Google apps
Main menu

Post a Comment On: The Dreamcast Junkyard

"Forensic Examination Of The Dreamcast Corpse - File 1 of 2"

20 Comments -

1 – 20 of 20
Blogger The 1 Ross said...

Nice nice article. The Atomiswave was a great little system.

"Despite what Wikipedia claims, the Atomiswave specs are practically identical to the Dreamcast (and not the NAOMI as is often misreported)." I'm interested to hear why you think the Atomiswave's hardware and architecture is more similar to the Dreamcast that the Naomi. All three have almost identical specs.

Saturday, May 30, 2015

Blogger The 1 Ross said...

In fact the only area that I can see they differ is in their RAM; the Naomi and Atomiswave had 32mb of ram where as the Dreamcast only has 24.Atomiswave roms can also be played on the Naomi via Netbooting, but I don't think there is thus far any way to play Naomi or Atomiswave games on the Dreamcast.

Saturday, May 30, 2015

Blogger The 1 Ross said...

Also, I hope you realise that the majority of your Atomiswave carts are fake...they have the exact same serial number as my fakes :)

Saturday, May 30, 2015

Blogger Tom Charnock said...

Wow - some pressing questions there. Doc - the floor is yours!

Saturday, May 30, 2015

Blogger doceggfan said...

When I started the article, it was based on places like system-16 stressing that the Atomiswave is DC based and not Naomi. Until I had opened it up, my incorrect assumption was that it could literally by a DC mobo with jamma pinouts retrofitted, which would explain where the backlog of DC systems went. I was a little disappointed to find that the AW was a whole new PCB, as it's unlikely that they would have desoldered complete dcs to recycle the components, but they could have repurposed any excess supplies of unused sh4s and pvr2s originally intended for dc manufacture.

I guess it's a moot point - the DC, NAOMI and AW are all part of the same family, but perhaps it's more accurate to say that the DC is the parent of 2 siblings, rather than the AW being spawned from the NAOMI. It's also a step back from the NAOMI specs in terms of memory, and the AW's compact design more closely resembles the DC.

I didn't know about AW games running on NAOMI boards though. Are they unmodified AW Roms? That's really interesting, and perhaps blows my argument out of the water...

Saturday, May 30, 2015

Blogger doceggfan said...

PS.. Yeah, I am aware they're bootlegs. shhhh, don't tell anyone.

Saturday, May 30, 2015

Blogger doceggfan said...

PPS. A minor correction regarding “Sammy's first foray into the Arcade games market ” That would actually be the Sammy Seta Visco SSV, which I only became aware of just now.

Saturday, May 30, 2015

Comment deleted

This comment has been removed by the author.

Saturday, May 30, 2015

Blogger doceggfan said...

Another similarity between DC and AW that I didn't have time to explore was the networking/modem expansion port on both systems, both located in the same spot on the board when considering the AW's upside-down orientation. This gave the AW access to AW.NET, which I believe was used for competitive play between different machines in different arcades, and would later spawn the ALL.NET once Sega and Sammy merged. I don't think the NAOMI was ever used in this way, though it did get networking expansions via the Network DIMM board and the Satellite terminals, but I think these were only ever used for local networks within individual arcades, rather than across different locations.

I could be totally wrong here and making lots of assumptions, happy to be corrected if anyone knows more.

Saturday, May 30, 2015

Blogger doceggfan said...

Did some further research on the subject (and am overrunning the comments section).

NAOMI 1 (Unknown revision, probably circa. 1998)

CPU: SH-4, HD6417091
GPU: SEGA 315-6201


Dreamcast Rev 0

CPU: SH-4, HD6417091
GPU: SEGA 315-6225

Dreamcast Rev 0, Aug 99

CPU: SH-4, HD6417091R
GPU: SEGA 315-6225

Dreamcast Rev 1, Jan 00

CPU: SH-4, HD6417091R
GPU: SEGA 315-6226-X1

Dreamcast Rev 1, May 00

CPU: SH-4, HD6417091R
GPU: SEGA 315-6227


Atomiswave AM3AGA-06, 2003

CPU: SH-4, HD6417091RA
GPU: SEGA 315-6227


Of course, these chip revisions probably have no differences between them other than dates of manufacture, but based on this evidence alone, the Atomiswave would be more closely related to a late model Dreamcast than an early model NAOMI.

However, it's likely that the NAOMI would have undergone revisions too during this time, but these are the only component numbers I could find. If I had a NAOMI 1, I'd be persuaded to crack it open and have a look, but I've only got a NAOMI 2.

Sunday, May 31, 2015

Blogger doceggfan said...

And some further research:

Naomi

Main Memory = 32MB
Graphic Memory = 16MB
Sound Memory = 8MB

Atomiswave

Main Memory = 16MB
Graphic Memory = 16MB
Sound Memory = 8MB

Dreamcast

Main Memory = 16MB
Graphic Memory = 8MB
Sound Memory = 2MB

The reason Atomiswave games are more easily ported to NAOMI than Dreamcast is because the two arcade systems are designed to have their games graphics and sound all loaded into memory at start up, whereas the Dreamcast cuts corners on memory and get around it by spooling it in during play from the GD when required (resulting in pesky loading times). Since the NAOMI has more memory than the Atomiswave, that makes it easier to port, simply requiring a bit of tweaking and changing the game to recognise the NAOMI's JVS standard button inputs instead of the Atomiswave's JAMMA inputs.

So the Atomiswave sort of sits in the middle between the 3 machines, and is basically what you'd end up with if you beefed up the Dreamcast's memory to load all of the game at start up. The NAOMI just sits above this a little with a bit more beef.

Sunday, May 31, 2015

Blogger Quzar said...

Following on an earlier comment, I have an email from SEGA back in the day where the Hitatchi date code (3 character code on the top right of the chip) was explained.

Quoting from SEGA Support:

"The Hitachi MCU date code is three characters long. Here is the general
format:
XYZ, where:
-X is the last digit of the year of manufacture. For example, if X=5,
the year could be 1995, 1985, etc.
-Y is the month of manufacture:
A=Jan, B=Feb, C=Mar, D=Apr, E=May, F=Jun, G=Jul, H=Aug, J=Sep, K=Oct,
L=Nov, M=Dec. "I" is not used.
-Z is the work week of the month of manufacture, 1, 2, 3, 4 or 5."

Based off that, the SH4 processor in the Atomiswave pictured in the article was manufactured on the first week of September 2000. This may just be a coincidence, or standard practice, but through the life of the Dreamcast the chips were manufactured relatively shortly before the assembly of the console. These processors were also not 'off the shelf', as they had customizations for SEGA.

Sunday, May 31, 2015

Blogger doceggfan said...

Cool Quzar, thanks for the info.

According to the most recent DreamPod, Adam did mention that Dreamcast production did slow down towards the end of 2000, so it could be that Hitachi were still supplying SH-4 chips, but it looks like Sega didn't end up using them until they palmed them off to Sammy in 2003.

Or alternatively, they could have been desoldered and recycled them from unsold Dreamcasts, but I don't think this would be very likely. I'd imagine there would be too much risk of damage and defective chips to make the process worthwhile (at least based on the way that I hamfistedly desolder things).

Sunday, May 31, 2015

Blogger Tom Charnock said...

Fascinating stuff. Loving these comments.

Sunday, May 31, 2015

Blogger Retro Raider said...

Great article, now eagerly anticipating the follow up article. I'm loving the new team at the yard, keep up all the great work.

Sunday, May 31, 2015

Blogger Mongroovy said...

Great article, really interesting story!

Sunday, May 31, 2015

Blogger The 1 Ross said...

I find the relation between these three systems and the Naomi 2 and Hiakru to a lesser extent, really interesting and I'm certainly not saying I'm right and anybody else is wrong. The history and development of most arcade systems just isn't as well documented as their console counterparts so it's a real struggle to find the 'absolute truth' so to speak.

For example, was the Naomi based on the Dreamcast or was the Dreamcast based on the Naomi? This is another question that I've seen answered both ways but never any real hard proof for either. I was actually doing some research today at work (sshh, don't tell anyone) in Japanese and I discovered some things that I've never seen written in English anywhere on the net. My guess has always been that they were developed alongside each other rather than one based on the other, but now I'm even more sure that is the case. I'm going to try and make a video in the coming weeks talking about all five of the 'Dreamcast' systems. If I don't get round to it then I'll at least post them on the Facebook group in writing at some point.

As for the Atomiswave, my gut tells me that it wasn't specifically based on the Naomi, Naomi 2, Hikaru or Dreamcast, but rather it was decided to make another system within this family and then suitable components and architecture were chosen for it. I'll be doing some more research on Japanese language sites over the next week so I'll keep you posted.

It's a really interesting topic anyway, thanks for bringing it up. I think when people talk about the history of the Dreamcast they often neglect to include these systems as a part of it. When in actuality their histories are all intertwined.

Monday, June 01, 2015

Blogger The 1 Ross said...

Edit: I'm going to try and make a video in the coming weeks talking about all five of the systems within the 'Dreamcast' family.

Monday, June 01, 2015

Blogger Tom Charnock said...

Cool - look forward to seeing that.

Monday, June 01, 2015

Blogger doceggfan said...

Me too, interested to hear about the untranslated Japanese stuff you've found. Since you raised the question which made me look into it further, I've seen lots of arguments from both sides. As you say, it's probably best not to dwell on who begat who and view them all as kind of independent but part of the same family. Maybe we'll get to the bottom of this one day - and you'll hear it first on the junkyard (maybe)

Monday, June 01, 2015

You can use some HTML tags, such as <b>, <i>, <a>

This blog does not allow anonymous comments.

Comment moderation has been enabled. All comments must be approved by the blog author.

You will be asked to sign in after submitting your comment.
Please prove you're not a robot