Ouch!
-- Shmuel (Seymour J.) Metz http://mason.gmu.edu/~smetz3 ________________________________________ From: IBM Mainframe Discussion List [[email protected]] on behalf of Michael Stein [[email protected]] Sent: Friday, June 2, 2023 6:51 PM To: [email protected] Subject: Re: Q: Transient SVC ? (2301 drum & SVCLIB) > I heard a legend of a system, probably not mainframe, on which a > programmer made the disk error handling routines transient. It worked > fine until it didn't. We had a 360/91 with a 2301 drum on selector channel 1. This had SVCLIB on it... At some point we got another 2301 and moved a small high usage local file there (partial parallel jobq). The initialization code for this "calculated" the number of records per track by running a channel program like: CCW read-count TIC *-8 And at the 2nd index point it got "no record found" leaving the last (highest) count field in storage. 2301 drums don't give "no record found" for this, so the channel program just kept running. Canceling it failed since it needed a transient area module and the channel path to SVCLIB was busy... Looking up the address in the selector channel lights and doing a small storage change to turn off the chaining bit in the read count CCW freed things up. PS: This storage change wasn't typing, lots of switches, one for each bit... http://www.columbia.edu/cu/computinghistory/img_2631.jpg ---------------------------------------------------------------------- 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
