It seems that as SAS was removing access to the SAS launch command by pushing users off SAS desktop and onto EG, they also moved the option to unbuffer the log to the commande line.
In V6 we had command line option -$logflush, then program option UNBUFLOG in V7, then invocation option again in V9 with option LOGPARM.
Not having the option to unbuffer the log output means that when your SAS session fails, it is very likely that the last bits of log information, which are the bits of interest for investigating the failure, will not be available.