Umm Johnny it must have been late when you wrote this.. The last release for VAX was 7.3. Anything later is alpha or ia64. 7.3-1 was only released for alpha. The address space for VAX is 32 bits, no page bits. And 2**32 is 4G. Where did you find 16 GB? ------Origineel bericht------ Van:Johnny Billquist Afzender:owner-hecnet at Update.UU.SE Aan: hecnet at Update.UU.SE Beantwoorden:hecnet at Update.UU.SE Onderwerp: Re: [HECnet] SIMH VAX memory weirdness Verzonden: 29 november 2010 02:03 On 2010-11-28 21:20, Sampsa Laine wrote: I just increased the memory on one of my SIMH VAX VM's to 512 MB from 64 MB - the system boots fine but SHOW MEMORY (under OpenVMS 7.3-1) still reports 64 MB. Do I need to tell the VMS installation about the new RAM somehow? How much RAM does 7.3-1 (VAX) support anyway? 7.3-1 ??? I thought the last version of VMS for VAXen was 7.3 As for memory, VMS (on VAX) supports up to (in theory atleast) 16G of physical memory. However, that requires the extended memory mode PTEs, which only came with NVAX, so no luck with simh. The "older" layout supports a max of 1G, but I think all architectures machines split that into 512M of RAM and 512M for I/O space. Oh, and when you add memory, you need to run an AUTOGEN afterwards, to change a bunch of parameters to the new hardware config (whould be obvious ;-) ). Johnny -- Johnny Billquist || "I'm on a bus || on a psychedelic trip email: bqt at softjar.se || Reading murder books pdp is alive! || tryin' to stay hip" - B. Idol Verzonden vanaf mijn draadloze BlackBerry -toestel