There were several Check-GD discs (also known as DC Checker) created for the Dreamcast. Some discs are just later builds of earlier disc's software, or variant versions of the software intended for different use cases.
Known pressed & labelled GD-ROMs
- SDPS-1: Loop Checker / 1.00 / SEGA CS / 01/06/2000 (dumped)
- SDPS-2: Unknown (undumped)
- SDPS-3: DC checker for REPAIR / 2.15R / CS.R&D / 01/12/2000 (undumped)
- SDPS-4: DC checker for MP / 2.16M / CS / 02/02/2000 (dumped)
- SDPS-5: DC checker for REPAIR / 2.16R / CS / 02/02/2000 (undumped)
- SDPS-6: Unknown (undumped)
- SDPS-7: Himozuke Family / 2.40 / CS / 07/14/2000 (undumped)
- Internal Printing Disc (HKT-999999) - (undumped) No images available, believed to be the same software as GD Drive Repair Program silver disc?
Known pressed silvers
- DC Checker for Repair v2.05R (DCSC205R) (dumped) (10/27/1999 date in IP.BIN)
- GD Drive Repair Program 0.1 (DCGD01) (dumped) (12/01/1998 date in IP.BIN)
There are multiple modes that the disc can be run in depending on what buttons you hold down at the IP.BIN screen:
- Holding nothing: Full checker
- Holding A + B: Full checker but without modem checks, req. for Asian modemless consoles to pass
- Holding X + Down on D-Pad: MP Checker mode, skips critical tests but runs the other tests
- Holding X + Right on D-Pad: Single test mode, disables test script and allows you to scroll through the individual tests and pick them at will
- Holding Y + Up on D-Pad: CLX Signature check, which renders a scene and compares calculated graphics data against reference data
- Holding Y + Right: CLX Signature Aging test, which performs the above test repeatedly on a loop. This test is available with and without a GD drive seek test included in the test loop.
- Holding Y + Down on D-Pad: Sonic Cube mode, which allows you to run several Holly samples, basically the same ones that are run during the scripted test modes, but you can control them with controller.
- Non-Tex Cube
- Tex Cube
- Punch-Thru Cube (X+Up/Down increases/decreases number of cubes, Y+Up/Down zooms in and out, start pauses/resumes motion)
- Vertex Test (B toggles mirror map and transparency, d-pad moves screen)
- Torus test (A changes number of doughnuts, Y+Up/Down zooms in/out, start pauses/resumes motion)
- Holding X + Left: FlashROM viewer mode, which displays information about the console stored in the FlashROM (serial number, factory codes, etc.)
- Holding X + Up: Katana Set5 checker mode, which runs the same diagnostic tests as those built into the BIOS of the Katana Set5
- Holding A + B + X + Down: Address checker mode, which displays a blank screen but allows the user to control a "tiny address checker" program via serial link
Console bricking risk
During the test process, the console flashROM is subject to both read and write tests, which result in the flashROM being completely erased (along with all console settings, ISP settings, Phantasy Star Online serial number & access code, etc.). This will not cause issues on a stock console, however, if the console has been modified with the region change mod and the write-enable wire has not been removed, the console's region coding will be erased and the console will no longer boot any software unless the flashROM is repaired or a region-free BIOS is installed.