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1200-Baud Archeology 211

Posted by kdawson
from the when-men-were-men-and-interpreters-ran-in-4k dept.
jamie found this singularly geeky article on reconstructing Apple I BASIC from a cassette tape. It claims to offer the first confirmed perfect dump (BIN) of the 4096 bytes of this venerable interpreter. Terrific fun for the whole family. "The Apple I is extremely rare. Only 200 were built, and less than 100 are believed to be in existence. Neither Steve nor Woz own an Apple I any more, and neither does Apple Inc. The cassettes are even rarer, as not every Apple I came with one... So here is how to decode the signal. Let us first open the audio file in Audacity and look at the waveform... It is now time to write a small program to measure and dump the width of the pulses."
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1200-Baud Archeology

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  • Alternative tools (Score:5, Interesting)

    by stryyker (573921) on Tuesday July 15, 2008 @05:35AM (#24193315)
    Probably would have been useful for the person to look at how C64 emulators and people handle transfer C64 tapes to PC.
    • Re:Alternative tools (Score:5, Interesting)

      by Alioth (221270) <no@spam> on Tuesday July 15, 2008 @06:03AM (#24193465) Journal

      Yes - I thought this too - the article's slashdotted at the moment but the summary makes me think he made a mountain from a molehill. In the Sinclair Spectrum world, loading Speccy tapes on to a PC, and encoding them in a useful format (TZX) has been a solved problem for years.

      All these tape formats were physically pretty similar when it comes to how they were encoded, and the same techniques could have been used by looking at any home computer emulator that loaded stuff from tape even if the details were different.

      • by KGIII (973947) on Tuesday July 15, 2008 @06:31AM (#24193593) Journal
        I was actually thinking VIC 20. (I painfully admit that the first was not a woman but a PET and my father and I built a wooden case for it but that predated the VIC 20 by about a year or so.) I played FLOG off of tape and saved my SkiDownHillFaster game to tape damn it! Now somoene better get off my lawn but probably not you.
      • by lpontiac (173839) on Tuesday July 15, 2008 @06:47AM (#24193665)

        the summary makes me think he made a mountain from a molehill.

        I think the emphasis is more on the historical significance, given the rarity of the tapes and the fact that the only digitised copy floating about has been patched.

      • by Dan East (318230)

        The article comes up fine for me. He lists a simple C routine comprised of 15 or so lines of code. So it wasn't like he made that big of a mountain out of it.

        • Re: (Score:3, Insightful)

          by YeeHaW_Jelte (451855)

          The code being simple does not necessarily mean the though process of coming to those 15 lines was simple and/or straightforward.

      • Re:Alternative tools (Score:5, Interesting)

        by Lumpy (12016) on Tuesday July 15, 2008 @07:43AM (#24193953) Homepage

        Didn't the Apple I use PSK instead of FSK encoding for the tape audio?

        I though instead of Shifting frequency they shifted phase which is quite a but harder to detect than frequency shift.

        BTW: Computer Tapes worked great to load software across Ham radio. 2 meter radio, I would load a game from a friend across the city over 2 meters by simply patching audio from the rig to the computer.

        Luckily the C64 had a very slow bitrate (even the floppy drive was slow as hell) for it's storage tapes so it worked great.

        • Re:Alternative tools (Score:5, Interesting)

          by daBass (56811) on Tuesday July 15, 2008 @09:07AM (#24194573)

          There used to be a Dutch radio program in the 80s called "NOS Hobbyscoop" that had their own basic interpreter for many computers of the day. (MSX, Acorn, Sharp MZ, etc.)

          They actually broadcast computer programs every week on medium wave AM. They'd count down, you start the cassette recorder and you had some new programs.

          Fun for the whole family, even if a bit painful on the ears!

          • Re:Alternative tools (Score:5, Interesting)

            by C0vardeAn0nim0 (232451) on Tuesday July 15, 2008 @11:02AM (#24196527) Journal

            here in brasil, UFRGS (federeal university of rio grande do sul) broadcasted test programs using stereo FM. one chanel would broadcast audio, the other encoded text to be decoded by an MSX computer and displayed on screen. the idea was to make talk radio accessible to def people.

          • Re: (Score:3, Interesting)

            by Tumbleweed (3706) *

            There used to be a Dutch radio program in the 80s called "NOS Hobbyscoop" that had their own basic interpreter for many computers of the day. (MSX, Acorn, Sharp MZ, etc.)

            They actually broadcast computer programs every week on medium wave AM. They'd count down, you start the cassette recorder and you had some new programs.

            Very interesting - that may be the first instance of P2P!

        • Re:Alternative tools (Score:5, Interesting)

          by Mr Z (6791) on Tuesday July 15, 2008 @09:58AM (#24195381) Homepage Journal

          No. It's FSK, but it used a constant number of zero crossings per bit, rather than a constant bit period. So, to decode it, you count the average time between zero crossings rather than the number of zero crossings in a fixed time window.

          On the plus side, it seems like the Woz scheme has some benefits. If you assign the shorter bit period to the more common bit value (likely, '0'), you shorten your average recording length a little. On the minus side, if you get an extra zero crossing in there (say, due to noise that wasn't filtered away by a Schmitt trigger or other hysteresis somewhere), recovery may be awkward.

          BTW, the C64 floppy drives were slow as heck, but that had nothing to do with the bitrate for its media. There's some goofy history there, involving bugs in the shift register on the VIC-20's PIA, the decision to use CPU control loops instead to determine the bit period when communicating between the drive and the machine, and then the greater cycle-stealing period of the VIC-II as you get to the C64 throwing a monkey wrench in the works. The fast-load carts worked by restoring the native CIA hardware shift register to get rid of the CPU-controlled bit shifting to read bits from the floppy, restoring its speed to performance levels similar to the old IEEE-488 based bus they used back in the Commodore PET era. But that's a different story for another day.

          --Joe

          • by Temkin (112574)

            You forgot that there were more signal lines available, but unused. They had serial in and serial out. The fastload cartridges turned one line around and implemented a 2-bit parallel transfer. Fastload carts also offered a great place to solder in a reset button.

            I'd tell you to get of my lawn, but that would just make more rocking chair ruts...

            • by Mr Z (6791)

              The 2-bit thing is still a hack that only buys back some of the performance. The original intention was to use the VIA's (I mistakenly called it the PIA) shift register, which would have kept it fast. For those of you who really care, someone actually wrote this all up on Wikipedia. [wikipedia.org]

              And you're right, I was thinking of a different loader [cs.tut.fi] that uses the synchronous serial mode, and that requires a hardware mod. *sigh* I never owned a C64 back in the day (though I have one now), so I only got to hear about

          • by Alioth (221270)

            That's also how the Spectrum loading scheme worked, too. A zero took less time than a 1. As a consequence there wasn't a fixed baud rate, but the average speed with the Spectrum's scheme was 1500 bps. Custom schemes were also made too, but they were all generally the same 'constant number of zero crossings per bit', but at different frequencies (generally for higher loading speed, or to make tape copying less trivial). Some people even used Manchester encoding (which was faster for the same fundamental freq

            • Re:Alternative tools (Score:4, Interesting)

              by Mr Z (6791) on Tuesday July 15, 2008 @11:18AM (#24196781) Homepage Journal

              Probably the most elaborate scheme I've seen so far is the Mattel Electronics Keyboard Component [spatula-city.org]. It encodes everything into blocks of 32 10-bit words, each protected by a 5-bit detect-2-correct-1 Hamming code. The 32 words are then re-interleaved as 15 32-bit words. Each 32-bit word gets prefixed with a 5-bit framing header. That's prefixed by a block of zeros and a special 64-bit sync pattern per block. (I believe the whole sync structure was about 256 bits long.) The whole shebang is then Manchester encoded and put out to tape. Furthermore, the drive had a carrier-detect signal that it supplied in addition to the Manchester decoded bits.

              The net result is a fairly robust protocol. Because the 32 data words were interleaved, dropout errors would get spread among multiple words. Thus, a burst error would show up only as 1 or 2 bit errors in each individual word. In addition, if a given word shows up as non-correctable, it was sometimes recoverable by flipping bits based on where the carrier was lost and trying again.

              Other nifty aspects of its design: There was an additional pre-header on blocks that was recorded at (I think) 1/3rd the normal carrier frequency. This allowed the drive to detect interesting headers while fast-forwarding or rewinding. Since the drive was computer controlled, it allowed for fully automatic operation, including hardware seeks.

              What was the bit rate? Well, I believe the raw bit rate for data bits coming off the tape was about 3000 bps. Factoring in encoding overhead, though, I'd say the final throughput was less than half that. A quick calculation suggests a nominal throughput around 1200 baud, give or take.

              --Joe

              • by Mr Z (6791)
                Just a quick followup: By 3000bps, I'm referring to the Manchester decoded bits. As I recall, the hardware actually did the Manchester decode, and then interrupted the CPU with every new bit. Good thing the Keyboard Component was a dual-CPU system. :-)
        • by Creepy (93888)

          I have no idea how they formatted it, but it worked in any cassette player that had a line out (and a counter if you wanted to load any other program on the same tape). The Apple tape drive was no speedster either, although the one I was familiar with came with the 48k Apple ][ (with DOS 3.1 it took about 15 minutes to load - if you were lucky - sometimes it took 2-3 tries). My experience with the tape drive was short lived, however, as my school got Disk ][s that school year and we immediately switched (

          • Re: (Score:3, Interesting)

            by HTH NE1 (675604)

            What really got me hooked on the ][ was the release of Sabotage and Sneakers in 1981.

            Heh, I liked SABOTAGE so much I first repackaged it as a SYS file to run it under ProDOS, then a full disassembly of it, which led to removal the last bit of copy protection in it (intended to prevent memory dump cards, it would periodically test the data in the second text screen's screen holes and go into a memory-wiping loop, which also prevented going into the Apple IIgs Control Panel to adjust the processor speed).

            I had intended eventually to upgrade the game to use Apple IIgs graphics, a saved high sc

      • by linhux (104645) on Tuesday July 15, 2008 @10:06AM (#24195553) Homepage

        When I was a teenager, I used to decode FAT tables and directory structures by hand, using pen and paper and printouts from a raw hex dump of a hard disk. I didn't do this because there was a problem needed to be solved; I knew what was on the disk and there sure were plenty of tools to read the data (like MS-DOS). But it was a fun challenge and I learned how FAT worked.

        I can see how this is a similar challenge. It's nothing more than a geeky sudoku.

    • Re: (Score:3, Interesting)

      by CharlieG (34950)

      Actually, If I remember right (digging back oh, nearly 30 years into the recesses of my mind), the C-64 had a fairly unusual tape format, unlike almost everyone else, just like their disk drive was unique (everyone else used a fixed number of sectors/track, where Commodore used a variable number, with more sectors/track as you moved out, to get more data on the disk)

    • Has anyone written a program that can take a .wav sample of a poor-quality c64/vic 20 tape (stretched tape, warbling output, drifting volume level, etc) and do modern DSP analysis on it to turn it into something the more mundane .wav->.tap converters can handle? I unfortunately don't have the background to actually implement such a beast, but from what I know about both DSP and the way signals were recorded to tape by a Datasette/C2N, it *should* be a somewhat straightforward exercise. In theory, it migh

      • Re: (Score:3, Informative)

        by Detritus (11846)
        I've done work on recovering data from old analog tapes. You could clean up the signal by running it through a DC-blocking filter, which is a high-pass filter with a very low cut-off, and a software AGC with a short time-constant. Some of the noise can be eliminated with a low-pass filter. There isn't much that can done to eliminate speed variations. The best thing that you can do is to write a demodulator routine that can track the speed variations and has generous allowances for timing errors in the signa
  • by Anonymous Coward on Tuesday July 15, 2008 @05:38AM (#24193327)

    *off to bathroom*

    I'll report my findings later

  • by jcr (53032) <jcr@mac. c o m> on Tuesday July 15, 2008 @05:40AM (#24193343) Journal

    It would be way cool to have an Apple I emulator on my phone. Come to think of it, a DEC PDP-1 emulator with SpaceWar would be pretty sweet, too.

    -jcr

  • It is now time to write a small program to measure and dump the width of the pulses

    Its just an FSK modem. I have an old computer right here in my house which would demodulate that, once I bumped the clock rate up by a factor of four.

    • by Hal_Porter (817932) on Tuesday July 15, 2008 @06:12AM (#24193513)

      Yes. But a few people did some very magical things with tapes before the became obsolete. I saw a demo of a turbo tape system on an Atari 800XL which could load games "faster than a disk drive". Actually it about tied, but that was still impressive. The disk drive could probably managed 9600 baud sustained.

      The modulator / demodulator was lump of potted electronics I could easily fit in my hand. Potting compound was a blank gunk you applied to electronics you didn't want people to tamper with, in this case to stop people seeing the components used. But whatever they were they could modulate and demodulate data at around 9600 baud. This was in the 80's back before DSPs too, so whatever circuit was used must have been made of Op Amps, transistors and passive components.

      I never worked out how it worked. Though I can imagine exploiting the stereo nature of the tapes to send one carrier and phase shifted signal might work. Phase modulation is easy and demodulation is too if you have the carrier. Still phase modulation at 9kbaud+ would be a tight fit on an audio tape. I don't think things like QAM would be possible given the size of the package, the selling price (about twenty English pounds, or $40), and the primitive nature of 80's technology.

      • Re: (Score:3, Interesting)

        by MichaelSmith (789609)
        My 6502 system accessed the tape at 300 baud. I used an old cassette recorder for the job. I had my eyes on my uncles reel to reel hi-fi system. I reckon I could have got 9600 baud out of that just by exploiting the frequency response.
      • But that had a dedicated "digital" tape drive (ie. it was optimized for recording those sorts of signals, not music.

      • QAM (Score:3, Interesting)

        by tepples (727027)

        Still phase modulation at 9kbaud+ would be a tight fit on an audio tape. I don't think things like QAM would be possible given the size of the package

        Quadrature amplitude modulation was in use in the 1960s: it's just two AM carriers out of phase by 90 degrees. The color encoding in NTSC and PAL used QAM.

      • by Angstroem (692547)

        The hardware itself probably isn't much more than a compander and signal cleaner, e.g. some LM111 plus according resistors/capacitors like I used on my ZX81 to get 2k4 and 3k6.

        To go into the 9k6 range, you could eventually go for 4 different frequencies marking 00, 01, 10, and 11 instead of just mark and space. A slightly more dedicated hardware therefore would also install 1 LP (00), 1 HP (11), and 2 BP (01, 10) filters to avoid any confusion.

        I wonder if DTMF was ever used for data recording, giving you 16

      • by Lumpy (12016)

        That black potting compound was easy to defeat. I did it weekly back then yanking proms off of Digicipher boards for Satellite receivers.

      • by v1 (525388)

        Potting compound was a blank gunk you applied to electronics you didn't want people to tamper with

        They weren't so much worried about tampering as they were about reverse-engineering. Nowadays they have a different process they use on chips for cable boxes, which we saw an article here awhile ago on.

  • Teach it! (Score:5, Insightful)

    by VincenzoRomano (881055) on Tuesday July 15, 2008 @05:59AM (#24193447) Homepage Journal
    I think that at least the basic interpreter should be taught to the new generations.
    They don't feel confortable enough in less than 1 GB, what if they had just 4 KB?
    • Re:Teach it! (Score:5, Interesting)

      by Technician (215283) on Tuesday July 15, 2008 @06:28AM (#24193583)

      I think that at least the basic interpreter should be taught to the new generations.

      To rain on the parade, I wonder if there is a copyright violation in posting the code online un-edited. How long is copyright nowdays?

      It's something we need to address in this age of IP property where the market has expired years ago but the copyright is in force for many more decades.

      • Re:Teach it! (Score:5, Insightful)

        by Digital Vomit (891734) on Tuesday July 15, 2008 @07:07AM (#24193761) Homepage Journal

        How long is copyright nowdays?

        Functionally "forever".

      • Re:Teach it! (Score:5, Insightful)

        by QuantumG (50515) * <qg@biodome.org> on Tuesday July 15, 2008 @07:17AM (#24193809) Homepage Journal

        If Apple tried to sue, Woz would likely pay for your defense.

        • Re:Teach it! (Score:5, Interesting)

          by Anonymous Coward on Tuesday July 15, 2008 @12:30PM (#24198133)

          Of course I would! But this gets sticky. I gave away the Apple I schematics and monitor ROM (256 bytes to replace a front panel with a keyboard) but only a couple of copies of the BASIC, which I also intended to be in the open domain. I don't know if I ever gave away the completed Apple I BASIC because by then it was virtually the same for the Apple ][ (now completed) as well. We took the steps to retain the copyright for BASIC on the Apple ][. Any steps we took for the Apple I would be in the gray. I can't believe that it matters to Apple at all anyway.

      • by 3waygeek (58990) on Tuesday July 15, 2008 @07:52AM (#24194003)

        There's a simple solution; post it as a hex (or binary or octal) dump. You can then claim that it's just an excerpt of the first trillion or so digits of pi. By the time Apple's lawyers determine it isn't, the guys who decoded & published it will be long dead.

        • by object88 (568048)

          You can then claim that [the hex/binary/octal dump is] just an excerpt of the first trillion or so digits of pi. By the time Apple's lawyers determine it isn't, the guys who decoded & published it will be long dead.

          Lawyer1: Is the first digit "3"?

          Lawyer2: No.

          Lawyer1: UNLEASH THE HOUNDS!!

      • Re: (Score:3, Insightful)

        How long is copyright nowdays?

        How old is Mickey Mouse?

        • by Zaatxe (939368)
          How old is Mickey Mouse?

          80 years this year. I get your point, but Wikipedia says [wikipedia.org] that copyright usually last between 50 and 100 years after the creator's death. Walt Disney died in 1966, that is 42 years ago.
      • by rirugrat (255768)

        Seeing that the Apple I was made out of parts that Jobs and Woz stole from Atari, I imagine there's copyright violations all over the place!

  • by ga5p0d3 (1326207) on Tuesday July 15, 2008 @06:15AM (#24193521)
    Reminds me of my housemate and I at university ('92-'95) using the tape control relay on an Acorn Electron wired to a PC serial port to rip the ROM so we could start writing an emulator. A small BASIC program PWM encoded the whole ROM in about an hour IIRC. Was a great start to the project, we got as far as CPU emulator, multi-window debugger, VGA display driver, and had it running basic no problems. He got it reading WAV's of games recorded from tape too. Got as far as the in-game screen of Chuckie Egg before we ran out of knowledge and became stuck trying to fathom the hardware keyboard input. (for the BASIC interpreter we just injected characters into the key buffer). Ahh, happy days. :o)
  • Very interesting (Score:3, Interesting)

    by Dan East (318230) on Tuesday July 15, 2008 @06:18AM (#24193531) Homepage Journal

    I have a TI-99/4A that has been dead for nearly two decades, along with several hours worth of data stored on cassettes. I would love to recover the data off of those tapes. Most of it is the type of stuff a 10 year old would write in TI BASIC (and Extended Basic!), and it would really bring back some fond memories and certainly some good laughs.

    Are there any generic utilities that can extract binary out of low-baud modem audio files? With the advantage of performing various audio processing and analysis in a non-linear, non-realtime manner, certainly data could be extracted by modern software that not even the actual legacy computer could decode.

    • Re:Very interesting (Score:4, Interesting)

      by clickety6 (141178) on Tuesday July 15, 2008 @07:45AM (#24193959)
    • by zakezuke (229119)

      I have a TI-99/4A that has been dead for nearly two decades, along with several hours worth of data stored on cassettes. I would love to recover the data off of those tapes. Most of it is the type of stuff a 10 year old would write in TI BASIC (and Extended Basic!), and it would really bring back some fond memories and certainly some good laughs.

      Are there any generic utilities that can extract binary out of low-baud modem audio files? With the advantage of performing various audio processing and analysis in a non-linear, non-realtime manner, certainly data could be extracted by modern software that not even the actual legacy computer could decode.

      I'm sure there are emulators for the TI there. I met a few that came with a pretty complete cartridge collection including extended basic. Copyright is bound to be a little querky as there is TI stuff and there is Geneve. I think TI might have given up on their copyright, since their stuff has NO commercial value presently save the speech synthesizer.

      http://www.mrousseau.org/programs/ti99sim/README.html [mrousseau.org]

      Claims to be able to convert .wav file TI files to binary.

      But it's rather funny, the TV tape drive was

      • by Mr Z (6791)

        Slightly OT, but will it decode this [spatula-city.org] copy of Pirate Adventure? ;-)

  • Uhh... (Score:5, Funny)

    by consonant (896763) <shrikant,n&gmail,com> on Tuesday July 15, 2008 @06:28AM (#24193579) Homepage

    Terrific fun for the whole family.

    That must be one weird family...

    • by Zaatxe (939368)
      That must be one weird family...

      I have a 14-years-old step-daughter who is crazy about Star Trek. Families are sure weird.
  • Nick Hodge Says (Score:4, Interesting)

    by Anonymous Coward on Tuesday July 15, 2008 @07:02AM (#24193735)
    (scroll down to the comments, in case you ever RTFA):

    Apple Inc does own an Apple I

    It is actually owned by Apple Computer Australia, and on loan and display at the Powerhouse Museum in Sydney.

    For many years, it was under a glass box in the foyer of the Apple Australia offices.

    • by argent (18001)

      I wonder if that was the one that was on display at Apple's only distributor in Sydney when I used to go in (damn, I can almost remember the bus lines I took) and write game programs on the display models in the back. They didn't have much software back then so they let kids write stuff and leave it running as an early "attract mode". There was an Apple I in a display case... it was never powered on when I was there.

  • Memories (Score:3, Insightful)

    by buddhaunderthetree (318870) on Tuesday July 15, 2008 @07:17AM (#24193815)

    I tell my kids about loading programs off cassette tapes but they just don't get it. I guess they'll never know the agony of having a program ruined by fragility of magnetic tape.

  • MP3 ? (Score:4, Informative)

    by XNormal (8617) on Tuesday July 15, 2008 @07:50AM (#24193987) Homepage

    The psychoacoustic models of MP3 compression must have done wonders for the ancient recording.

    It's like compressing a bitmap of line art with JPEG.

  • Pom1 (Score:4, Informative)

    by anarkavre (904651) on Tuesday July 15, 2008 @07:50AM (#24193991) Homepage
    I wrote, ahem, ported a Java Apple 1 emulator about a year ago to SDL and added a few of my own features. Haven't done much more to it since then. But for those nostalgic geeks out there, you can find it at the following link.

    http://pom1.sourceforge.net/ [sourceforge.net]
    • Re: (Score:2, Funny)

      Hmmm....an Apple in Java....I'll have to try that.

      *dunks a piece of Washington Golden Delicious in his coffee*

      *munch*Not*munch*bad*munch*

  • by pslam (97660) on Tuesday July 15, 2008 @07:54AM (#24194017) Homepage Journal

    The interesting thing about this article is:

    • a) The MP3 encoding process didn't totally mangle the signal. A decent encoder should have dropped all those 1ms duration waves due to masking. Must be a crappy encoder or a forced high bitrate :)
    • b) I get the distinct impression the author doesn't know what FSK is, or that it's the encoding for the signal. Yet he still manages to decode it. The HARD way.

    This could have been done so much more easily :)

    • I get the distinct impression the author doesn't know what FSK is, or that it's the encoding for the signal. Yet he still manages to decode it. The HARD way.

      The author treated it as period shift keying, which is equivalent to frequency shift keying. What makes decoding an FSK signal in the period domain "the hard way"?

    • by pla (258480)
      A decent encoder should have dropped all those 1ms duration waves due to masking.

      a 1ms pulse (if you mean rise, 1ms hold, fall) corresponds to 500hz - Pretty much smack dab in the middle of the human auditory range.

      Any encoder that filtered that out would most likely only appeal to bats and insects, who don't tend to write all that much audio processing code.
    • by fm6 (162816)

      You obviously know more about DSP than I do (which doesn't say much!) but perhaps the non-mangling has to do with the fact that the signal is not 1200 baud. As I recall, cassette tape interfaces recorded at 110 baud.

      An interesting mistake. The author would seem to be somebody who is old enough to remember 1200 bps modems (technically, not 1200 baud, though most people called them that) and just can't conceive of any data channel being slower than that!

  • by macs4all (973270) on Tuesday July 15, 2008 @08:03AM (#24194057)

    I own an Apple 1. ...And a copy of Apple 1 BASIC on cassette, and Woz's Mini-Assembler that is "origin-ed" for the Apple 1. (This is the same Mini-Assembler that was in the Apple ][ ROMs, at $F666). And a few other Apple 1 goodies.

    Do you realize that the cassette interface for the Apple 1 and the Apple ][ are identical?

    Yep, you can read an Apple 1 audio cassette with any old, easy-to-find Apple ][. And from there, you can use any one of a million methods to get the data out of memory and onto another medium.

    Also, you can simply use the Apple ][ to create a NEW cassette for your Apple 1 (if you happen to be lucky enough to have one).

    BTW, I think mine is "serial number" 0064. At least that's what I think the "0064 that is written in Sharpie on the PC board means...

  • by Digital_Mercenary (136288) on Tuesday July 15, 2008 @08:32AM (#24194213) Homepage Journal

    Many seasons ago, in a high school computer lab in the Bronx. I would save programs from computer labs Commodore PET to tape and wonder why they would always be blank the next day. Over time I realized that riding the NYC trains with my school bag on the car floor was not such a cool idea. NYC trains were somehow erasing the tapes when they were place closed to the floor. Until I figured this out there were many nights spent pondering what the gods of computing had against me. Curse you Number 6 Line! Curse you!!!

    "Ahhh the suffering...."

    • by Gordonjcp (186804) on Tuesday July 15, 2008 @08:54AM (#24194405) Homepage

      That's because they're electric trains with big spinning magnets ;-)

      The BBC used to get people to take taxis rather than use the Underground, for the same reason.

    • Re: (Score:3, Informative)

      by Detritus (11846)
      It's those traction motors. They are notorious for emitting a magnetic field that is strong enough to erase magnetic tape. If they can move a train, they can erase your tapes. The same thing used to happen to couriers transporting 9-track magnetic tapes in NYC via the subway.
  • by marcomarrero (521557) on Tuesday July 15, 2008 @09:48AM (#24195217)

    MESS emulates the Apple I, can read WAVE files, and the entire source code is available. :)

    I miss my old CoCo3, but I hated cassette tapes. The saddest thing is that Audio Cassettes were designed to be lousy as a data storage media - they used two sides (interference), and were created to record just human voice. The only other option were floppy drives, and back then they were expensive and/or overpriced ($200 and up) which is equivalent to $400+ now in 2008. Most drives had to include the entire controller I/O inside the unit, and probably also a disk OS.

  • I disassembled a few dozen bytes of the dump to see what it looked like. I have no idea what it's supposed to be doing, but seeing the code does take me back a few decades...

    E000 4C B0 E2 JMP $E2B0
    E003 AD 11 D0 LDA $D011
    E006 10 FB BPL $E003
    E008 AD 10 D0 LDA $D010
    E00B 60 RTS
    E00C 8A TXA
    E00D 29 20 AND #$20
    E00F F0 23 BEQ $E034
    E011 A9 A0 LDA #$A0
    E013 85 E4 STA $E4
    E015 4C C9 E3 JMP $E3C9
    E018 A9 20 LDA #$20
    E01A C5 24 CMP $24
    E01C B0 0C BCS $E02A
    E01E A9 8D LDA #$8D
    E020 A0 07 LDY #$07
    E022 20 C9 E3 JSR $E3C9
    E025 A9 A0 LDA #$A0
    E027 88 DEY
    E028 D0 F8 BNE $E022
    E02A A0 00 LDY #$00
    E02C B1 E2 LDA ($E2),Y
    E02E E6 E2 INC $E2
    E030 D0 02 BNE $E034
    E032 E6 E3 INC $E3
    E034 60 RTS

    Back in my C64 days, I used to practically think in 65xx assembly code... ah, memories.

  • Surprised none of the other grammar nazis* picked up on this:

    "...neither Steve nor Woz..."

    Erm, isn't Steve Wozniak one person?** Perhaps he meant "...neither Jobs nor Woz..."?

    * sorry if I mis-capitalized/mis-punctuated "Nazi's"

    ** spare the fat jokes

  • by SteveWoz (152247) on Tuesday July 15, 2008 @12:39PM (#24198317) Homepage

    I still own a couple Apple I's.

egrep -n '^[a-z].*\(' $ | sort -t':' +2.0

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