Depending on why you 'need' to sort the data, you may not have to at all. Instead a compound index on the three variables you normally want to sort by.

proc datasets lib=mylib; modify mydata; index create sortby3=(var1 var2 var3); run;

any datastep or proc with a by var1 var2 var3; will utilize the index to pull out obs in sorted order.

Rich

Robert Virgile wrote in message <3729FDD2.6A3BA077@mediaone.net>... >If you try this, run it overnight. It sometimes chews up enormous amounts of >CPU time: > >proc sort data=whatever tagsort; >by byvars; > >The tagsort option uses less space, usually at the expense of CPU time. It >sorts just the by variables plus a tag to the observation number, then retrieves >the remaining variables based on the observation number. > >Bob Virgile > > >jgropp1 wrote: > >> I have a data set with 7569504 observations and 7 variables and I'm trying >> to sort it by 3 variables and I'm having trouble with the work space >> available for sorting. The data is approx. 407 MB itself and there is about >> 1.5 GB of remaining space on the hard drive. I figured even if SAS rewrote >> the file 3 times during the sort procedure then the would still leave about >> 300MB of space, however I still run out of disk space. I know that one can >> play around with the Proc Sort options to correct my problem but I am leery >> about changing some parameters without some guidance. I'm using SAS 6.12 >> for Windows on a system with WIN98 350mhz/64mb ram. Any ideas? >> >> Thanks, >> Jeff