From: utzoo!decvax!wivax!dyer Newsgroups: net.unix-wizards Title: Re: dump/restor SLOW -- why? Article-I.D.: wivax.4456 Posted: Sun Jan 30 19:16:44 1983 Received: Mon Jan 31 03:46:50 1983 References: pwa-b.55 At BBNCC, we were concerned about the speed of "restor" (V7), mainly because we were in the midst of recovering from a operator-induced file-system crash. Full restor's were taking about 30-40 minutes, most of it in the CPU-intensive phase BEFORE the tape starts moving. After compiling a profiling version of restor, it turned out that a large amount of its time was spent in two routines, copy and clearblk, (guess what they do?). On the C/70, by replacing them with microcode routines having the same semantics, the time to perform a "restor" dropped to roughly to 5-10 minutes. It might be interesting to construct a version of "restor" for the VAX, using an appropriately configured "asm.sed" to replace calls to copy() and clearblk() with equvalent VAX block-move and block-copy single instructions. Steve Dyer sdyer@bbn-unix decvax!wivax!dyer dyer.Wang-Inst@udel-relay