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Internal HDD

SMS can read media straight off the PlayStation 2's internal hard drive — in two completely different ways. There's the classic APA / PFS scheme (the same format HDD-OSD and the OPL-era tools use), where SMS browses a dedicated SMS_Media partition; and there's the modern route, a plain exFAT drive read through the ATA block driver, which shows up as an ordinary massN: device you can fill with files from any PC. Both live on the same physical disk, so you pick one per boot.

⚠ You need the hardware first
The internal HDD is optional PS2 hardware. A fat PS2 needs the Network Adapter (the expansion-bay module that carries the internal IDE connector); the drive itself sits in the HDD bay behind it. Slim consoles have no internal HDD bay at all. If your console has no drive fitted, skip this page and use USB, MX4SIO or SMB instead.

Two ways to use the HDD

SMS is a media player, not a game loader — so the HDD is just another place to keep your video, music and pictures. The catch is that the internal drive can be formatted in one of two schemes, and SMS reaches each one through a different driver stack:

💽APA / PFSThe classic SMS_Media partition 🗂️exFAT via ATAA plain drive as massN:

They are mutually exclusive: both paths want to own the internal ATA bus, so whichever one starts first takes it and the other quietly steps aside. You choose which by picking the matching Autostart toggle — see Choosing one below.

How it appearsAPA / PFSexFAT via ATA (BDM)
Format on the diskSony's APA partition scheme + PFS filesystemPlain exFAT partition
What SMS browsesThe SMS_Media partition on the driveThe whole exFAT volume, any folders
Device name in SMSInternal HDD (APA)massN: (shared BDM mass namespace)
Made withHDD-OSD / OPL-era APA & PFS toolsAny PC — format exFAT, copy files
Enable withAutostart HDD APAAutostart HDD BDM

APA / PFS — the SMS_Media partition

The APA partition scheme and PFS filesystem are the PS2's own native HDD formats — the same ones used by Sony's HDD-OSD (the "PlayStation BB Navigator" era) and by the classic homebrew HDD tools. On this kind of drive, SMS looks for a dedicated media partition named SMS_Media, mounts it, and lets you browse and play whatever media files you've placed inside.

ℹ Where the name comes from
SMS's internal-HDD path mounts a PFS partition set aside for media and presents its contents in the file list. Because this is the classic PS2 HDD format, an SMS_Media (PFS) partition you prepared with any standard APA/PFS tool is exactly what SMS expects to find — there's no separate SMS-only formatting step.

Preparing an APA drive

SMS doesn't format drives or create partitions itself — you do that ahead of time with the usual PS2 HDD tools (HDD-OSD, or a homebrew APA/PFS partition manager such as uLaunchELF). The short version:

Format the drive as APA

Initialise the internal drive with the standard PS2 APA scheme, the same way you would for any HDD-OSD / OPL-era setup. This is a one-time step done from a HDD tool, not from SMS.

Create a PFS media partition

Make a PFS partition to hold your media and name it SMS_Media. Copy your video, audio and picture files into it (folders inside are fine — SMS browses the raw tree).

Enable the APA path in SMS

Turn on Autostart HDD APA in the settings (or use Start HDD APA now — see Enabling & tips). SMS starts the HDD driver stack and mounts the SMS_Media partition.

Browse and play

Pick the internal-HDD icon in the device menu, press Down into the file list, and open any file with Cross. It behaves exactly like every other SMS source — the raw filesystem, no mandatory folder layout.

⚠ APA drives are ~2 TB and older-drive friendly
The APA scheme addresses drives up to about 2 TB. If you have a larger drive — or you'd simply rather copy files from a PC without any PS2-side tools — use the exFAT route below instead.

exFAT via ATA

The modern alternative skips APA entirely. Format the internal drive as plain exFAT on your PC, drop your media anywhere on it, and let SMS read the drive through its ATA block driver. Because that driver plugs into the same Block Device Manager (BDM) that handles USB, MX4SIO and i.LINK, the internal drive simply appears as another massN: device in SMS — no PS2-specific formatting, no partition juggling.

ℹ One shared massN: namespace
USB, MX4SIO, the exFAT internal HDD and i.LINK all mount into the same massN: pool (N = 0, 1, 2…). The number is assigned as devices come up, so a drive is mass0: if it mounts first, mass1: if a USB stick got there ahead of it, and so on. You browse it by picking its device icon in the top row, not by memorising the number.

Preparing an exFAT drive

Format exFAT on your PC

Connect the drive to a computer (or format it in-bay with a PC-side tool) and format it as exFAT. Leave the allocation-unit / cluster size at the default for the drive's capacity rather than choosing a custom value.

Copy your media

Drag your video, audio and picture files onto the drive — into any folders you like. SMS browses the raw filesystem, so there is no required folder tree (no OPL-style DVD//CD/ layout).

Fit the drive and enable the BDM path

Install the drive in the console's HDD bay, then turn on Autostart HDD BDM in SMS (or Start HDD BDM now). SMS brings up the ATA driver and the exFAT volume mounts as massN:.

Browse and play

Select the internal-HDD icon in the device menu and open files just like any other massN: device.

⚠ Copy large files one at a time
The PS2 reads far better from files that aren't fragmented. When you copy a batch to an exFAT drive, add big video files individually rather than dumping the whole folder in one go — many PC copy operations interleave a large batch, fragmenting every file. Sequential copies keep playback smooth.

Choosing one — they're mutually exclusive

Here's the important constraint: the APA/PFS path and the exFAT/ATA path both own the internal ATA bus, so only one can be active at a time. SMS enforces this with a simple "first come, first served" rule — whichever backend starts first claims the bus, and the other declines to start for that session.

ℹ First to start owns the bus
If the APA HDD path comes up first, the exFAT/ATA path won't start (and vice versa). This isn't an error — it's SMS keeping two drivers that both drive the same internal disk from stepping on each other. To switch schemes, disable the one you don't want (or don't autostart it) and reboot so the other can claim the bus cleanly.

Practically, that means you decide up front which scheme your drive is formatted for and enable the matching autostart:

Your drive is…Turn onLeave off
APA-formatted with an SMS_Media partitionAutostart HDD APAAutostart HDD BDM
exFAT-formatted (a plain drive)Autostart HDD BDMAutostart HDD APA

Autostart HDD BDM is the ATA/exFAT path — "BDM" because the exFAT drive is read through the same Block Device Manager as your other mass devices. Autostart HDD APA is the classic native-partition path.

⚠ Don't enable both
Turning on both autostarts doesn't get you both drives — it just means whichever one happens to initialise first wins the bus, and the result depends on start order. Pick the one that matches how your drive is formatted and leave the other off.
Can the HDD run alongside USB, MX4SIO, MMCE and SMB?

Yes — the internal-HDD bus contention is only between the two HDD schemes. Whichever HDD path you choose can run happily at the same time as USB, i.LINK and SMB. Note two other exclusions elsewhere in SMS: MX4SIO and MMCE share the memory-card (SIO2) bus, so only one of those two runs at once; and the exFAT/ATA HDD is a massN: device like USB and MX4SIO, so they simply each take their own slot in that shared namespace.

Enabling & tips

On a clean install nothing auto-starts — you turn on exactly what you need. The relevant controls live in the settings menu:

ℹ If a start stalls, watch the status line
Starting the internal HDD spins the drive up and probes it, which takes a moment. SMS shows the current stage on the status line as it goes; if a start ever hangs on an unusual drive layout, the last message on screen tells you exactly which stage it reached. Because the HDD isn't set to auto-start on a clean install, a failed manual start won't stop SMS from booting next time — just reboot and try the other scheme, or fall back to USB/MX4SIO.

Practical tips

🗂️Devices OverviewHow every source fits together 🔌USBThe other big massN: device 🔗i.LINKFireWire storage, also BDM mass 🔧Settings ReferenceEvery autostart toggle