09107: pcipc(s7): Bios cannot recognize the hard disk size correctly.

ID	Category [?]	Severity [?]	Reproducibility	Date Submitted	Last Update
09107	Media Support	Major	Always	Feb 8, 2025, 04:12	Feb 22, 2025, 14:41

Tester	VasiliyFamiliya	View Status	Public	Platform	MAME (Official Binary)
Assigned To		Resolution	Invalid report	OS	Windows 10/11 (64-bit)
Status [?]	Closed			Driver	pc/pcipc.cpp
Version	0.274	Fixed in Version		Build	64-bit
		Fixed in Git Commit		Github Pull Request #

Summary	09107: pcipc(s7): Bios cannot recognize the hard disk size correctly.
Description	As a result, we have a stuck at the middle of formatting before OS install.
Steps To Reproduce	Select an attached blank CHD as a hard disk image (its actual logical size is 5120 MB) and go to BIOS settings menu.
Additional Information	sis85c496 machine from pcipc_sis driver also has this bug (see the screenshots).
Github Commit

Flags
Regression Version
Affected Sets / Systems	pcipc(s7)

Attached Files	pcipc.png (12,648 bytes) Feb 8, 2025, 04:12 Uploaded by VasiliyFamiliya
	pcipcs7.png (12,572 bytes) Feb 8, 2025, 04:13 Uploaded by VasiliyFamiliya
	sis85c496.png (19,591 bytes) Feb 8, 2025, 04:13 Uploaded by VasiliyFamiliya
	MyWin.zip (5,605 bytes) Feb 8, 2025, 04:14 Uploaded by VasiliyFamiliya

No.22970 Robbbert Moderator Feb 8, 2025, 04:48 edited on: Feb 8, 2025, 04:48	A lot of older bioses had limits on what size hard drive they could properly support. For example, a 386 computer would not normally handle more than 512MB. DOS itself is limited to 2GB maximum. Using a 5.4 GB drive? No idea what support you could expect.
No.22971 VasiliyFamiliya Tester Feb 8, 2025, 05:19	As I noted earlier, the real HD size is 5.0 GB. For some reason, BIOS "sees" a 249 MB more than HD really have.
No.23027 cuavas Administrator Feb 21, 2025, 23:30 edited on: Feb 24, 2025, 03:35	What C/H/S parameters did you use to create the disk? The numbers it’s showing are correct for the suggested C/H/S mappings: * 512×652×25563 = 5,362,882,560 bytes, rounded to 5,363 million bytes 512×16,384×16×40 = 5,368,709,120 bytes, rounded to 5,369 million bytes * 512×8,192×32×40 = 5,368,709,120 bytes, rounded to 5,369 million bytes 5 GiB = 5×1024×1024*1024 = 5,368,709,120 bytes. It’s seeing the correct size, and giving three suggested mappings that give no more than the actual size. You’re confusing the displayed value in megabytes (MB, 10^6) for mebibytes (MiB, 2^20). If you can’t give actual evidence that it isn’t detecting the disk correctly, this should be closed.
No.23033 cuavas Administrator Feb 22, 2025, 14:41	The premise of the report, that the BIOS is choosing an incorrect size when detecting the disk and choosing geometry, is incorrect and based on a bad assumption.