Subject: RE: VAXstation 3100/76 SCSI disk over 1GB From: "Antonio Carlini" <a.carlini at ntlworld.com> Date: Fri, 22 Apr 2005 19:20:00 +0100 To: "'General Discussion: On-Topic and Off-Topic Posts'" <cctalk at classiccmp.org> The console disk driver is used early on in the boot process (until enough of OpenVMS has been loaded that it can switch to its own full-featured driver) and also during crash dumping (since the console driver is in eprom, it can be relied on not have become corrupt). If any of the files needed during boot end up past the 1.073GB mark, the system will not boot. Event if the files happen to lie in accessible places initially, they might be moved by a subsequent upgrade or disk defragmentation. Much, much worse is the behaviour during a crash. If the crashdump file happens to be beyond the 1.073GB mark, then anything actually at the wrapped around address is at risk! There are ways around this problem, but the only easy one is to use an RZ26 (1GB disk) as the system disk. That's not a problem at least for releases up until OpenVMS V7.1. I stopped getting updates at that point so I don't know how much bigger VAX releases have become. The problem is not such an issue with *BSD since you can effectively control what lives where. The issue affects all VAXstation 3100s, the MicroVAX 3100 Models 10 and 20 and the early releases of the MicroVAX 3100 Models 10e and 20e. I believe that a fix was produced for the 10e and 20e and ROMs dated after April 1992 are fine. The OpenVMS FAQ has more details. So just because it seems to work, does not make it a good idea :-)