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Thread: How did analog cassette tape loading protocols work?

  1. #21
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    Quote Originally Posted by Trixter View Post
    However, getting one helpful pointer to what I asked for among ten "that's a stupid idea" responses has put me off of the project for good.
    I don't think it's neccesarily a stupid idea, but I don't think it (or anything else) can meet the ADT-alike goal, for the target machine. However, I'd like to say that the communications interface portion of what you want to do already exists, many times over. So writing software that writes files to disk, or entire disks, might still be beneficial. Reading/writing files from a sound card is already very doable on 80386 and later systems. Probably 80286 as well. We certainly have it for TRS-80, C64, and others. But I'm positive nothing exists with the intent to write a boot disk, and probably anything on a 5150. I'm trying to think of the best way to present what exists already to you. I'm not well versed in it.

    I suppose the next time someone asks for an ADTPro-like-thing for PCs will be told to purchase a gotek floppy emulator. (I am personally not a fan of those, as they change the outside appearance of the system, but I'll pass along the recommendation.)
    I think Unknown_K has the best solution. At least whilst USB floppy drives are on the market.

  2. #22
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    Well maybe someone else here who is into "soundcard modes" will be able to explain this. I couldn't find anything on the web that's helpful. Everyone assumes you are already familiar with this stuff. Even ARRL has pretty lacking information, at least on their website.

    This might be a good start: http://www.arrl.org/shop/Get-on-the-...l-2nd-Edition/

  3. #23

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    You know laplink had a simple bootstrap. I don't recall all of how it was done.
    If you can get into a monitor or basic you should be able to bootstrap the machine. I did similar for the H89/H8 years ago. I had a about 50 bytes that one typed in the monitor. Connected to a serial, it would then download enough code to format and write to the disk, whatever disk image you wanted. You could even make a disk with the code to write disk that booted to that code ( quicker than entering the 50 bytes again ).
    Kansas City wasn't always the same. Many used different headers but the same basic two tone signal.
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  4. #24

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    Quote Originally Posted by Dwight Elvey View Post
    You know laplink had a simple bootstrap. I don't recall all of how it was done.
    You use the MODE and CTTY commands at the DOS prompt to configure and then transfer control over to the serial port, and then LapLink transfers itself to the client computer. But you still need a bootable DOS disk for that to work.

    Instructions here: http://www.minuszerodegrees.net/tran...3/laplink3.htm

  5. #25

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    Quote Originally Posted by vwestlife View Post
    You use the MODE and CTTY commands at the DOS prompt to configure and then transfer control over to the serial port, and then LapLink transfers itself to the client computer. But you still need a bootable DOS disk for that to work.

    Instructions here: http://www.minuszerodegrees.net/tran...3/laplink3.htm
    Ah Yes, now I remember. You copy the serial to a file, change the name and execute it. You still need a booted DOS disk.
    Dwight

  6. #26
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    Assuming I want to just do the serial route (which would result in the least amount of typing by the end user anyway), what would be practical from the sender side? I'm guessing a terminal program that supported sending via xmodem would be simplest. Looks like there are PuTTY variants/modules that do this (I don't want to write a sender program).
    Offering a bounty for:
    - The software "Overhead Express" (doesn't have to be original, can be a copy)
    - A working Sanyo MBC-775, Olivetti M24, or Logabax 1600
    - Documentation and original disks for: Panasonic Sr. Partner, Zenith Z-160 series
    - Music Construction Set, IBM Music Feature edition (has red sticker on front stating IBM Music Feature)

  7. #27
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    Kermit works. I don't like it for the same reason I don't like ADT: it requires constant user interaction on both the sender and receiver side, but it works.

    Xmodem works, too.

  8. #28
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    Trying to keep it simple for a BASIC type-in program. Since the application will be a serial cable between two computers, I don't think robust error-checking would be required, and simple xmodem (128-byte payload) should be sufficient. (That, and 15 minutes of searching "kermit file transfer protocol specification" has been fruitless; Columbia's unnecessarily obtuse and self-congratulatory website wants you to buy a book, and James Huggins' "Kermit: Specifications and Verification" is laughably unreadable. I did eventually find it in http://www.kermitproject.org/onlinebooks/kermitbook.pdf but by then I already decided xmodem was much simpler to implement.)
    Offering a bounty for:
    - The software "Overhead Express" (doesn't have to be original, can be a copy)
    - A working Sanyo MBC-775, Olivetti M24, or Logabax 1600
    - Documentation and original disks for: Panasonic Sr. Partner, Zenith Z-160 series
    - Music Construction Set, IBM Music Feature edition (has red sticker on front stating IBM Music Feature)

  9. #29
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    I don't disagree. The only reason I bring up Kermit is that it seems to be easier to find turn-key versions of it for a greater number of platforms.

    But you've found the same thing I found about it.

  10. #30

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    As long as you keep the cable length short, there is no reason to do any error checking, at least for the first level of boot strap. You just want the minimum code to setup the serial and read a specific number of bytes into memory. It would then jump to that code. The code could be xmodem or what ever. The code you enter in basic would then be quite short. In my H89/8 program, even with 50 bytes, a person is likely to make a mistake. Once the minimal code is there, what it loads is whatever you want. Don't expect the first level of boot strapping to be a fancy protocol. It should be simple. Just get the byte from the serial, put it into memory and sequence to the next location. I wrote my code such that when it was done transferring it would over write part of the loader and start executing what was loaded. This allowed the boot strap to be the smallest possible amount of code. You don't need to be that fancy, you can just use the basic to jump to the program.
    Dwight

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