amos@instable.UUCP (Amos Shapir) (12/21/86)
In article <7426@utzoo.UUCP> henry@utzoo.UUCP (Henry Spencer) writes: [under the original Subject Re: what's a word] >The only reason it's called a longword is because of all the semi-subliminal >it's-really-just-a-big-pdp11-so-don't-worry-about-incompatibility marketing >horseshit that surrounded the vax in its early days. Remember when a 780's >official designation was a "VAX-11/780"? Actually, DEC had made a brilliant (may be unintentional) upgrade, changing architecture while keeping the customers, doing it both radically and gradually at the same time. There are very few cases (that I know of) in which an architecture upgrade had managed to keep all the good parts and leave out all the bad parts - the hardest part is convincing the users that it won't hurt; providing 'compatibility mode' is an excellent cushion, and, unlike other vendors' upgrades, you dont need to know about it if you dont use it. -- Amos Shapir National Semiconductor (Israel) 6 Maskit st. P.O.B. 3007, Herzlia 46104, Israel (011-972) 52-522261 amos%nsta@nsc 34.48'E 32.10'N
bjorn@alberta.UUCP (Bjorn R. Bjornsson) (12/23/86)
In article <653@instable.UUCP>, amos@instable.UUCP (Amos Shapir) writes: > In article <7426@utzoo.UUCP> henry@utzoo.UUCP (Henry Spencer) writes: > >Remember when a 780's > >official designation was a "VAX-11/780"? > > Actually, DEC had made a brilliant (may be unintentional) upgrade, It could have been brilliant, but was greatly marred by flaws like the following: RTI and RTT ignore the mode bits in the PSW image on the stack, and set the mode to user without trapping. If RTI / RTT had trapped mode changes, or simply been left unimplemented, you could have written or ported real PDP-11 operating systems to run on the VAX. As it turned out, the AME (pseudo RSX-11M on a VAX), was useless except for trivial RSX applications, this because they left out socalled PLAS directives. What it did do was allow DEC to push the VAX through the door without any software. My suspicion has always been that DEC included compatibility mode in the early VAXen for this reason and this reason only. After the fashion of computer manufacturers, you then proceed advertise it as a feature. When you take it away, you can again advertise that as a feature, this time saying it's not taking up any resources, and users don't have to pay for something they don't need or want. Remember VMS versions 1 through 2. Almost utilities and compilers ran in compatibility mode. Yeah, DCL translated COPY commands to RSX PIP invocations, ditto for RENAME, DELETE, ad nauseum. The Fortran compiler was a modestly hacked version of PDP-11 Fortran-IV-Plus, and on and on and on. After version 2, more and more things started showing up in native mode. Until finally DEC was in a position to release VAXen without a PDP-11 mode, which is basically when they turfed it. It's easy to imagine that DEC would have been at least a year later in introducing the VAX without compatibility mode. Makes you wonder what the world would look like today, if that had been the case. Don't ascribe to brilliance, that which can be explained by simple expediency, Bjorn R. Bjornsson alberta!bjorn
bjorn@alberta.UUCP (Bjorn R. Bjornsson) (12/23/86)
In article <166@pembina.alberta.UUCP>, I wrote: > If RTI / RTT had trapped mode changes, or simply been left > unimplemented, you could have written or ported real PDP-11 > operating systems to run on the VAX. Come to think of it, this was probably intentional, just so that PDP-11 operating systems could not be ported to the VAX. Brilliant! Bjorn R. Bjornsson alberta!bjorn
amos@instable.UUCP (Amos Shapir) (12/24/86)
In article <166@pembina.alberta.UUCP> bjorn@alberta.UUCP (Bjorn R. Bjornsson) writes: >It's easy to imagine that DEC would have been at least a year >later in introducing the VAX without compatibility mode. Makes >you wonder what the world would look like today, if that had >been the case. This is *exactly* what I meant by 'brilliance'! There were many projects that were so advanced they came out years too late because it took too long to write the software for them. The brilliant idea was: 'let's not wait for native VAX software, PDP11 software should be just fine for the introduction phase'. It *is* a success, and you can't argue with that. (Disclaimer: I do not, and never did, work for DEC). -- Amos Shapir National Semiconductor (Israel) 6 Maskit st. P.O.B. 3007, Herzlia 46104, Israel (011-972) 52-522261 amos%nsta@nsc 34.48'E 32.10'N
dave@onfcanim.UUCP (Dave Martindale) (12/28/86)
bjorn@alberta.UUCP (Bjorn R. Bjornsson) writes: >It's easy to imagine that DEC would have been at least a year >later in introducing the VAX without compatibility mode. amos%nsta@nsc (Amos Shapir) writes: >The brilliant idea was: 'let's not wait >for native VAX software, PDP11 software should be just fine for the >introduction phase'. Let's not forget that the early emergence of the VAX line was also very good for those of us that didn't (and still don't) care about DEC-supplied software. I doubt that DEC saw this as an advantage, but they pretty much ignored UNIX* in those days anyway. * In "those days", UNIX was a noun, not an adjective.
kary@hplsdla.HP.COM (Dan Kary) (12/30/86)
> >It's easy to imagine that DEC would have been at least a year > >later in introducing the VAX without compatibility mode. Makes > >you wonder what the world would look like today, if that had > >been the case. > This is *exactly* what I meant by 'brilliance'! There were many projects > that were so advanced they came out years too late because it took too > long to write the software for them. The Apple Macintosh is a good example. It was two years late. If their delivery had been more timely MS-DOS and intel processors might be as popular as they deserve to be. Dan Kary