The ASE was started by some account on the Linux host.
Typically, an account for a user named "sybase" is created when the
Linux system admins install ASE, but the account name really
can be anything. ASE is sometimes installed under the root account,
but that isn't recommended (xp_cmdshell can then be used to
cause some mischief). The linix user who started the ASE is
the one that needs the permissions to access /dev/*
All accounts on ASE that have permission to run DISK INIT
essentially act as the OS (linux) user who started ASE when
it comes to permissions on the OS.
-bret