 second processors and even teletext adapter but I never had one that talked GPIB, FFS, out geeked again!
At the end of the day it make me realise what a small world it is - there are probably literally a handful of people that have been there and done that in the same level of technical arena that I have had in my life. This person is close, but he did more radio ham than I ever did. I think I have done more coding than he has. But we are a rare breed and becoming rarer I think.
Hopefully one of those useful contacts in life for personal and business progressing in various ways. Some times it is who you know and not what you know, but knowing both helps even more.
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YOU ARE IN A MAZE OF TWISTY LITTLE PASSAGES, ALL DIFFERENT.
ReplyDeleteYOU ARE IN A LITTLE MAZE OF TWISTING PASSAGES, ALL DIFFERENT.
YOU ARE IN A MAZE OF TWISTING LITTLE PASSAGES, ALL DIFFERENT.
YOU ARE IN A LITTLE MAZE OF TWISTY PASSAGES, ALL DIFFERENT.
YOU ARE IN A TWISTING MAZE OF LITTLE PASSAGES, ALL DIFFERENT.
YOU ARE IN A TWISTING LITTLE MAZE OF PASSAGES, ALL DIFFERENT.
YOU ARE IN A TWISTY LITTLE MAZE OF PASSAGES, ALL DIFFERENT.
YOU ARE IN A TWISTY MAZE OF LITTLE PASSAGES, ALL DIFFERENT.
YOU ARE IN A LITTLE TWISTY MAZE OF PASSAGES, ALL DIFFERENT.
YOU ARE IN A MAZE OF LITTLE TWISTING PASSAGES, ALL DIFFERENT.
YOU ARE IN A MAZE OF LITTLE TWISTY PASSAGES, ALL DIFFERENT.
Elite was a protected game so it could have been that. A friend of mine broke the protection on the second processor version, I had a Master 128 with the internal R65C02 co-processor which was great for playing Elite.
ReplyDeleteI recently found a web site by a bunch of people emulating the tube in software using a Raspberry Pi, and then emulating a 6502 on the Pi. They were trying to get second processor Elite running on this setup. I couldn't quite work out from the site whether it was fully working or not.
I remember Frak! had a Captain Pugwash song, and also spoke threatened that if you copied the game you would get a visit "from very big men with very big boots" that would kick the something out of you "for a very long indeed" which was hidden.
ReplyDeleteOut of curiosity I opened the Frak! image file in a suitable notepad to peer at it for the first time in forever. I then saw "You are in a maze of twisty little passages, all alike" - something which I never found there originally, and perhaps is the game your meeting geek referred to. :)
About the game text, this is the kind of thing that tcrf.net documents...
ReplyDeleteGoogle has three hits for '"Does you mother know you do this?" protection'. The first two point to this page. The third is a post on alt.folklore.computers from 1990...
ReplyDelete"Well in the micro model Bs first version (and still one of the best versions) of Elite (THE Space Simulator game!) it had a small string
Does you mother know you do this?
Heard this one from someone who was backing up their copy of the game"
So here's some BBC geekery... My secondary school had one of the first and last Econet installations in the country. About 40 BBC Master 128s and a handful of BBC B 32k machines, with and RM fileserver and shared hard drive. Proper (almost) heirarchical filesystem with user accounts, permissions and everything.
ReplyDeleteA friend read the rather good Econet manual and discovered that all the traffic passes through a single memory address on every machine, unencrypted. Not even XORed. A week later we had the admin (SYST) password. A week after that we had a little program set up that would allow us to remote view the screen of any machine and send keypresses including a soft break. We spent lunch hours causing confusion for other students by inserting random text into their word processor documents and changing the answers on their maths puzzle game just before they hit enter. We were mean. This was well before anyone outside of higher education had heard of the Internet.
The BBC Eco[net]system was way ahead of its time. A unique expandable machine with masses of potential for hobbyists.
Which School? Sounds like mine...
DeleteIt's at least 30 years since I looked at this during my A levels, but from memory I think the disk based Elite on the BBC B had an initial loader that decrypted its own code while running (it was the bit that drew the planet with a ring around it by filling in dots one at a time - if you tried to use a debugger it just got stuck there and kept drawing more and more dots rather than loading the rest of the game). If you could get past the decryption to the point where it loaded the main part of the game I think this was where you could see the secret message - I'm pretty sure there was something, but don't remember if it was the 'does your mother know' text.
ReplyDeleteAll the earlier Acornsoft games (Planetoid etc) had a 256 byte self decrypting loader as well that you couldn't set traditional breakpoints on as the breakpoint changed the memory that was being decrypted and the decryption code itself was part of the key (or something like that - like I said, it's a long time)
In my loft I still have the computer and the floppy disks with the version of Elite with the protection stripped that I created, they've come with me through every move since university, but no idea if any of it still works.
I recall one tape format used in a game that have a block structure but would deliberately blow its own stack and break the structure part way through some blocks, IIRC. That was entertaining.
DeleteSo I also "studied" the Elite loader code. At the time it was the most complicated disassembly I'd done because of the loader routine which overwrote the end of the loop so you couldn't stick a breakpoint in.
ReplyDeleteI can't remember how I then got to the next stage but I do remember looking at the text representation of memory and being amazed the with "does your mother know you do this?" Such fun times...
LOL, brilliant.
DeleteI studied another one that had a deliberate stack overflow in the code as part of loading.