Not all IDE drives compatible with PS2.I have tried 160GB USB HDD but PS2 cant see it.I made a partition about 110GB and formatted with FAT32 filesystem then it recognized.For internal use(U have FAT PS2 right?) I know you cannot use WD IDE HDDs because other IDE drives' pinout is 4x2 but on WDs 5x2 so it cant fit to network adapter.If you want to use via USB make it about 100-110GB(I cant remember what size exactly) max.
SCPH-50004 PAL with Messiah II Pro
PSP-3004 on 6.60 Pro-C
160 GB Slim PS3 (Upgraded to 320GB) on Rogero 4.40 with 4.41 Spoof
160 GB Slim PS3 (Dead while trying to DG)
And blocked account(over £50 in wallet). DAMN $ONY!!!