Yayyyy!!! I saw those and there were some tapes their that looked like my PDP-12 might enjoy then. Sent from my iPad

On 3/16/18 10:39 AM, Josh Dersch via cctalk wrote: Josh forwarded images and extracted files to me. They are up now under http://bitsavers.org/bits/DEC/pdp11/dectape/LCM_Early_PDP-11 The BASIC source is an early MUBAS

On 3/24/2018 8:23 PM, Nigel Williams via cctalk wrote: I dumped the tapes and can confirm that this is not an error during recovery and is what was on the original tape; each tape had a printed directory listing taped to it and this listing matches the listing I got when extracting the data.? I assume it was misnamed or overwritten at some point back in the day. There is a BASIC.P11 on another tape that has actual BASIC source in it. There's also what looks like some very early RSTS source in there. - Josh

I looked over these, more precisely the ones that related to the PDP11. Here are some notes. The most significant item from my point of view is that it contains much of a very early RSTS (so early that it was still called BTSS). Together with a scanned listing I have of the BTSS kernel it may amount to just about a complete system. I need to get that scan run through OCR... paul 118647.tu56: palx11.mac: PDP11 cross-assembler. This was used to build PDP11 software early on, such as RSTS-11. 118652.tu56: iox.p11: appears to be sources for the IOX "paper tape I/O" package, described as "experimental I/O system". That wasn't what it was called when it finally shipped, I believe. odtx.p11: ODT debugger for IOX. rts.p11: Early Basic-PLUS for RSTS (referred to as "BTSS" in the comments). rtsdoc.rno: Brief documentation for some of the operation codes in rts.p11. sim11x.sav: I wonder if this might be the famous "Mimic". Someone with a suitable PDP-10 system should try to find out. syslod.p11: tool to create a bootable DECtape. Later on, "syslod" was the name of the OS loader program, the one booted from DECtape to load the OS (at least in the case of DOS). 118653.tu56: oo.p11: RSTS file processor components. It's not entirely clear but I believe these are functions that were implemented as overlays. Not everything is precisely file I/O related; as in RSTS-11 V4, the Basic-PLUS string garbage collector is implemented as a "file processor" overlay. rts.p11: Basic-PLUS, similar to the one in 118652.tu56 but appears to be slightly newer. 118654.tu56: dos.spp: design spec for DOS-11 V3. edit11.man: user manual for DOS-11 EDIT program. fort.spc: design spec for DOS-11 FORTRAN. l.spc: design spec for DOS-11 LINK. 118656.tu56: basic.p11: Multi-user BASIC (this is not Basic-PLUS) syslod.p11: Another copy of the OS loader, essentially the same as the one on 118652.tu56 but with a few comments cleaned up. 118660.tu56: p.001 through p.011: software floating point library, appears to be THREE word format (two word mantissa, one word exponent). I believe this was used in RSTS through version 3; in V4A, RSTS-11 switched to the hardware standard 2-word or 4-word floating point format. test.001 through test.009: appear to be test programs for the above.