STRUCT PRIVATE_BIOS_DATA(9)

💾 struct private_bios_data

okay so bestie, welcome to the Kernel API Manual entry for struct private_bios_data — it's literally bios private data for boot devices, and we're gonna read it together. No cap, it's giving tiny-but-iconic. 💅✨

🌸 NAME 🌸

struct private_bios_data — bios private data for boot devices.

🦋 SYNOPSIS 🦋

Here's the whole struct, copied exactly so you can trust the vibe:

       struct private_bios_data {
           uint8_t geometry        :4;
           uint8_t unused          :4;
           uint8_t boot_drv;
           uint8_t rsvd[12];
           uint16_t cksum;
        };

🎀 Members 🎀

• geometry — bits 0-3 - BIOS geometry, 0x0001 - 1GB, 0x0010 - 2GB, 0x1000 - 8GB, all other values are invalid.
• unused — bits 4-7 are unused.
• boot_drv — logical drive set as boot drive, 0..7 - for 8LD cards, 0..39 - for 40LD cards.
• cksum — 0-(sum of first 13 bytes of this structure).

👑 SEE ALSO 👑

• Kernel file ./drivers/scsi/megaraid/mbox_defs.h — go peek, bestie, that's where the lore lives. 🫶

okay that's the page! source/version: ./drivers/scsi/megaraid • date: October 2026 • struct private_bios_data(9) — mwah, ily! 💋🎀