Path: utzoo!utgpu!news-server.csri.toronto.edu!rutgers!att!linac!pacific.mps.ohio-state.edu!zaphod.mps.ohio-state.edu!rpi!crdgw1!uunet!comp.vuw.ac.nz!gp.co.nz!zl2tnm!don From: don@zl2tnm.gp.co.nz (Don Stokes) Newsgroups: comp.sys.dec Subject: Re: pdp-11's Message-ID: <7JmX46w163w@zl2tnm.gp.co.nz> Date: 22 Jun 91 20:15:17 GMT References: Organization: Computer Archaeologists Lines: 24 rocker@bucsf.bu.edu (The Long Haired One) writes: > These are probably a very simple questions. I just don't know the answers. > I noticed that Pdp11's come in 2 types - qbus and unibus. Do the numbers > of the machines like pdp-11/23 and pdp-11/24 relate to which is which type? > > And can someone tell me the differences between qbus-ing and unibuses, as > to which is possibly better or what drawbacks they might hold. If the last digit is a 3, then it's Qbus. Anything else indicates a Unibus machine, ie: 04,05,10,20,24,30,34,35,40,44,45,50,60,70,84,94 Unibus 03,23,53,73,83,93 Qbus All modern Unibus machines have 4 as their last digit since the /34. Where there are models with both n3 and n4 numbers, the two usually have equivalent processors (not sure about the /03 and /04 -- are these the same chipset?). Don Stokes, ZL2TNM / / don@zl2tnm.gp.co.nz (home) Systems Programmer /GP/ GP PRINT LIMITED Wellington, don@gp.co.nz (work) __________________/ / ---------------- New_Zealand__________________________