There is nothing as good as having to describe a problem concisely, to ensure that one can solve it oneself! The clue was in my last comment, about the satellite not waiting long enough. So, after trying different values, I concluded that the SET XQ THROTTLE was a red herring and made little useful difference. However throttling the CPU back to say 30% made a reliable connection every time, and I then used EXPECT to trigger a reversion to full throttle once the boot process was past the boot drivers and into VMS proper.
; Set SIMH options set cpu model=VAXstation ; avoid timeouts on PEDRIVER connecting, but see EXPECT below set throttle 30% ; ; Boot the VAX, but set up an EXPECT to set full throttle later expect "SYSINIT" boot cpu ; break to here after EXPECT - no longer using boot drivers set nothrottle set cpu idle continue ; end of EXPECT SYSINIT sequence -- Paul Hardy -----Original Message----- From: Simh [mailto:simh-boun...@trailing-edge.com] On Behalf Of paulhar...@btinternet.com Sent: 25 February 2018 21:03 To: simh@trailing-edge.com Subject: [Simh] SimH VAX cluster connect timeouts At home I run a hobbyist VMScluster with three SimH VAX instances - the boot node MicroVAX HARDY1 is on an Intel i5 NUC running Windows 10, one VAXStation satellite is Raspberry Pi 3, and I recently added a second-hand Intel I5 PC running Debian (Raspberry desktop) called HARDY3 as another satellite VAXStation. When I network boot the Debian satellite HARDY3, it gets its boot from HARDY1, and then repeatedly says "%VAXcluster, no connection to disk server" with no pauses, and then crashes. See log below. I suspect this due in some way to the speed of the networking interface of the Debian host (Gb Ethernet) - on a real VAX there would be a significant pause between these messages if the connection was not established immediately. On the Raspberry Pi, I sometimes get a few of these messages before the connection is established. I tracked down that SimH has a SET XQ THROTTLE command, but trying SET XQ THROTTLE=ON didn't seem to help. I then saw that the XQ THROTTLE has three further parameters, TIME, BURST and DELAY with default values of 5, 4 and 10, so I tried SET XQ THROTTLE=TIME=10;BURST=2;DELAY=20, and after 16 rapid "no connection" messages, it did connect, and VMS booted and ran normally. I did feel that this was rather by skin of teeth, and I don't really understand how one should tune these values, so am asking the collective wisdom of the SimH list for optimal parameters to SET XQ THROTTLE, or alternative ways of ensuring a clean boot. Any ideas? An explanation of how the throttle parameters are likely to interact with the VAXcluster connection logic would help! Or have I got hold of the wrong end of the stick - do these messages indicate that the satellite is not waiting long enough for a response from the boot server, and if so, do I need to be experimenting with CPU throttling during this early boot phase? Regards, Paul. KA655-B V5.3, VMB 2.7 Performing normal system tests. 40..39..38..37..36..35..34..33..32..31..30..29..28..27..26..25.. 24..23..22..21..20..19..18..17..16..15..14..13..12..11..10..09.. 08..07..06..05..04..03.. Tests completed. >>>b xq (BOOT/R5:0 XQ 2.. -XQA0 1..0.. %VAXcluster, system loaded from node HARDY1 (AA-00-04-00-01-04) %VAXcluster, no connection to disk server %VAXcluster, no connection to disk server %VAXcluster, no connection to disk server %VAXcluster, no connection to disk server %VAXcluster, no connection to disk server %VAXcluster, no connection to disk server %VAXcluster, no connection to disk server %VAXcluster, no connection to disk server %VAXcluster, no connection to disk server %VAXcluster, no connection to disk server %VAXcluster, no connection to disk server %VAXcluster, no connection to disk server %VAXcluster, no connection to disk server %VAXcluster, no connection to disk server %VAXcluster, no connection to disk server %VAXcluster, no connection to disk server %VAXcluster, no connection to disk server %VAXcluster, no connection to disk server %VAXcluster, no connection to disk server %VAXcluster, no connection to disk server %VAXcluster, PE boot driver initialization failed, maximum retry limit exceeded %VAXcluster, boot driver unable to establish a virtual circuit HALT instruction, PC: 00005368 (BRB 5367) sim> The HARDY3 instance of SimH is running a very recent version of SimH: sim> sh ver VAXStation 3900 (KA655) simulator V4.0-0 Beta Simulator Framework Capabilities: 64b data 64b addresses Threaded Ethernet Packet transports:PCAP:TAP:VDE:NAT:UDP Idle/Throttling support is available Virtual Hard Disk (VHD) support RAW disk and CD/DVD ROM support Asynchronous I/O support (Lock free asynchronous event queue) Asynchronous Clock support FrontPanel API Version 12 Host Platform: Compiler: GCC 6.3.0 20170516 Simulator Compiled as C arch: x86 (Release Build) on Feb 23 2018 at 22:13:52 Memory Access: Little Endian Memory Pointer Size: 32 bits Large File (>2GB) support SDL Video support: SDL Version 2.0.5 PCRE RegEx support for EXPECT commands OS clock resolution: 1ms Time taken by msleep(1): 1ms OS: Linux HardyWC1D 4.9.0-6-amd64 #1 SMP Debian 4.9.82-1+deb9u2 (2018-02-21) x86_64 GNU/Linux git commit id: e3543cbb The relevant lines from the SimH ini file are: ; ; Attach Ethernet to a network interface set xq mac=08-00-2B-AA-BB-CE attach xq eth0 set xq throttle=on set xq throttle=time=10;burst=2;delay=20 ; Set SIMH options set cpu idle set cpu model=VAXstation -- Paul Hardy web: www.paulhardy.net _______________________________________________ Simh mailing list Simh@trailing-edge.com http://mailman.trailing-edge.com/mailman/listinfo/simh _______________________________________________ Simh mailing list Simh@trailing-edge.com http://mailman.trailing-edge.com/mailman/listinfo/simh
