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Why did Coleco Scrap the original SGM in favor of the ADAM?

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55 minutes ago, retroillucid said:

 

 

quick_data_microwafer_advert.png

Look at the shipping costs at the bottom right of the Ad...

 

In the U.S. - $3.00 for standard shipping and $10 for overnight shipping

 

Those were the days!

 

Edited by NIAD
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I'm kind of impressed at entrepo beat MS by 4 years in bundling together a suite of packages including Word and spreadsheet programs and calling it "office"!

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10 hours ago, retroillucid said:

You can clearly see in the first prototype it uses the Entrepo drive

As why I'm sure the 2nd one is using the Exaltron, this very same prototype has been shown in CES in June 1983

There's various photos showing the 2nd prototype along with Exaltron tape
The initial release date was September, 1983

Why would Coleco had re-designed the ADAM and posponed the release in October?

Can you post a photo of that second prototype with an entrepo/exatron tape.  It looks more like the cassette drive in the released adam than the side loading entrepo/exatron drive.

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10 hours ago, mr_me said:

  It looks more like the cassette drive in the released adam than the side loading entrepo/exatron drive.

That's only because the String Tape is the same size as a DDP 

Like I said earlier, if it was not the case, why Coleco would completely re-designed the ADAM just 2 months before the initial release date (September 1st) ? 

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The prototype in that second photo looks like it has DDP cassette drives, but I have no evidence to reference.  It could be an early DDP based prototype that was later changed.

 

To me the Entrepo QDD microwafers look a lot like Exatron ESF wafers with a write protect tab added.

Edited by mr_me

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11 hours ago, mr_me said:

Can you post a photo of that second prototype with an entrepo/exatron tape.  It looks more like the cassette drive in the released adam than the side loading entrepo/exatron drive.

The ADAM prototype #1 (as well as the Prototype ColecoVision Super Game Module) that used the Entrepo "WAFER" drive was side loading like the drives manufactured and sold for other computers by Entrepo. Retroillucid has posted example pics previously of the ADAM prototype #1 as well as the DK Jr. Super Game on a Wafer.

 

The ADAM prototype #2 used the Exatron Stringy Tape Cassette drive and Exatron referred to these cassettes as digital data packs which Coleco obviously picked up on and used this name for their drive and tapes that evolved from the Exatron product. There is no rhyme or reason why Coleco decided to change the orientation of the drive from it's original side loading style (probably easier to remove an eaten tape as we all know from dealing with car cassette decks that are side loading when tapes get eaten), but they did and it's pictured in the second prototype and the Stringy Tape cassette is pictured previously (Buck Rogers Super Game). Anyway, to make a long story short, Coleco tried using storage drives that already existed in order to speed up the development of the ADAM in order to make the stated release date. These existing drives proved to be too unreliable to use and their In-House R&D (probably along with help from JVC and/or Teac) improved upon the Exatron design to come up with the Digital Data Drive and Digital data Packs.

 

The picture attached looks to be a pretty accurate time line of the ADAM prototype development using the 3 different drives, from left to right:

 

- Expansion Module #3 ADAM with Entrepo Wafer Drive (prototype #1)

- Stand-Alone ADAM with Entrepo Wafer Drive (prototype #1)

- Expansion Module #3 ADAM with Exatron Stringy Tape Drive and no door release (prototype #2)

- Retail Stand-Alone ADAM with Digital Data Drives and the prototype external 5 1/4" FDD on top covering the DDD door release buttons

 

ADAM Computer - Prototypes.jpg

Edited by NIAD
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31 minutes ago, mr_me said:

The prototype in that second photo looks like it has DDP cassette drives, but I have no evidence to reference.  It could be an early DDP based prototype that was later changed.

 

To me the Entrepo QDD microwafers look a lot like Exatron ESF wafers with a write protect tab added.

The reason is the Exalton String tape is the same size as a DDP 

Hence why the drives looks similar to the DDP drives

 

While I agree the Micro Wafer looks ''similar'' to an Exatron String Tape, their size are completely different

 

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Here's a couple of photos of the exatron ESF wafers.  I think this is their original design that  goes back to 1978 and found success with the TRS-80 I and III.  They are about the size of a business card, 3/16" thick with a 1/16" continuous loop tape inside, 64kB max.

http://www.trs-80.org/exatron-stringy-floppy/

download.jpeg.762450b14e39d1e2b751d802d1612c6e.jpeghardware_esf_wafer_snappedr.jpg.ba1507954598cfdc15877b2082af09a4.jpg

 

I think the entrepo QDD drive and microwafer is a 1983 update that was marketed for the c64 and zx spectrum without much success.  It's sized at 67x45x6mm with a 1/16" continuous loop tape inside, 128kB max.  Something like this was probably used for the first coleco prototypes but looks slightly different.

Microwafers-QDD.jpg.ddd431327b535bf1410d9eeacb256718.jpg

 

Neither of these looks like the Buck Rogers supergame pack posted earlier.  That one looks more like an audio cassette housing but I have no idea what's inside.  Perhaps exatron/entrepo was trying to create something new for coleco or could it be coleco themselves.  I'm thinking their old design, used for trs-80, was working okay.  Their updated drive was not as they tried to cram in more capacity maybe by using thinner tape.

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11 minutes ago, mr_me said:

Here's a couple of photos of the exatron ESF wafers.  I think this is their original design that  goes back to 1978 and found success with the TRS-80 I and III.  They are about the size of a business card, 3/16" thick with a 1/16" continuous loop tape inside, 64kB max.

http://www.trs-80.org/exatron-stringy-floppy/

download.jpeg.762450b14e39d1e2b751d802d1612c6e.jpeghardware_esf_wafer_snappedr.jpg.ba1507954598cfdc15877b2082af09a4.jpg

 

I think the entrepo QDD drive and microwafer is a 1983 update that was marketed for the c64 and zx spectrum without much success.  It's sized at 67x45x6mm with a 1/16" continuous loop tape inside, 128kB max.  Something like this was probably used for the first coleco prototypes but looks slightly different.

Microwafers-QDD.jpg.ddd431327b535bf1410d9eeacb256718.jpg

 

Neither of these looks like the Buck Rogers supergame pack posted earlier.  That one looks more like an audio cassette housing but I have no idea what's inside.  Perhaps exatron/entrepo was trying to create something new for coleco or could it be coleco themselves.  I'm thinking their old design, used for trs-80, was working okay.  Their updated drive was not as they tried to cram in more capacity maybe by using thinner tape.

The ones made for Coleco had proprietary design exclusive to Coleco
For copy protection I suppose

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Sure but coleco's first prototype is likely based on the same 1/16" 128kB drive and internal tape mechanism used in the c64 and zx spectrum drives by exatron/entrepo.  That buck rogers tape looks completely different.  It looks like it has two spools like an audio cassette which would mean it's not continuous loop.  If it was developed by exatron/entrepo it's completely different than what they've had in the past.

Edited by mr_me

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Coleco SGM is a cassette tape? :-o

 

I thought it would be a cartridge supports over 32k.

 

I wonder if a diskette, likes NES in Japan, would work better. It has 64k each size.

 

At this time, diskettes are expensive.

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31 minutes ago, Serguei2 said:

...

At this time, diskettes are expensive

So were 32k rom cartridges.  These are the reasons they went with tape.  And you don't need an expansion module to have cartridges over 32k.

Edited by mr_me

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1 hour ago, mr_me said:

So were 32k rom cartridges.  These are the reasons they went with tape.  And you don't need an expansion module to have cartridges over 32k.

At the time, yes you did. Bankswitching over 32K implied using 64K ROM chips, or 128K, or higher. Those bigger ROM chips weren't commercially viable until the NES came long a few years later.

 

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Do you mean 128 kbit rom chips because there were 48kB rom cartridges in the 1980s.  In 1983 we started seeing 24kB cartridges, then 32kB in 1984, and then 40kB and 48kB cartridges as rom prices were coming down.  Coleco was out of video games by this time.

Edited by mr_me

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2 hours ago, mr_me said:

Do you mean 128 kbit rom chips because there were 48kB rom cartridges in the 1980s.

No, I mean 128 Kbytes, like what was used in The Legend of Zelda on NES.

 

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Sure, but that was 1987 and nintendo was already overcharging for cartridges.  Are you saying there were no 128kbit or 256kbit rom chips before then.

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You said a 512 kbit (64kB) rom chip was required for bank switching cartridges greater than 32kB.  I would have thought they could have used smaller chips.  Either way 1985 would have been about the time these larger cartridges would have been expected, as you said.

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