WARNOCK@prism.clemson.EDU (Todd Warnock) (09/04/87)
Can anyone supply information on where these are documented and what they do ? (Any other undocumented parameter information would also be appreciated !) Thanks ! Todd Warnock VAX Systems Clemson University Clemson, South Carolina 29634-2803 ARPA: Warnock@Prism.Clemson.EDU BITnet: Warnock@Clemson CSnet: Warnock@Clemson.CSnet
carl@CITHEX.CALTECH.EDU.UUCP (09/07/87)
> Can anyone supply information on where these are documented and what > they do ? (Any other undocumented parameter information would also > be appreciated !) They are documented (if nowhere else) in SYS$HELP:SYSGEN.HLB. The following is the help info given by sysgen: $ SYSGEN:==$SYSGEN $ SYSGEN HELP PAR IOTA Parameters IOTA (Special Parameter) I/O time allowance - This parameter sets the number of 10 millisecond units to charge the current residence quantum for each voluntary wait. The correct value approximates the cost of a disk I/O neglecting wait time. $ SYSGEN HELP PI Parameters PIXSCAN (Special Parameter) PIXSCAN specifies the number of process index slots scanned per second for computable or computable-outswapped processes. Such processes will receive an automatic priority boost for 1 QUANTUM, assuming that the priority of the currently executing process is not in the realtime range (16-31). The priority boost is implemented to avoid potential deadlocks, such as when a process executing below DEFPRI acquires a volume lock on a critical disk and cannot release it, because the process is unable to access the CPU.
klb@philabs.Philips.Com (Ken Bourque) (09/08/87)
Here are the descriptions of the special parameters as documented in the Sysgen help library (sys$help:sysgen.hlb). The descriptions are also accessible from Help while in Sysgen. -------------------- 2 DLCKEXTRASTK (Special Parameter) Deadlock extra stack - Amount of extra interrupt stack to leave when doing a deadlock search. 2 LRPMIN (Special Parameter) Minimum allocation request for large request packets. 2 SRPMIN (Special Parameter) Minimum allocation request for small request packets. 2 MPW_THRESH (Special Parameter) Modified page writer threshold - Lower limit threshold stopping the use of the modified page writer from being used as the primary mechanism to recover memory. 2 MPW_WAITLIMIT (Special Parameter) Modified page writer busy wait limit - Threshold of when to put a process into resource wait if it is generating a modified page and the size of the modified list is greater than this parameter. 2 SWPALLOCINC (Special Parameter) Swap file allocation increment value - The size in blocks to use to backup swap file space allocation in the swap or page file. Space in the file will be allocated multiples of this unit up to WSQUOTA to guarantee swap space. 2 PANUMPOLL (Special Parameter) CI port - number of ports to poll each interval. Not currently implemented. 2 VMS (Special Parameters) Digital reserved SYSGEN parameters are VMSD1, VMSD2, VMSD3, VMSD4, VMS5, VMS6, VMS7, and VMS8. 2 PAGTBLPFC (Special Parameter) Default page table page fault cluster size - specifies the maximum number of page tables to attempt to read to satisfy a fault for a non-resident page table. 2 SYSPFC (Special Parameter) Page fault cluster for system paging - The number of pages read from disk on each system paging operation. Not currently implemented. 2 EXUSRSTK (Special Parameter) Extra user stack automatically provided by the image activator so that the operating system can recover from a stack overflow. 2 CHANNELCNT (Special Parameter) Permanent I/O channel count - specifies the number of permanent I/O channels to provide. 2 IMGIOCNT (Special Parameter) Default number of pages of image I/O address space used by the image activator if not specified at program link time. 2 MPW_PRIO (Special Parameter) Modified page writer I/O priority - This parameter sets the priority of I/O transfers initiated by the modified page writer. 2 SWP_PRIO (Special Parameter) Swapper I/O priority - This parameter sets the priority of I/O transfers initiated by the swapper. 2 TBSKIPWSL (Special Parameter) Maximum number of working set list entries that may be skipped while scanning for a "good" entry to discard. Set to 0 to disable skipping. 2 PHYSICALPAGES (Special Parameter) Maximum number of physical pages to be used - permits testing of smaller memory configurations without actually removing memory boards. 2 PFRATS (Special Parameter) Page fault rate system threshold - This parameter sets the target system page fault threshold. Not currently implemented. 2 SWPRATE (Special Parameter) Swap rate control - This parameter sets the swapping rate and serves to limit the consumption of disk bandwidth by swapping. 2 IOTA (Special Parameter) I/O time allowance - This parameter sets the number of 10 millisecond units to charge the current residence quantum for each voluntary wait. The correct value approximates the cost of a disk I/O neglecting wait time. 2 SWPFAIL (Special Parameter) Swap fail count - This parameter sets the number of consecutive swap schedule failures to occur before the swap schedule algorithm changes to ignore the swap quantum protection. 2 LOCKRETRY (Special Parameter) Number of retries to perform when trying to lock a multi-processor data structure. 2 NOAUTOCONFIG (Special Parameter) Auto configuration inhibit - inhibits the automatic configuration of all devices. 2 NOCLOCK (Special Parameter) No clock - inhibits the starting of the interval timer for debugging purposes. 2 NOCLUSTER (Special Parameter) Clustering inhibit - inhibits all page read clustering. 2 WRITABLESYS (Special Parameter) Leave system writable - for debugging purposes leaves system code writable. 2 RESALLOC (Special Parameter) Enable resource allocation checking. 2 SSINHIBIT (Special Parameter) Set to inhibit system services on a per process basis. 2 CONCEAL_DEVICES (Special Parameter) Set to enable concealed devices. 2 PIXSCAN (Special Parameter) PIXSCAN specifies the number of process index slots scanned per second for computable or computable-outswapped processes. Such processes will receive an automatic priority boost for 1 QUANTUM, assuming that the priority of the currently executing process is not in the realtime range (16-31). The priority boost is implemented to avoid potential deadlocks, such as when a process executing below DEFPRI acquires a volume lock on a critical disk and cannot release it, because the process is unable to access the CPU. 2 LOADERAPAT (Special Parameter) Load the file ERAPATLOA.EXE into the EXEC in place of the default $ERAPAT. 2 LOADCHKPRT (Special Parameter) Load the file CHKPRTLOA.EXE into the EXEC in place of the default $CHKPRT. 2 WRITESYSPARAMS Parameters were modified during SYSBOOT and will be written out to VAXVMSSYS.PAR by STARTUP.COM. 2 SRPSIZE Small request packet size - Number of bytes to allocate to an SRP. 2 POOLPAGING Pool paging - Enable paging of pageable dynamic pool. 2 SBIERRENABLE SBI error detection flag - Enables SBI error detection and logging. 2 SYSPAGING Page system code - Enables paging of system code in the system working set. Super-secret parameters, listed in Show/Special but not documented anywhere: ---------------------------------------------------------------------------- PIOPAGES 245 245 10 -1 Pages CTLPAGES 50 50 10 -1 Pages CTLIMGLIM 35 35 0 -1 Pages PE1 0 0 0 -1 D PE2 0 0 0 -1 D PE3 0 0 0 -1 D PE4 0 0 0 -1 D PE5 0 0 0 -1 PE6 0 0 0 -1 CJFLOAD 0 0 0 1 Boolean CJFSYSRUJ 0 0 0 1 Boolean LOADMTACCESS 0 0 0 1 Boolean TTY_DEFPORT 0 0 0 -1 Bit-Encoded