External Hard Drives on Lion?

Format the drive as HFS+ and you'll be fine. There is no difference in compatibility between Leopard, Snow Leopard, Lion or Mountain Lion.

Format A Hard Drive Using Disk Utility (which is in your /Applications/Utilities folder)

Choose the appropriate format:

HFS+ (Hierarchical File System, a.k.a. Mac OS Extended (Journaled) Don't use case-sensitive)

• Read/Write HFS+ from native Mac OS X
• Required for Time Machine or Carbon Copy Cloner or SuperDuper! backups of Mac OS X system files.
  [*]To Read/Write HFS+ from Windows, Install MacDrive
  [*]To Read HFS+ (but not Write) from Windows, Install HFSExplorer
• Maximum file size: 8EiB
• Maximum volume size: 8EiB
• Mac OS X: Mac OS Extended format (HFS Plus) volume and file limits
• You can use this format if you only use the drive with Mac OS X, or use it for backups of your Mac OS X internal drive, or if you only share it with one Windows PC (with MacDrive installed on the PC)

NTFS (Windows NT File System)

• Read/Write NTFS from native Windows.
• Read only NTFS from native Mac OS X
  [*]To Read/Write/Format NTFS from Mac OS X, here are some alternatives:
  • For Mac OS X 10.4 or later (32 or 64-bit), install Paragon ($19.95) (Best Choice for Lion and Mountain Lion)
  • For Mac OS X 10.5 and later, including Lion, FUSE for OS X
  • For 32-bit Mac OS X, install NTFS-3G for Mac OS X (free) (does not work in 64-bit mode)
  • For 64-bit Snow Leopard, read this: MacFUSE for 64-bit Snow Leopard
  • Some have reported problems using Tuxera (approx $36).
  • Native NTFS support can be enabled in Snow Leopard and later versions, but is not advisable, due to instability.
• AirPort Extreme (802.11n) and Time Capsule do not support NTFS
• Maximum file size: 16 TB
• Maximum volume size: 256TB
• You can use this format if you routinely share a drive with multiple Windows systems.

exFAT (FAT64)

• Supported in Mac OS X only in 10.6.5 or later.
• Not all Windows versions support exFAT. See disadvantages.
• exFAT (Extended File Allocation Table)
• AirPort Extreme (802.11n) and Time Capsule do not support exFAT
• Maximum file size: 16 EiB
• Maximum volume size: 64 ZiB
• You can use this format if it is supported by all computers with which you intend to share the drive. See "disadvantages" for details.

FAT32 (File Allocation Table)

• Read/Write FAT32 from both native Windows and native Mac OS X.
  [*]Maximum file size: 4GB.
• Maximum volume size: 2TB
• You can use this format if you share the drive between Mac OS X and Windows computers and have no files larger than 4GB.

While not as fast as Firewire, USB 2.0 will work fine.

 

I have a Western Digital external My Book formatted in HFS+ that has successfully made the move from Tiger to Leopard to Snow Leopard to Lion and now Mountain Lion.

 

How is your experience with the My Book? Is it the one that uses ethernet for its connection? I looked them up on Amazon.com and got some strongly polarized reviews.

 

Mine have all been FW800 and they have worked great. Used the 1TB, 2TB and 4TB models and will soon be moving to the 6TB units.

 

exFAT is for flash media. It's not well suited for HDD or SSD. The usage is for predominately "large" files (music, photo, video files), with operations that are predominately read or write rather than mixed read and write, and operations with sequential writes (or reads), one file at a time like what you'd expect a camera dumping Raw or JPEG files to flash media; or the user importing those same files from flash media.

In other uses in particular across platforms, the incidence of file system corruption goes up. exFAT has only one FAT, whereas FAT32 has two FATs making repairs more successful. If an exFAT volume experiences corruption, there's a better chance of data loss.

The most cross platform file system is NTFS, for Mac, Windows, and Linux.