On Thu, 16 Jan 2003, David Evans wrote: [snip] maketape will pad each of "mtboot", "mtboot", and "boot" out to an even length of 512 bytes. The "cat | dd" method will not pad the first two out. I discovered this while trying to create a bootable tape image for simh. I needed to emulate the maketape behavior for it to work. Andru -- Andru Luvisi, Programmer/Analyst Quote Of The Moment: Quidquid latine dictum sit, altum viditur. ( Whatever is said in Latin sounds profound. )

On Thu, 16 Jan 2003, David Evans wrote: Probably not. Repeated "dd"s will not produce the same result. This is the typical error when not understanding that tapes actually are not a stream of characters. (And also a good example when the Unix paradigm fails pretty bad). Each write to the tape device will create a block. You cannot do two writes after each other to extend the block. You will instead get two different blocks. Boot tapes for VAXen (and PDP-11s) are expected to have 512 byte blocks. Actually, the first block should be repeated twice, and this is the primary boot block. After that you can put whatever you want. Most primary boot blocks however also expects to read 512 byte blocks, which means that the next file (secondary booter or the system itself) also most often is written with 512 byte blocks. Don't. The moment you copy a tape file to disk, you will loose meta information unless you use a program specifically designed to preserve that information. Johnny Johnny Billquist || "I'm on a bus || on a psychedelic trip email: bqt(a)update.uu.se || Reading murder books pdp is alive! || tryin' to stay hip" - B. Idol

On Thu, 16 Jan 2003, David Evans wrote: [snip] How about: ( dd if=mtboot conv=sync bs=512 dd if=mtboot conv=sync bs=512 dd if=boot conv=sync bs=512 ) |dd of=/dev/whatever bs=512 Andru -- Andru Luvisi, Programmer/Analyst Quote Of The Moment: It has been said very justly that every virtue is, as it were, a middle course between two opposite vices. Thus, courage is midway between cowardice and rashness; thrift is midway between acquisitiveness and improvidence; morality is midway between prudery and licentiousness; and so forth. In like manner, justification stands half-way between the faults of pedantry, on the one hand, and the failures of ignorance, on the other. - Nevil Maskelyne

On Thu, 16 Jan 2003, Johnny Billquist wrote: [snip] I misread David's post the first time. I thought he was thinking of doing an installation on simh (using a bootable tape image) and then dd'ing the disk image onto a SCSI disk to boot the real PDP-11 from. Is there any reason this wouldn't work? Andru -- Andru Luvisi, Programmer/Analyst Quote Of The Moment: If you tell the truth you don't have to remember anything. -- Mark Twain

On Thu, Jan 16, 2003 at 06:40:24PM +0100, Johnny Billquist wrote: No, bootable disk is what I was after. The tape image idea floated into my brain for a moment, but it didn't last long since I'm certain it would not work. -- David Evans (NeXTMail/MIME OK) dfevans(a)bbcr.uwaterloo.ca Ph.D. Candidate, Computer/Synth Junkie http://bbcr.uwaterloo.ca/~dfevans/ University of Waterloo "Default is the value selected by the composer Ontario, Canada overridden by your command." - Roland TR-707 Manual

On Thu, Jan 16, 2003 at 09:34:16AM -0800, Andru Luvisi wrote: Ahh--I was asleep at the wheel and forgot that there's no convenient way to concatenate the files using dd. Duh. Oh yeah--I saw that but forgot about it. Just not my day. :P -- David Evans (NeXTMail/MIME OK) dfevans(a)bbcr.uwaterloo.ca Ph.D. Candidate, Computer/Synth Junkie http://bbcr.uwaterloo.ca/~dfevans/ University of Waterloo "Default is the value selected by the composer Ontario, Canada overridden by your command." - Roland TR-707 Manual

David Evans wrote: Just because you try to boot a 2.11BSD, the last three letters should tell you something. Go for FreeBSD, NetBSD, or something with a "BSD" in the name ... ;-)