Hi Phil, On Thu, Sep 02, 2010 at 03:07:05PM +0100, Philip Rowlands wrote: > Found the answer (I think); all parms are not created equal. > Parms from memory are not case-adjusted; these include parms from zipl > -P, zipl -p, and those punched following the kernel image if using a > virtual reader. These parms have a 896-byte limit.
There are different parameters on the kernel command line, for example, kernel or module parameters, or others for the initrd / installer.. For s390x, the kernel command line are concatenated from different sources. Typically, parameters are specified in the zipl boot configuration, but you can use the IPL PARM or LOADDEV SCPDATA to add or replace parameters. The 896-byte limit applies to the zipl boot configuration and to the parmfile that is used by IPLing from reader. With IPL PARM or SCPDATA you can extend the size (up to max 4K (but only with SCPDATA ;-)) > Parms from registers are case-adjusted; these are parms passed with the > IPL ... PARM ... > syntax. These parms are limited to 64 bytes (or maybe 41). The IPL PARM is used to specify up to 64 characters (56 when IPLing from NSS). Because you enter the PARM in a CMS/CP session, CP converts them all to upper case. The conversion to lower case happens only if all characters are in upper case. To pass parameters in mixed case, you can do this in a REXX script (using the "address command" statement). > RH bugzilla 475530 appears to add IPL ... PARM support, but I can't find > any documented description of case handling, just empirical tests. For documentation, take a look at http://public.dhe.ibm.com/software/dw/linux390/docu/lk34dd06.pdf (http://www.ibm.com/developerworks/linux/linux390/documentation_dev.html). We recently added a new chapter about kernel and module parameters. There you can also find the documentation for IPL PARM. If you have further question, please let me know. Thanks and kind regards, Hendrik -- Hendrik Brueckner [email protected] | IBM Deutschland Research & Development GmbH Linux on System z Development | Schoenaicher Str. 220, 71032 Boeblingen IBM Deutschland Research & Development GmbH Vorsitzender des Aufsichtsrats: Martin Jetter Geschaeftsfuehrung: Dirk Wittkopp Sitz der Gesellschaft: Boeblingen Registergericht: Amtsgericht Stuttgart, HRB 243294 ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390 ---------------------------------------------------------------------- For more information on Linux on System z, visit http://wiki.linuxvm.org/
