Transient area loading used WAIT.
-- Shmuel (Seymour J.) Metz http://mason.gmu.edu/~smetz3 ________________________________________ From: IBM Mainframe Discussion List [[email protected]] on behalf of Paul Gilmartin [[email protected]] Sent: Thursday, June 1, 2023 12:39 PM To: [email protected] Subject: Re: Q: Transient SVC ? On Wed, 31 May 2023 21:28:34 -0700, Michael Stein wrote: > > ... So any SVC number ending in 0 resulted in a >last character of x'c0' or '{'. > >from: MVT source pds AAPVT member IEATRANS > >TRANSVC LH RWORK3,SVCID(RRB) . GET SVCID > CVD RWORK3,SVCNAME . CONVERT SVC NUMBER TO DECIMAL > UNPK SVCLPANM+4(4),SVCNAME+5(3) .UNPACK TO 4 DIGITS > That could have been fixed with a simple "OI X'F0', SVCLPANM+7", but storage was precious in the day. >While SVCLIB was a PDS with a directory as normal, for performance >reasons, modules were NOT usually locaed by name. Instead a module which >transfered control to another had the name along with a place for the TTR >(disk address) of the target module. > ... >So transient area "program fetch" just had to read the block >(at most 1K) from the specified TTR... > Did it do a proper check for I/O completion, or just rely on bit-spinning? I recall a PDP-8 paper tape bootstrap loaded that kept reading until it overlaid an instruction with a branch to the loaded program. > There was a program which had to >be run anytime SVCLIB was reorganized which used the names to update >all the TTRs in the SVC modules. Also the SVC table entry for SVCs >not in link pack contained the TTR of the module. > Backup recommended. -- gil ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
