Just to follow up. When I try to copyworm with c[w0w1]f{h0h2}, or f{h0h2}, or fh0 I get the following right after `beginning copyworm in 8 seconds' fworm: read 0 i/o error reading fh0 block 0 panic: no blocks to copy on fh0 cpu 0 exiting I should say that things like history, yesterday, 9fs dump have been working as advertised, so I do have a functioning worm. I also tried to make main h0 and be explicit about the fake worm-ness of output, which I hadn't been before (filsys output f{w2w3}). This was definitely different. For one, it took even longer than my other tries. But, instead of the `copyworm finished ... looping ... reset any time' message, it had rebooted itself. I'm going to stop this effort for a little while. At least until I get console logging set up, so that I can be sure to be accurate when I report what happened. Thanks again. Greg -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= Geoff Collyer 7 Aug 2006 wrote: I think I understand your problem now. If you were copying a fake worm to a device of identical size, you could use copydev from h0, but when copying a fake worm, you need to use copyworm from fh0 or possibly even your normal main (c[w0w1]f{h0h2}). check reports an fsize of 712733, so that's the highest block number so far consumed by your fake worm, and is what copyworm should print as your limit (plus or minus a few blocks) when you copy from fh0 or your normal main. When you copied from h0, copyworm just used the size of h0 as its upper limit. Perhaps copyworm should complain if the source file system does not contain a worm.