ASE : What's next available device number?

In the old version (before 12.5), whenever we need to create a new device, we have to calculate the next availabe device number. The way to do it is run

select max(low/16777216) from sysdevices

then use the number + 1 as next available device number. and make sure sp_configure ‘nubmer of device’ is higer enough. In Sybase 12.5, device no is no longer required, sybase will automatically pick the next available number for any new device.