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3

Having never written Unix I/O code beyond munging text files, read what follows with a grain of salt. In uni we were a VMS shop. I still recall when the VAX 11/780 in the walled-off computer room was replaced by a single DECStation 3100 on a desk. That machine ran both OSes and we (the OS course's 12-or-so members) began to compare and contrast the ...


3

Solely based on the source link to Dave's comment, I can't really tell what he meant. That said, Benno Rice recently gave an excellent talk at linux.conf.au called What UNIX Cost Us. The TL,DR of that talk is that many of UNIX's core assumptions, though extensible, no longer apply in current and next gen environments, which makes supporting new paradigms ...


18

At the operating system level – as seen by applications – files in VMS are very record oriented. Guide to OpenVMS File Applications (336 page, 2MB PDF) probably goes into far more detail than anyone should be expected to know, but you can get a feel from the Introduction (emphasis mine): 1.1 File Concepts A computer file is an organized collection of ...


6

At that time, computing model was very rich API, complex CPUs, complex tools, etc. Filesystem were almost structured files oriented, etc. UNIX came with its "uniform" vision of I/O, everything is a file, a file is just a stream of bytes. That wasn't so easy for people trained on former OSes to understand why UNIX is a good model. While I loosely remember the ...


21

While I am sure that the merits of Cutler's stated "low opinion" could be debated, I'm interested to better understand exactly what he was referring to here. There's no citation, and I haven't found a good explanation critiquing his criticism. Honestly, at face value, it's a naive criticism. Cutler was not naive, so, it's likely just a sound bite poke ...


54

The I/O model on "Cutler systems" -- RSX-11M, VAX/VMS, Windows NT -- is an asynchronous packet-driven I/O model, rather than the fundamentally synchronous I/O model of Unix. At its core, you fire off an I/O request, and get a notification of when it's complete. Meanwhile, execution continues. Of course, it's trivial for the system to provide synchronous I/...


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