Comment by rahen
2 hours ago
A lot of mistakes in this article, although it's well-intentioned.
There is a direct lineage from the PDP-1 to the PDP-4, and the 18-bit lineage ends with the PDP-15 (missing).
The dual-mode PDP-12 (PDP-8 + LINC) is missing from the 12-bit lineage.
The VAX (VAX-11 initially) was an offspring of the PDP-11 and the VAX-11 could natively run PDP-11 user-mode code. DEC then tried to use the VAX to unify both the 10 and 11 markets.
The PDP-11 and VAX software heritage lives on mostly in C and UNIX (NetBSD being the closest relative), and in VMS / NT. The PDP-10 heritage lives on mostly in Emacs.
"However, even its most powerful configuration wasn’t powerful enough to attract many pdp-10 users." They didn’t serve the same markets.
The PDP-10 was a time-sharing system that shone more for LISP than FORTRAN. For heavy number crunching and matmuls (the FORTRAN playground), 16-bit PDP-11s were usually used, with an auxiliary array processor such as the AP-120B or the CSPI MiniMAP. Those array processors could deliver more than 10 MFLOPS back then, when a minicomputer with a 50-100 KFLOPS FPU was already considered fast (FPUs were an expensive option back then).
Not very familiar with PDP history, but PDP-12 missing also caught my attention.
Regarding later heritage, to my understanding, several developers of the VMS kernel moved on to work on the Windows NT kernel. Whether it's really only coincidence that every letter of the acronym got shifted by one?
The first few versions of Windows NT had a very strong API resemblance with VMS, which is why Microsoft settled to pay to DEC a 9-digit $ amount, to avoid a legal battle. Though eventually that deal was less advantageous for DEC than it appeared from the amount of money, because it included the support of Windows NT for DEC computers.
The parts of the initial Windows NT API that did not resemble VMS looked liked cleaned-up versions of the UNIX API, e.g. the functions for handling file and device I/O.
The central role of asynchronous I/O in Windows NT was inherited from VMS, which in turn had inherited it from the RSX-11M operating system for PDP-11 computers (Dave Cutler had a major role in the development of all these 3 operating systems).
Whether VMS => WNT is a joke like IBM => HAL, is anyone's guess. A more certain thing is that IBM was named such as to be a hyperbolic substitute of the name of its main competitor, NCR (National => International, Cash Register => Business Machines)
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