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Dreamcast CHECK-GD

Blai

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The Dreamcast CHECK-GD


Description

Dreamcast Check-GD is a piece of software for the Sega Dreamcast contained in a specially labelled GD-ROM disc used by Sega to test the Dreamcast hardware. It runs a diagnostic check on the system and identifies any problems with the console it's running on.

CheckGD_US_Disc[1].jpg

The Check-GD comes in two parts:
  • A disc, which is placed inside of the Dreamcast console to run the diagonostics (this disc contains all the code).
  • An adaptor, which plugs into the Dreamcast's serial port to check its functionality. The disc will fail the SCIF test if the adaptor is not connected.

675px-Dc_checker_for_mp[1].png
CHECK-GD and adaptor, property of Adam Koralik.

The Check-GD tests all aspects of the hardware, curiously using art from Sonic Jam and music from the Japanese version of Sonic CD while doing so.

Check-GDs were not sold to the general public, and were unlikely to be used outside of Sega's testing facilities.


Versions

There's several versions of this disc floating around. On the old assemblergames forums somebody tried to make a list of them but it was not accurate.
Here's what I could come up with based on actual photos and dumps of the different revisions:


Pressed

Title Loop Checker
Version 1.00
Date - 01/06/2000
Disco No. SDPS-1
Dumped

Title DC checker for MP
Version 2.15M
Date 01/12/2000
Disc No. SDPS-4
Dumped

Title DC checker for REPAIR
Version 2.15R
Date 01/12/2000
Disc No. SDPS-4

Title DC checker for MP
Version 2.16M
Date 02/02/2000
Disco No. SDPS-4

Title DC checker for REPAIR
Version 2.16R
Date 02/02/2000
Disco No. SDPS-5

Title Himozuke Family
Version 2.40
Date 07/14/2000
Disc No. SDPS-7


Silver

Title DC Checker for Repair
Version v2.05R
Date 10/27/1999
Dumped

Title GD Drive Repair Program
Version 0.1
Date 12/01/1998
Dumped


Questions

  • What's the difference between 'DC checker for MP' and 'DC checker for REPAIR'?
  • Were there any CHECK-GDs also used in any SEGA office in Europe?
  • Are there any other versions of this disc?

References

https://segaretro.org/Dreamcast_Check-GD
https://hiddenpalace.org/DC_Checker_for_Repair_(Oct_27,_1999_version)
https://hiddenpalace.org/DC_Checker_for_MP_(Jan_12,_2000_version)
https://hiddenpalace.org/Loop_Checker_(Nov_9,_1999_version)
https://dreamcast.wiki/Check-GD
 
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MetalliC

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An adaptor, which plugs into the Dreamcast's serial port. Its main use is to flash a replacement BIOS onto the console.
afaik it is nothig but serial port cable, it has nothing with the BIOS.

What's the difference between 'DC checker for MP' and 'DC checker for REPAIR'?
MP stands for "Mass Production", i.e. for some facilities which do that.
REPAIR obviously for repair workshops.

Are there any other versions of this disc?
I do believe each facility got pesonal unique checker disc, which have encoded unique IDs, dates etc of target facility.
so, I think there exists as many different checker discs as was repair / servicing / etc workshops involved in Dreamcast project.
 

Blai

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Thanks for your answers @MetalliC

With facilities you mean factories were they assembled Dreamcast consoles or SEGA's customer service locations?
 

darcagn

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The two silver discs that are listed are in my possession. Regarding your references, the Hidden Palace articles were mostly written by me and the dreamcast.wiki page was completely written by me, based mostly off of collecting info from the internet.

An adaptor, which plugs into the Dreamcast's serial port. Its main use is to flash a replacement BIOS onto the console.
The disc refuses to boot without the adaptor inserted, even if the adaptor is not connected to a computer as originally intended.

These statements are false and as far as I can tell is just some BS that Adam Koralik made up. It's a shame that he has such a large collection of rare Dreamcast hardware that he doesn't understand at all and uses it to make videos that misinform instead of teach.

The BIOS in a Dreamcast is a maskROM and cannot be flashed or modified. The cable has nothing to do with the BIOS at all.
Without the serial cable plugged in, the disc works just fine, but the software will fail at the SCIF test. You could also use the button configuration I detailed on the dreamcast.wiki page to skip the SCIF test outright.

Knowing this, I deduced that the cable is just a serial loopback cable, so I made a serial loopback cable by grabbing a NeoGeo Pocket <-> Dreamcast connection cable, disconnecting the serial lead from the internal PCB, and connecting pin 4 (RX2) to pin 5 (TXD) and connecting pin 6 (RTS) to pin 7 (CTS). This allows the DC Checker software to use the loopback to test the serial connectivity and with this setup the test will pass.

  • What's the difference between 'DC checker for MP' and 'DC checker for REPAIR'?
Like MetalliC said, one is MP (i.e. mass production -- for production facilities) and one is for repair facilities.
The difference is the tests that are run by default when you put the disc in. But by using button combos you should be able to run any test.

  • Were there any CHECK-GDs also used in any SEGA office in Europe?

The two silver discs that I have in my possession were sourced from European contacts. The same contacts also provided SOE repair documentation, so the same discs were used in European repair facilities.

  • Are there any other versions of this disc?

The list on dreamcast.wiki contains all of the versions I could find pictures/information for on the internet.

I do believe each facility got pesonal unique checker disc, which have encoded unique IDs, dates etc of target facility.
so, I think there exists as many different checker discs as was repair / servicing / etc workshops involved in Dreamcast project.

It is certainly possible that such unique information is encoded in some way on the disc, but I haven't personally noticed anything on these discs which ties it to a specific facility. If you have any more information which points to this I'd love to know more
 

Blai

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Thanks @darcagn for your replies. I've now modified the main post to accomodate the new information.
 

MetalliC

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It is certainly possible that such unique information is encoded in some way on the disc, but I haven't personally noticed anything on these discs which ties it to a specific facility. If you have any more information which points to this I'd love to know more
I've analyzed a lot of checkers various code, including routines which display or generate flash ROM "factory sector", you may see result ot this work there - https://github.com/mamedev/mame/blo...86c8b10addeb/src/mame/drivers/dccons.cpp#L730
where documented all the fields.

all these data (except of "stuff roll" list of creators) generated by checker software, including - tool_number, tool_version, dates, factory code, etc. which identify this exact checker disc and hardcoded in executable binary.

but, if you grab several of DC flash dumps, you'll see there different tool-related numbers, which means there was quite many of different discs which was used to generate flash system sectors.
 
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