Re: Bootstrap Idea

There are a few good tricks to get PDP11 with odd configurations to load. The first is the venerable paper tape bootstrap. It consists of only 8 instructions (28 bytes) and works on serial ports. It then loads the 'absolute loader' which will load formatted data (paper tape!). The format is trival and has checksums and stop/transfer blocks. The trick is to convert the unix secordary boot loader from V7 or BSD 2.9-2.11 and then you have mini loader with lots of device drivers. I can provide some of these programs including the paper tape listings and images (heck, I still have a working paper tape reader/punch). You can load ANY PDP-11 this way! Another approach if you have any of the LSI-11 based cpus with microcoded console emulator is to use the Xinu suite. It does an initial bootstrap by sending console commands and then loading a binary boostrap. On the subject of bad blocks, V6 and V7 offered no bad block strategies. The DEC spec for RK05's was 200 tracks by 12 sectors by 2 surface plus 3 bad block tracks for 4800 blocks plus 72 spare. The media was generally pretty good, and all Unix versions used 4872 block filesystems. Files-11 (IAS/RSX) was the only system to offer bad block replacement (I cannot be sure for RSTS). When bigger disk drives started showing up, like the RM02/3's and RM05, the usual practive was to buy packs with 'zero' defects. Received: (from major@localhost) by minnie.cs.adfa.oz.au (8.8.5/8.8.5) id LAA11254 for pups-liszt; Mon, 15 Sep 1997 11:20:27 +1000 (EST) X-Authentication-Warning: minnie.cs.adfa.oz.au: major set sender to owner-pups(a)minnie.cs.adfa.oz.au using -f