Do you really need a dedicated audio HD to record 24/96 tracks in Protools LE 8?

[amurray35]

I am planning on purchasing a used Mbox 2 Pro w/Pro Tools 8 LE package because my older Dell laptop fullfills the system requirements (barely) to run the software plus has a FireWire interface, but only two working USB ports.

The problem is that it only has one i394 port (unpowered), which will be taken up by the Mbox 2 Pro interface, so I can't add another FireWire HD. However, according to the Pro Tools knowledge base it states:

•Full 32 track, 24 bit, 48 KHz performance from just one dedicated IDE/ATA or SATA audio drive is supported.

•Full 32 track, 24 bit, 96 KHz performance from two dedicated IDE/ATA or SATA audio drives is supported.

However, it also says that "drive performance depends on a number of factors, including track count, edit density, and the use of crossfades or processing such as plug-ins". So my first question is, can I still record and play back a reduced number of tracks on my system HD, or when it says "just one dedicated IDE/ATA or SATA audio drive" does it mean one IN ADDITION to the system drive?

If I need a dedicated audio drive, can I get away with using a USB 2.0 external HD, and if so, how many tracks can I realistically expect my system to handle with just the minimum hardware requirements (2.4 Ghz core duo uP, 1G RAM, 120G 7200 rpm HD) ?

I would like to be able to record in 24 bit/96Hz mode, but typically only use 10 - 12 tracks for demos and amateur recordings and such...

TIA