Any command other than TIC requires a non-zero count; otherwise the channel gives a program check. '03'X is a control command and, per Enterprise Systems Architecture/390 Common I/O-Device Commands, Second Edition, IBM, April 1992, SA22-7204-01, no-op. I know of no device that looks at the data for a no-op, and certainly not a printer.
-- Shmuel (Seymour J.) Metz http://mason.gmu.edu/~smetz3 ________________________________________ From: IBM Mainframe Discussion List [IBM-MAIN@LISTSERV.UA.EDU] on behalf of Paul Gilmartin [0000000433f07816-dmarc-requ...@listserv.ua.edu] Sent: Monday, December 6, 2021 8:38 PM To: IBM-MAIN@LISTSERV.UA.EDU Subject: Re: DFSORT job to convert FBM to FBA On Mon, 6 Dec 2021 13:34:05 -0700, Sri h Kolusu wrote: >> X'03' is "No operation" i.e. "don't print". C'+' is "Print >withoutspacing." > >X'03' is "No operation" for "Machine withOUT data" > I believe even a no-op CCW (used to?) need a nonzero count, else the channel threw an error. Perhaps the channel didn't know what the command meant to the device. I believe the data were transferred but the printer didn't print them. I don't know whether an invalid character in a no-op caused a data error. It's all probably model-dependent. -- gil\ ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
