Date: Fri, 7 Dec 2001 07:59:56 -0600
Reply-To: greg.woolridge@TAP.COM
Sender: "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From: Greg Woolridge <greg.woolridge@TAP.COM>
Subject: Re: How does SAS work?
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What SAS does is to write the output to a temporary file during the PROC or
DATA step. Once the step is complete, the file is then copied to the data
set named for the output. Therefore; if you are reading and writing to the
same data set, SAS first creates the temporary data set, copies the
temporary data set over the original one and then deletes the temporary
data set. This is why you must have at least 2x the needed disk space for
any data set SAS creates.
Greg M. Woolridge
Manager, Study Programming
TAP Pharmaceutical Products Inc.
e-mail: greg.woolridge@tap.com
phone: 847-582-2332
fax: 847-582-2403
"Stanley A.
Gorodenski" To: SAS-L@LISTSERV.UGA.EDU
<vvgsgor@DE.ST cc:
ATE.AZ.US> Subject: How does SAS work?
Sent by:
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Discussion"
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12/07/01 07:38
AM
Please respond
to "Stanley A.
Gorodenski"
Within one procedure, such as proc summary or proc sort, I can read from
and write to the same file, such as in:
proc summary data=cy1998.temp;
by assn ernumber;
var wage981 wage982 wage983 wage984;
output out=cy1998.temp
max(wage981 wage982 wage983 wage984)=;
This is IBM mainframe and in my JCL I have the following
allocation for the file:
//CY1998 DD DSN=USRG.TEST.OF.IT.STAN,UNIT=3390,
// DISP=(NEW,CATLG,DELETE),
// SPACE=(CYL,(10,10),RLSE),DCB=(BUFNO=2,BLKSIZE=4096)
How does SAS do this, i.e., read from and write to the same file
in one procedure? If this were SPSS, the job would abort,
with the message: 'File is already in use and not closed'.
Thanks.
Stan
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