Category C (Class 2) LGV / HGV training runs around Ipswich, Suffolk and uses the DVSA Test Centre in Ipswich. C is the category that allows you to drive a rigid vehicle over 3,500kg.
USB 2.0 is much faster than the DVD data rate. DVD 1x (slowest) write speed is 1.39MB/s. DVD 24x (fastest) write speed is 33.24MB/s. USB 2.0 write speed is up to 35MB/s. A 24x DVD max is about 32MB/s while USB2 max is about 60MB/s.
Yes but only if there is not enough system memory. In this case the system uses the hard drive as RAM (swap file) and this makes the computer quite slow. The USB-Solution is better than the swap file solution but much slower than more RAM, because USB 2.0 is limited to 50 or 60 MB/s transfer-speed.