Home Forums Hardware Mac Desktops & Notebooks Slow startup, slow shutdown

OK, here is what Micromat said:

"Thanks for your kind comments.

The Surface Scan reads raw data (blocks) from an entire device, from the first block to the last. It does not read files. Its operation is not affected by the partition map scheme or the types of volumes on the drive. The drive does not even have to have a partition map or any volumes on it. Think of a tone arm on a phonograph playing a record from the first groove to the runout groove, and you will have a useful, though not perfect analogy.

If other processes are making use of the drive or device for reading or writing while the Surface Scan is in progress, the scan will take more time, but it will in no way be less accurate. The operating system handles requests for reading and writing from devices, and puts them into a queue. The requests get executed in an orderly fashion.

The amount of free space has absolutely no effect on the time it takes to read every block on the device. The Surface Scan does not distinguish blocks that belong to files from blocks that do not. It just reads blocks, to make sure they can be read.

The faster the drive and the bus, the faster the scan will go. One would expect most of the reading to be sequential."

So, it looks like it is OK (and safe?) to be doing other tasks while a Surface Scan is going on. But, note that the Surface Scan will slow down some. And as others have pointed out, using other tasks will be somewhat slow also.

I suspected the amount of free space has nothing to do with a Surface Scan, and Micromat confirmed it.

And, as I suspected the speed of the Surface Scan depends upon the speed of the drive, the type of connectivity, the bus speed, etc.

Myself, I will still let Surface Scans run while nothing else is going on with either of my Macs.