Storage

This section is in beta. See the note on the cheat sheet.

The PS2 has three storage devices a homebrew project might use: the disc, the memory card and the hard disk (rarely used today). All three are reached through the IOP. Each has a low-level driver and a filesystem layer on top of it.

Disc

• cdvd (core) is the low-level EE-side interface to the drive: raw sector reads and tray and disc status.
• cdvdfsv (core) is the IOP-side CD/DVD filesystem server, the ISO9660 layer that turns raw sectors into files and directories.
• cdfs (core) registers the cdfs: device (built on cdvdman, the low-level IOP driver) that your program opens files through.

Memory card

The memory card is physically a SIO2 peripheral (see Controllers), but it is used for storage and has its own filesystem layer:

• mc (core) is the EE-side RPC client and mcman (core) is the IOP driver it talks to, the same client and driver pattern as pad and padman.
• mcserv (core) is a higher-level IOP-side filesystem server on top of mcman. It understands the memory card's directory and file structure, not only raw sector access.
• fs-osd and hdd-osd (core) implement PFS, the filesystem format used by the PS2 BIOS save-game browser. Required for save data to appear in the system's memory-card management screen, on a memory card or the HDD (see below).
• mmceman (world) targets a memory card emulator. It backs save data with something other than a physical card without changing the mc API.

Hard disk and block devices

The HDD (rare on retail hardware, more common in development setups) and USB mass storage share a different layer, because neither is a SIO2 peripheral:

• apa (core) is the APA partition manager, the PS2's disk-partitioning scheme. It registers hdd0: as a device.
• bdm (core) is a block-device manager. It parses MBR and GPT partition tables for devices that are not APA-formatted, such as a USB drive.
• bdmfs_fatfs (core) is a FAT12/16/32 filesystem driver on top of bdm. It makes a FAT-formatted USB drive readable as files.
• fs-osd and hdd-osd (the same PFS packages as above) also provide BIOS-browser-compatible save data on the HDD.

See also

• Controllers - the memory card as a SIO2 device
• EE, IOP, and SIF - the RPC pattern behind mc and cdvd