Not XBAND, Sega Channel.

Former Xbanders on SNES or Genesis can get in touch with each other here. Also for people who wish to help with the Xband revival project.
Auto-Fox
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Not XBAND, Sega Channel.

Post by Auto-Fox »

This service, which, surprisingly, was successful enough to only be canceled upon the death of the Genesis hardware. It had a healthy number of subscribers, so I have learned, and was well liked.
Sega Channel did not enable multiplayer, but was a game download service which streamed code and video demos over a cable connection, much like the (telephone line) GameLine and (cable) PlayCable systems of the previous decade.
This would mean that a Sega Channel modem would not actually need to establish two-way communications with any sort of server. It simply waits for the appropriate block of code to come along the wire and downloads it.
This means something extraordinary.
Far-fetched scenario: a VCR recording of the Sega Channel could hold the appropriate code for one or more games, which could be downloaded by a Sega Channel modem when played into it via a connection from a VCR directly into the modem. Unfortunately, the chances of finding an authentic Sega Channel recording are slim at best.
However, if the code/equipment for a Sega Channel broadcast game could somehow be recorded in the present, it would mean that someone with a Sega Channel modem could simply pop in a VHS or DVD of a few recorded game code blocks, and use the Sega Channel modem to access them.
No need for a huge, bulky collection of games. A single good long-play tape could probably hold tons of them!
Potential problems might include tape deterioration and limited recording bandwidth which the Sega Channel modem might have been able to access, but a recording might not pick up.
Thoughts?
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Post by Warp2063 »

If I understand the Sega Channel article on Wikipedia correctly, then it used two channels simultaneously. I don't think there's any way to record two channels onto a tape simultaneously.

Furthermore, the Sega Channel would display a list of games, from which the user would then select the one they wanted to play. This indicates that there was bi-directional communication occurring - the user's Sega Channel cartridge must have been able to communicate with the server in order to get the download in the first place. I assume there was some authentication process involved. I do not believe that you could use something unable to respond to specific requests - like a VHS tape or a DVD - to circumvent this. You would need something that could dynamically change its responses to fit the situation - some kind of program.
I have my Saturns, I have some of my games, I have a RasPi. Gotta put all this stuff together!
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Post by xDerekRx »

My cousin had Sega Channel when I was younger. It was a beast sitting on top of the system. I honestly remember nothing about it other than playing around with it for a day and the size of it.
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Post by Warp2063 »

Further clarification on my previous post:
When you download a file, transfer requests and acknowledgments of receipt occur all the time - a recording would not be able to properly respond to these.

Further making this infeasible: how many Sega Channels are even out there? How many games were converted, if conversion was necessary, for the Sega Channel? If the files were specially encrypted or specially converted, where would we get them from? Who has the hardware to pull this off, anyway? The Sega Channel sounds like a specialized, early version of the cable modem. In fact, that's pretty much what it is - you subscribe to an ISP who then provides you with a cable modem. Your internet connection is sent via the existing cable network.

It sounds cool... but who could use it? And finally, it's so much easier to use a ROM than it would be to use this, provided you could get it to work somehow.
I have my Saturns, I have some of my games, I have a RasPi. Gotta put all this stuff together!
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Post by Auto-Fox »

From what I can tell, the Sega Channel modem wasn't capable of communicating with an outside server directly. I'm pretty sure the menus and games were all downloaded off the cable connection each time the modem powered up.
I imagine it would work off some kind of non-interactive recording, though upon further research, it has become apparent that, as you say, the service operated on two channels simultaneously, which would be hard to duplicate.
The Wikipedia article had this to say, however, on the nature of the broadcasts:

"Sega Channel was not a video-on-demand service per se; rather, as the service's name would suggest, it actually was a broadcast channel, similar to premium broadcast channels which (at the time) required a separate piece of addressable cable converter equipment to access. The program code for the on-screen menus and the 50 available monthly games was continuously broadcast as a sort-of "sequential access" RF signal. The menu system would be loaded into memory on power-up (which took about 30 seconds), and when a game was selected, the machine would "wait" for the requisite program code to be broadcast, then download it into volatile RAM."

Difficult, but not impossible to replicate.
And I'm not saying it's practical, I'm just saying it'd be cool. I'm fond of these little thought experiments.
Last edited by Auto-Fox on Sat Jan 23, 2010 9:25 pm, edited 1 time in total.
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Post by Warp2063 »

I never said it was impossible.

I wonder how it worked. I suppose if we were able to reverse engineer the code of the Sega Channel, we might be able to deduce how the signals were broadcast... but it would be extremely difficult to do. Technical documents would probably be much more helpful, but also difficult to come by.

If someone really wants to attempt it, I'm willing to offer whatever advice I can... but I really don't want to get involved in it, as there's no advantage to pursuing this that isn't easier and more accessible through ROMs and emulation. Even if there was a special downloadable game or a demo for the Sega Channel that wasn't available through retail channels, the only way to have preserved it until now would be to either possess the original file, or find a way to download them off a Sega Channel that had not been turned off since the day a game was downloaded onto it.
I have my Saturns, I have some of my games, I have a RasPi. Gotta put all this stuff together!
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Post by Auto-Fox »

Not saying it's practical myself, either. I'm just putting the idea out there. Also, it'd give people who HAVE Sega Channel modems something to do other than letting these relics collect dust.
As for games, it would probably be feasible to modify existing ROMs for Sega Channel compatibility, if, as you say, it could be deduced exactly how the signals were broadcast in the first place, and how the Sega Channel read them.
But I'm not really trying to start a project, just provoke discussion.
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Post by Warp2063 »

Well, as for finding whatever channels it connected to... theoretically you could find the frequency by analyzing the hardware. If the channels were variable, then the frequencies would be stored in software somewhere.

I do think it's kind of a marvel... up to... I believe they said four megabits? Half a megabyte, then, could be transferred to the Sega Channel. Say there were 50 games+menu being broadcast... If each one was half a megabyte big... that's 25 megabytes being transferred every minute (they said it took about a minute to download a game). That's almost 42KB/sec, or 336Kb/sec, which would have been an incredible internet transfer speed for the time.
I have my Saturns, I have some of my games, I have a RasPi. Gotta put all this stuff together!
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Post by Auto-Fox »

Well, it WAS essentially a cable connection.
And it was probably only one way, which helped I would imagine.
As the Wikipedia article says, larger games had to be either cut down or broken up into separate downloads.
As for operating channels, according to Wikipedia the modems were "tunable to 68 different operating frequencies between 51 and 118 MHz".
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Post by Warp2063 »

Auto-Fox wrote:As for operating channels, according to Wikipedia the modems were "tunable to 68 different operating frequencies between 51 and 118 MHz".
Probably so that each provider wouldn't have to use the same channel frequency, so they wouldn't have to "move" all their programming from one channel to another to make room for the Sega Channel. This also would open up the opportunity for the cable services to put the Sega Channel in a block of channels not normally available to other customers.

I wonder if the channel was set in hardware or software?
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Post by Auto-Fox »

Hardware most likely... still, maybe software. It's possible different cable services could set their own preferences on the unit prior to shipping. That would have been a big advantage.
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Post by Krazystyle83 »

Reviving this thread as well....
I've contacted Vandana Hedge and left a message on her voicemail.
Hopefully she gives me a call back.

http://www.linkedin.com/in/vandanahegde

I will be asking for any documentation since she worked on ( and honestly I imagine pretty much solo'ed) the server software for the sega channel.

Hopefully she'd be willing to hook us up with some documentation.

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Post by Warp2063 »

I personally don't think this project is worth pursuing. It's pretty darn tough to get hold of a Sega Channel device nowadays, and this would require a TON of work - far more than the XBAND. Telecommunications through a one-way repeating loop over a television signal. It was a cool idea, but there's no practical use for it these days. Not to mention we don't have any of the loops that they streamed. I don't remember if you could save one of those demos to the Sega Channel or not, but even assuming we could somehow pull it off of there, it would be much easier to just run that binary in an emulator than it would be to simulate a repeating loop of programming.
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Post by Krazystyle83 »

So the sega channel worked like Token Ring?
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Post by Warp2063 »

The Sega Channel was a basically a subscriber cable TV channel. However, instead of broadcasting a visible TV signal, they transmitted some kind of digital signal. This digital signal was a loop of all the content that was available on the service. When you would turn on your Sega Channel device, it would "tune in" to that TV channel, wait until it found the menu program in that signal loop, then load it into memory. At that point, you could use the menu program to select what demo or software you wanted to play. Then, the device would wait until THAT software came up on the loop, load it into memory, and allow you to play. No information was uploaded to the service - it was one-way communication, just like a regular television program. At least, this is how I understand it.

Without that loop, we have no software for the Sega Channel. Even if we had access to a specific game or demo from it, that game would just be a regular Genesis binary, and I'm sure it would take little to no effort to make it playable on a Genesis emulator. Even if we could somehow dump the Sega Channel's ROM, we'd only have whatever software was required to connect to the Sega Channel service. Without that dedicated Sega Channel being aired... we have no source of demos or games for the device, and therefore nothing of any use to dump or play.


Maybe if someone had used a VCR to record the Sega Channel back in the day... maybe we'd have something. But I don't know if it was a channel that could be readily recorded, or even if it would record or playback properly. Even then, it would be pretty pointless to emulate the full system if you could just glean the individual binaries from the loop.
I have my Saturns, I have some of my games, I have a RasPi. Gotta put all this stuff together!
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