On Tue, 18 Sep 2007 11:40:07 -0400, Craddock, Chris <[EMAIL PROTECTED]> wrote: -snip- >There does not seem to be anything magical about that length. The >content of the text macro parameter ends up being tacked onto the end of >the CIB and the CIBX follows behind that. It is -possible- that the >limit is in fact larger, but where the book specifies an actual number I >tend to treat it as gospel. Someone from IBM can probably tell us >whether the limit is real or a doc apar waiting to be noticed.
No magic, only ancient constraints. When MGCRE was introduced, there were minimal structural changes made to the rest of SVC34 proper. The front end module (IEE0003D) was updated to accept a new kind of parameter list and munge that data to look like a command was issued. Notable changes were the 4-byte console id, console name and CART. It wasn't until the console restructure that MCS support was actually changed to issue MGCRE, about 15 years after it was introduced. The control blocks that transport the command to the various exit points, routers and command processors were really only tweaked to use the new source/target console information, so the 126-byte limit was never relieved. On Wed, 19 Sep 2007 02:24:19 -0400, Jim Mulder <[EMAIL PROTECTED]> wrote: -snip- >> How does this match with the 126 char length limit described in >> MGCRE? > > Given a maximum command length of 126, the maximum possible >operand length is >126 > - 1 (minimum command verb abbreviation length) > - 1 (minimum number of spaces between the verb and the operand) > = 124. Precisely. The stingy use of memory dates from a time that the CSCBs and CIBs were in 24-bit common. After moving the control blocks above the line and command flooding support, the constraint is relieved, but the history lives on. If there's a line for relieving the constraint, I'll bet on the over. :) Scott Fagen Enterprise Systems Management ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
