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Apple ][ game server

asciiexpress.net

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Re: Apple ][ game server

#31

Post by rbanffy »

jaysonelliot wrote: post #27
rbanffy wrote: post #14

Earlier quoted context omitted.

I loved those Amdek monitors. Never got one for myself. Now that I am a grownup who can afford such eccentric hobbies, I got myself a pair of http://tulip-house.ddo.jp/digital/SDISK2/english.html and one http://dreher.net/?s=projects/CFforAppleII&c=projects/CF... Worth every penny.

You mean I could put my library of software on an SD card and convince the Apple computer that it was reading from a floppy drive? Wow.

The sdisk is not that clever - I got it for a clone that has an onboard disk II and no slot 7. For the more Apple-like I got the CFFA, which is very smart and can emulate an HDD controller and a disk II

Re: Apple ][ game server

#32

Post by zak_mc_kracken »

rumblestrut wrote: post #12

In my Steve Jobs memorial ( http://www.ericjgruber.com/blog/2011/10/thank-you-steve-jobs... ), I opined about the Apple IIe and one of my favorite games growing up, Montezuma's Revenge. And sure enough, it's there. Seeing this made me wish I could play it again. Excellent job.

http://www.virtualapple.org/montezumasrevengedisk.html

Re: Apple ][ game server

#33

Post by datajerk »

landyman wrote: post #23
agentgt wrote: post #17

Where is the hell is Oregon trail? I could have sworn that was Apple 2 maybe it was 2e.

I think it was Apple 2 as well. This was the first thing I looked for.

Sorry guys. The Apple Game Server can only stream single binary RAM-only games. Disk-based games can be streamed to disk at http://asciiexpress.net/diskserver. I added Oregon Trail.

Re: Apple ][ game server

#34

Post by jashmenn »

So I am basically clueless on how to transfer bits via audio without data loss (doesn't noise corrupt the bits?)

Does anyone have any links or resources on how to do a 'hello world' of audio-based data transfer?

Re: Apple ][ game server

#35

Post by datajerk »

jashmenn wrote: post #34

So I am basically clueless on how to transfer bits via audio without data loss (doesn't noise corrupt the bits?) Does anyone have any links or resources on how to do a 'hello world' of audio-based data transfer?

Yes, noise corrupts the bits.

"the most common cause of error is external sounds being piped into the download stream (e.g. mail alerts) and low volume" -- http://asciiexpress.net/gameserver/readme.html

There are many ways to transfer info via audio (e.g. google for modem or frequency-shift keying). The Apple Game (and Disk) Server does not use FSK however. It relies on the Apple II cassette port which is nothing more than a 1-bit digital-analog-converter. IOW, it can detect the shift from positive to negative (zero crossing). The game server WAV files encode the game @ 48K samples/second using a single 12kHz wave for the zeros and a single 8kHz wave for the ones. IOW, 4 pulses for 12kHz (2 +, 2-) and 6 pulses for the 8kHz. The Apple II has a 1023000 cycles/second clock. So I have to detect the zero crossing, chksum and write the data in 1023000/12000 ~= 85 clock cycles. As long as the audio stream is clean and perfect (something only a computer or CD player can do), then it works every time.

If you load up any of the games in Audacity (freeware waveform editor), you can actually "see" the 0's and 1's. The 0's will be thinner.

Lastly, I will be publishing an article on my blog (http://jerkwerks.com) this month with how it works and all the source code.

Re: Apple ][ game server

#36

Post by jeffbarr »

jashmenn wrote: post #34

So I am basically clueless on how to transfer bits via audio without data loss (doesn't noise corrupt the bits?) Does anyone have any links or resources on how to do a 'hello world' of audio-based data transfer?

Back in the old days, my young friend, we had these awesome devices called modems. They translated digital data to sounds (and back) for transmission across telephone lines. I'm sure you can find a picture and complete technical details somewhere.

Re: Apple ][ game server

#37

Post by quadhome »

jashmenn wrote: post #34

So I am basically clueless on how to transfer bits via audio without data loss (doesn't noise corrupt the bits?) Does anyone have any links or resources on how to do a 'hello world' of audio-based data transfer?

As to the noise and data corruption:

http://en.wikipedia.org/wiki/Error_Control_Coding#Data_stora...

Re: Apple ][ game server

#38

Post by Urgo »

So very very cool! I bought an apple iie off ebay a year and a half ago since it was the first computer I ever used and had been meaning to get some games for it but just haven't had the time. When I saw this post today I was like a kid all over! I searched frantically for a cable to plug my phone into the apple iie but ended up having to go out and buy one but it was so worth it :)

Anyway I put up a video about it as well and figured I'd share it here as well. Thanks so much for this!

http://www.youtube.com/watch?v=e_e8wYEC72I

Re: Apple ][ game server

#39

Post by wiradikusuma »

I remember a couple of years ago, I was on a bus and there's an old lady sitting next to me. We had a chat, then she said that she owned a "useless old computer called Apple 2." She really wanted to get rid of it in exchange of small amount of money.

I said, "Cool, let me see what I can do, here's my email."

I was an idiot, really. I forgot that she might not know how to use email, and I didn't ask her contact.

Re: Apple ][ game server

#40

Post by jaysonelliot »

rbanffy wrote: post #31
jaysonelliot wrote: post #27

Earlier quoted context omitted.

You mean I could put my library of software on an SD card and convince the Apple computer that it was reading from a floppy drive? Wow.

The sdisk is not that clever - I got it for a clone that has an onboard disk II and no slot 7. For the more Apple-like I got the CFFA, which is very smart and can emulate an HDD controller and a disk II

Thanks for the tip. I emailed the CFFA guy to get on the list for the next batch.

How much did it cost? I can't see a price on his site.

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